WorldWideScience

Sample records for wide field x-ray

  1. Wide Field-of-View (FOV) Soft X-Ray Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Wide Field-of-View (FOV) Soft X-Ray Imager proposes to be a state-of-art instrument with applications for numerous heliospheric and planetary...

  2. Wide field monitoring of the X-ray sky using Rotation Modulation Collimators

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren

    1995-01-01

    Wide field monitoring is of particular interest in X-ray astronomy due to the strong time-variability of most X-ray sources. Not only does the time-profiles of the persistent sources contain characteristic signatures of the underlying physical systems, but, additionally, some of the most intriguing...... sources have long periods of quiesense in which they are almost undetectable as X-ray sources, interspersed with relatively brief periods of intense outbursts, where we have unique opportunities of studying dynamical effects, in, for instance, the evolution of accretion discs. Another question for which...... wide field monitors may provide key information, is the origin and nature of the cosmic gamma ray bursts.Rotation Modulation Collimators (RMC's) were originally introduced in X-ray astronomy to provide accurate source localizations over extended fields. This role has since been taken over...

  3. Wide field imaging spectrometer for ESA's future X-ray mission: XEUS

    CERN Document Server

    Strüder, L

    1999-01-01

    An active pixel sensor (APS) based on the DEpleted P-channel junction Field Effect Transistor (DEPFET) concept will be described as a potential wide field imager for ESA's high resolution, high throughput mission: 'X-ray Evolving Universe Spectroscopy' (XEUS). It comprises a parallel multichannel readout, low noise at high speed readout, backside illumination and a fill factor of 100% over the whole field of view. The depleted thickness will be 500 microns. These design parameters match the scientific requirements of the mission. The fabrication techniques of the DEPFET arrays are related to the high resistivity process of the X-ray pn-CCDs. Potential extensions of the already realized DEPFET structures are a non-destructive repetitive readout of the signal charges. This concept will be presented. As an alternative solution, frame store pn-CCDs are considered having the same format and pixel sizes as the proposed DEPFET arrays. Their development is a low risk, straightforward continuation of the XMM devices. ...

  4. ISS-Lobster: A Proposed Wide-Field X-Ray Telescope on the International Space Station

    Science.gov (United States)

    Camp, Jordan

    2012-01-01

    The Lobster wide-field imaging telescope combines simultaneous high FOV, high sensitivity and good position resolution. These characteristics can open the field of X-Ray time domain astronomy, which will study many interesting transient sources, including tidal disruptions of stars, supernova shock breakouts, and high redshift gamma-ray bursts. Also important will be its use for the X-ray follow-up of gravitational wave detections. I will describe our present effort to propose the Lobster concept for deployment on the International Space Station through a NASA Mission of Opportunity this fall.

  5. Development of digital system for the wide-field x-ray imaging detector aboard Kanazawa-SAT3

    Science.gov (United States)

    Kagawa, Yasuaki; Yonetoku, Daisuke; Sawano, Tatsuya; Mihara, Tatehiro; Kyutoku, Koutarou; Ikeda, Hirokazu; Yoshida, Kazuki; Ina, Masao; Ota, Kaichi; Suzuki, Daichi; Miyao, Kouga; Watanabe, Syouta; Hatori, Satoshi; Kume, Kyo; Mizushima, Satoshi; Hasegawa, Takashi

    2017-08-01

    We are planning to launch a micro satellite, Kanazawa-SAT3 , at the end of FY2018 to localize X-ray transients associated with gravitational wave sources. Now we are testing a prototype model of wide-field Xray imaging detector named T-LEX (Transient Localization EXperiment). T-LEX is an orthogonally distributed two sets of 1-dimensional silicon strip detectors with coded aperture masks, and covers more than 1 steradian field of view in the energy range of 1 - 20 keV. Each dimension has 512 readout electrodes (totally 1,024 channels), and they are read out with application specific integrated circuits (ASICs) controlled by two onboard FPGAs. Moreover, each FPGA calculates the cross correlation between the X-ray intensity and mask patterns every 64 msec, makes a histogram of lightcurves and energy spectra, and also plays a role of telemetry/command interface to mission CPU. In this paper, we report an overview of digital electronics system. Especially, we focus on the high-speed imaging processor on FPGA and demonstrate its performance as an X-ray imaging system.

  6. Concerning the Development of the Wide-Field Optics for WFXT Including Methods of Optimizing X-Ray Optical Prescriptions for Wide-Field Applications

    Science.gov (United States)

    Weisskopf, M. C.; Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.

    2010-01-01

    We present a progress report on the various endeavors we are undertaking at MSFC in support of the Wide Field X-Ray Telescope development. In particular we discuss assembly and alignment techniques, in-situ polishing corrections, and the results of our efforts to optimize mirror prescriptions including polynomial coefficients, relative shell displacements, detector placements and tilts. This optimization does not require a blind search through the multi-dimensional parameter space. Under the assumption that the parameters are small enough so that second order expansions are valid, we show that the performance at the detector can be expressed as a quadratic function with numerical coefficients derived from a ray trace through the underlying Wolter I optic. The optimal values for the parameters are found by solving the linear system of equations creating by setting derivatives of this function with respect to each parameter to zero.

  7. Wide-field-of-view phase-contrast imaging of nanostructures with a comparatively large polychromatic soft x-ray plasma source.

    Science.gov (United States)

    Gasilov, S V; Faenov, A Ya; Pikuz, T A; Fukuda, Y; Kando, M; Kawachi, T; Skobelev, I Yu; Daido, H; Kato, Y; Bulanov, S V

    2009-11-01

    Polychromatic soft x-ray plasma sources were not previously considered to be among the sources suitable for the propagation based phase contrast imaging because of their comparatively large emission-zone size. In the current work a scheme based on the combination of soft x-ray emission of multicharged ions, generated by the interaction of femtosecond laser pulses with an ultrasonic jet of gas clusters, and an LiF crystal detector was used to obtain phase-enhanced high-resolution images of micro- and nanoscale objects in a wide field of view.

  8. Simulations of the x-ray imaging capabilities of the silicon drift detectors (SDD) for the LOFT wide-field monitor

    DEFF Research Database (Denmark)

    Evangelista, Y.; Campana, R.; Del Monte, E.

    2012-01-01

    The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the four Cosmic Vision M3 candidate missions to undergo an assessment phase, will revolutionize the study of compact objects in our galaxy and of the brightest supermassive black holes in active galactic nuclei. The Large Area...... Detector (LAD), carrying an unprecedented effective area of 10 m^2, is complemented by a coded-mask Wide Field Monitor, in charge of monitoring a large fraction of the sky potentially accessible to the LAD, to provide the history and context for the sources observed by LAD and to trigger its observations...

  9. Development of Tiled Imaging CZT Detectors for Sensitive Wide-Field Hard X-Ray Surveys to EXIST

    Science.gov (United States)

    Grindlay, J.; Hong, J.; Allen, B.; Barthelmy, S.; Baker, R.

    2011-01-01

    Motivated by the proposed EXIST mission, a "medium-class" space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first "large" area 256 sq cm close-tiled (0.6 mm gaps) hard X-ray (20-600 keV) imaging detector employing pixelated (2.5 mm) CdZnTe (CZT) detectors, each 2 x 2 x 0.5 cubic cm. We summarize the design, development and operation of this detector array (8 x 8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40 km) balloon flight in October. 2009, as the ProtoEX1STl payload. We then outline our current development of a second-generation imager, ProtcEXIST2. with 0.6 mm pixels on a 32 x 32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST. Other applications of this technology will also be mentioned.

  10. Development of tiled imaging CZT detectors for sensitive wide-field hard X-ray surveys to EXIST

    Science.gov (United States)

    Grindlay, J.; Hong, J.; Allen, B.; Barthelmy, S.; Baker, R.

    2011-10-01

    Motivated by the proposed EXIST mission, a "medium-class" space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first "large" area 256 cm 2 close-tiled (0.6 mm gaps) hard X-ray (20-600 keV) imaging detector employing pixelated (2.5 mm) CdZnTe (CZT) detectors, each 2×2×0.5 cm 3. We summarize the design, development and operation of this detector array (8×8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40 km) balloon flight in October, 2009, as the ProtoEXIST1 payload. We then outline our current development of a second-generation imager, ProtoEXIST2, with 0.6 mm pixels on a 32×32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST. Other applications of this technology will also be mentioned.

  11. Flight performance of an advanced CZT imaging detector in a balloon-borne wide-field hard X-ray telescope—ProtoEXIST1

    Science.gov (United States)

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

    2011-10-01

    We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes such as the High Energy Telescope (HET) in the Energetic X-ray Imaging Survey Telescope (EXIST). The CZT detector plane in ProtoEXIST1 consists of an 8×8 array of closely tiled 2 cm×2 cm×0.5 cm thick pixellated CZT crystals, each with 8×8 pixels, mounted on a set of readout electronics boards and covering a 256 cm2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30-600 keV band for imaging, allowing a fully coded field of view of 9°×9° (and 19°×19° for 50% coding fraction) with an angular resolution of 20‧. In order to reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm×26 cm×2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as ≳100keV background photons from below. The flight duration was only about 7.5 h due to strong winds (60 knots) at float altitude (38-39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1, a bright black hole binary system, for ˜1h at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4° off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2σ in the 30-100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very

  12. Laboratory full-field transmission x-ray microscopy

    Science.gov (United States)

    Seim, Christian; Baumann, Jonas; Legall, Herbert; Redlich, Christoph; Mantouvalou, Ioanna; Blobel, G.; Stiel, Holger; Kanngießer, Birgit

    2012-01-01

    X-ray microscopy in the water window has become a valuable imaging tool for a wide field of applications with a resolution in the nanometer regime. The emergence and the development of laboratory based transmission X-ray microscopes (LTXM) can be of great benefit to users, since LTXM provides access to a method previously limited to synchrotron facilities only. In recent years, measuring times in the laboratory have been reduced to the point, where tomography of aqueous cryofixated samples has become feasible. We report on a laboratory full-field transmission X-ray microscope based on a laser induced plasma source located at the Berlin Laboratory for innovative X-ray Technologies. A short introduction on full-field X-ray microscopy in the water window is given. We demonstrate that, with a thin disk laser-system (TDL), which provides an average power of ~15 W a spatial resolution of Δx = 41 nm +/- 3 nm (half-pitch) is feasible. An image of a diatom recorded at 15 W average laser power with a magnification of 1125x captured in 5 min is presented.

  13. Dark field X-ray microscopy for studies of recrystallization

    DEFF Research Database (Denmark)

    Ahl, Sonja Rosenlund; Simons, Hugh; Jakobsen, Anders Clemen

    2015-01-01

    We present the recently developed technique of Dark Field X-Ray Microscopy that utilizes the diffraction of hard X-rays from individual grains or subgrains at the (sub)micrometre- scale embedded within mm-sized samples. By magnifying the diffracted signal, 3D mapping of orientations and strains...... external influences. The capabilities of Dark Field X- Ray Microscopy are illustrated by examples from an ongoing study of recrystallization of 50% cold-rolled Al1050 specimens....

  14. Wide band focusing x-ray spectrograph with spatial resolution.

    Science.gov (United States)

    Pikuz, S A; Douglass, J D; Shelkovenko, T A; Sinars, D B; Hammer, D A

    2008-01-01

    A new, wide spectral bandwidth x-ray spectrograph, the wide-bandwidth focusing spectrograph with spatial resolution (WB-FSSR), based on spherically bent mica crystals, is described. The wide bandwidth is achieved by combining three crystals to form a large aperture dispersive element. Since the WB-FSSR covers a wide spectral band, it is very convenient for application as a routine diagnostic tool in experiments in which the desired spectral coverage is different from one test to the next. The WB-FSSR has been tested in imploding wire-array experiments on a 1 MA pulsed power machine, and x-ray spectra were recorded in the 1-20 A spectral band using different orders of mica crystal reflection. Using a two mirror-symmetrically placed WB-FSSR configuration, it was also possible to distinguish between a real spectral shift and a shift of recorded spectral lines caused by the spatial distribution of the radiating plasma. A spectral resolution of about 2000 was demonstrated and a spatial resolution of approximately 100 microm was achieved in the spectral band of 5-10 A in second order of mica reflection. A simple method of numerical analysis of spectrograph capability is proposed.

  15. Full-field transmission x-ray imaging with confocal polycapillary x-ray optics

    OpenAIRE

    Sun, Tianxi; MacDonald, C.A.

    2013-01-01

    A transmission x-ray imaging setup based on a confocal combination of a polycapillary focusing x-ray optic followed by a polycapillary collimating x-ray optic was designed and demonstrated to have good resolution, better than the unmagnified pixel size and unlimited by the x-ray tube spot size. This imaging setup has potential application in x-ray imaging for small samples, for example, for histology specimens.

  16. Full-field transmission x-ray imaging with confocal polycapillary x-ray optics.

    Science.gov (United States)

    Sun, Tianxi; Macdonald, C A

    2013-02-07

    A transmission x-ray imaging setup based on a confocal combination of a polycapillary focusing x-ray optic followed by a polycapillary collimating x-ray optic was designed and demonstrated to have good resolution, better than the unmagnified pixel size and unlimited by the x-ray tube spot size. This imaging setup has potential application in x-ray imaging for small samples, for example, for histology specimens.

  17. Invited Article: First flight in space of a wide-field-of-view soft x-ray imager using lobster-eye optics: Instrument description and initial flight results.

    Science.gov (United States)

    Collier, Michael R; Porter, F Scott; Sibeck, David G; Carter, Jenny A; Chiao, Meng P; Chornay, Dennis J; Cravens, Thomas E; Galeazzi, Massimiliano; Keller, John W; Koutroumpa, Dimitra; Kujawski, Joseph; Kuntz, Kip; Read, Andy M; Robertson, Ina P; Sembay, Steve; Snowden, Steven L; Thomas, Nicholas; Uprety, Youaraj; Walsh, Brian M

    2015-07-01

    We describe the development, launch into space, and initial results from a prototype wide field-of-view soft X-ray imager that employs lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The sheath transport observer for the redistribution of mass is the first instrument using this type of optics launched into space and provides proof-of-concept for future flight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the Moon, and the solar wind interaction with planetary bodies like Venus and Mars [Kuntz et al., Astrophys. J. (in press)].

  18. Energy weighted x-ray dark-field imaging.

    Science.gov (United States)

    Pelzer, Georg; Zang, Andrea; Anton, Gisela; Bayer, Florian; Horn, Florian; Kraus, Manuel; Rieger, Jens; Ritter, Andre; Wandner, Johannes; Weber, Thomas; Fauler, Alex; Fiederle, Michael; Wong, Winnie S; Campbell, Michael; Meiser, Jan; Meyer, Pascal; Mohr, Jürgen; Michel, Thilo

    2014-10-06

    The dark-field image obtained in grating-based x-ray phase-contrast imaging can provide information about the objects' microstructures on a scale smaller than the pixel size even with low geometric magnification. In this publication we demonstrate that the dark-field image quality can be enhanced with an energy-resolving pixel detector. Energy-resolved x-ray dark-field images were acquired with a 16-energy-channel photon-counting pixel detector with a 1 mm thick CdTe sensor in a Talbot-Lau x-ray interferometer. A method for contrast-noise-ratio (CNR) enhancement is proposed and validated experimentally. In measurements, a CNR improvement by a factor of 1.14 was obtained. This is equivalent to a possible radiation dose reduction of 23%.

  19. Mapping misoriented fibers using X-ray dark field tomography

    DEFF Research Database (Denmark)

    Lauridsen, Torsten; Lauridsen, Erik Mejdal; Feidenhans’l, Robert

    2014-01-01

    X-ray grating interferometers produce three distinct signals; an absorption signal, a differential phase signal and a dark field signal. Until now a method for successfully creating dark field tomograms of nonisotropic samples has not been demonstrated. In this paper we test a method for creating...

  20. Wide Bandgap Semiconductor Detector Optimization for Flash X-Ray Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Roecker, Caleb Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schirato, Richard C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-17

    Charge trapping, resulting in a decreased and spatially dependent electric field, has long been a concern for wide bandgap semiconductor detectors. While significant work has been performed to characterize this degradation at varying temperatures and radiation environments, this work concentrates upon examining the event-to-event response in a flash X-ray environment. The following work investigates if charge trapping is a problem for CZT detectors, with particular emphasis on flash X-ray radiation fields at cold temperatures. Results are compared to a non-flash radiation field, using an Am-241 alpha source and similar temperature transitions. Our ability to determine if a response change occurred was hampered by the repeatability of our flash X-ray systems; a small response change was observed with the Am-241 source. Due to contrast of these results, we are in the process of revisiting the Am-241 measurements in the presence of a high radiation environment. If the response change is more pronounced in the high radiation environment, a similar test will be performed in the flash X-ray environment.

  1. X-Ray Topographic Measurements of Strain Fields.

    Science.gov (United States)

    1983-08-01

    Measurements of Strain Fields 6. PERFORMING ORG. REPORT NUMDER 17. AUTHOR(.) S. CONTRACT OR GRANT NUMSER(a) S.R. Stock, Haydn Chen and H.K. Birnbaum USN...STRAIN FIELDS S.R. Stock, Haydn Chen and H.K. Birnbaum University of Illinois at Urbana-Champaign Department of Metallurgy and Mining Eng. Urbana, IL...any purpose of the U.S. government is permitted. 88 09 07 18. - " mIII X-RAY TOPOGRAPHIC MEASUREMENT OF STRAIN FIELDS S.R. Stock*, Haydn Chen and H.K

  2. Relationship between x-ray illumination field size and flat field intensity and its impacts on x-ray imaging.

    Science.gov (United States)

    Dong, Xue; Niu, Tianye; Jia, Xun; Zhu, Lei

    2012-10-01

    X-ray cone-beam CT (CBCT) is being increasingly used for various clinical applications, while its performance is still hindered by image artifacts. This work investigates a new source of reconstruction error, which is often overlooked in the current CBCT imaging. The authors find that the x-ray flat field intensity (I(0)) varies significantly as the illumination volume size changes at different collimator settings. A wrong I(0) value leads to inaccurate CT numbers of reconstructed images as well as wrong scatter measurements in the CBCT research. The authors argue that the finite size of x-ray focal spot together with the detector glare effect cause the I(0) variation at different illumination sizes. Although the focal spot of commercial x-ray tubes typically has a nominal size of less than 1 mm, the off-focal-spot radiation covers an area of several millimeters on the tungsten target. Due to the large magnification factor from the field collimator to the detector, the penumbra effects of the collimator blades result in different I(0) values for different illumination field sizes. Detector glare further increases the variation, since one pencil beam of incident x-ray is scattered into an area of several centimeters on the detector. In this paper, the authors study these two effects by measuring the focal spot distribution with a pinhole assembly and the detector point spread function (PSF) with an edge-spread function method. The authors then derive a formula to estimate the I(0) value for different illumination field sizes, using the measured focal spot distribution and the detector PSF. Phantom studies are carried out to investigate the accuracy of scatter measurements and CT images with and without considering the I(0) variation effects. On our tabletop system with a Varian Paxscan 4030CB flat-panel detector and a Varian RAD-94 x-ray tube as used on a clinical CBCT system, the focal spot distribution has a measured full-width-at-half-maximum (FWHM) of around 0

  3. The Athena X-ray Integral Field Unit

    Science.gov (United States)

    Barret, D.

    2017-10-01

    The Athena X-ray Integral Field Unit (X-IFU) is a high-resolution X-ray spectrometer, providing 2.5 eV spectral resolution, over a 5' (equivalent diameter) field of view, and count rate capabilities up to 1 Crab in the 0.2-12 keV range. Approaching the end of its feasibility study (scheduled around the end of 2017), I will briefly recall the scientific objectives of Athena driving the X-IFU specifications and will describe its current baseline configuration and the expected performances. I will outline the on-going technology developments that will enable the X-IFU. The X-IFU will be developed by an international consortium led by France (IRAP/CNES), the Netherlands (SRON), Italy (IAPS), with ESA member state contributions from Belgium, Finland, Germany, Poland, Spain and Switzerland, and international partner contributions from Japan and the United States. This talk is given on behalf of the X-IFU Consortium.

  4. A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Lipp, J; Mir, J A; Simmons, J E; Spill, E J; Stephenson, R; Dobson, B R; Farrow, R C; Helsby, W I; Mutikainen, R; Suni, I

    2002-01-01

    The Gas Microstrip Detector has counting rate capabilities several orders of magnitude higher than conventional wire proportional counters while providing the same (or better) energy resolution for X-rays. In addition the geometric flexibility provided by the lithographic process combined with the self-supporting properties of the substrate offers many exciting possibilities for X-ray detectors, particularly for the demanding experiments carried out on Synchrotron Radiation Sources. Using experience obtained in designing detectors for Particle Physics we have developed a detector for Wide Angle X-ray Scattering studies. The detector has a fan geometry which makes possible a gas detector with high detection efficiency, sub-millimetre spatial resolution and good energy resolution over a wide range of X-ray energy. The detector is described together with results of experiments carried out at the Daresbury Laboratory Synchrotron Radiation Source.

  5. Tracing the Accretion History of the Universe using X-rays from the Red Galaxy Population in the Bootes Field.

    Science.gov (United States)

    Brand, K.; Brown, M. J.; Dey, A.; Jannuzi, B.; Najita, J.; Kochanek, C.; Watson, C. R.; Green, P.; Fabricant, D.; Fazio, G.; Forman, W.; Jones, C.; Kenter, A.; Murray, S.; Vikhlinin, A.; McNamara, B.; Shields, J.; Rieke, M.

    2004-05-01

    The Chandra survey within the Bootes region of the NOAO Deep Wide-Field Survey (NDWFS) is unique in its large (9 deg2) contiguous area at relatively deep flux limits as well as the comprehensive deep multi-wavelength coverage that exists within the same region. As such, it can be used to determine the X-ray properties of well defined populations of galaxies from the NDWFS. We will present a stacking analysis of the X-rays from the red galaxy population in the NDWFS. These galaxies have well determined photometric redshifts and thus can be used to study the evolution of the average X-ray emission from this population out to redshifts of z ˜1. At the depths we are considering, X-rays are expected to be emitted from both AGN and ultra-luminous X-ray binaries (as well as a possible soft X-ray contribution from hot gas). We will discuss how we measure the contribution of nuclear X-ray emission and how the X-ray luminosity and thus also the acretion rate changes with redshift. Preliminary results show that the both the X-ray luminosity and the relative fraction of hard X-rays increases with redshift. Our research is supported by the National Optical Astronomy Observatory which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the National Science Foundation. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO3-4176 issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics and Space Administration under contract NAS8-39073.

  6. Geant4 simulations of a wide-angle x-ray focusing telescope

    Science.gov (United States)

    Zhao, Donghua; Zhang, Chen; Yuan, Weimin; Zhang, Shuangnan; Willingale, Richard; Ling, Zhixing

    2017-06-01

    The rapid development of X-ray astronomy has been made possible by widely deploying X-ray focusing telescopes on board many X-ray satellites. Geant4 is a very powerful toolkit for Monte Carlo simulations and has remarkable abilities to model complex geometrical configurations. However, the library of physical processes available in Geant4 lacks a description of the reflection of X-ray photons at a grazing incident angle which is the core physical process in the simulation of X-ray focusing telescopes. The scattering of low-energy charged particles from the mirror surfaces is another noteworthy process which is not yet incorporated into Geant4. Here we describe a Monte Carlo model of a simplified wide-angle X-ray focusing telescope adopting lobster-eye optics and a silicon detector using the Geant4 toolkit. With this model, we simulate the X-ray tracing, proton scattering and background detection. We find that: (1) the effective area obtained using Geant4 is in agreement with that obtained using Q software with an average difference of less than 3%; (2) X-rays are the dominant background source below 10 keV; (3) the sensitivity of the telescope is better by at least one order of magnitude than that of a coded mask telescope with the same physical dimensions; (4) the number of protons passing through the optics and reaching the detector by Firsov scattering is about 2.5 times that of multiple scattering for the lobster-eye telescope.

  7. A wide-acceptance Compton spectrometer for spectral characterization of a medical x-ray source

    Science.gov (United States)

    Espy, Michelle A.; Gehring, A.; Belian, A.; Haines, T.; Hunter, J.; James, M.; Klasky, M.; Mendez, J.; Moir, D.; Sedillo, R.; Shurter, R.; Stearns, J.; Van Syoc, K.; Volegov, P.

    2016-03-01

    Accurate knowledge of the x-ray spectra used in medical treatment and radiography is important for dose calculations and material decomposition analysis. Indirect measurements via transmission through materials are possible. However, such spectra are challenging to measure directly due to the high photon fluxes. One method of direct measurement is via a Compton spectrometer (CS) method. In this approach, the x-rays are converted to a much lower flux of electrons via Compton scattering on a converter foil (typically beryllium or aluminum). The electrons are then momentum selected by bending in a magnetic field. With tight angular acceptance of electrons into the magnet of ~ 1 deg, there is a linear correlation between incident photon energy and electron position recorded on an image plate. Here we present measurements of Bremsstrahlung spectrum from a medical therapy machine, a Scanditronix M22 Microtron. Spectra with energy endpoints from 6 to 20 MeV are directly measured, using a CS with a wide energy range from 0.5 to 20 MeV. We discuss the sensitivity of the device and the effects of converter material and collimation on the accuracy of the reconstructed spectra. Approaches toward improving the sensitivity, including the use of coded apertures, and potential future applications to characterization of spectra are also discussed.

  8. Invited Article: First Flight in Space of a Wide-field-of-view Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results

    Science.gov (United States)

    Collier, Michael; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chomay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massiniliano; Keller, John; Koutroumpa, Dimitra

    2015-01-01

    We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars.

  9. High energy X-ray phase and dark-field imaging using a random absorption mask.

    Science.gov (United States)

    Wang, Hongchang; Kashyap, Yogesh; Cai, Biao; Sawhney, Kawal

    2016-07-28

    High energy X-ray imaging has unique advantage over conventional X-ray imaging, since it enables higher penetration into materials with significantly reduced radiation damage. However, the absorption contrast in high energy region is considerably low due to the reduced X-ray absorption cross section for most materials. Even though the X-ray phase and dark-field imaging techniques can provide substantially increased contrast and complementary information, fabricating dedicated optics for high energies still remain a challenge. To address this issue, we present an alternative X-ray imaging approach to produce transmission, phase and scattering signals at high X-ray energies by using a random absorption mask. Importantly, in addition to the synchrotron radiation source, this approach has been demonstrated for practical imaging application with a laboratory-based microfocus X-ray source. This new imaging method could be potentially useful for studying thick samples or heavy materials for advanced research in materials science.

  10. Dark-field X-ray imaging of unsaturated water transport in porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Yang, F., E-mail: fei.yang@empa.ch, E-mail: michele.griffa@empa.ch; Di Bella, C.; Lura, P. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600 (Switzerland); Institute for Building Materials (IfB), ETH Zurich, Zürich 8093 (Switzerland); Prade, F.; Herzen, J.; Sarapata, A.; Pfeiffer, F. [Physik-Department and Institut für Medizintechnik, Technische Universität München, Garching (Germany); Griffa, M., E-mail: fei.yang@empa.ch, E-mail: michele.griffa@empa.ch; Jerjen, I. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600 (Switzerland)

    2014-10-13

    We introduce in this Letter an approach to X-ray imaging of unsaturated water transport in porous materials based upon the intrinsic X-ray scattering produced by the material microstructural heterogeneity at a length scale below the imaging system spatial resolution. The basic principle for image contrast creation consists in a reduction of such scattering by permeation of the porosity by water. The implementation of the approach is based upon X-ray dark-field imaging via Talbot-Lau interferometry. The proof-of-concept is provided by performing laboratory-scale dark-field X-ray radiography of mortar samples during a water capillary uptake experiment. The results suggest that the proposed approach to visualizing unsaturated water transport in porous materials is complementary to neutron and magnetic resonance imaging and alternative to standard X-ray imaging, the latter requiring the use of contrast agents because based upon X-ray attenuation only.

  11. The X-Ray Integral Field Unit and the Athena mission

    Science.gov (United States)

    Piro, Luigi; Barret, Didier; Den herder, Jan-willem

    The Athena+ mission concept is designed to implement the Hot and Energetic Universe science theme submitted to the European Space Agency in response to the call for White Papers for the definition of the L2 and L3 missions of its science program. The Athena+ science payload consists of a large aperture high angular resolution X-ray optics and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2.5 eV spectral resolution, with ˜ 5’’ pixels, over a field of view of 5 arc minutes in diameter. In this talk, we briefly describe the Athena+ mission concept and the X-IFU performance being driven by science requirements. We then present the X-IFU detector and readout electronics principles, the current design of the focal plane assembly, the cooling chain and review the global architecture design. Finally, we describe the current performance estimates, in terms of effective area, particle background rejection, count rate capability and velocity measurements. Finally, we emphasize on the latest technology developments concerning TES array fabrication, spectral resolution and readout performance achieved to show that significant progresses are being accomplished towards the demanding X-IFU requirements.

  12. The X-ray Integral Field Unit (X-IFU) for Athena

    Science.gov (United States)

    Ravera, Laurent; Barret, Didier; Willem den Herder, Jan; Piro, Luigi; Cledassou, Rodolphe; Pointecouteau, Etienne; Peille, Philippe; Pajot, Francois; Arnaud, Monique; Pigot, Claude; hide

    2014-01-01

    Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload consists of a large aperture high angular resolution X-ray optics (2 m2 at 1 keV) and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager. The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), oering 2.5 eV spectral resolution, with approximately 5" pixels, over a field of view of 5' in diameter. In this paper, we present the X-IFU detector and readout electronics principles, some elements of the current design for the focal plane assembly and the cooling chain. We describe the current performance estimates, in terms of spectral resolution, effective area, particle background rejection and count rate capability. Finally, we emphasize on the technology developments necessary to meet the demanding requirements of the X-IFU, both for the sensor, readout electronics and cooling chain.

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

    NARCIS (Netherlands)

    Barret, Didier; Lam Trong, Thien; den Herder, Jan-Willem; Piro, Luigi; Barcons, Xavier; Huovelin, Juhani; Kelley, Richard; Mas-Hesse, J. Miguel; Mitsuda, Kazuhisa; Paltani, Stéphane; Rauw, Gregor; RoŻanska, Agata; Wilms, Joern; Barbera, Marco; Bozzo, Enrico; Ceballos, Maria Teresa; Charles, Ivan; Decourchelle, Anne; den Hartog, Roland; Duval, Jean-Marc; Fiore, Fabrizio; Gatti, Flavio; Goldwurm, Andrea; Jackson, Brian; Jonker, Peter; Kilbourne, Caroline; Macculi, Claudio; Mendez, Mariano; Molendi, Silvano; Orleanski, Piotr; Pajot, François; Pointecouteau, Etienne; Porter, Frederick; Pratt, Gabriel W.; Prêle, Damien; Ravera, Laurent; Renotte, Etienne; Schaye, Joop; Shinozaki, Keisuke; Valenziano, Luca; Vink, Jacco; Webb, Natalie; Yamasaki, Noriko; Delcelier-Douchin, Françoise; Le Du, Michel; Mesnager, Jean-Michel; Pradines, Alice; Branduardi-Raymont, Graziella; Dadina, Mauro; Finoguenov, Alexis; Fukazawa, Yasushi; Janiuk, Agnieszka; Miller, Jon; Nazé, Yaël; Nicastro, Fabrizio; Sciortino, Salvatore; Torrejon, Jose Miguel; Geoffray, Hervé; Hernandez, Isabelle; Luno, Laure; Peille, Philippe; André, Jérôme; Daniel, Christophe; Etcheverry, Christophe; Gloaguen, Emilie; Hassin, Jérémie; Hervet, Gilles; Maussang, Irwin; Moueza, Jérôme; Paillet, Alexis; Vella, Bruno; Campos Garrido, Gonzalo; Damery, Jean-Charles; Panem, Chantal; Panh, Johan; Bandler, Simon; Biffi, Jean-Marc; Boyce, Kevin; Clénet, Antoine; DiPirro, Michael; Jamotton, Pierre; Lotti, Simone; Schwander, Denis; Smith, Stephen; van Leeuwen, Bert-Joost; van Weers, Henk; Brand, Thorsten; Cobo, Beatriz; Dauser, Thomas; de Plaa, Jelle; Cucchetti, Edoardo

    2016-01-01

    The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5" pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5

  14. Diagnosing and mapping pulmonary emphysema on X-ray projection images: incremental value of grating-based X-ray dark-field imaging.

    Directory of Open Access Journals (Sweden)

    Felix G Meinel

    Full Text Available PURPOSE: To assess whether grating-based X-ray dark-field imaging can increase the sensitivity of X-ray projection images in the diagnosis of pulmonary emphysema and allow for a more accurate assessment of emphysema distribution. MATERIALS AND METHODS: Lungs from three mice with pulmonary emphysema and three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Median signal intensities of transmission (T, dark-field (V and a combined parameter (normalized scatter were compared between emphysema and control group. To determine the diagnostic value of each parameter in differentiating between healthy and emphysematous lung tissue, a receiver-operating-characteristic (ROC curve analysis was performed both on a per-pixel and a per-individual basis. Parametric maps of emphysema distribution were generated using transmission, dark-field and normalized scatter signal and correlated with histopathology. RESULTS: Transmission values relative to water were higher for emphysematous lungs than for control lungs (1.11 vs. 1.06, p<0.001. There was no difference in median dark-field signal intensities between both groups (0.66 vs. 0.66. Median normalized scatter was significantly lower in the emphysematous lungs compared to controls (4.9 vs. 10.8, p<0.001, and was the best parameter for differentiation of healthy vs. emphysematous lung tissue. In a per-pixel analysis, the area under the ROC curve (AUC for the normalized scatter value was significantly higher than for transmission (0.86 vs. 0.78, p<0.001 and dark-field value (0.86 vs. 0.52, p<0.001 alone. Normalized scatter showed very high sensitivity for a wide range of specificity values (94% sensitivity at 75% specificity. Using the normalized scatter signal to display the regional distribution of emphysema provides color-coded parametric maps, which show the best correlation with histopathology. CONCLUSION: In a murine model, the complementary information provided by X-ray

  15. X-ray variability of serendipitous AGNs discovered in Swift GRB Fields

    Science.gov (United States)

    Turriziani, S.; Vagnetti, F.; Trevese, D.; Puccetti, S.; Giommi, P.; Perri, M.

    2008-10-01

    Active Galactic Nuclei are variable in all wave bands and in a wide range of time scales. In the X-ray band, short time scale (10^3-10^5 s) variability provides evidence that the emission comes from a compact region around the central supermassive black hole. In the optical bands the ensemble analysis on large optical samples was made possible by the Sloan Digital Sky Survey, and provided a characterization of the dependence of optical variability on luminosity, redshift, wavelength and time delay. A similar analysis can be performed in the X-rays, taking advantage of the catalogue of serendipitous sources extracted from ~230 SWIFT GRB fields, which contains about 7000 objects down to ~10^-15 erg/cm^2/s flux in the 0.5-10 keV band and ~800 objects down to 5x10^-14 erg/cm^2/s. The temporal sampling of Swift observations is designed to follow, in the X-ray band, the GRB evolution with typical intervals of a few days for a duration of weeks to months, and simultaneous UV-optical monitoring of the field. I will present preliminary results on the ensemble analysis of variability for a subsample of serendipitous sources with known redshift extracted from the Swift archive.

  16. Experimental study on hard X-ray generation of relativistic electron beams in azimuthal magnetic field

    CERN Document Server

    Fan Ya Jun; Qiu Aici

    2002-01-01

    Experimental study on hard X-ray generation was carried out on Flash 2 accelerator, with the method of relativistic electron beams transported in a low pressure gas via azimuthal magnetic field and interacted with Ta target. At 47 cm transporting distance, the measured areal integral of hard X-ray dose rate was 2.1 x 10 sup 1 sup 0 Gy centre dot cm sup 2 /s, total areal integral of hard X-ray dose was 1843 Gy centre dot cm sup 2 , and X-ray convert rate was 108 Gy centre dot cm sup 2 /kJ

  17. A beam hardening and dispersion correction for x-ray dark-field radiography.

    Science.gov (United States)

    Pelzer, Georg; Anton, Gisela; Horn, Florian; Rieger, Jens; Ritter, André; Wandner, Johannes; Weber, Thomas; Michel, Thilo

    2016-06-01

    X-ray dark-field imaging promises information on the small angle scattering properties even of large samples. However, the dark-field image is correlated with the object's attenuation and phase-shift if a polychromatic x-ray spectrum is used. A method to remove part of these correlations is proposed. The experimental setup for image acquisition was modeled in a wave-field simulation to quantify the dark-field signals originating solely from a material's attenuation and phase-shift. A calibration matrix was simulated for ICRU46 breast tissue. Using the simulated data, a dark-field image of a human mastectomy sample was corrected for the finger print of attenuation- and phase-image. Comparing the simulated, attenuation-based dark-field values to a phantom measurement, a good agreement was found. Applying the proposed method to mammographic dark-field data, a reduction of the dark-field background and anatomical noise was achieved. The contrast between microcalcifications and their surrounding background was increased. The authors show that the influence of and dispersion can be quantified by simulation and, thus, measured image data can be corrected. The simulation allows to determine the corresponding dark-field artifacts for a wide range of setup parameters, like tube-voltage and filtration. The application of the proposed method to mammographic dark-field data shows an increase in contrast compared to the original image, which might simplify a further image-based diagnosis.

  18. Mapping strain fields in ultrathin bonded Si wafers by x-ray scattering

    DEFF Research Database (Denmark)

    Nielsen, Mourits; Poulsen, Mette; Bunk, Oliver

    2002-01-01

    X-ray scattering reveals the atomic displacements arising from rotational misalignment in ultrathin silicon bonded wafers. For a 4.3 nm top wafer, the strain field penetrates from the bonded interface to the surface and produces distinctive finite-size oscillations in x-ray data. Analytical...... calculations permit the atomic displacements throughout the thin top wafer to be modeled....

  19. First experience with x-ray dark-field radiography for human chest imaging (Conference Presentation)

    Science.gov (United States)

    Noel, Peter B.; Willer, Konstantin; Fingerle, Alexander A.; Gromann, Lukas B.; De Marco, Fabio; Scherer, Kai H.; Herzen, Julia; Achterhold, Klaus; Gleich, Bernhard; Münzel, Daniela; Renz, Martin; Renger, Bernhard C.; Fischer, Florian; Braun, Christian; Auweter, Sigrid; Hellbach, Katharina; Reiser, Maximilian F.; Schröter, Tobias; Mohr, Jürgen; Yaroshenko, Andre; Maack, Hanns-Ingo; Pralow, Thomas; van der Heijden, Hendrik; Proksa, Roland; Köhler, Thomas; Wieberneit, Nataly; Rindt, Karsten; Rummeny, Ernst J.; Pfeiffer, Franz

    2017-03-01

    Purpose: To evaluate the performance of an experimental X-ray dark-field radiography system for chest imaging in humans and to compare with conventional diagnostic imaging. Materials and Methods: The study was institutional review board (IRB) approved. A single human cadaver (52 years, female, height: 173 cm, weight: 84 kg, chest circumference: 97 cm) was imaged within 24 hours post mortem on the experimental x-ray dark-field system. In addition, the cadaver was imaged on a clinical CT system to obtain a reference scan. The grating-based dark-field radiography setup was equipped with a set of three gratings to enable grating-based dark-field contrast x-ray imaging. The prototype operates at an acceleration voltage of up to 70 kVp and with a field-of-view large enough for clinical chest x-ray (>35 x 35 cm2). Results: It was feasible to extract x-ray dark-field signal of the whole human thorax, clearly demonstrating that human x-ray dark-field chest radiography is feasible. Lung tissue produced strong scattering, reflected in a pronounced x-ray dark-field signal. The ribcage and the backbone are less prominent than the lung but are also distinguishable. Finally, the soft tissue is not present in the dark-field radiography. The regions of the lungs affected by edema, as verified by CT, showed less dark-field signal compared to healthy lung tissue. Conclusion: Our results reveal the current status of translating dark-field imaging from a micro (small animal) scale to a macro (patient) scale. The performance of the experimental x-ray dark-field radiography setup offers, for the first time, obtaining multi-contrast chest x-ray images (attenuation and dark-field signal) from a human cadaver.

  20. Study of Increased Radiation When an X-ray Tube is Placed in a Strong Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Z.F.; /Stanford U., Dept. Radiol. /Stanford U., Phys. Dept.; Pelc, N.J.; /Stanford U., Dept. Radiol. /Stanford U., Dept. Bioeng.; Nelson, W.R.; /SLAC; Fahrig, R.; /Stanford U., Dept. Radiol.

    2007-01-12

    When a fixed anode x-ray tube is placed in a magnetic field (B) that is parallel to the anode-cathode axis, the x-ray exposure increases with increasing B. It was hypothesized that the increase was caused by backscattered electrons which were constrained by B and reaccelerated by the electric field onto the x-ray tube target. We performed computer simulations and physical experiments to study the behavior of the backscattered electrons in a magnetic field, and their effects on the radiation output, x-ray spectrum, and off-focal radiation. A Monte Carlo program (EGS4) was used to generate the combined energy and angular distribution of the backscattered electrons. The electron trajectories were traced and their landing locations back on the anode were calculated. Radiation emission from each point was modeled with published data (IPEM Report 78), and thus the exposure rate and x-ray spectrum with the contribution of backscattered electrons could be predicted. The point spread function for a pencil beam of electrons was generated and then convolved with the density map of primary electrons incident on the anode as simulated with a finite element program (Opera-3d, Vector Fields, UK). The total spatial distribution of x-ray emission could then be calculated. Simulations showed that for an x-ray tube working at 65 kV, about 54% of the electrons incident on the target were backscattered. In a magnetic field of 0.5 T, although the exposure would be increased by 33%, only a small fraction of the backscattered electrons landed within the focal spot area. The x-ray spectrum was slightly shifted to lower energies and the half value layer (HVL) was reduced by about 6%. Measurements of the exposure rate, half value layer and focal spot distribution were acquired as functions of B. Good agreement was observed between experimental data and simulation results. The wide spatial distribution of secondary x-ray emission can degrade the MTF of the x-ray system at low spatial

  1. Note: Grazing incidence small and wide angle x-ray scattering combined with imaging ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Koerstgens, V.; Meier, R.; Ruderer, M. A.; Guo, S.; Chiang, H.-Y.; Mueller-Buschbaum, P. [Technische Universitaet Muenchen, Physik-Department, Lehrstuhl fuer Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching (Germany); Perlich, J.; Roth, S. V.; Gehrke, R. [HASYLAB, DESY, Notkestr. 85, 22607, Hamburg (Germany)

    2012-07-15

    The combination of grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) with optical imaging ellipsometry is presented as an upgrade of the available measurement techniques at the wiggler beamline BW4 of the Hamburger Synchrotronstrahlungslabor. The instrument is introduced with the description of the alignment procedure to assure the measurement of imaging ellipsometry and GISAXS/GIWAXS on the same sample spot. To demonstrate the possibilities of the new instrument examples of morphological investigation on films made of poly(3-hexylthiophene) and [6,6]-phenyl-C{sub 61} butyric acid methyl ester as well as textured poly(9,9-dioctylfluorene-alt-benzo-thia-diazole) are shown.

  2. Graphical method for analyzing wide-angle x-ray diffraction

    Science.gov (United States)

    Chen, XiaoHui; Xue, Tao; Liu, DongBing; Yang, QingGuo; Luo, BinQiang; Li, Mu; Li, XiaoYa; Li, Jun

    2018-01-01

    Wide-angle X-ray diffraction on large-scale laser facility is a well-established experimental method, which is used to study the shock response of single crystal materials by recording X-rays diffracted from numerous lattice planes. We present a three-dimensional graphical method for extracting physical understanding from the raw diffraction data in shocked experiments. This method advances beyond the previous iterative process by turning abstract diffraction theories in shock physics into mathematic issues, providing three-dimensional visualization and quick extraction of data characteristics. The capability and versatility of the method are exhibited by identifying lattice planes for single crystal samples with different orientations and quantitatively measuring the lattice compression and rotation under dynamic loading.

  3. Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: a truly hybrid x-ray/MR imaging system.

    Science.gov (United States)

    Fahrig, R; Wen, Z; Ganguly, A; DeCrescenzo, G; Rowlands, J A; Stevens, G M; Saunders, R F; Pelc, N J

    2005-06-01

    Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation.

  4. X-ray dark-field imaging and its application. Laue case analyzer

    CERN Document Server

    Ando, M

    2003-01-01

    A system on X-ray dark-field imaging under development and its application is reported. That comprises an asymmetric monochromator and a Laue case analyzer that has a specified thickness for a given X-ray photon energy or wavelength and a sample locating inbetween these. This system uses Si 4,4,0 diffraction for both X-ray optics element in a parallel arrangement. In order to achieve the dark-field imaging condition the Si Laue analyzer should be 1.075 mm in thickness for the X-ray energy of 35 keV. Since this system is very simple one can expect a variety of applications including material science, biology, palaeontology and clinical medicine where a large view area with size of 100 mm x 100 mm is needed. (author)

  5. Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

    Science.gov (United States)

    Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

    1987-01-01

    Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

  6. Synchrotron X-ray Characterization of Structural Defects in III-Nitride Wide Bandgap Semiconductors

    Science.gov (United States)

    Wu, Shuang

    III-nitrides have long been viewed as promising semiconductor materials for their wide-band gap and high efficiency for emitting light. They have been widely used in electronic and optoelectronic devices, even in the extreme environments such as high frequencies, high voltages and high temperatures. Despite their favorable properties, their performance is strongly affected by factors; such as the growth method employed and consequently the defect types generated and their quantity. In this thesis, the wide bandgap III-nitrides, aluminum nitride (AlN) and gallium nitride (GaN) will be discussed in the aspect of structure, properties and defects characterization. The density of defects, particularly basal plane dislocations and threading edge and screw dislocations, will be measured across multiple wafers and analyzed in order to gain insights into origins of these defects with respect to the growth process employed. Other defects like low angle grain boundaries and prismatic slip bands are also observed and analyzed. In this study, synchrotron white beam and monochromatic X-ray topography are the main techniques employed to characterize samples, with Nomarski optical microscopy used in a complementary manner. For physical vapor transport (PVT) grown AlN wafers, the distribution of basal plane dislocations and threading dislocations imaged and analyzed synchrotron X-ray topography reveals a wide range of densities from as low as 1.7x102cm-2 to greater than 106cm -2, the resolution limit for X-ray topography techniques. For basal plane dislocations (BPDs), the average density is 1.6747x104 cm-2. As for threading dislocations (TDs), both screw and edge, the average dislocation density is about 1.5515x10 4 cm-2 ranging from a low of 3.00x102 cm-2 to a high of 4.477x104cm -2. These differences among the wafers, is clearly attributable to variations in growth conditions. For hydride vapor phase epitaxy (HVPE) grown GaN wafers on ammonothermal GaN substrates, the threading

  7. X-Ray Lasers 2016

    CERN Document Server

    Bulanov, Sergei; Daido, Hiroyuki; Kato, Yoshiaki

    2018-01-01

    These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications.   The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.

  8. The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32

    Science.gov (United States)

    Kummer, K.; Fondacaro, A.; Jimenez, E.; Velez-Fort, E.; Amorese, A.; Aspbury, M.; Yakhou-Harris, F.; van der Linden, P.; Brookes, N. B.

    2016-01-01

    A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the beam and up to 4 T orthogonal to the beam. It is connected to a cluster of ultra-high-vacuum chambers that offer a comprehensive set of surface preparation and characterization techniques. The endstation and the beam properties have been designed to provide optimum experimental conditions for X-ray magnetic linear and circular dichroism experiments in the soft X-ray range between 400 and 1600 eV photon energy. User operation started in November 2014. PMID:26917134

  9. The spatial clustering of X-ray selected AGN in the XMM-COSMOS field

    NARCIS (Netherlands)

    Gilli, R.; Zamorani, G.; Miyaji, T.; Silverman, J.; Brusa, M.; Mainieri, V.; Cappelluti, N.; Daddi, E.; Porciani, C.; Pozzetti, L.; Civano, F.; Comastri, A.; Finoguenov, A.; Fiore, F.; Salvato, M.; Vignali, C.; Hasinger, G.; Lilly, S.; Impey, C.; Trump, J.; Capak, P.; McCracken, H.; Scoville, N.; Taniguchi, Y.; Carollo, C. M.; Contini, T.; Kneib, J. -P.; Le Fevre, O.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Cimatti, A.; Coppa, G.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovac, K.; Lamareille, F.; Le Borgne, J. -F.; Le Brun, V.; Maier, C.; Mignoli, M.; Pello, R.; Peng, Y.; Montero, E. Perez; Ricciardelli, E.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Abbas, U.; Bottini, D.; Cappi, A.; Cassata, P.; Fumana, M.; Guzzo, L.; Leauthaud, A.; Maccagni, D.; Marinoni, C.; Memeo, P.; Meneux, B.; Oesch, P.; Scaramella, R.; Walcher, J.

    We study the spatial clustering of 538 X-ray selected AGN in the 2 deg(2) XMM-COSMOS field that are spectroscopically identified with I(AB) <23 and span the redshift range z = 0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L(0.5-10) = 6.3 x 10(43) erg s(-1),

  10. Enhancement of X-ray Production in Z-Pinch Plasmas Using Magnetic Fields

    Science.gov (United States)

    Edison, N. S.; Etlicher, B.; Attelan, S.; Rouillé, C.; Chuvatin, A. S.; Aliaga, R.

    1994-03-01

    We are investigating the effects of an axial magnetic field to stabilize an aluminum vapor z-pinch. An aluminum plasma jet is created from an exploding foil in a DC magnetic field (Bz0 ≤ 300 G). The applied field is small compared to the azimuthal field, Bz0 ≫ Bϑ, and is intended to reduce the growth of instabilities during the compression phase. The pinch is driven by a 2 Ω, 0.1 TW generator (250 kA in 80 ns). Additionally, a micron sized wire may be placed on the pinch axis leading to the plasma-on-wire (POW) configuration. Qualitatively, increasing the axial magnetic field improves the pinch with the m=1 instabilities becoming negligible for fields higher than 150 G. We find that the externally applied fields can enhance x-ray production up to a critical field. Above this critical field x-ray emission decreases even though the pulse length of the radiation may still be increasing. As the applied field increases, the period of x-ray emission increases with the harder spectrum affected the least. The x-ray yield peaks for the POW and Al jet alone configurations at 150 G and 50 G respectively. Diagnostics include filtered PIN x-ray diodes, time-resolved schlieren photography, and time-integrated multiple filtered pinholes. We will present the results comparing the POW and aluminum jet configurations described above.

  11. Physiologically gated microbeam radiation using a field emission x-ray source array

    Energy Technology Data Exchange (ETDEWEB)

    Chtcheprov, Pavel, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Biomedical Engineering, University of North Carolina, 152 MacNider Hall, Campus Box 7575, Chapel Hill, North Carolina 27599 (United States); Burk, Laurel; Inscoe, Christina; Ger, Rachel; Hadsell, Michael; Lu, Jianping [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 (United States); Yuan, Hong [Department of Radiology, University of North Carolina, 2006 Old Clinic, CB #7510, Chapel Hill, North Carolina 27599 (United States); Zhang, Lei [Department of Applied Physical Sciences, University of North Carolina, Chapman Hall, CB#3216, Chapel Hill, North Carolina 27599 (United States); Chang, Sha [Department of Radiation Oncology, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States); Zhou, Otto, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States)

    2014-08-15

    Purpose: Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. Methods: The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic{sup ©} films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only

  12. Diagnosing and Mapping Pulmonary Emphysema on X-Ray Projection Images: Incremental Value of Grating-Based X-Ray Dark-Field Imaging

    Science.gov (United States)

    Meinel, Felix G.; Schwab, Felix; Schleede, Simone; Bech, Martin; Herzen, Julia; Achterhold, Klaus; Auweter, Sigrid; Bamberg, Fabian; Yildirim, Ali Ö.; Bohla, Alexander; Eickelberg, Oliver; Loewen, Rod; Gifford, Martin; Ruth, Ronald; Reiser, Maximilian F.; Pfeiffer, Franz; Nikolaou, Konstantin

    2013-01-01

    Purpose To assess whether grating-based X-ray dark-field imaging can increase the sensitivity of X-ray projection images in the diagnosis of pulmonary emphysema and allow for a more accurate assessment of emphysema distribution. Materials and Methods Lungs from three mice with pulmonary emphysema and three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Median signal intensities of transmission (T), dark-field (V) and a combined parameter (normalized scatter) were compared between emphysema and control group. To determine the diagnostic value of each parameter in differentiating between healthy and emphysematous lung tissue, a receiver-operating-characteristic (ROC) curve analysis was performed both on a per-pixel and a per-individual basis. Parametric maps of emphysema distribution were generated using transmission, dark-field and normalized scatter signal and correlated with histopathology. Results Transmission values relative to water were higher for emphysematous lungs than for control lungs (1.11 vs. 1.06, pemphysema provides color-coded parametric maps, which show the best correlation with histopathology. Conclusion In a murine model, the complementary information provided by X-ray transmission and dark-field images adds incremental diagnostic value in detecting pulmonary emphysema and visualizing its regional distribution as compared to conventional X-ray projections. PMID:23555692

  13. Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment

    Energy Technology Data Exchange (ETDEWEB)

    Bottaro, Marcio; Nagy, Balazs Vince; Soares, Fernanda Cristina Salvador; Rosendo, Danilo Cabral, E-mail: marcio@iee.usp.br [Universidade de Sao Paulo (USP), SP (Brazil); Optics and Engineering Informatics, Budapest University of Technology and Economics, Budapest (Hungary)

    2017-04-15

    Introduction: To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods: Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naive human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results: In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion: As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer's edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers’ edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients. (author)

  14. The influence of an extrapolation chamber over the low energy X-ray beam radiation field

    Energy Technology Data Exchange (ETDEWEB)

    Tanuri de F, M. T.; Da Silva, T. A., E-mail: mttf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    The extrapolation chambers are detectors whose sensitive volume can be modified by changing the distance between the electrodes and has been widely used for beta particles primary measurement system. In this work, was performed a PTW 23392 extrapolation chamber Monte Carlo simulation, by mean the MCNPX code. Although the sensitive volume of an extrapolation chamber can be reduced to very small size, their packaging is large enough to modify the radiation field and change the absorbed dose measurements values. Experiments were performed to calculate correction factors for this purpose. The validation of the Monte Carlo model was done by comparing the spectra obtained with a CdTe detector according to the ISO 4037 criteria. Agreements smaller than 5% for half value layers, 10% for spectral resolution and 1% for mean energy, were found. It was verified that the correction factors are dependent of the X-ray beam quality. (Author)

  15. The X-Ray Luminosity Functions of Field Low-Mass X-Ray Binaries in Early-Type Galaxies: Evidence for a Stellar Age Dependence

    Science.gov (United States)

    Lehmer, B. D.; Berkeley, M.; Zezas, A.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Kalogera, V.; hide

    2014-01-01

    We present direct constraints on how the formation of low-mass X-ray binary (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span approximately equal to 3-10 Gyr. X-ray binary population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background AGN/galaxies. We find that the "young" early-type galaxy NGC 3384 (approximately equals 2-5 Gyr) has an excess of luminous field LMXBs (L(sub x) approximately greater than (5-10) × 10(exp 37) erg s(exp -1)) per unit K-band luminosity (L(sub K); a proxy for stellar mass) than the "old" early-type galaxies NGC 3115 and 3379 (approximately equals 8-10 Gyr), which results in a factor of 2-3 excess of L(sub X)/L(sub K) for NGC 3384. This result is consistent with the X-ray binary population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray binary population synthesis models.

  16. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  17. X-ray dark-field interface radiography; Roentgen-Interface-Radiographie im Dunkelfeld

    Energy Technology Data Exchange (ETDEWEB)

    Kupsch, Andreas; Hentschel, Manfred P.; Lange, Axel; Mueller, Bernd R. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2013-07-01

    This article presents an X-ray imaging method for weakly absorbing objects which makes use of the contrast effects created by X-ray refraction at surfaces and interfaces. A slightly curved monocrystal in which the Bragg condition is met locally in a small zone of the irradiated cross-section is used to generate what is referred to as a dark field. Beam components deflected by refraction within this zone appear as brightly luminant structures. Biological and technical structures are used as examples in creating 2D high-resolution images from the synthesis of several dark-field stripes.

  18. Dark-field X-ray microscopy for multiscale structural characterization

    DEFF Research Database (Denmark)

    Simons, Hugh; King, A.; Ludwig, W.

    2015-01-01

    Many physical and mechanical properties of crystalline materials depend strongly on their internal structure, which is typically organized into grains and domains on several length scales. Here we present dark-field X-ray microscopy; a non-destructive microscopy technique for the three...... of the interactions between crystalline elements is a key step towards the formulation and validation of multiscale models that account for the entire heterogeneity of a material. Furthermore, dark-field X-ray microscopy is well suited to applied topics, where the structural evolution of internal nanoscale elements...

  19. Detection of sub-pixel fractures in X-ray dark-field tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lauridsen, Torsten; Feidenhans' l, Robert [University of Copenhagen, Niels Bohr Institute, Copenhagen (Denmark); Willner, Marian; Pfeiffer, Franz [Technische Universitaet Muenchen, Department of Physics and Institute of Medical Engineering, Garching (Germany); Bech, Martin [Lund University, Medical Radiation Physics, Lund (Sweden)

    2015-11-15

    We present a new method for detecting fractures in solid materials below the resolution given by the detector pixel size by using grating-based X-ray interferometry. The technique is particularly useful for detecting sub-pixel cracks in large samples where the size of the sample is preventing high-resolution μCT studies of the entire sample. The X-ray grating interferometer produces three distinct modality signals: absorption, phase and dark field. The method utilizes the unique scattering features of the dark-field signal. We have used tomograms reconstructed from each of the three signals to detect cracks in a model sample consisting of stearin. (orig.)

  20. Evaluation of the effectiveness of X-ray protective aprons in experimental and practical fields.

    Science.gov (United States)

    Mori, Hiroshige; Koshida, Kichiro; Ishigamori, Osamu; Matsubara, Kosuke

    2014-01-01

    Few practical evaluation studies have been conducted on X-ray protective aprons in workplaces. We examined the effects of exchanging the protective apron type with regard to exposure reduction in experimental and practical fields, and discuss the effectiveness of X-ray protective aprons. Experimental field evaluations were performed by the measurement of the X-ray transmission rates of protective aprons. Practical field evaluations were performed by the estimation of the differences in the transit doses before and after the apron exchange. A 0.50-mm lead-equivalent-thick non-lead apron had the lowest transmission rate among the 7 protective aprons, but weighed 10.9 kg and was too heavy. The 0.25 and 0.35-mm lead-equivalent-thick non-lead aprons differed little in the practical field of interventional radiology. The 0.35-mm lead apron had lower X-ray transmission rates and transit doses than the 0.25-mm lead-equivalent-thick non-lead apron, and each of these differences exceeded 8% in the experimental field and approximately 0.15 mSv/month in the practical field of computed tomography (p lead-equivalent-thick aprons and 0.35-mm lead apron are effective for interventional radiology operators and computed tomography nurses, respectively.

  1. Soft x-ray free-electron laser imaging by LiF crystal and film detectors over a wide range of fluences.

    Science.gov (United States)

    Pikuz, Tatiana A; Faenov, Anatoly Ya; Fukuda, Yuji; Kando, Masaki; Bolton, Paul; Mitrofanov, Alexander; Vinogradov, Alexander V; Nagasono, Mitsuru; Ohashi, Haruhiko; Yabashi, Makina; Tono, Kensuke; Senba, Yasunori; Togashi, Tadashi; Ishikawa, Tetsuya

    2013-01-20

    LiF crystal and film detectors were used to measure the far-field fluence profile of a self-amplified spontaneous-emission free-electron laser beam and diffraction imaging with high spatial resolution. In these measurements the photoluminescence (PL) response of LiF crystal and film was compared over a wide range of soft x-ray fluences. It was found that the soft x-ray fluence dependences of LiF crystal and film differ. At low fluence, the LiF crystal shows higher PL response compared to LiF film, while this comparison is the opposite at higher fluence. Accurate measurement of LiF crystal and film PL response is important for precise characterization of the spatial, spectral, and coherence features of x-ray beams across the full profile and in localized areas. For such measurements, crucial LiF detector attributes are high spatial resolution and high dynamic range.

  2. Introducing a standard method for experimental determination of the solvent response in laser pump, x-ray probe time-resolved wide-angle x-ray scattering experiments on systems in solution

    DEFF Research Database (Denmark)

    Kjær, Kasper Skov; Brandt van Driel, Tim; Kehres, Jan

    2013-01-01

    In time-resolved laser pump, X-ray probe wide-angle X-ray scattering experiments on systems in solution the structural response of the system is accompanied by a solvent response. The solvent response is caused by reorganization of the bulk solvent following the laser pump event, and in order to ...

  3. Local and long range order in promoted iron-based Fischer–Tropsch catalysts: a combined in situ X-ray absorption spectroscopy/wide angle X-ray scattering study

    NARCIS (Netherlands)

    de Smit, E.|info:eu-repo/dai/nl/304824232; Beale, A.M.|info:eu-repo/dai/nl/325802068; Nikitenko, S.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2009-01-01

    The structural properties of three Fe-based Fischer–Tropsch synthesis (FTS) catalysts containing different amounts of Cu, K and SiO2 additives were investigated during pretreatment and FTS in a fixed bed-like reactor using combined in situ X-ray absorption fine structure (XAFS)/wide angle X-ray

  4. Electric Field Dependence on Charge Collection of CdZnTe X-Ray Detectors.

    Science.gov (United States)

    Giakos, G C; Pillai, B; Vedantham, S; Chowdhuri, S; Odogba, J; Dasgupta, A; Vega-Lozada, V; Guntupalli, R; Suryanarayanan, S; Endorf, R J; Passalaqua, A; Kollipara, S

    1997-01-01

    In this study, the electric field dependence on the charge collection process of CdZnTe detectors, at different x-ray tube settings, within the x-ray diagnostic energy range, is investigated. In addition, the detector contrast at different applied bias voltages and x-ray tube settings have been experimentally determined. The experimental results suggest that an efficient charge collection process is obtained by increasing the applied bias voltage. Once the applied bias voltage is sufficiently high, charge collection becomes complete and the detector operates in the saturation region. This is a prerequisite for high contrast and spatial resolution. As a result, the detector contrast is enhanced significantly. Therefore, CdZnTe detectors appear to be potential candidates for digital radiographic applications.

  5. X-ray dark-field imaging for detection of foreign bodies in food

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Schou; Lauridsen, Torsten; Feidenhans'l, Robert Krarup

    2013-01-01

    Conventional X-ray transmission radiography has long been used for online detection of foreign bodies in food products relying on the absorption contrast between the foreign body and food product. In this paper, we present a novel approach for detection of organic foreign bodies such as paper...... and insects in two food products using X-ray dark-field imaging with a grating interferometer. The ability to detect the foreign bodies is quantified using a measure of the contrast-to-noise ratio....

  6. Time variability of X-ray sources in the M 31 centre field

    OpenAIRE

    Stiele, H.; Pietsch, W.; Haberl, F.; Freyberg, M.

    2008-01-01

    We present an extension to our XMM-Newton X-ray source catalogue of M 31, containing 39 newly found sources. In order to classify and identify more of the sources we search for X-ray time variability in XMM-Newton archival data of the M 31 centre field. As a source list we used our extended catalogue based on observations covering the time span from June 2000 to July 2004. We then determined the flux or at least an upper limit at the source positions for each observation. Deriving the flux ra...

  7. Electrostatic focal spot correction for x-ray tubes operating in strong magnetic fields.

    Science.gov (United States)

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Fahrig, Rebecca

    2014-11-01

    A close proximity hybrid x-ray/magnetic resonance (XMR) imaging system offers several critical advantages over current XMR system installations that have large separation distances (∼5 m) between the imaging fields of view. The two imaging systems can be placed in close proximity to each other if an x-ray tube can be designed to be immune to the magnetic fringe fields outside of the MR bore. One of the major obstacles to robust x-ray tube design is correcting for the effects of the MR fringe field on the x-ray tube focal spot. Any fringe field component orthogonal to the x-ray tube electric field leads to electron drift altering the path of the electron trajectories. The method proposed in this study to correct for the electron drift utilizes an external electric field in the direction of the drift. The electric field is created using two electrodes that are positioned adjacent to the cathode. These electrodes are biased with positive and negative potential differences relative to the cathode. The design of the focusing cup assembly is constrained primarily by the strength of the MR fringe field and high voltage standoff distances between the anode, cathode, and the bias electrodes. From these constraints, a focusing cup design suitable for the close proximity XMR system geometry is derived, and a finite element model of this focusing cup geometry is simulated to demonstrate efficacy. A Monte Carlo simulation is performed to determine any effects of the modified focusing cup design on the output x-ray energy spectrum. An orthogonal fringe field magnitude of 65 mT can be compensated for using bias voltages of +15 and -20 kV. These bias voltages are not sufficient to completely correct for larger orthogonal field magnitudes. Using active shielding coils in combination with the bias electrodes provides complete correction at an orthogonal field magnitude of 88.1 mT. Introducing small fields (field in addition to the orthogonal field does not affect the electrostatic

  8. Broadband X-ray Imaging in the Near-Field Region of an Airblast Atomizer

    Science.gov (United States)

    Li, Danyu; Bothell, Julie; Morgan, Timothy; Heindel, Theodore

    2017-11-01

    The atomization process has a close connection to the efficiency of many spray applications. Examples include improved fuel atomization increasing the combustion efficiency of aircraft engines, or controlled droplet size and spray angle enhancing the quality and speed of the painting process. Therefore, it is vital to understand the physics of the atomization process, but the near-field region is typically optically dense and difficult to probe with laser-based or intrusive measurement techniques. In this project, broadband X-ray radiography and X-ray computed tomography (CT) imaging were performed in the near-field region of a canonical coaxial airblast atomizer. The X-ray absorption rate was enhanced by adding 20% by weight of Potassium Iodide to the liquid phase to increase image contrast. The radiographs provided an estimate of the liquid effective mean path length and spray angle at the nozzle exit for different flow conditions. The reconstructed CT images provided a 3D map of the time-average liquid spray distribution. X-ray imaging was used to quantify the changes in the near-field spray characteristics for various coaxial airblast atomizer flow conditions. Office of Naval Research.

  9. Elemental mapping in a contemporary miniature by full-field X-ray fluorescence imaging with gaseous detector vs. scanning X-ray fluorescence imaging with polycapillary optics

    Science.gov (United States)

    Silva, A. L. M.; Cirino, S.; Carvalho, M. L.; Manso, M.; Pessanha, S.; Azevedo, C. D. R.; Carramate, L. F. N. D.; Santos, J. P.; Guerra, M.; Veloso, J. F. C. A.

    2017-03-01

    Energy dispersive X-ray imaging can be used in several research fields and industrial applications. Elemental mapping through energy dispersive X-ray imaging technique has become a promising method to obtain positional distribution of specific elements in a non-destructive way. To obtain the elemental distribution of a sample it is necessary to use instruments capable of providing a precise positioning together with a good energy resolution. Polycapillary beams together with silicon drift chamber detectors are used in several commercial systems and are considered state-of-the-art spectrometers, however they are usually very costly. A new concept of large energy dispersive X-ray imaging systems based on gaseous radiation detectors emerged in the last years enabling a promising 2D elemental detection at a very reduced price. The main goal of this work is to analyze a contemporary Indian miniature with both X-ray fluorescence imaging systems, the one based on a gaseous detector 2D-THCOBRA and the state-of-the-art spectrometer M4 Tornado, from Bruker. The performance of both systems is compared and evaluated in the context of the sample's analysis.

  10. Carbon Fiber Morphology. 2. Expanded Wide-Angle X-Ray Diffraction Studies of Carbon Fibers

    Science.gov (United States)

    1991-02-01

    X- Ray Diffraction," JPS. Polym. Phys. Ed., 16, 939 (1978). 17. Rosalind E. Franklin , "The Structure of Graphitic Carbons," Acta Cryst., 4, 253 (1951...18. Rosalind E. Franklin , "The Interpretation of Diffuse X-ray Diagrams of Carbon," Acta CrL, 3, 107 (1950). 19. K. Jain and A. S. Abhiraman...been generally mentioned much earlier by Franklin [17,18]. Jain and Abhiraman [19] demonstrated that these corrections can make significant differences

  11. Reconstruction of scalar and vectorial components in X-ray dark-field tomography.

    Science.gov (United States)

    Bayer, Florian L; Hu, Shiyang; Maier, Andreas; Weber, Thomas; Anton, Gisela; Michel, Thilo; Riess, Christian P

    2014-09-02

    Grating-based X-ray dark-field imaging is a novel technique for obtaining image contrast for object structures at size scales below setup resolution. Such an approach appears particularly beneficial for medical imaging and nondestructive testing. It has already been shown that the dark-field signal depends on the direction of observation. However, up to now, algorithms for fully recovering the orientation dependence in a tomographic volume are still unexplored. In this publication, we propose a reconstruction method for grating-based X-ray dark-field tomography, which models the orientation-dependent signal as an additional observable from a standard tomographic scan. In detail, we extend the tomographic volume to a tensorial set of voxel data, containing the local orientation and contributions to dark-field scattering. In our experiments, we present the first results of several test specimens exhibiting a heterogeneous composition in microstructure, which demonstrates the diagnostic potential of the method.

  12. Effect of common building materials in narrow shaped X-ray fields transmission

    Science.gov (United States)

    Vlachos, I.; Tsantilas, X.; Fountos, G.; Delis, H.; Kandarakis, I.; Panayiotakis, G.

    2015-09-01

    Diagnostic and interventional radiology, are an essential part of present day medical practice. Advances in X-ray imaging technology, together with developments in digital imaging have had a significant impact on the practice of radiology. This includes improvement in image quality, reduction in dose and a broader range of available applications resulting to better patient diagnosis and treatment. X-rays have the potential for damaging healthy cells and tissues, therefore all medical procedures employing X-ray equipment must be carefully managed. In all facilities and for all equipment types, procedures must be in place in order to ensure that exposures to patients, staff and the public are kept as low as reasonably achievable. Commonly used construction materials such as, ceramic tiles and plasterboards can provide a certain degree of protection against X-radiation. In this study, the secondary radiation transmission through common building materials is investigated, in the case of narrow shaped X-ray fields. Double plasterboard and double reinforced in thickness ceramic tile provided better radiation protection results.

  13. Preclinical x-ray dark-field imaging: foreign body detection

    Science.gov (United States)

    Braig, Eva-Maria; Muenzel, Daniela; Fingerle, Alexander; Herzen, Julia; Rummeny, Ernst; Pfeiffer, Franz; Noel, Peter

    2017-03-01

    The purpose of this study was to evaluate the performance of X-ray dark-field imaging for detection of retained foreign bodies in ex-vivo hands and feet. X-ray dark-field imaging, acquired with a three-grating Talbot-Lau interferometer, has proven to provide access to sub-resolution structures due to small-angle scattering. The study was institutional review board (IRB) approved. Foreign body parts included pieces of wood and metal which were placed in a formalin fixated human ex-vivo hand. The samples were imaged with a grating-based interferometer consisting of a standard microfocus X-ray tube (60 kVp, 100 W) and a Varian 2520-DX detector (pixel size: 127 μm). The attenuation and the dark-field signals provide complementary diagnostic information for this clinical task. With regard to detecting of wooden objects, which are clinically the most relevant, only the dark-field image revealed the locations. The signal is especially strong for dry wood which in comparison is poorly to non-visible in computed tomography. The detection of high atomic-number or dense material and wood-like or porous materials in a single X-ray scan is enabled by the simultaneous acquisition of the conventional attenuation and dark-field signal. Our results reveal that with this approach one can reach a significantly improved sensitivity for detection of foreign bodies, while an easy implementation into the clinical arena is becoming feasible.

  14. Three-dimensional propagation in near-field tomographic X-ray phase retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Ruhlandt, Aike, E-mail: aruhlan@gwdg.de; Salditt, Tim [Institut für Röntgenphysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, Göttingen (Germany)

    2016-01-29

    An extension of phase retrieval algorithms for near-field X-ray (propagation) imaging to three dimensions is presented, enhancing the quality of the reconstruction by exploiting previously unused three-dimensional consistency constraints. This paper presents an extension of phase retrieval algorithms for near-field X-ray (propagation) imaging to three dimensions, enhancing the quality of the reconstruction by exploiting previously unused three-dimensional consistency constraints. The approach is based on a novel three-dimensional propagator and is derived for the case of optically weak objects. It can be easily implemented in current phase retrieval architectures, is computationally efficient and reduces the need for restrictive prior assumptions, resulting in superior reconstruction quality.

  15. Simulations of multi-contrast x-ray imaging using near-field speckles

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom and Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Herzen, Julia; Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany)

    2016-01-28

    X-ray dark-field and phase-contrast imaging using near-field speckles is a novel technique that overcomes limitations inherent in conventional absorption x-ray imaging, i.e. poor contrast for features with similar density. Speckle-based imaging yields a wealth of information with a simple setup tolerant to polychromatic and divergent beams, and simple data acquisition and analysis procedures. Here, we present a simulation software used to model the image formation with the speckle-based technique, and we compare simulated results on a phantom sample with experimental synchrotron data. Thorough simulation of a speckle-based imaging experiment will help for better understanding and optimising the technique itself.

  16. The Measurement of Strain Fields by X-Ray Topographic Contour Mapping.

    Science.gov (United States)

    1985-05-01

    FIELDS BY X-RAY TOPOGRAPHIC CONTOUR MAPPING S.R. Stock, Haydn Chen and H.K. Birnbaum University of Illinois Department of Metallurgy Urbana, IL 61801...TOPOGRAPHIC CONTOUR MAPPING S. R. Stock*# Haydn Chen and H. K. Birnbaum Department of Metallurgy and Mining Engineering University of Illinois at Urbana...Birnbaum, - - H. K. and Chen, Haydn , Topographic EXAFS, Nature 309: 336 . - (1984). Hart, M., Bragg angle measurement and mapping, J. Cryst. Growth

  17. X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge

    Directory of Open Access Journals (Sweden)

    Carla Bittencourt

    2012-04-01

    Full Text Available We demonstrate that near-edge X-ray-absorption fine-structure spectra combined with full-field transmission X-ray microscopy can be used to study the electronic structure of graphite flakes consisting of a few graphene layers. The flake was produced by exfoliation using sodium cholate and then isolated by means of density-gradient ultracentrifugation. An image sequence around the carbon K-edge, analyzed by using reference spectra for the in-plane and out-of-plane regions of the sample, is used to map and spectrally characterize the flat and folded regions of the flake. Additional spectral features in both π and σ regions are observed, which may be related to the presence of topological defects. Doping by metal impurities that were present in the original exfoliated graphite is indicated by the presence of a pre-edge signal at 284.2 eV.

  18. Crystal-field and covalency effects in uranates: an X-ray spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Butorin, Sergei M. [Molecular and Condensed Matter Physics, Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Kvashnina, Kristina O. [European Synchrotron Radiation Facility, CS40220, Grenoble (France); Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Dresden (Germany); Smith, Anna L. [Department of Radiation Science and Technology, TU Delft (Netherlands); Popa, Karin [European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe (Germany); Martin, Philippe M. [CEA Marcoule, CEA, DEN, DTEC/SECA/LCC, Bagnols-sur-Ceze (France)

    2016-07-04

    The electronic structure of U{sup V}- and U{sup VI}-containing uranates NaUO{sub 3} and Pb{sub 3}UO{sub 6} was studied by using an advanced technique, namely X-ray absorption spectroscopy (XAS) in high-energy-resolution fluorescence-detection (HERFD) mode. Due to a significant reduction in core-hole lifetime broadening, the crystal-field splittings of the 5f shell were probed directly in HERFD-XAS spectra collected at the U 3d edge, which is not possible by using conventional XAS. In addition, the charge-transfer satellites that result from U 5f-O 2p hybridization were clearly resolved. The crystal-field parameters, 5f occupancy, and degree of covalency of the chemical bonding in these uranates were estimated by using the Anderson impurity model by calculating the U 3d HERFD-XAS, conventional XAS, core-to-core (U 4f-3d transitions) resonant inelastic X-ray scattering (RIXS), and U 4f X-ray photoelectron spectra. The crystal field was found to be strong in these systems and the 5f occupancy was determined to be 1.32 and 0.84 electrons in the ground state for NaUO{sub 3} and Pb{sub 3}UO{sub 6}, respectively, which indicates a significant covalent character for these compounds. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Design of Magnetic Shielding and Field Coils for a TES X-Ray Microcalorimeter Test Platform

    Science.gov (United States)

    Miniussi, Antoine R.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron M.; Doriese, William B.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; hide

    2017-01-01

    The performance of Transition-Edge Sensors (TES) and their SQUID multiplexed read-outs are very sensitive to the ambient magnetic field from Earth and fluctuations that can arise due to fluctuating magnetic fields outside of the focal plane assembly from the Adiabatic Demagnetization Refrigerator (ADR).Thus, the experimental platform we are building to test the FPA of the X-ray Integral Field Unit (X-IFU) of the Athena mission needs to include a series of shields and a coil in order to meet the following requirement of magnetic field density and uniformity.

  20. Flexible Field Emitter for X-ray Generation by Implanting CNTs into Nickel Foil

    Science.gov (United States)

    Sun, Bin; Wang, Yan; Ding, Guifu

    2016-09-01

    This paper reports on a flexible Ni micro wire with CNTs embedded into its surface. By using micromachining technology, for the first time, we could implant nanoscale materials into micro-scale metal substrate at room temperature. Thanks to the effective direct contact and the strong interactions between CNTs and the substrate, field emission current of 1.11 mA (current density of 22.2 mA/cm2) could be achieved from the micro wire. Moreover, the wire shows excellent mechanical properties for large amplitude bending, which is beneficial for geometric designing. To check the practical application of the wire, a simplified X-ray imaging system was set up by modifying a conventional tube. The gray shade that appears on the sensitive film after being exposed to the radiation confirms the X-ray generation.

  1. X-ray studies of neutron stars and their magnetic fields

    Science.gov (United States)

    MAKISHIMA, Kazuo

    2016-01-01

    Utilizing results obtained over the past quarter century mainly with Japanese X-ray astronomy satellites, a review is given to some aspects of neutron stars (NSs), with a particular emphasis on the magnetic fields (MFs) of mass-accreting NSs and magnetars. Measurements of electron cyclotron resonance features in binary X-ray pulsars, using the Ginga and Suzaku observatories, clarified that their surface MFs are concentrated in a narrow range of (1–7) × 108 T. Extensive studies of magnetars with Suzaku reinforced their nature as neutron stars with truly strong MFs, and revealed several important clues to their formation, evolution, and physical states. Taking all these results into account, a discussion is made on the origin and evolution of these strong MFs. One possible scenario is that the MF of NSs is a manifestation of some fundamental physics, e.g., neutron spin alignment or chirality violation, and the MF makes transitions from strong to weak states. PMID:27169348

  2. X-ray studies of neutron stars and their magnetic fields.

    Science.gov (United States)

    Makishima, Kazuo

    2016-01-01

    Utilizing results obtained over the past quarter century mainly with Japanese X-ray astronomy satellites, a review is given to some aspects of neutron stars (NSs), with a particular emphasis on the magnetic fields (MFs) of mass-accreting NSs and magnetars. Measurements of electron cyclotron resonance features in binary X-ray pulsars, using the Ginga and Suzaku observatories, clarified that their surface MFs are concentrated in a narrow range of (1-7) × 10(8) T. Extensive studies of magnetars with Suzaku reinforced their nature as neutron stars with truly strong MFs, and revealed several important clues to their formation, evolution, and physical states. Taking all these results into account, a discussion is made on the origin and evolution of these strong MFs. One possible scenario is that the MF of NSs is a manifestation of some fundamental physics, e.g., neutron spin alignment or chirality violation, and the MF makes transitions from strong to weak states.

  3. Measurement of a wide-range of X-ray doses using specialty doped silica fibres

    Science.gov (United States)

    Abdul Sani, S. F.; Hammond, R.; Jafari, S. M.; Wahab, Norfadira; Amouzad Mahdiraji, G.; Siti Shafiqah, A. S.; Abdul Rashid, H. A.; Maah, M. J.; Aldousari, H.; Alkhorayef, M.; Alzimami, M.; Bradley, D. A.

    2017-08-01

    Using six types of tailor-made doped optical fibres, we carry out thermoluminescent (TL) studies of X-rays, investigating the TL yield for doses from 20 mGy through to 50 Gy. Dosimetric parameters were investigated for nominal 8 wt% Ge doped fibres that in two cases were co-doped, using B in one case and Br in the other. A comparative measurement of surface analysis has also been made for non-annealed and annealed capillary fibres, use being made of X-ray Photoelectron Spectroscopy (XPS) analysis. Comparison was made with the conventional TL phosphor LiF in the form of the proprietary product TLD-100, including dose response and glow curves investigated for X-rays generated at 60 kVp over a dose range from 2 cGy to 50 Gy. The energy response of the fibres was also performed for X-rays generated at peak accelerating potentials of 80 kVp, 140 kVp, 250 kVp and 6 MV photons for an absorbed dose of 2 Gy. Present results show the samples to be suitable for use as TL dosimeters, with good linearity of response and a simple glow curve (simple trap) distribution. It has been established that the TL performance of an irradiated fibre is not only influenced by radiation parameters such as energy, dose-rate and total dose but also the type of fibre.

  4. The Relation Between Magnetic Fields and X-ray Emission for Solar Microflares and Active Regions

    Science.gov (United States)

    Kirichenko, A. S.; Bogachev, S. A.

    2017-09-01

    We present the result of a comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we used the monochromatic MgXII Imaging Spectroheliometer (MISH), the Full-disk EUV Telescope (FET), and the Solar PHotometer in X-rays (SphinX) instruments onboard the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon CORONAS- Photon spacecraft because of their high sensitivity in soft X-rays. The peak flare flux (PFF) for solar microflares was found to depend on the strength of the magnetic field and on the total unsigned magnetic flux as a power-law function. In the spectral range 2.8 - 36.6 Å, which shows very little increase related to microflares, the power-law index of the relation between the X-ray flux and magnetic flux for active regions is 1.48 ±0.86, which is close to the value obtained previously by Pevtsov et al. ( Astrophys. J. 598, 1387, 2003) for different types of solar and stellar objects. In the spectral range 1 - 8 Å, the power-law indices for PFF(B) and PFF(Φ) for microflares are 3.87 ±2.16 and 3 ±1.6, respectively. We also make suggestions on the heating mechanisms in active regions and microflares under the assumption of loops with constant pressure and heating using the Rosner-Tucker-Vaiana scaling laws.

  5. Characterization of X-ray fields at the center for devices and radiological health

    Energy Technology Data Exchange (ETDEWEB)

    Cerra, F. [Center for Devices and Radiological Health, Rockville, MD (United States)

    1993-12-31

    This talk summarizes the process undertaken by the Center for Devices and Radiological Health (CDRH) for establishing reference x-ray fields in its accredited calibration laboratory. The main considerations and their effects on the calibration parameters are discussed. The characterization of fields may be broken down into two parts: (1) the initial setup of the calibration beam spectra and (2) the ongoing measurements and controls which ensure consistency of the reference fields. The methods employed by CDRH for both these stages and underlying considerations are presented. Uncertainties associated with the various parameters are discussed. Finally, the laboratory`s performance, as evidenced by ongoing measurement quality assurance results, is reported.

  6. Controlled X-ray pumping in a wide range of piezo-electric oscillation frequencies

    CERN Document Server

    Navasardyan, M A; Galoyan, K G

    1986-01-01

    In case of Laue diffraction the transmitted X-ray reflection in shown to be effectively controllable in the perfect quartz single crystal when it generates ultrasonic oscillations at the resonance frequency or in its vicinity. The maximum effective amplitude of applied sinusoidal oscillations is equal to 70 V. The pumping degree depends on the voltage amplitude. In this work monochromatic K subalpha sub 1 and K subalpha sub 2 molybdenum lines satisfying the thin crystal condition, mu t<=1, are used (mu is the linear absorption coefficient of the sample for the given wavelength and t is its thickness). The radiation was reflected from different planes such as (1011), (1011), (2022) etc. The complete pumping strongly restricts the structural factor possibilities in estimating the intensity of diffracted X-rays in case of considerable deformations in the bulk of perfect single crystal.

  7. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas.

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark

    2014-11-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10(4) T (100 Megagauss) over small volumes (∼10(-10)m(3)) at high plasma densities (∼10(28)m(-3)) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  8. Anisotropic X-Ray Dark-Field Tomography: A Continuous Model and its Discretization

    Science.gov (United States)

    Wieczorek, M.; Schaff, F.; Pfeiffer, F.; Lasser, T.

    2016-10-01

    The x-ray dark-field signal measured in grating interferometers is anisotropic, depending on both the beam direction and the grating orientation with respect to the sample. We present a novel general closed-form, continuous forward model of the anisotropic dark-field signal. Furthermore, we derive a discretization using spherical harmonics, leading to a large-scale linear inverse problem. We present first experimental results of a wooden sample, demonstrating marked advantages over previous results, in particular, the resolution of multiple scattering directions in one volume element.

  9. Flexible Field Emitter for X-ray Generation by Implanting CNTs into Nickel Foil

    Science.gov (United States)

    Sun, Bin; Wang, Yan; Ding, Guifu

    2016-07-01

    This paper reports a novel implanting micromachining technology. By using this method, for the first time, we could implant nano-scale materials into milli-scale metal substrates at room temperature. Ni-based flexible carbon nanotube (CNT) field emitters were fabricated by the novel micromachining method. By embedding CNT roots into Ni foil using polymer matrix as transfer media, effective direct contact between Ni and CNTs was achieved. As a result, our novel emitter shows relatively good field emission properties such as low turn-on field and good stability. Moreover, the emitter was highly flexible with preservation of the field emission properties. The excellent field emission characteristics attributed to the direct contact and the strong interactions between CNTs and the substrate. To check the practical application of the novel emitter, a simple X-ray imaging system was set up by modifying a traditional tube. The gray shadow that appears on the sensitive film after being exposed to the radiation confirms the successful generation of X-ray.

  10. Determination of the Crystallinity of Semicrystalline Poly(3-hexyl thiophene) by Means of Wide Angle X-Ray Scattering

    Science.gov (United States)

    Balko, Jens; Lohwasser, Ruth; Thelakkat, Mukundan; Sommer, Michael; Pascui, Ovidiu; Saalwaechter, Kay; Thurn-Albrecht, Thomas

    2013-03-01

    Poly(3-hexyl thiophene) (P3HT) is a common polymer semiconductor, often used as material or component in organic field effect transistors or solar cells. The crystallinity of this semicrystalline material is among other parameters governing the electronic mobility. However, at present there is no routine method available to determine an absolute value for the crystallinity, and the values given in the literature e.g. for the enthalpy of melting vary by a factor of three. Wide Angle X-Ray Scattering (WAXS) probes the crystals as well the amorphous parts of the sample. We present an approach for the determination of the crystallinity based on the evaluation of WAXS intensities at low scattering vectors emanating from the amorphous regions. The result is used for a calibration of the melting enthalpy (34 J/g) that can serve as a reference value for more convenient calorimetric techniques and compared to the results of recent NMR investigations. We discuss the crystallinity for a number of chemically well-defined samples, with different molecular weight and a typical commercial sample with broad molecular weight distribution. Despite the high crystallinities of 60 to 80% the crystallites exhibit a large amount of disorder.

  11. Modelling microscopic features of streamer encounters, electric fields, electron beams and X-ray bursts

    Science.gov (United States)

    Koehn, C.; Kochkin, P.; Ebert, U.

    2015-12-01

    Thunderstorms emit terrestrial gamma-ray flashes (TGFs), beams of photons with quantum energies ofup to 40 MeV. Likewise electric discharges in the laboratory, mimicing lightning on a small spatial andenergetic scale, emit X-rays whose energies are limited by the available potential difference betweenthe two electrodes. For a maximal available difference of 1 MV and a gap distance of 1 m between the twoelectrodes, we will present the energy and spatial distribution of generated X-rays.For that we have followed the motion of preaccelerated, monoenergetic and monodirectional electronbeams with energies between 100 keV and the maximal available energy of 1 MeV for different electricfield configurations using a particle Monte Carlo code. Omitting any field, we present the subsequent energy and spatial distribution of X-raysand analyse how the photon number depends on the initial electron energy. Fig. 1 shows the position and energy of photons generated by Bremsstrahlung after 0.3 ns by beams of 500 000 electrons with initial energies of 1 MeV moving in the zdirection in STP air. The electrons have generated electron avalanches and all have cooleddown and attached to oxygen after 0.3 ns. Every cross represents one photon projected onto the xz plane; the photon energies Eγ are color coded. We see that photons with energies of approx. 1 MeV can be produced and that the high-energy tail of X-rays is beamedtowards the direction of the initial electron beam whereas low-energy photons show a more isotropicbehaviour. Analysing the cross sections of photons interacting with air we conclude that photons travelseveral meters in air and can reach detectors several meters from the position of the discharge. Byestimating the electric field ahead of the discharge corona and by simulating the motion of electronbeams in these fields, we exclude that electrons travel as far as photons and disturb the measured X-raysignal.

  12. X-ray laser studies using plasmas created by optical field ionization

    Energy Technology Data Exchange (ETDEWEB)

    Krushelnick, K.M.; Tighe, W.; Suckewer, S.

    1995-01-01

    X-ray laser experiments involving the creation of fast recombining plasmas by optical field ionization of preformed targets were conducted. A nonlinear increase in the intensity of the 13.5nm Lyman-{alpha} line in Li III with the length of the target plasma was observed but only for distances less than the laser confocal parameter and for low plasma electron temperatures. Multiphoton pumping of resonant atomic transitions was also examined and the process of multiphoton ionization of FIII was found to be more probable than multiphoton excitation.

  13. A high-pressure vessel for X-ray diffraction experiments for liquids in a wide temperature range

    CERN Document Server

    Hosokawa, S

    2001-01-01

    An internally heated high-pressure vessel was developed for angle-dispersive X-ray scattering experiments on liquids at high-temperatures and high-pressures. It consists of a closed-end Al cylinder and a steel flange. Continuous windows made of Be cover a scattering angle range up to 55 deg. In combination with a single-crystal sapphire cell and a small heating system inside the vessel, we were able to carry out diffraction measurements for liquids in a wide temperature range up to 2000 K at high pressures up to 150 bars. Some of our recent X-ray scattering experiments using synchrotron radiation, such as inelastic scattering, high-energy elastic scattering, and anomalous scattering, are also reported.

  14. X-ray diffraction study with small- and wide-angle simultaneous measurement of polymorphic crystallization of triacylglycerols

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Satoru [Hiroshima Univ., Faculty of Applied Biological Science, Higashi-Hiroshima, Hiroshima (Japan)

    2002-01-01

    Polymorphism of triacylglycerols (TAGs) is an important phenomenon which influences the physical chemical properties of fats employed in foods, pharmaceuticals, cosmetics etc. In particular, precise analysis of kinetic properties of polymorphic crystallization is closely related to technical control of fat crystallization in confectionery and food industry. In the melt-mediated crystallization, which is one of the typical methods of crystallizing the more stable form for industrial use, the more stable form is induced by rapidly melting the less stable forms. Recently, X-ray diffraction spectroscopy using a synchrotron radiation source has been used in study of dynamic processes of polymorphic transformations of many TAGs. This approach has allowed us to gain a better understanding of the kinetics of processes occurring during the polymorphic crystallization and transformations of TAGs at the molecular level. In the present study, polymorphic crystallization of TAG has been examined with the time-resolved X-ray diffraction method with small- and wide-angle simultaneous measurement using synchrotron radiation. The main result is as follows: the melt mediation gave rise to the formation of a liquid crystalline structure having long spacing values of 5.1 nm and 4.6 nm in SOS (sn-1,3-distearoyl-2-oleoyl glycerol). Consequently, the use of the time-resolved X-ray diffraction method with small- and wide-angle simultaneous measurement using synchrotron radiation unveiled quite newer aspects of the polymorphic crystallization of the triacylglycerols from neat liquid, which were not detectable in conventional XRD techniques. (author)

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

    Science.gov (United States)

    Barret, Didier; Lam Trong, Thien; den Herder, Jan-Willem; Piro, Luigi; Barcons, Xavier; Huovelin, Juhani; Kelley, Richard; Mas-Hesse, J. Miguel; Mitsuda, Kazuhisa; Paltani, Stéphane; Rauw, Gregor; RoŻanska, Agata; Wilms, Joern; Barbera, Marco; Bozzo, Enrico; Ceballos, Maria Teresa; Charles, Ivan; Decourchelle, Anne; den Hartog, Roland; Duval, Jean-Marc; Fiore, Fabrizio; Gatti, Flavio; Goldwurm, Andrea; Jackson, Brian; Jonker, Peter; Kilbourne, Caroline; Macculi, Claudio; Mendez, Mariano; Molendi, Silvano; Orleanski, Piotr; Pajot, François; Pointecouteau, Etienne; Porter, Frederick; Pratt, Gabriel W.; Prêle, Damien; Ravera, Laurent; Renotte, Etienne; Schaye, Joop; Shinozaki, Keisuke; Valenziano, Luca; Vink, Jacco; Webb, Natalie; Yamasaki, Noriko; Delcelier-Douchin, Françoise; Le Du, Michel; Mesnager, Jean-Michel; Pradines, Alice; Branduardi-Raymont, Graziella; Dadina, Mauro; Finoguenov, Alexis; Fukazawa, Yasushi; Janiuk, Agnieszka; Miller, Jon; Nazé, Yaël.; Nicastro, Fabrizio; Sciortino, Salvatore; Torrejon, Jose Miguel; Geoffray, Hervé; Hernandez, Isabelle; Luno, Laure; Peille, Philippe; André, Jérôme; Daniel, Christophe; Etcheverry, Christophe; Gloaguen, Emilie; Hassin, Jérémie; Hervet, Gilles; Maussang, Irwin; Moueza, Jérôme; Paillet, Alexis; Vella, Bruno; Campos Garrido, Gonzalo; Damery, Jean-Charles; Panem, Chantal; Panh, Johan; Bandler, Simon; Biffi, Jean-Marc; Boyce, Kevin; Clénet, Antoine; DiPirro, Michael; Jamotton, Pierre; Lotti, Simone; Schwander, Denis; Smith, Stephen; van Leeuwen, Bert-Joost; van Weers, Henk; Brand, Thorsten; Cobo, Beatriz; Dauser, Thomas; de Plaa, Jelle; Cucchetti, Edoardo

    2016-07-01

    The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5" pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV up to 7 keV. In this paper, we first review the core scientific objectives of Athena, driving the main performance parameters of the X-IFU, namely the spectral resolution, the field of view, the effective area, the count rate capabilities, the instrumental background. We also illustrate the breakthrough potential of the X-IFU for some observatory science goals. Then we brie y describe the X-IFU design as defined at the time of the mission consolidation review concluded in May 2016, and report on its predicted performance. Finally, we discuss some options to improve the instrument performance while not increasing its complexity and resource demands (e.g. count rate capability, spectral resolution).

  16. Dynamic X-ray radiography reveals particle size and shape orientation fields during granular flow.

    Science.gov (United States)

    Guillard, François; Marks, Benjy; Einav, Itai

    2017-08-15

    When granular materials flow, the constituent particles segregate by size and align by shape. The impacts of these changes in fabric on the flow itself are not well understood, and thus novel non-invasive means are needed to observe the interior of the material. Here, we propose a new experimental technique using dynamic X-ray radiography to make such measurements possible. The technique is based on Fourier transformation to extract spatiotemporal fields of internal particle size and shape orientation distributions during flow, in addition to complementary measurements of velocity fields through image correlation. We show X-ray radiography captures the bulk flow properties, in contrast to optical methods which typically measure flow within boundary layers, as these are adjacent to any walls. Our results reveal the rich dynamic alignment of particles with respect to streamlines in the bulk during silo discharge, the understanding of which is critical to preventing destructive instabilities and undesirable clogging. The ideas developed in this paper are directly applicable to many other open questions in granular and soft matter systems, such as the evolution of size and shape distributions in foams and biological materials.

  17. Visualization of neonatal lung injury associated with mechanical ventilation using x-ray dark-field radiography

    Science.gov (United States)

    Yaroshenko, Andre; Pritzke, Tina; Koschlig, Markus; Kamgari, Nona; Willer, Konstantin; Gromann, Lukas; Auweter, Sigrid; Hellbach, Katharina; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz; Hilgendorff, Anne

    2016-04-01

    Mechanical ventilation (MV) and supplementation of oxygen-enriched gas, often needed in postnatal resuscitation procedures, are known to be main risk factors for impaired pulmonary development in the preterm and term neonates. Unfortunately, current imaging modalities lack in sensitivity for the detection of early stage lung injury. The present study reports a new imaging approach for diagnosis and staging of early lung injury induced by MV and hyperoxia in neonatal mice. The imaging method is based on the Talbot-Lau x-ray grating interferometry that makes it possible to quantify the x-ray small-angle scattering on the air-tissue interfaces. This so-called dark-field signal revealed increasing loss of x-ray small-angle scattering when comparing images of neonatal mice undergoing hyperoxia and MV-O2 with animals kept at room air. The changes in the dark field correlated well with histologic findings and provided superior differentiation than conventional x-ray imaging and lung function testing. The results suggest that x-ray dark-field radiography is a sensitive tool for assessing structural changes in the developing lung. In the future, with further technical developments x-ray dark-field imaging could be an important tool for earlier diagnosis and sensitive monitoring of lung injury in neonates requiring postnatal oxygen or ventilator therapy.

  18. Lung respiration motion modeling: a sparse motion field presentation method using biplane x-ray images

    Science.gov (United States)

    Chen, Dong; Xie, Hongzhi; Zhang, Shuyang; Gu, Lixu

    2017-10-01

    Respiration-introduced tumor location uncertainty is a challenge in the precise lung biopsy for lung lesions. Current statistical modeling approaches hardly capture the complex local respiratory motion information. In this study, we formulate a statistical respiratory motion model using biplane x-ray images to improve the accuracy of motion field estimation by efficiently preserving local motion details for specific patients. Given CT data sets of 18 healthy subjects at end-expiratory and end-inspiratory breathing phases, the respiratory motion field is constructed based on deformation vector fields which are extracted from these CT data sets, and a lung contour motion repository respiratory is generated dependent on displacements of boundary control points. By varying the sparse weight coefficients of the statistical sparse motion field presentation (SMFP) method, the newly-input motion field is approximately presented by a sparse linear combination of a subset of the motion repository. The SMFP method is employed twice in the coefficient optimization process. Finally, these non-zero coefficients are fine-tuned to maximize the similarity between the projection image of reconstructed volumetric images and the current x-ray image. We performed the proposed method for estimating respiratory motion field on ten subject datasets and compared the result with the PCA method. The maximum average target registration error of the PCA-based and the SMFP-based respiratory motion field estimation are 3.1(2.0) and 2.9(1.6) mm, respectively. The maximum average symmetric surface distance of two methods are 2.5(1.6) and 2.4(1.3) mm, respectively.

  19. Field control of single x-ray photons in nuclear forward scattering

    CERN Document Server

    Kong, Xiangjin; Pálffy, Adriana

    2013-01-01

    Means to coherently control single x-ray photons in resonant scattering of light off nuclei by electric or magnetic fields are investigated theoretically. In order to derive the time response in nuclear forward scattering, we adapt the Maxwell-Bloch equations known from quantum optics to describe the resonant light pulse propagation through a nuclear medium. Two types of time-dependent perturbations of nuclear forward scattering are considered for coherent control of the resonantly scattered x-ray quanta. First, the simultaneous coherent propagation of two pulses through the nuclear sample is addressed. We find that the signal of a weak pulse can be enhanced or suppressed by a stronger pulse simultaneously propagating through the sample in counter-propagating geometry. Second, the effect of a time-dependent hyperfine splitting is investigated and we put forward a scheme that allows parts of the spectrum to be shifted forward in time. This is the inverse effect of coherent photon storage and may become a valua...

  20. A new rabbit model of impaired wound healing in an X-ray-irradiated field.

    Directory of Open Access Journals (Sweden)

    Kazutoshi Fujita

    Full Text Available Radiation is an important therapy for cancer with many benefits; however, its side effects, such as impaired wound healing, are a major problem. While many attempts have been made to overcome this particular disadvantage, there are few effective treatments for impaired wound healing in an X-ray-irradiated field. One reason for this deficiency is the lack of experimental models, especially animal models. We have previously reported a mouse model of impaired wound healing in which the irradiation area was restricted to the hindlimbs. In this mouse model, due to the size of the animal, a diameter of five millimeters was considered the largest wound size suitable for the model. In addition, the transplanted cells had to be harvested from other inbred animals. To investigate larger wounds and the impact of autologous specimen delivery, a rabbit model was developed. Rabbits were kept in a special apparatus to shield the body and hindlimbs while the irradiation field was exposed to radiation. Six weeks after irradiation, a 2 x 2 cm, full-thickness skin defect was made inside the irradiation field. Then, the wound area was observed over time. The wound area after irradiation was larger than that without irradiation at all time points. Both angiogenesis and collagen formation were reduced. For further study, as an example of using this model, the effect of autologous platelet-rich plasma (PRP was observed. Autologous PRP from peripheral blood (pb-PRP and bone marrow aspirate (bm-PRP was processed and injected into the wounds in the irradiated field. Two weeks later, the wounds treated with bm-PRP were significantly smaller than those treated with phosphate buffer vehicle controls. In contrast, the wounds treated with pb-PRP were not significantly different from the controls. This rabbit model is useful for investigating the mechanism of impaired wound healing in an X-ray-irradiated field.

  1. 100-OL-1 Operable Unit Field Portable X-Ray Fluorescence (XRF) Analyzer Pilot Study Plans

    Energy Technology Data Exchange (ETDEWEB)

    Bunn, Amoret L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fritz, Brad G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wellman, Dawn M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-07-01

    A pilot study is being conducted to support the approval of the Remedial Investigation/Feasibility Study (RI/FS) Work Plan to evaluate the 100-OL-1 Operable Unit (OU) pre-Hanford orchard lands. Based on comments received by the U.S. Environmental Protection Agency (EPA) and Washington State Department of Ecology, the pilot study will evaluate the use of field portable X-ray fluorescence (XRF) spectrometry measurements for evaluating lead and arsenic concentrations on the soil surface as an indicator of past use of lead arsenate pesticide residue in the OU. The work will be performed in the field during the summer of 2014, and assist in the planning for the characterization activities in the RI/FS.

  2. Rapidly Rotating, X-Ray Bright Stars in the Kepler Field

    Science.gov (United States)

    Howell, Steve B.; Mason, Elena; Boyd, Patricia; Smith, Krista Lynne; Gelino, Dawn M.

    2016-01-01

    We present Kepler light curves and optical spectroscopy of twenty X-ray bright stars located in the Kepler field of view. The stars, spectral type F-K, show evidence for rapid rotation including chromospheric activity 100 times or more above the Sun at maximum and flaring behavior in their light curves. Eighteen of our objects appear to be (sub)giants and may belong to the class of FK Com variables, which are evolved rapidly spinning single stars with no excretion disk and high levels of chromospheric activity. Such stars are rare and are likely the result of W UMa binary mergers, a process believed to produce the FK Com class of variable and their descendants. The FK Com stage, including the presence of an excretion disk, is short lived but leads to longer-lived stages consisting of single, rapidly rotating evolved (sub)giants with high levels of stellar activity.

  3. Coherent x-ray optics

    CERN Document Server

    Paganin, David M

    2006-01-01

    'Coherent X-Ray Optics' gives a thorough treatment of the rapidly expanding field of coherent x-ray optics, which has recently experienced something of a renaissance with the availability of third-generation synchrotron sources.

  4. Structural properties of resonant electric and magnetic fields correlation with X-ray generation and MHD activity in tokamak

    Science.gov (United States)

    Salar Elahi, A.; Ghoranneviss, M.

    In this research we have investigated on a Runaway electron generation in IR-T1 tokamak. For this purpose we used the hard X-ray spectroscopy and magnetic diagnostic. Hard X-ray emission produces due to collision of the Runaway electrons with the plasma particles or tokamak limiters. Runaway electrons in tokamaks can cause serious damage to the first wall of the reactor and decrease its life time. Also, hard X-ray emission generated from high energy Runaway electrons lead to the plasma energy loss. Therefore, suggesting methods to minimize Runaway electrons in tokamaks are very important. Applying external resonant field is one of the methods for controlling the Magnetohydrodynamic (MHD) activity. Present study attempts to investigate the effects of limiter biasing and Resonant Helical magnetic Field (RHF) on the generation of Runaway electrons. For this purpose, plasma parameters such as plasma current, MHD oscillation, loop voltage, emitted hard X-ray intensity, Hα impurity, safety factor in the presence and absence of external fields, were measured. Frequency activity was investigated with FFT analysis. The results show that applying resonant fields can control the MHD activity, and then hard X-ray emitted from the Runaway electrons.

  5. First attempt of at-cavity cryogenic X-ray detection in a CEBAF cryomodule for field emission monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Daly, Edward [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Drury, Michael [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    We report on the first result of at-cavity X-ray detection in a CEBAF cryomodule for field emission monitoring. In the 8-cavity cryomodule F100, two silicon diodes were installed near the end flange of each cavity. Each cavity was individually tested during the cryomodule test in JLab’s cryomodule test facility. The behaviors of these at-cavity cryogenic X-ray detectors were compared with those of the standard ‘in air’ Geiger-Muller (G-M) tubes. Our initial experiments establish correlation between X-ray response of near diodes and the field emission source cavity in the 8-cavity string. For two out of these eight cavities, we also carried out at-cavity X-ray detection experiment during their vertical testing. The aim is to track field emission behavior uniquely from vertical cavity testing to horizontal cavity testing in the cryomodule. These preliminary results confirmed our expectation and warrant further effort toward the establishment of permanent at-cavity cryogenic X-ray detection for SRF development and operation.

  6. Classification of the micromorphology of breast calcifications in x-ray dark-field mammography

    Science.gov (United States)

    Willer, Konstantin; Scherer, Kai; Braig, Eva; Ehn, Sebastian; Schock, Jonathan; Wolf, Johannes; Birnbacher, Lorenz; Chabior, Michael; Mayr, Doris; Grandl, Susanne; Sztrókay-Gaul, Aniko; Hellerhof, Karin; Reiser, Maximilian; Pfeiffer, Franz; Herzen, Julia

    2017-03-01

    The distant goal of this investigation is to reduce the number of invasive procedures associated with breast micro calcification biopsies, by improving and refining conventional BIRADS micro calcification assessments with x-ray dark-field mammography. The study was institutional review board (IRB) approved. A dedicated grating-based radiography setup (Mo-target, 40 keV, 70 mA) was used to investigate one breast mastectomy and 31 biopsies with dark-field mammography. Comparing the absorption and scattering properties of micro calcifications clusters enables accessing information on the interior morphology on the micron-scale retrieved in a non-invasive manner. Insights underlying the micro morphological nature of breast calcifications were verified by comprehensive high-resolution micro-CT measurements. It was found that Dark-field mammography allows a micro-structural classification of breast micro calcification as ultra-fine, fine, pleomorphic and coarse textured using conventional detectors. Dark-field mammography is thereby highly sensitive to minor structural deviations. Finally, the determined micro-texture of the investigated micro calcifications was correlated with findings obtained from histopathological work up. The presented results demonstrate that dark-field mammography yields the potential to enhance diagnostic validity of current micro calcification analysis - which is yet limited to the exterior appearance of micro calcification clusters - and thereby reduce the number of invasive procedures.

  7. X-ray lasers

    CERN Document Server

    Elton, Raymond C

    2012-01-01

    The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

  8. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... x-rays. top of page What does the equipment look like? The equipment typically used for bone x-rays consists of ... and joint abnormalities, such as arthritis. X-ray equipment is relatively inexpensive and widely available in emergency ...

  9. X-ray Nanodiffraction on a Single SiGe Quantum Dot inside a Functioning Field-Effect Transistor

    Science.gov (United States)

    2011-01-01

    For advanced electronic, optoelectronic, or mechanical nanoscale devices a detailed understanding of their structural properties and in particular the strain state within their active region is of utmost importance. We demonstrate that X-ray nanodiffraction represents an excellent tool to investigate the internal structure of such devices in a nondestructive way by using a focused synchotron X-ray beam with a diameter of 400 nm. We show results on the strain fields in and around a single SiGe island, which serves as stressor for the Si-channel in a fully functioning Si–metal–oxide semiconductor field-effect transistor. PMID:21627099

  10. Reconstruction of the near-field distribution in an X-ray waveguide array.

    Science.gov (United States)

    Zhong, Qi; Melchior, Lars; Peng, Jichang; Huang, Qiushi; Wang, Zhanshan; Salditt, Tim

    2017-06-01

    Iterative phase retrieval has been used to reconstruct the near-field distribution behind tailored X-ray waveguide arrays, by inversion of the measured far-field pattern recorded under fully coherent conditions. It is thereby shown that multi-waveguide interference can be exploited to control the near-field distribution behind the waveguide exit. This can, for example, serve to create a secondary quasi-focal spot outside the waveguide structure. For this proof of concept, an array of seven planar Ni/C waveguides are used, with precisely varied guiding layer thickness and cladding layer thickness, as fabricated by high-precision magnetron sputtering systems. The controlled thickness variations in the range of 0.2 nm results in a desired phase shift of the different waveguide beams. Two kinds of samples, a one-dimensional waveguide array and periodic waveguide multilayers, were fabricated, each consisting of seven C layers as guiding layers and eight Ni layers as cladding layers. These are shown to yield distinctly different near-field patterns.

  11. Development of an expanded-field irradiation technique using a gimbaled x-ray head

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Tomohiro; Miyabe, Yuki, E-mail: miyabe@kuhp.kyoto-u.ac.jp; Yamada, Masahiro; Yokota, Kenji; Kaneko, Shuji; Monzen, Hajime; Mizowaki, Takashi; Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Sawada, Akira [Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Kyoto 622-0041 (Japan); Kokubo, Masaki [Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan and Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe 650-0047 (Japan)

    2014-10-15

    Purpose: The Vero4DRT has a maximum field size of 150.0 × 150.0 mm. The purpose of the present study was to develop expanded-field irradiation techniques using the unique gimbaled x-ray head of the Vero4DRT and to evaluate the dosimetric characteristics thereof. Methods: Two techniques were developed. One features gimbal swing irradiation and multiple static segments consisting of four separate fields exhibiting 2.39° gimbal rotation around two orthogonal axes. The central beam axis for each piecewise-field is shifted 40 mm from the isocenters of the left–right (LR) and superior–inferior (SI) directions, and, thus, the irradiation field size is expanded to 230.8 × 230.8 mm. Adjacent regions were created at the isocenter (a center-adjacent expandedfield) and 20 mm from the isocenter (an off-adjacent expandedfield). The field gaps or overlaps of combined piecewise-fields were established by adjustment of gimbal rotation and movement of the multileaf collimator (MLC). Another technique features dynamic segment irradiation in which the beam is delivered while rotating the gimbal. The dose profile is controlled by a combination of gimbal swing motion and opening and closing of the MLC. This enabled the authors to expand the irradiation field on the LR axis because the direction of MLC motion is parallel to that axis. A field 220.6 × 150.0 mm in dimensions was configured and examined. To evaluate the dosimetric characteristics of the expandedfields, films inserted into water-equivalent phantoms at depths of 50, 100, and 150 mm were irradiated and field sizes, penumbrae, flatness, and symmetry analyzed. In addition, the expanded-field irradiation techniques were applied to intensity-modulated radiation therapy (IMRT). A head-and-neck IMRT field, created using a conventional Linac (the Varian Clinac iX), was reproduced employing an expanded-field of the Vero4DRT. The simulated dose distribution for the expanded-IMRT field was compared to the measured

  12. Development of an expanded-field irradiation technique using a gimbaled x-ray head.

    Science.gov (United States)

    Ono, Tomohiro; Miyabe, Yuki; Yamada, Masahiro; Yokota, Kenji; Kaneko, Shuji; Sawada, Akira; Monzen, Hajime; Mizowaki, Takashi; Kokubo, Masaki; Hiraoka, Masahiro

    2014-10-01

    The Vero4DRT has a maximum field size of 150.0 × 150.0 mm. The purpose of the present study was to develop expanded-field irradiation techniques using the unique gimbaled x-ray head of the Vero4DRT and to evaluate the dosimetric characteristics thereof. Two techniques were developed. One features gimbal swing irradiation and multiple static segments consisting of four separate fields exhibiting 2.39° gimbal rotation around two orthogonal axes. The central beam axis for each piecewise-field is shifted 40 mm from the isocenters of the left-right (LR) and superior-inferior (SI) directions, and, thus, the irradiation field size is expanded to 230.8 × 230.8 mm. Adjacent regions were created at the isocenter (a center-adjacent expandedfield) and 20 mm from the isocenter (an off-adjacent expandedfield). The field gaps or overlaps of combined piecewise-fields were established by adjustment of gimbal rotation and movement of the multileaf collimator (MLC). Another technique features dynamic segment irradiation in which the beam is delivered while rotating the gimbal. The dose profile is controlled by a combination of gimbal swing motion and opening and closing of the MLC. This enabled the authors to expand the irradiation field on the LR axis because the direction of MLC motion is parallel to that axis. A field 220.6 × 150.0 mm in dimensions was configured and examined. To evaluate the dosimetric characteristics of the expandedfields, films inserted into water-equivalent phantoms at depths of 50, 100, and 150 mm were irradiated and field sizes, penumbrae, flatness, and symmetry analyzed. In addition, the expanded-field irradiation techniques were applied to intensity-modulated radiation therapy (IMRT). A head-and-neck IMRT field, created using a conventional Linac (the Varian Clinac iX), was reproduced employing an expanded-field of the Vero4DRT. The simulated dose distribution for the expanded-IMRT field was compared to the measured dose distribution. The

  13. Increasing the field of view in grating based X-ray phase contrast imaging using stitched gratings.

    Science.gov (United States)

    Meiser, J; Willner, M; Schröter, T; Hofmann, A; Rieger, J; Koch, F; Birnbacher, L; Schüttler, M; Kunka, D; Meyer, P; Faisal, A; Amberger, M; Duttenhofer, T; Weber, T; Hipp, A; Ehn, S; Walter, M; Herzen, J; Schulz, J; Pfeiffer, F; Mohr, J

    2016-03-17

    Grating based X-ray differential phase contrast imaging (DPCI) allows for high contrast imaging of materials with similar absorption characteristics. In the last years' publications, small animals or parts of the human body like breast, hand, joints or blood vessels have been studied. Larger objects could not be investigated due to the restricted field of view limited by the available grating area. In this paper, we report on a new stitching method to increase the grating area significantly: individual gratings are merged on a carrier substrate. Whereas the grating fabrication process is based on the LIGA technology (X-ray lithography and electroplating) different cutting and joining methods have been evaluated. First imaging results using a 2×2 stitched analyzer grating in a Talbot-Lau interferometer have been generated using a conventional polychromatic X-ray source. The image quality and analysis confirm the high potential of the stitching method to increase the field of view considerably.

  14. Simulations of x-ray speckle-based dark-field and phase-contrast imaging with a polychromatic beam

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine, E-mail: marie-christine.zdora@diamond.ac.uk [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2015-09-21

    Following the first experimental demonstration of x-ray speckle-based multimodal imaging using a polychromatic beam [I. Zanette et al., Phys. Rev. Lett. 112(25), 253903 (2014)], we present a simulation study on the effects of a polychromatic x-ray spectrum on the performance of this technique. We observe that the contrast of the near-field speckles is only mildly influenced by the bandwidth of the energy spectrum. Moreover, using a homogeneous object with simple geometry, we characterize the beam hardening artifacts in the reconstructed transmission and refraction angle images, and we describe how the beam hardening also affects the dark-field signal provided by speckle tracking. This study is particularly important for further implementations and developments of coherent speckle-based techniques at laboratory x-ray sources.

  15. In-vivo dark-field and phase-contrast x-ray imaging.

    Science.gov (United States)

    Bech, M; Tapfer, A; Velroyen, A; Yaroshenko, A; Pauwels, B; Hostens, J; Bruyndonckx, P; Sasov, A; Pfeiffer, F

    2013-11-13

    Novel radiography approaches based on the wave nature of x-rays when propagating through matter have a great potential for improved future x-ray diagnostics in the clinics. Here, we present a significant milestone in this imaging method: in-vivo multi-contrast x-ray imaging of a mouse using a compact scanner. Of particular interest is the enhanced contrast in regions related to the respiratory system, indicating a possible application in diagnosis of lung diseases (e.g. emphysema).

  16. Experimental evaluation of dual multiple aperture devices for fluence field modulated x-ray computed tomography

    Science.gov (United States)

    Mathews, A. J.; Gang, G.; Levinson, R.; Zbijewski, W.; Kawamoto, S.; Siewerdsen, J. H.; Stayman, J. W.

    2017-03-01

    Acquisition of CT images with comparable diagnostic power can potentially be achieved with lower radiation exposure than the current standard of care through the adoption of hardware-based fluence-field modulation (e.g. dynamic bowtie filters). While modern CT scanners employ elements such as static bowtie filters and tube-current modulation, such solutions are limited in the fluence patterns that they can achieve, and thus are limited in their ability to adapt to broad classes of patient morphology. Fluence-field modulation also enables new applications such as region-of-interest imaging, task specific imaging, reducing measurement noise or improving image quality. The work presented in this paper leverages a novel fluence modulation strategy that uses "Multiple Aperture Devices" (MADs) which are, in essence, binary filters, blocking or passing x-rays on a fine scale. Utilizing two MAD devices in series provides the capability of generating a large number of fluence patterns via small relative motions between the MAD filters. We present the first experimental evaluation of fluence-field modulation using a dual-MAD system, and demonstrate the efficacy of this technique with a characterization of achievable fluence patterns and an investigation of experimental projection data.

  17. Observation and theory of X-ray mirages.

    Science.gov (United States)

    Magnitskiy, Sergey; Nagorskiy, Nikolay; Faenov, Anatoly; Pikuz, Tatiana; Tanaka, Mamoko; Ishino, Masahiko; Nishikino, Masaharu; Fukuda, Yuji; Kando, Masaki; Kawachi, Tetsuya; Kato, Yoshiaki

    2013-01-01

    The advent of X-ray lasers allowed the realization of compact coherent soft X-ray sources, thus opening the way to a wide range of applications. Here we report the observation of unexpected concentric rings in the far-field beam profile at the output of a two-stage plasma-based X-ray laser, which can be considered as the first manifestation of a mirage phenomenon in X-rays. We have developed a method of solving the Maxwell-Bloch equations for this problem, and find that the experimentally observed phenomenon is due to the emergence of X-ray mirages in the plasma amplifier, appearing as phase-matched coherent virtual point sources. The obtained results bring a new insight into the physical nature of amplification of X-ray radiation in laser-induced plasma amplifiers and open additional opportunities for X-ray plasma diagnostics and extreme ultraviolet lithography.

  18. Development of an alternating magnetic-field-assisted finishing process for microelectromechanical systems micropore x-ray optics.

    Science.gov (United States)

    Riveros, Raul E; Yamaguchi, Hitomi; Mitsuishi, Ikuyuki; Takagi, Utako; Ezoe, Yuichiro; Kato, Fumiki; Sugiyama, Susumu; Yamasaki, Noriko; Mitsuda, Kazuhisa

    2010-06-20

    X-ray astronomy research is often limited by the size, weight, complexity, and cost of functioning x-ray optics. Micropore optics promises an economical alternative to traditional (e.g., glass or foil) x-ray optics; however, many manufacturing difficulties prevent micropore optics from being a viable solution. Ezoe et al. introduced microelectromechanical systems (MEMS) micropore optics having curvilinear micropores in 2008. Made by either deep reactive ion etching or x-ray lithography, electroforming, and molding (LIGA), MEMS micropore optics suffer from high micropore sidewall roughness (10-30nmrms) which, by current standards, cannot be improved. In this research, a new alternating magnetic-field-assisted finishing process was developed using a mixture of ferrofluid and microscale abrasive slurry. A machine was built, and a set of working process parameters including alternating frequency, abrasive size, and polishing time was selected. A polishing experiment on a LIGA-fabricated MEMS micropore optic was performed, and a change in micropore sidewall roughness of 9.3+/-2.5nmrms to 5.7+/-0.7nmrms was measured. An improvement in x-ray reflectance was also seen. This research shows the feasibility and confirms the effects of this new polishing process on MEMS micropore optics.

  19. Improved In vivo Assessment of Pulmonary Fibrosis in Mice using X-Ray Dark-Field Radiography

    Science.gov (United States)

    Yaroshenko, Andre; Hellbach, Katharina; Yildirim, Ali Önder; Conlon, Thomas M.; Fernandez, Isis Enlil; Bech, Martin; Velroyen, Astrid; Meinel, Felix G.; Auweter, Sigrid; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz

    2015-12-01

    Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with a median life expectancy of 4-5 years after initial diagnosis. Early diagnosis and accurate monitoring of IPF are limited by a lack of sensitive imaging techniques that are able to visualize early fibrotic changes at the epithelial-mesenchymal interface. Here, we report a new x-ray imaging approach that directly visualizes the air-tissue interfaces in mice in vivo. This imaging method is based on the detection of small-angle x-ray scattering that occurs at the air-tissue interfaces in the lung. Small-angle scattering is detected with a Talbot-Lau interferometer, which provides the so-called x-ray dark-field signal. Using this imaging modality, we demonstrate-for the first time-the quantification of early pathogenic changes and their correlation with histological changes, as assessed by stereological morphometry. The presented radiography method is significantly more sensitive in detecting morphological changes compared with conventional x-ray imaging, and exhibits a significantly lower radiation dose than conventional x-ray CT. As a result of the improved imaging sensitivity, this new imaging modality could be used in future to reduce the number of animals required for pulmonary research studies.

  20. A case for ZnO nanowire field emitter arrays in advanced x-ray source applications

    Science.gov (United States)

    Robinson, Vance S.; Bergkvist, Magnus; Chen, Daokun; Chen, Jun; Huang, Mengbing

    2016-09-01

    Reviewing current efforts in X-ray source miniaturization reveals a broad spectrum of applications: Portable and/or remote nondestructive evaluation, high throughput protein crystallography, invasive radiotherapy, monitoring fluid flow and particulate generation in situ, and portable radiography devices for battle-front or large scale disaster triage scenarios. For the most part, all of these applications are being addressed with a top-down approach aimed at improving portability, weight and size. That is, the existing system or a critical sub-component is shrunk in some manner in order to miniaturize the overall package. In parallel to top-down x-ray source miniaturization, more recent efforts leverage field emission and semiconductor device fabrication techniques to achieve small scale x-ray sources via a bottom-up approach where phenomena effective at a micro/nanoscale are coordinated for macro-scale effect. The bottom-up approach holds potential to address all the applications previously mentioned but its entitlement extends into new applications with much more ground-breaking potential. One such bottom-up application is the distributed x-ray source platform. In the medical space, using an array of microscale x-ray sources instead of a single source promises significant reductions in patient dose as well as smaller feature detectability and fewer image artifacts. Cold cathode field emitters are ideal for this application because they can be gated electrostatically or via photonic excitation, they do not generate excessive heat like other common electron emitters, they have higher brightness and they are relatively compact. This document describes how ZnO nanowire field emitter arrays are well suited for distributed x-ray source applications because they hold promise in each of the following critical areas: emission stability, simple scalable fabrication, performance, radiation resistance and photonic coupling.

  1. Development of concave-convex imaging mirror system for a compact and achromatic full-field x-ray microscope

    Science.gov (United States)

    Yamada, Jumpei; Matsuyama, Satoshi; Yasuda, Shuhei; Sano, Yasuhisa; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-08-01

    A full-field X-ray microscope utilizing advanced Kirkpatrick-Baez optics, which comprises four concave mirrors, provides high-resolution X-ray images without chromatic aberration. However, a large distance is required between the mirrors and the detector to obtain sufficiently high magnification factor. To achieve reduce this distance, this paper proposes a novel X-ray imaging mirror system consisting of two pairs of concave and convex mirrors, which enables the effective focal length to be decreased by shifting the principal surface. For developing the proposed optics, the mirrors were fabricated with an ion beam figuring system and stitching interferometer, developed by our group, with a peak-to-valley accuracy of 2 nm. Analysis results indicate that the fabricated mirrors can achieve nearly diffraction-limited imaging performance. We report the mirror fabrication results and the characteristics of the fabricated mirrors.

  2. Low-temperature high magnetic field powder x-ray diffraction setup for field-induced structural phase transition studies from 2 to 300 K and at 0 to 8-T field

    Science.gov (United States)

    Shahee, Aga; Sharma, Shivani; Kumar, Dhirendra; Yadav, Poonam; Bhardwaj, Preeti; Ghodke, Nandkishor; Singh, Kiran; Lalla, N. P.; Chaddah, P.

    2016-10-01

    A low-temperature and high magnetic field powder x-ray diffractometer (XRD) has been developed at UGC-DAE CSR (UGC: University Grant Commission, DAE: Department of Atomic Energy, and CSR: Consortium for scientific research), Indore, India. The setup has been developed around an 18 kW rotating anode x-ray source delivering Cu-Kα x-rays coming from a vertical line source. It works in a symmetric θ-2θ parallel beam geometry. It consists of a liquid helium cryostat with an 8 T split-pair Nb-Ti superconducting magnet comprising two x-ray windows each covering an angular range of 65°. This is mounted on a non-magnetic type heavy duty goniometer equipped with all necessary motions along with data collection accessories. The incident x-ray beam has been made parallel using a parabolic multilayer mirror. The scattered x-ray is detected using a NaI detector through a 0.1° acceptance solar collimator. To control the motions of the goniometer, a computer programme has been developed. The wide-angle scattering data can be collected in a range of 2°-115° of 2θ with a resolution of ˜0.1°. The whole setup is tightly shielded for the scattered x-rays using a lead hutch. The functioning of the goniometer and the artifacts arising possibly due to the effect of stray magnetic field on the goniometer motions, on the x-ray source, and on the detector have been characterized by collecting powder XRD data of a National Institute of Standards and Technology certified standard reference material LaB6 (SRM-660b) and Si powder in zero-field and in-field conditions. Occurrence of field induced structural-phase transitions has been demonstrated on various samples like Pr0.5Sr0.5MnO3, Nd0.49Sr0.51MnO3-δ and La0.175Pr0.45Ca0.375MnO3 by collecting data in zero field cool and field cool conditions.

  3. Low-temperature high magnetic field powder x-ray diffraction setup for field-induced structural phase transition studies from 2 to 300 K and at 0 to 8-T field.

    Science.gov (United States)

    Shahee, Aga; Sharma, Shivani; Kumar, Dhirendra; Yadav, Poonam; Bhardwaj, Preeti; Ghodke, Nandkishor; Singh, Kiran; Lalla, N P; Chaddah, P

    2016-10-01

    A low-temperature and high magnetic field powder x-ray diffractometer (XRD) has been developed at UGC-DAE CSR (UGC: University Grant Commission, DAE: Department of Atomic Energy, and CSR: Consortium for scientific research), Indore, India. The setup has been developed around an 18 kW rotating anode x-ray source delivering Cu-Kα x-rays coming from a vertical line source. It works in a symmetric θ-2θ parallel beam geometry. It consists of a liquid helium cryostat with an 8 T split-pair Nb-Ti superconducting magnet comprising two x-ray windows each covering an angular range of 65°. This is mounted on a non-magnetic type heavy duty goniometer equipped with all necessary motions along with data collection accessories. The incident x-ray beam has been made parallel using a parabolic multilayer mirror. The scattered x-ray is detected using a NaI detector through a 0.1° acceptance solar collimator. To control the motions of the goniometer, a computer programme has been developed. The wide-angle scattering data can be collected in a range of 2°-115° of 2θ with a resolution of ∼0.1°. The whole setup is tightly shielded for the scattered x-rays using a lead hutch. The functioning of the goniometer and the artifacts arising possibly due to the effect of stray magnetic field on the goniometer motions, on the x-ray source, and on the detector have been characterized by collecting powder XRD data of a National Institute of Standards and Technology certified standard reference material LaB6 (SRM-660b) and Si powder in zero-field and in-field conditions. Occurrence of field induced structural-phase transitions has been demonstrated on various samples like Pr0.5Sr0.5MnO3, Nd0.49Sr0.51MnO3-δ and La0.175Pr0.45Ca0.375MnO3 by collecting data in zero field cool and field cool conditions.

  4. Time-Resolving Study of Stress-Induced Transformations of Isotactic Polypropylene through Wide Angle X-ray Scattering Measurements

    Directory of Open Access Journals (Sweden)

    Finizia Auriemma

    2018-02-01

    Full Text Available The development of a highly oriented fiber morphology by effect of tensile deformation of stereodefective isotactic polypropylene (iPP samples, starting from the unoriented γ form, is studied by following the transformation in real time during stretching through wide angle X-ray scattering (WAXS measurements. In the stretching process, after yielding, the initial γ form transforms into the mesomorphic form of iPP through mechanical melting and re-crystallization. The analysis of the scattering invariant measured in the WAXS region highlights that the size of the mesomorphic domains included in the well oriented fiber morphology obtained at high deformations increases through a process which involves the coalescence of the small fragments formed by effect of tensile stress during lamellar destruction with the domain of higher dimensions.

  5. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids

    Science.gov (United States)

    Nguyen, Hung T.; Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois; Case, David A.

    2014-12-01

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb+ and Sr2+) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein-Zernike equations, with results from the Kovalenko-Hirata closure being closest to experiment for the cases studied here.

  6. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids.

    Science.gov (United States)

    Nguyen, Hung T; Pabit, Suzette A; Meisburger, Steve P; Pollack, Lois; Case, David A

    2014-12-14

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb(+) and Sr(2+)) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein-Zernike equations, with results from the Kovalenko-Hirata closure being closest to experiment for the cases studied here.

  7. First experiences with in-vivo x-ray dark-field imaging of lung cancer in mice

    Science.gov (United States)

    Gromann, Lukas B.; Scherer, Kai; Yaroshenko, Andre; Bölükbas, Deniz A.; Hellbach, Katharina; Meinel, Felix G.; Braunagel, Margarita; Eickelberg, Oliver; Reiser, Maximilian F.; Pfeiffer, Franz; Meiners, Silke; Herzen, Julia

    2017-03-01

    Purpose: The purpose of the present study was to evaluate if x-ray dark-field imaging can help to visualize lung cancer in mice. Materials and Methods: The experiments were performed using mutant mice with high-grade adenocarcinomas. Eight animals with pulmonary carcinoma and eight control animals were imaged in radiography mode using a prototype small-animal x-ray dark-field scanner and three of the cancerous ones additionally in CT mode. After imaging, the lungs were harvested for histological analysis. To determine their diagnostic value, x-ray dark-field and conventional attenuation images were analyzed by three experienced readers in a blind assessment. Results radiographic imaging: The lung nodules were much clearer visualized on the dark-field radiographs compared to conventional radiographs. The loss of air-tissue interfaces in the tumor leads to a significant loss of x-ray scattering, reflected in a strong dark-field signal change. The difference between tumor and healthy tissue in terms of x-ray attenuation is significantly less pronounced. Furthermore, the signal from the overlaying structures on conventional radiographs complicates the detection of pulmonary carcinoma. Results CT imaging: The very first in-vivo CT-imaging results are quite promising as smaller tumors are often better visible in the dark-field images. However the imaging quality is still quite low, especially in the attenuation images due to un-optimized scanning parameters. Conclusion: We found a superior diagnostic performance of dark-field imaging compared to conventional attenuation based imaging, especially when it comes to the detection of small lung nodules. These results support the motivation to further develop this technique and translate it towards a clinical environment.

  8. Large field-of-view tiled grating structures for X-ray phase-contrast imaging

    Science.gov (United States)

    Schröter, Tobias J.; Koch, Frieder J.; Meyer, Pascal; Kunka, Danays; Meiser, Jan; Willer, Konstantin; Gromann, Lukas; Marco, Fabio D.; Herzen, Julia; Noel, Peter; Yaroshenko, Andre; Hofmann, Andreas; Pfeiffer, Franz; Mohr, Jürgen

    2017-01-01

    X-ray grating-based interferometry promises unique new diagnostic possibilities in medical imaging and materials analysis. To transfer this method from scientific laboratories or small-animal applications to clinical radiography applications, compact setups with a large field of view (FoV) are required. Currently the FoV is limited by the grating area, which is restricted due to the complex manufacturing process. One possibility to increase the FoV is tiling individual grating tiles to create one large area grating mounted on a carrier substrate. We investigate theoretically the accuracy needed for a tiling process in all degrees of freedom by applying a simulation approach. We show how the resulting precision requirements can be met using a custom-built frame for exact positioning. Precise alignment is achieved by comparing the fringe patterns of two neighboring grating tiles in a grating interferometer. With this method, the FoV can be extended to practically any desired length in one dimension. First results of a phase-contrast scanning setup with a full FoV of 384 mm × 24 mm show the suitability of this method.

  9. Performance Assessment of Different Pulse Reconstruction Algorithms for the ATHENA X-Ray Integral Field Unit

    Science.gov (United States)

    Peille, Phillip; Ceballos, Maria Teresa; Cobo, Beatriz; Wilms, Joern; Bandler, Simon; Smith, Stephen J.; Dauser, Thomas; Brand, Thorsten; Den Haretog, Roland; de Plaa, Jelle; hide

    2016-01-01

    The X-ray Integral Field Unit (X-IFU) microcalorimeter, on-board Athena, with its focal plane comprising 3840 Transition Edge Sensors (TESs) operating at 90 mK, will provide unprecedented spectral-imaging capability in the 0.2-12 keV energy range. It will rely on the on-board digital processing of current pulses induced by the heat deposited in the TES absorber, as to recover the energy of each individual events. Assessing the capabilities of the pulse reconstruction is required to understand the overall scientific performance of the X-IFU, notably in terms of energy resolution degradation with both increasing energies and count rates. Using synthetic data streams generated by the X-IFU End-to-End simulator, we present here a comprehensive benchmark of various pulse reconstruction techniques, ranging from standard optimal filtering to more advanced algorithms based on noise covariance matrices. Beside deriving the spectral resolution achieved by the different algorithms, a first assessment of the computing power and ground calibration needs is presented. Overall, all methods show similar performances, with the reconstruction based on noise covariance matrices showing the best improvement with respect to the standard optimal filtering technique. Due to prohibitive calibration needs, this method might however not be applicable to the X-IFU and the best compromise currently appears to be the so-called resistance space analysis which also features very promising high count rate capabilities.

  10. Design and characterization of a spatially distributed multibeam field emission x-ray source for stationary digital breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Qian Xin; Rajaram, Ramya; Calderon-Colon, Xiomara; Yang Guang; Phan, Tuyen; Lalush, David S.; Lu Jianping; Zhou, Otto [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) and Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina 27659 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) and Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States)

    2009-10-15

    Digital breast tomosynthesis (DBT) is a limited angle computed tomography technique that can distinguish tumors from its overlying breast tissues and has potentials for detection of cancers at a smaller size and earlier stage. Current prototype DBT scanners are based on the regular full-field digital mammography systems and require partial isocentric motion of an x-ray tube over certain angular range to record the projection views. This prolongs the scanning time and, in turn, degrades the imaging quality due to motion blur. To mitigate the above limitations, the concept of a stationary DBT (s-DBT) scanner has been recently proposed based on the newly developed spatially distributed multibeam field emission x-ray (MBFEX) source technique using the carbon nanotube. The purpose of this article is to evaluate the performance of the 25-beam MBFEX source array that has been designed and fabricated for the s-DBT system. The s-DBT system records all the projection images by electronically activating the multiple x-ray beams from different viewing angles without any mechanical motion. The configuration of the MBFEX source is close to the published values from the Siemens Mammomat system. The key issues including the x-ray flux, focal spot size, spatial resolution, scanning time, beam-to-beam consistency, and reliability are evaluated using the standard procedures. In this article, the authors describe the design and performance of a distributed x-ray source array specifically designed for the s-DBT system. They evaluate the emission current, current variation, lifetime, and focal spot sizes of the source array. An emission current of up to 18 mA was obtained at 0.5x0.3 mm effective focal spot size. The experimentally measured focal spot sizes are comparable to that of a typical commercial mammography tube without motion blurring. Trade-off between the system spatial resolution, x-ray flux, and scanning time are also discussed. Projection images of a breast phantom were

  11. Complex dark-field contrast and its retrieval in x-ray phase contrast imaging implemented with Talbot interferometry.

    Science.gov (United States)

    Yang, Yi; Tang, Xiangyang

    2014-10-01

    Under the existing theoretical framework of x-ray phase contrast imaging methods implemented with Talbot interferometry, the dark-field contrast refers to the reduction in interference fringe visibility due to small-angle x-ray scattering of the subpixel microstructures of an object to be imaged. This study investigates how an object's subpixel microstructures can also affect the phase of the intensity oscillations. Instead of assuming that the object's subpixel microstructures distribute in space randomly, the authors' theoretical derivation starts by assuming that an object's attenuation projection and phase shift vary at a characteristic size that is not smaller than the period of analyzer grating G₂ and a characteristic length dc. Based on the paraxial Fresnel-Kirchhoff theory, the analytic formulae to characterize the zeroth- and first-order Fourier coefficients of the x-ray irradiance recorded at each detector cell are derived. Then the concept of complex dark-field contrast is introduced to quantify the influence of the object's microstructures on both the interference fringe visibility and the phase of intensity oscillations. A method based on the phase-attenuation duality that holds for soft tissues and high x-ray energies is proposed to retrieve the imaginary part of the complex dark-field contrast for imaging. Through computer simulation study with a specially designed numerical phantom, they evaluate and validate the derived analytic formulae and the proposed retrieval method. Both theoretical analysis and computer simulation study show that the effect of an object's subpixel microstructures on x-ray phase contrast imaging method implemented with Talbot interferometry can be fully characterized by a complex dark-field contrast. The imaginary part of complex dark-field contrast quantifies the influence of the object's subpixel microstructures on the phase of intensity oscillations. Furthermore, at relatively high energies, for soft tissues it can be

  12. X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fenster, A. [Univ. of Western Ontario, J.P. Robarts Institute, London, Ontario (Canada); Yaffe, M.J. [Univ. of Toronto, Depts. of Medical Biophysics and Medical Imaging, North York, Ontario (Canada)

    1995-09-01

    In this article, we briefly review the principles of x-ray imaging, consider some of its applications in medicine and describe some of the developments in this area which have taken place in Canada. X rays were first used for diagnosis and therapy in medicine almost immediately after the report of their discovery by Roentgen in 1895. X-ray imaging has remained the primary tool for the investigation of structures within the body up to the present time (Johns and Cunningham 1983). Medical x rays are produced in a vacuum tube by the electron bombardment of a metallic target. Electrons emitted from a heated cathode are accelerated through an electric field to energies of 20-150 keV (wavelength 6.2-0.83 nm) and strike a target anode. X rays appear in a spectrum of bremsstrahlung radiation with energies ranging from 0 to a value that is numerically equal to the peak voltage applied between the cathode and anode of the x-ray tube (Figure 1). In addition, where the energy of the impinging electrons exceeds the binding energy of inner atomic orbitals of the target material, electrons may be ejected from those shells. Filling of these shells by more loosely-bound electrons gives rise to x rays whose energies are equal to the difference of the binding energies of the donor and acceptor shells. The energies of these characteristic x rays are unique to the target material. Less than 1% of the energy of the incident electrons is converted to that of x rays, while the remainder is dissipated as heat in the target. For this reason, a tremendous amount of engineering has gone into the design of x-ray tubes that can yield a large fluence rate of quanta from a small effective source size, while withstanding the enormous applied heat loading (e.g. 10 kJ per exposure). Tungsten is by far the most common material used for targets in tubes for diagnostic radiology, because of its high melting point and its high atomic number; the efficiency of x-ray production is proportional to Z of the

  13. Probing BL Lac and Cluster Evolution via a Wide-angle, Deep X-ray Selected Sample

    Science.gov (United States)

    Perlman, E.; Jones, L.; White, N.; Angelini, L.; Giommi, P.; McHardy, I.; Wegner, G.

    1994-12-01

    The WARPS survey (Wide-Angle ROSAT Pointed Survey) has been constructed from the archive of all public ROSAT PSPC observations, and is a subset of the WGACAT catalog. WARPS will include a complete sample of >= 100 BL Lacs at F_x >= 10(-13) erg s(-1) cm(-2) . A second selection technique will identify ~ 100 clusters at 0.15 = 0.304 +/- 0.062 for XBLs but = 0.60 +/- 0.05 for RBLs. Models of the X-ray luminosity function (XLF) are also poorly constrained. WARPS will allow us to compute an accurate XLF, decreasing the error bars above by over a factor of two. We will also test for low-luminosity BL Lacs, whose non-thermal nuclear sources are dim compared to the host galaxy. Browne and Marcha (1993) claim the EMSS missed most of these objects and is incomplete. If their predictions are correct, 20-40% of the BL Lacs we find will fall in this category, enabling us to probe the evolution and internal workings of BL Lacs at lower luminosities than ever before. By removing likely QSOs before optical spectroscopy, WARPS requires only modest amounts of telescope time. It will extend measurement of the cluster XLF both to higher redshifts (z>0.5) and lower luminosities (LX<1x10(44) erg s(-1) ) than previous measurements, confirming or rejecting the 3sigma detection of negative evolution found in the EMSS, and constraining Cold Dark Matter cosmologies. Faint NELGs are a recently discovered major contributor to the X-ray background. They are a mixture of Sy2s, starbursts and galaxies of unknown type. Detailed classification and evolution of their XLF will be determined for the first time.

  14. 2D magnetic field warp reversal in images taken with DIXI (dilation x-ray imager)

    Science.gov (United States)

    Nagel, Sabrina R.; Hilsabeck, T. J.; Ayers, M. J.; Felker, B.; Piston, K. W.; Chung, T.; Bell, P. M.; Bradley, D. K.; Collins, G. W.; Kilkenny, J. D.; Hares, J. D.; Dymoke-Bradshaw, A. K. L.

    2013-09-01

    DIXI utilizes pulse-dilation technology to achieve x-ray imaging with temporal gate times below 10 ps. The longitudinal magnetic eld used to guide the electrons during the dilation process results in a warped image, similar to an optical distortion from a lens. Since the front end, where x-rays are converted into electrons at the beginning of the magnetic eld, determines the temporal resolution these distortions in uence the temporal width of the images at the back end, where it is captured. Here we discuss the measurements and methods used to reverse the magnetic warp e ect in the DIXI data. The x-ray measurements were conducted using the COMET laser facility at the Lawrence Livermore National Laboratory.

  15. Short period, high field cryogenic undulator for extreme performance x-ray free electron lasers

    Directory of Open Access Journals (Sweden)

    F. H. O’Shea

    2010-07-01

    Full Text Available Short period, high field undulators can enable short wavelength free electron lasers (FELs at low beam energy, with decreased gain length, thus allowing much more compact and less costly FEL systems. We describe an ongoing initiative to develop such an undulator based on an approach that utilizes novel cryogenic materials. While this effort was begun in the context of extending the photon energy regime of a laser-plasma accelerator based electron source, we consider here implications of its application to sub-fs scenarios in which more conventional injectors are employed. The use of such low-charge, ultrashort beams, which has recently been proposed as a method of obtaining single-spike performance in x-ray FELs, is seen in simulation to give unprecedented beam brightness. This brightness, when considered in tandem with short wavelength, high field undulators, enables extremely high performance FELs. Two examples discussed in this paper illustrate this point well. The first is the use of the SPARX injector at 2.1 GeV with 1 pC of charge to give 8 GW peak power in a single spike at 6.5 Å with a photon beam peak brightness greater than 10^{35}  photons/(s mm^{2} mrad^{2}  0.1%  BW, which will also reach LCLS wavelengths on the 5th harmonic. The second is the exploitation of the LCLS injector with 0.25 pC, 150 as pulses to lase at 1.5 Å using only 4.5 GeV energy; beyond this possibility, we present start-to-end simulations of lasing at unprecedented short wavelength, 0.15 Å, using 13.65 GeV LCLS design energy.

  16. Soft X-Ray Emissions from Planets and Moons

    Science.gov (United States)

    Bhardwaj, A.; Gladstone, G. R.; Elsner, R. F.; Waite, J. H., Jr.; Grodent, D.; Lewis, W. S.; Crary, F. J.; Weisskopf, M. C.; Howell, R. R.; Johnson, R. E.; hide

    2002-01-01

    The soft x-ray energy band (less than 4 keV) is an important spectral regime for planetary remote sensing, as a wide variety of solar system objects are now known to shine at these wavelengths. These include Earth, Jupiter, comets, moons, Venus, and the Sun. Earth and Jupiter, as magnetic planets, are observed to emanate strong x-ray emissions from their auroral (polar) regions, thus providing vital information on the nature of precipitating particles and their energization processes in planetary magnetospheres. X rays from low latitudes have also been observed on these planets, resulting largely from atmospheric scattering and fluorescence of solar x-rays. Cometary x-rays are now a well established phenomena, more than a dozen comets have been observed at soft x-ray energies, with the accepted production mechanism being charge-exchange between heavy solar wind ions and cometary neutrals. Also, Lunar x-rays have been observed and are thought to be produced by scattering and fluorescence of solar x-rays from the Moon's surface. With the advent of sophisticated x-ray observatories, e.g., Chandra and XMM-Newton, the field of planetary x-ray astronomy is advancing at a much faster pace. The Chandra X-ray Observatory (CXO) has recently captured soft x-rays from Venus. Venusian x-rays are most likely produced through fluorescence of solar x-rays by C and O atoms in the upper atmosphere. Very recently, using CXO we have discovered soft x-rays from the moons of Jupiter-Io, Europa, and probably Ganymede. The plausible source of the x-rays from the Galilean satellites is bombardment of their surfaces by energetic (greater than 10 KeV) ions from the inner magnetosphere of Jupiter. The Io plasma Torus (IPT) is also discovered by CXO to be a source of soft x-rays by CXO have revealed a mysterious pulsating (period approx. 45 minutes) x-ray hot spot is fixed in magnetic latitude and longitude and is magnetically connected to a region in the outer magnetosphere of Jupiter. These

  17. X-ray-bright optically faint active galactic nuclei in the Subaru Hyper Suprime-Cam wide survey

    Science.gov (United States)

    Terashima, Yuichi; Suganuma, Makoto; Akiyama, Masayuki; Greene, Jenny E.; Kawaguchi, Toshihiro; Iwasawa, Kazushi; Nagao, Tohru; Noda, Hirofumi; Toba, Yoshiki; Ueda, Yoshihiro; Yamashita, Takuji

    2017-11-01

    We construct a sample of X-ray-bright optically faint active galactic nuclei by combining Subaru Hyper Suprime-Cam, XMM-Newton, and infrared source catalogs. Fifty-three X-ray sources satisfying i-band magnitude fainter than 23.5 mag and X-ray counts with the EPIC-PN detector larger than 70 are selected from 9.1 deg2, and their spectral energy distributions (SEDs) and X-ray spectra are analyzed. Forty-four objects with an X-ray to i-band flux ratio FX/Fi > 10 are classified as extreme X-ray-to-optical flux sources. Spectral energy distributions of 48 among 53 are represented by templates of type 2 AGNs or star-forming galaxies and show the optical signature of stellar emission from host galaxies in the source rest frame. Infrared/optical SEDs indicate a significant contribution of emission from dust to the infrared fluxes, and that the central AGN is dust obscured. The photometric redshifts determined from the SEDs are in the range of 0.6-2.5. The X-ray spectra are fitted by an absorbed power-law model, and the intrinsic absorption column densities are modest (best-fit log NH = 20.5-23.5 cm-2 in most cases). The absorption-corrected X-ray luminosities are in the range of 6 × 1042-2 × 1045 erg s-1. Twenty objects are classified as type 2 quasars based on X-ray luminsosity and NH. The optical faintness is explained by a combination of redshifts (mostly z > 1.0), strong dust extinction, and in part a large ratio of dust/gas.

  18. Anisotropic x-ray scattering and orientation fields in cardiac tissue cells

    Science.gov (United States)

    Bernhardt, M.; Nicolas, J.-D.; Eckermann, M.; Eltzner, B.; Rehfeldt, F.; Salditt, T.

    2017-01-01

    X-ray diffraction from biomolecular assemblies is a powerful technique which can provide structural information about complex architectures such as the locomotor systems underlying muscle contraction. However, in its conventional form, macromolecular diffraction averages over large ensembles. Progress in x-ray optics has now enabled to probe structures on sub-cellular scales, with the beam confined to a distinct organelle. Here, we use scanning small angle x-ray scattering (scanning SAXS) to probe the diffraction from cytoskeleton networks in cardiac tissue cells. In particular, we focus on actin-myosin composites, which we identify as the dominating contribution to the anisotropic diffraction patterns, by correlation with optical fluorescence microscopy. To this end, we use a principal component analysis approach to quantify direction, degree of orientation, nematic order, and the second moment of the scattering distribution in each scan point. We compare the fiber orientation from micrographs of fluorescently labeled actin fibers to the structure orientation of the x-ray dataset and thus correlate signals of two different measurements: the native electron density distribution of the local probing area versus specifically labeled constituents of the sample. Further, we develop a robust and automated fitting approach based on a power law expansion, in order to describe the local structure factor in each scan point over a broad range of the momentum transfer {q}{{r}}. Finally, we demonstrate how the methodology shown for freeze dried cells in the first part of the paper can be translated to alive cell recordings.

  19. Photoneutron intensity variation with field size around radiotherapy linear accelerator 18-MeV X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghamdi, H.; Fazal-ur-Rehman [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Jarallah, M.I. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: mibrahim@kfupm.edu.sa; Maalej, N. [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2008-08-15

    In X-ray radiotherapy accelerators, neutrons are produced mainly by ({gamma},n) reaction when high energy X-rays interact with high Z materials of the linear accelerator head. These materials include the lead (Pb) used as shielding in the collimator, tungsten (W) target used for the production of X-rays and iron (Fe) in the accelerator head. These unwanted neutrons contaminate the therapeutic beam and contribute to the patient dose during the treatment of a cancer patient. Knowing the neutron distribution around the radiotherapy accelerator is therefore desired. CR-39 nuclear track detectors (NTDs) were used to study the variation of fast and thermal neutron relative intensities around an 18 MeV linear accelerator X-ray beam with the field sizes of 0, 10x10, 20x20, 30x30 and 40x40cm{sup 2}. For fast neutron detection, bare NTDs were used. For thermal neutron detection, NTDs were covered with lithium tetra borate (Li{sub 2}B{sub 4}O{sub 7}) converters. The NTDs were placed at different locations in the direction perpendicular to the treatment couch (transversal) and in the direction parallel to the treatment couch (longitudinal) with respect to the isocenter of the accelerator. The fast neutron relative intensity is symmetrical about the beam axis and exhibits an exponential-like drop with distance from the isocenter of the accelerator for all the field sizes. At the primary beam (isocenter), the relative fast neutron intensity is highest for 40x40cm{sup 2} field size and decreases linearly with the decrease in the field size. However, fast neutron intensities do not change significantly with beam size for the measurements outside the primary beam. The fast neutron intensity in the longitudinal direction outside the primary beam decreases linearly with the field size. The thermal neutron intensity, at any location, was found to be almost independent of the field size.

  20. Neutron Stars in X-ray Binaries and their Environments

    Indian Academy of Sciences (India)

    Biswajit Paul

    2017-09-07

    Sep 7, 2017 ... Abstract. Neutron stars in X-ray binary systems are fascinating objects that display a wide range of timing and spectral phenomena in the X-rays. Not only parameters of the neutron stars, like magnetic field strength and spin period evolve in their active binary phase, the neutron stars also affect the binary ...

  1. Spin period change and the magnetic fields of neutron stars in Be X-ray binaries in the SMC

    Directory of Open Access Journals (Sweden)

    Klus H.

    2014-01-01

    Full Text Available We report on the long term average spin period, rate of change of spin period and X-ray luminosity during outbursts for 42 Be X-ray binary systems in the Small Magellanic Cloud. We also collect and calculate parameters of each system and use this data to determine that all systems contain a neutron star which is accreting via a disc, rather than a wind, and that if these neutron stars are near spin equilibrium, then over half of them, including all with spin periods over about 100 seconds, have magnetic fields over the quantum critical level of 4.4×1013 G. If these neutron stars are not close to spin equilibrium, then their magnetic fields are inferred to be much lower, on the order of 106-1010 G, comparable to the fields of neutron stars in low mass X-ray binaries. Both results are unexpected and have implications for the rate of magnetic field decay and the isolated neutron star population.

  2. Design of an ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline.

    Science.gov (United States)

    Xue, L; Reininger, R; Wu, Y-Q; Zou, Y; Xu, Z-M; Shi, Y-B; Dong, J; Ding, H; Sun, J-L; Guo, F-Z; Wang, Y; Tai, R-Z

    2014-01-01

    A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20-2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 10(10) photons s(-1) at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick-Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.

  3. Nanometric deformations of thin Nb layers under a strong electric field using soft x-ray laser interferometry

    OpenAIRE

    Jamelot, Gérard; Ros, David; Carillon, A.; Rus, Bedrich; Mocek, T.; Kozlova, M.; Prag, A.R; Joyeux, Denis; Phalippou, Daniel; Boussoukaya, M.; Kalmykow, M.; Ballester, F; Jacques, E.

    2005-01-01

    International audience; We present measurements of in situ nanometric-resolution topographical modifications of thin niobium layers subjected to strong electric fields. The Nb layers, deposited on a fused silica substrate, are interferometrically flash probed using soft x-ray laser (XRL) at the wavelength of 21.2 nm. Its pulses are reflected by the probed sample under grazing incidence angle, and the information about surface deformation is obtained by a Fresnel wave-front-division interferom...

  4. Exploring Pore Formation of Atomic Layer-Deposited Overlayers by in Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian P.; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show the porosity is formed by the phase transition but also that the pore size increases with temperature.

  5. Exploring Pore Formation of Atomic Layer-Deposited Overlayers by in Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian P.; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show that the porosity is formed by this phase transition but also that the pore size increases with temperature.

  6. Estimating photometric redshifts for X-ray sources in the X-ATLAS field using machine-learning techniques

    Science.gov (United States)

    Mountrichas, G.; Corral, A.; Masoura, V. A.; Georgantopoulos, I.; Ruiz, A.; Georgakakis, A.; Carrera, F. J.; Fotopoulou, S.

    2017-12-01

    We present photometric redshifts for 1031 X-ray sources in the X-ATLAS field using the machine-learning technique TPZ. X-ATLAS covers 7.1 deg2 observed with XMM-Newton within the Science Demonstration Phase of the H-ATLAS field, making it one of the largest contiguous areas of the sky with both XMM-Newton and Herschel coverage. All of the sources have available SDSS photometry, while 810 additionally have mid-IR and/or near-IR photometry. A spectroscopic sample of 5157 sources primarily in the XMM/XXL field, but also from several X-ray surveys and the SDSS DR13 redshift catalogue, was used to train the algorithm. Our analysis reveals that the algorithm performs best when the sources are split, based on their optical morphology, into point-like and extended sources. Optical photometry alone is not enough to estimate accurate photometric redshifts, but the results greatly improve when at least mid-IR photometry is added in the training process. In particular, our measurements show that the estimated photometric redshifts for the X-ray sources of the training sample have a normalized absolute median deviation, nmad ≈ 0.06, and a percentage of outliers, η = 10-14%, depending upon whether the sources are extended or point like. Our final catalogue contains photometric redshifts for 933 out of the 1031 X-ray sources with a median redshift of 0.9. The table of the photometric redshifts is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A39

  7. The Wide Field Imager for Athena

    Science.gov (United States)

    Rau, A.; Nandra, K.; Meidinger, N.; Plattner, M.

    2017-10-01

    The Wide Field Imager (WFI) is one of the two scientific instruments of Athena, ESA's next large X-ray Observatory with launch in 2028. The instrument will provide two defining capabilities to the mission sensitive wide-field imaging spectroscopy and excellent high-count rate performance. It will do so with the use of two separate detectors systems, the Large Detector Array (LDA) optimized for its field of view (40'×40') with a 100 fold survey speed increase compared to existing X-ray missions, and the Fast Detector (FD) tweaked for high throughput and low pile-up for point sources as bright as the Crab. In my talk I will present the key performance parameters of the instrument and their links to the scientific goals of Athena and summarize the status of the ongoing development activities.

  8. An X-Ray Investigation of the NGC346 Field in the SMC (3): XMM-Newton Data

    Science.gov (United States)

    Naze, Yael; Manfroid, Jean; Corcoran, Michael F.; Stevens, Ian R.

    2004-01-01

    We present new XMM-Newton results on the field around the NGC346 star cluster in the SMC. This continues and extends previously published work on Chandra observations of the same field. The two XMM-Newton observations were obtained, respectively, six months before and six months after the previously published Chandra data. Of the 51 X-ray sources detected with XMM-Newton, 29 were already detected with Chandru. Comparing the properties of these X-ray sources in each of our three datasets has enabled us to investigate their variability on times scales of a year. Changes in the flux levels and/or spectral properties were observed for 21 of these sources. In addition, we discovered long-term variations in the X-ray properties of the peculiar system HD5980, a luminous blue variable star, that is likely to be a colliding wind binary system, which displays the largest luminosity during the first XMM-Newton observation.

  9. The universe in X-rays

    CERN Document Server

    Hasinger, Günther

    2008-01-01

    In the last 45 years, X-ray astronomy has become an integral part of modern astrophysics and cosmology. There is a wide range of astrophysical objects and phenomena, where X-rays provide crucial diagnostics. In particular they are well suited to study hot plasmas and matter under extreme physical conditions in compact objects. This book summarizes the present status of X-ray astronomy in terms of observational results and their astrophysical interpretation. It is written for students, astrophysicists as well a growing community of physicists interested in the field. An introduction including historical material is followed by chapters on X-ray astronomical instrumentation. The next two parts summarize in 17 chapters the present knowledge on various classes of X-ray sources in the galactic and extragalactic realm. While the X-ray astronomical highlights discussed in this book are mainly based on results from ROSAT, ASCA, RXTE, BeppoSAX, Chandra and XMM-Newton, a final chapter provides an outlook on observation...

  10. Development of frequency domain multiplexing for the X-ray Integral Field unit (X-IFU) on the Athena

    Science.gov (United States)

    Akamatsu, Hiroki; Gottardi, Luciano; van der Kuur, Jan; de Vries, Cor P.; Ravensberg, Kevin; Adams, Joseph S.; Bandler, Simon R.; Bruijn, Marcel P.; Chervenak, James A.; Kilbourne, Caroline A.; Kiviranta, Mikko; van der Linden, A. J.; Jackson, Brian D.; Smith, Stephen J.

    2016-07-01

    We are developing the frequency domain multiplexing (FDM) read-out of transition-edge sensor (TES) microcalorimeters for the X-ray Integral Field Unit (X-IFU) instrument on board of the future European X-Ray observatory Athena. The X-IFU instrument consists of an array of 3840 TESs with a high quantum efficiency (>90 %) and spectral resolution ΔE=2.5 eV @ 7 keV (E/ ΔE 2800). FDM is currently the baseline readout system for the X-IFU instrument. Using high quality factor LC filters and room temperature electronics developed at SRON and low-noise two stage SQUID amplifiers provided by VTT, we have recently demonstrated good performance with the FDM readout of Mo/Au TES calorimeters with Au/Bi absorbers. An integrated noise equivalent power resolution of about 2.0 eV at 1.7 MHz has been demonstrated with a pixel from a new TES array from NASA/Goddard (GSFC-A2). We have achieved X-ray energy resolutions 2.5 eV at AC bias frequency at 1.7 MHz in the single pixel read-out. We have also demonstrated for the first time an X-ray energy resolution around 3.0 eV in a 6 pixel FDM read-out with TES array (GSFC-A1). In this paper we report on the single pixel performance of these microcalorimeters under MHz AC bias, and further results of the performance of these pixels under FDM.

  11. Diffusion effects in semiconductor X-ray detectors with inhomogeneous distribution of electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Kozorezov, A.G. [Department of Physics, Lancaster University, Lancaster (United Kingdom)], E-mail: a.kozorezov@lancaster.ac.uk; Wigmore, J.K. [Department of Physics, Lancaster University, Lancaster (United Kingdom); Owens, A.; Hartog, R. den [Advanced Technologies Section, Science Projects Department, European Space Agency, ESTEC, Noordwijk (Netherlands)

    2009-10-21

    We derive an expression for the charge output of an X-ray semiconductor detector taking account of carrier drift and diffusion. It is found that diffusion effects may strongly influence charge collection patterns at the edges of the collection zones. We show that, in multi-electrode detectors, carrier diffusion across the boundaries between collection and non-collection zones depends on the nature of the boundary surfaces and the biasing conditions. Diffusion effects for a ring-drift detector are illustrated, and the conditions derived under which diffusion effects for collection around the outer edge of the collection zone are fully suppressed by the drift.

  12. Non-null full field X-ray mirror metrology using SCOTS: a reflection deflectometry approach.

    Science.gov (United States)

    Su, Peng; Wang, Yuhao; Burge, James H; Kaznatcheev, Konstantine; Idir, Mourad

    2012-05-21

    In a previous paper, the University of Arizona (UA) has developed a measurement technique called: Software Configurable Optical Test System (SCOTS) based on the principle of reflection deflectometry. In this paper, we present results of this very efficient optical metrology method applied to the metrology of X-ray mirrors. We used this technique to measure surface slope errors with precision and accuracy better than 100 nrad (rms) and ~200 nrad (rms), respectively, with a lateral resolution of few mm or less. We present results of the calibration of the metrology systems, discuss their accuracy and address the precision in measuring a spherical mirror.

  13. Exact solution of a variety of X-ray probes in the Falicov-Kimball model with dynamical mean-field theory

    Directory of Open Access Journals (Sweden)

    A.M. Shvaika

    2012-12-01

    Full Text Available We examine the core-level X-ray photoemission spectroscopy (XPS, X-ray absorption near-edge spectroscopy (XANES and X-ray emission spectroscopy (XES in the Falicov-Kimball model by using the exact solution from dynamical mean-field theory. XPS measures the core-hole propagator, XANES measures the absorption of X-rays when the core electron is excited to an unoccupied electronic state of the solid and is not emitted, and XES measures the spectra of light emitted as electrons fill the core-hole state created via some form of X-ray excitation. These three spectra are closely related to one another and display orthogonality catastrophe behavior at T=0. We show an efficient way of evaluating these spectra at finite temperature, with a primary focus on the details of XANES.

  14. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... widely available in emergency rooms, physician offices, ambulatory care centers, nursing homes and other locations, making it convenient for both patients and physicians. Because x-ray imaging is fast and easy, it is ... Radiation Exposure Special care is taken during x-ray examinations to use ...

  15. X-ray properties of the z ~ 4.5 Lyman-alpha Emitters in the Chandra Deep Field South Region

    OpenAIRE

    Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E.; Finkelstein, K. D.

    2010-01-01

    We report the first X-ray detection of 113 Lyman-alpha emitters at redshift z ~ 4.5. Only one source (J033127.2-274247) is detected in the Extended Chandra Deep Field South (ECDF-S) X-ray data, and has been spectroscopically confirmed as a z = 4.48 quasar with $L_X = 4.2\\times 10^{44}$ erg/s. The single detection gives a Lyman-alpha quasar density consistent with the X-ray luminosity function of quasars. The coadded counts of 22 Lyman-alpha emitters (LAEs) in the central Chandra Deep Field So...

  16. Animated simulation of the paths of X-ray wave fields in a crystal containing a dislocation : Spherical incident wave

    OpenAIRE

    Epelboin, Yves; Guidi-Morosini, Christian; Morris, François; Rimsky, Alexandre; Soyer, Alain

    1987-01-01

    The propagation of X-ray wave fields in a crystal containing a dislocation is computed according to the dynamical theory and the intensities inside the crystal are represented in false colours. The position of the core of the dislocation is represented by a white cross. The video illustrate the case of an incident spherical wave on a Silicon crystal 400 micron thick , reflection (3 3 -3) with Mo Kalpha radiation (Bragg angle 19.83 degrees). Increasing intensities are visualized with the follo...

  17. Joint x-ray

    Science.gov (United States)

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  18. Magnetic field-induced splitting of Bragg peaks in resonant magnetic x-ray diffraction from square artificial spin ice

    Science.gov (United States)

    Lee, James; Mishra, Shrawan; Bhat, Vinayak; Farmer, Barry; Shi, Xiaowen; de Long, Lance; Kevan, Steven; Roy, Sujoy

    Artificial spin ice (ASI) is a class of periodic magnetic nanostructures that can display magnetic phenomena like that of natural spin ices, including analogs of magnetic monopoles. Based on the ice structure and field history, ASI systems can form a variety of energetically degenerate magnetic structures. When we probed the magnetic structure of a square ASI using spatially coherent Fe L3 ( 707eV) x-rays, we found that ASI Bragg peaks split when exposed to magnetic fields. This field-induced splitting is reversible: Bragg peaks display gaussian profiles in zero-field. We will present a scattering model, analogous to the theory of anti-phase domains in alloys, that reveals the magnetic structure of the square ASI necessary to create split Bragg peaks. Funding provided by US DOE and NSF.

  19. Near-infrared Variability of Obscured and Unobscured X-Ray-selected AGNs in the COSMOS Field

    Science.gov (United States)

    Sánchez, P.; Lira, P.; Cartier, R.; Pérez, V.; Miranda, N.; Yovaniniz, C.; Arévalo, P.; Milvang-Jensen, B.; Fynbo, J.; Dunlop, J.; Coppi, P.; Marchesi, S.

    2017-11-01

    We present our statistical study of near-infrared (NIR) variability of X-ray-selected active galactic nuclei (AGNs) in the COSMOS field, using UltraVISTA data. This is the largest sample of AGN light curves in YJHKs bands, making it possible to have a global description of the nature of AGNs for a large range of redshifts and for different levels of obscuration. To characterize the variability properties of the sources, we computed the structure function. Our results show that there is an anticorrelation between the structure function A parameter (variability amplitude) and the wavelength of emission and a weak anticorrelation between A and the bolometric luminosity. We find that broad-line (BL) AGNs have a considerably larger fraction of variable sources than narrow-line (NL) AGNs and that they have different distributions of the A parameter. We find evidence that suggests that most of the low-luminosity variable NL sources correspond to BL AGNs, where the host galaxy could be damping the variability signal. For high-luminosity variable NL sources, we propose that they can be examples of “true type II” AGNs or BL AGNs with limited spectral coverage, which results in missing the BL emission. We also find that the fraction of variable sources classified as unobscured in the X-ray is smaller than the fraction of variable sources unobscured in the optical range. We present evidence that this is related to the differences in the origin of the obscuration in the optical and X-ray regimes.

  20. Large-area full field x-ray differential phase-contrast imaging using 2D tiled gratings

    Science.gov (United States)

    Schröter, Tobias J.; Koch, Frieder J.; Kunka, Danays; Meyer, Pascal; Tietze, Sabrina; Engelhardt, Sabine; Zuber, Marcus; Baumbach, Tilo; Willer, Konstantin; Birnbacher, Lorenz; Prade, Friedrich; Pfeiffer, Franz; Reichert, Klaus-Martin; Hofmann, Andreas; Mohr, Jürgen

    2017-06-01

    Grating-based x-ray differential phase-contrast imaging (DPCI) is capable of acquiring information based on phase-shift and dark-field signal, in addition to conventional x-ray absorption-contrast. Thus DPCI gives an advantage to investigate composite materials with component wise similar absorption properties like soft tissues. Due to technological challenges in fabricating high quality gratings over a large extent, the field of view (FoV) of the imaging systems is limited to a grating area of a couple of square centimeters. For many imaging applications (e.g. in medicine), however, a FoV that ranges over several ten centimeters is needed. In this manuscript we propose to create large area gratings of theoretically any extent by assembling a number of individual grating tiles. We discuss the precision needed for alignment of each microstructure tile in order to reduce image artifacts and to preserve minimum 90% of the sensitivity obtainable with a monolithic grating. To achieve a reliable high precision alignment a semiautomatic assembly system consisting of a laser autocollimator, a digital microscope and a force sensor together with positioning devices was built. The setup was used to tile a first four times four analyzer grating with a size of 200 mm  ×  200 mm together with a two times two phase grating. First imaging results prove the applicability and quality of the tiling concept.

  1. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... replacement and fracture reductions. look for injury, infection, arthritis , abnormal bone growths and bony changes seen in ... injuries, including fractures, and joint abnormalities, such as arthritis. X-ray equipment is relatively inexpensive and widely ...

  2. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... the patient in a hospital bed or the emergency room. The x-ray tube is connected to ... equipment is relatively inexpensive and widely available in emergency rooms, physician offices, ambulatory care centers, nursing homes ...

  3. Detection of short range order in SiO{sub 2} thin-films by grazing-incidence wide and small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Kohki, E-mail: nagata.koki@iri-tokyo.jp [Tokyo Metropolitan Industrial Technology Research Institute, 2-4-10 Aomi, Koto-ku, Tokyo 135-0064 (Japan); School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Ogura, Atsushi [School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Hirosawa, Ichiro [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Suwa, Tomoyuki; Teramoto, Akinobu; Ohmi, Tadahiro [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramakiazaaoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2016-04-21

    The effects of the fabrication process conditions on the microstructure of silicon dioxide thin films of <10 nm thickness are presented. The microstructure was investigated using grazing-incidence wide and small-angle X-ray scattering methods with synchrotron radiation. The combination of a high brilliance light source and grazing incident configuration enabled the observation of very weak diffuse X-ray scattering from SiO{sub 2} thin films. The results revealed different microstructures, which were dependent on oxidizing species or temperature. The micro-level properties differed from bulk properties reported in the previous literature. It was indicated that these differences originate from inner stress. The detailed structure in an amorphous thin film was not revealed owing to detection difficulties.

  4. Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rossle, Manfred [European Molecular Biology Laboratory (EMBL), France; Panine, Pierre [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL; Riekel, Christine [European Synchrotron Radiation Facility (ESRF)

    2004-04-01

    The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with {beta}-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 {micro}m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

  5. A new particle-induced X-ray emission set-up for laterally resolved analysis over wide areas

    Energy Technology Data Exchange (ETDEWEB)

    Hanf, D., E-mail: d.hanf@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany); Buchriegler, J. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany); Renno, A.D.; Merchel, S. [Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden (Germany); Munnik, F. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany); Ziegenrücker, R. [Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden (Germany); Scharf, O.; Nowak, S.H. [IFG Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany); Borany, J. von [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany)

    2016-06-15

    The recently installed and unique PIXE (particle-induced X-ray emission) set-up at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is mainly dedicated to applications for a detailed overview of elemental composition over large sample areas within a short time even at trace level. The so-called High-Speed-PIXE (HS-PIXE), a combination of a pnCCD-based pixel-detector with polycapillary X-ray optics, offers simultaneous imaging of sample areas up to 12 × 12 mm{sup 2} with a lateral resolution better than 100 μm. Each of the 264 × 264 individual pixels detects X-ray photons in an energy range from 2 keV to 20 keV with an energy resolution of 152 eV (@Mn-K{sub α}). A high precision sample manipulator offers the inspection of areas up to 250 × 250 mm{sup 2}. During first experiments the determined resolution is (76 ± 23) μm using a sample of well-known sharp-edged chromium patterns. Trace element analysis has been performed using a geological sample, a tin ore, with an average Ta-concentration below 0.1 at.%. Fine-zoned structures became visible in the Ta-L{sub α} intensity map within only 45 min. The High-Speed-PIXE closes a gap in the analytical process flow chain especially for geoanalytical characterisations. It is a unique and fast detection system to identify areas of interest in comparably short time at large-area scale for further analysis.

  6. Perspectives of the lobster-eye telescope: The promising types of cosmic X-ray sources

    Science.gov (United States)

    Šimon, V.

    2017-07-01

    We show the astrophysical aspects of observing the X-ray sky with the planned lobster-eye telescope. This instrument is important because it is able to provide wide-field X-ray imaging. For the testing observations, we propose to include also X-ray binaries in which matter transfers onto the compact object (mostly the neutron star). We show the typical features of the long-term X-ray activity of such objects. Observing in the soft X-ray band is the most promising because their X-ray intensity is the highest in this band. Since these X-ray sources tend to concentrate toward the center of our Galaxy, several of them can be present in the field of view of the tested instrument.

  7. X-Ray Polarization Measurements with the EXIST Hard X-Ray Survey Telescope

    Science.gov (United States)

    Krawczynski, Henric; Garson, A., III; Hong, J.; Grindlay, J. E.

    2009-01-01

    The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed NASA mission for scanning the entire sky in intermediate and hard X-rays. The EXIST mission includes a wide field of view High Energy Telescope (HET) covering the 5-600 keV energy range, and an infrared telescope. The HET has the capability to measure the energy dependent X-ray polarization properties of moderately bright and bright X-ray sources. Here we report on a study of the polarization sensitivity of EXIST as a function of the integration time. Broadband X-ray polarization measurements with EXIST have the potential to make important contributions to our understanding of a number of astrophysical source types including binary black holes, accreting neutron stars, magnetars, pulsar wind nebulae, active galactic nuclei and gamma-ray bursts. EXIST observations of the X-rays from binary black holes can be used to constrain the spins of black holes. Last but not least, EXIST observations of active galactic nuclei and gamma-ray bursts can be used for extremely sensitive Lorentz Invariance tests.

  8. TH-C-12A-03: Development of Expanded Field Irradiation Technique with Gimbaled X-Ray Head

    Energy Technology Data Exchange (ETDEWEB)

    Ono, T; Miyabe, Y; Yamada, M; Kaneko, S; Monzen, H; Mizowaki, T; Hiraoka, M [Kyoto University, Kyoto, Kyoto (Japan); Sawada, A [Kyoto College of Medical Science, Kyoto, kyoto (Japan); Kokubo, M [Institute of Biomedical Research and Innovation, Kobe, Hyogo (Japan)

    2014-06-15

    Purpose: The Vero4DRT has a maximum field size of 150×150 mm{sup 2}. The purposes of this study were to develop an expanded field irradiation technique using a unique gimbaled x-ray head of Vero4DRT and to evaluate its dosimetric characteristic. Methods: The expanded field irradiation consisted of four separate fields with 2.39 degree gimbal rotation around orthogonal two axes. The central beam axis for each field shifted 40 mm from the isocenter for longitudinal and lateral directions, and thus, the field size was expanded up to 230×230 mm{sup 2}. Adjacent region were created at the isocenter (center-adjacent expanded-field) and 20 mm from isocenter (offadjacent expanded-field). To create flat dose distribution in the combined piecewise-fields, the overlapping and gaps regions on the isocenter plane were adjusted with the gimbal rotating and the MLC. To evaluate dosimetric characteristic of the expanded-field, films inserted in water-equivalent phantoms at 50, 100 and 150 mm depth were irradiated and the field size, penumbra, flatness and symmetry were analyzed.In addition, the expandedfield irradiation technique was applied to IMRT. A head and neck IMRT field, which was planned for the conventional linac (Varian Clinac iX), was reproduced with the expanded-field of the Vero4DRT. The simulated dose distribution for the expanded IMRT field was compared to the measured dose distribution. Results: The field size, penumbra, flatness and symmetry of center- and off- adjacent expanded-fields were 230.2–232.1 mm, 7.8–10.7 mm, 2.3–6.5% and –0.5–0.4% at 100 mm depth. The 82.1% area of the expanded IMRT dose distribution was within 5% difference between measurement and simulation, which was analyzed upper 50% dose area, and the 3%/3 mm gamma pass rate was 98.4%. Conclusions: The expandedfield technique was developed using the gimbaled x-ray head. To extend applied targets, such as whole breast irradiations or head and neck IMRT, the expanded-field technique

  9. A facility for X-ray diffraction in magnetic fields up to 25 T and temperatures between 15 and 295 K

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Kovalev, A. E., E-mail: kovalev@magnet.fsu.edu; Suslov, A. V. [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Siegrist, T. [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310 (United States)

    2015-12-15

    A facility for X-ray diffraction has been developed at the National High Magnetic Field Laboratory. It brings diffraction capability to the 25 T Florida split coil magnet and implements temperature control in a range of 15–295 K using a cold finger helium cryostat. This instrument represents an alternative to pulsed magnetic field systems, and it exceeds the static magnetic fields currently available at synchrotron facilities. Magnetic field compatibility of an X-ray source and detectors with the sizable magnetic fringe fields emanating from the magnet constrained the design of the diffractometer.

  10. The Wide Field Imager Instrument for Athena

    OpenAIRE

    Meidinger, Norbert; Eder, Josef; Eraerds, Tanja; Nandra, Kirpal; Pietschner, Daniel; Plattner, Markus; Rau, Arne; Strecker, Rafael

    2017-01-01

    The WFI (Wide Field Imager) instrument is planned to be one of two complementary focal plane cameras on ESA's next X-ray observatory Athena. It combines unprecedented survey power through its large field of view of 40 amin x 40 amin together with excellent count rate capability (larger than 1 Crab). The energy resolution of the silicon sensor is state-of-the-art in the energy band of interest from 0.2 keV to 15 keV, e.g. the full width at half maximum of a line at 7 keV will be better than 17...

  11. An alma survey of submillimeter galaxies in the extended Chandra deep field-south: The agn fraction and X-ray properties of submillimeter galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. X.; Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Smail, I.; Alexander, D. M.; Danielson, A. L. R.; Karim, A.; Simpson, J. M.; Swinbank, A. M. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Hodge, J. A.; Walter, F. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Lehmer, B. D. [The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Wardlow, J. L. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Xue, Y. Q. [Key Laboratory for Research in Galaxies and Cosmology, Center for Astrophysics, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Coppin, K. E. K. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Dannerbauer, H. [Universität Wien, Institute für Astrophysik, Türkenschanzstraße 17, 1180 Wien (Austria); De Breuck, C. [European Southern Observatory, Karl-Schwarzschild Straße 2, D-85748 Garching (Germany); Menten, K. M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Van der Werf, P., E-mail: xxw131@psu.edu, E-mail: niel@astro.psu.edu [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

    2013-12-01

    The large gas and dust reservoirs of submillimeter galaxies (SMGs) could potentially provide ample fuel to trigger an active galactic nucleus (AGN), but previous studies of the AGN fraction in SMGs have been controversial largely due to the inhomogeneity and limited angular resolution of the available submillimeter surveys. Here we set improved constraints on the AGN fraction and X-ray properties of the SMGs with Atacama Large Millimeter/submillimeter Array (ALMA) and Chandra observations in the Extended Chandra Deep Field-South (E-CDF-S). This study is the first among similar works to have unambiguously identified the X-ray counterparts of SMGs; this is accomplished using the fully submillimeter-identified, statistically reliable SMG catalog with 99 SMGs from the ALMA LABOCA E-CDF-S Submillimeter Survey. We found 10 X-ray sources associated with SMGs (median redshift z = 2.3), of which eight were identified as AGNs using several techniques that enable cross-checking. The other two X-ray detected SMGs have levels of X-ray emission that can be plausibly explained by their star formation activity. Six of the eight SMG-AGNs are moderately/highly absorbed, with N {sub H} > 10{sup 23} cm{sup –2}. An analysis of the AGN fraction, taking into account the spatial variation of X-ray sensitivity, yields an AGN fraction of 17{sub −6}{sup +16}% for AGNs with rest-frame 0.5-8 keV absorption-corrected luminosity ≥7.8 × 10{sup 42} erg s{sup –1}; we provide estimated AGN fractions as a function of X-ray flux and luminosity. ALMA's high angular resolution also enables direct X-ray stacking at the precise positions of SMGs for the first time, and we found four potential SMG-AGNs in our stacking sample.

  12. Internal electric-field-lines distribution in CdZnTe detectors measured using X-ray mapping

    Energy Technology Data Exchange (ETDEWEB)

    Bolotnikov,A.E.; , .; Camarda, G.S.; Cui, Y.; Hossain, A.; Yang, G.; Yao, H.W.; James, R.B.

    2009-10-19

    The ideal operation of CdZnTe devices entails having a uniformly distributed internal electric field. Such uniformity especially is critical for thick long-drift-length detectors, such as large-volume CPG and 3-D multi-pixel devices. Using a high-spatial resolution X-ray mapping technique, we investigated the distribution of the electric field in real devices. Our measurements demonstrate that in thin detectors, <5 mm, the electric field-lines tend to bend away from the side surfaces (i.e., a focusing effect). In thick detectors, >1 cm, with a large aspect ratio (thickness-to-width ratio), we observed two effects: the electric field lines bending away from or towards the side surfaces, which we called, respectively, the focusing field-line distribution and the defocusing field-line distribution. In addition to these large-scale variations, the field-line distributions were locally perturbed by the presence of extended defects and residual strains existing inside the crystals. We present our data clearly demonstrating the non-uniformity of the internal electric field.

  13. X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    2016-01-01

    The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...... of air permeability (Ka) and saturated hydraulic conductivity (Ksat). The CT number of the matrix (CTmatrix), which represents the moist bulk density of the soil matrix, was obtained from the CT scans as the average CT number of the voxels in the grayscale image excluding macropores and stones...

  14. Volume digital image correlation to assess displacement field in compression loaded bread crumb under X-ray microtomography

    KAUST Repository

    Moussawi, Ali

    2014-10-01

    In this study, we present an original approach to assess structural changes during bread crumb compression using a mechanical testing bench coupled to 3D X-ray microtomography. X-ray images taken at different levels of compression of the bread crumb are processed using image analysis. A subset-based digital volume correlation method is used to achieve the 3D displacement field. Within the limit of the approach, deterministic search strategy is implemented for solving subset displacement in each deformed image with regards to the undeformed one. The predicted displacement field in the transverse directions shows differences that depend on local cell arrangement as confirmed by finite element analysis. The displacement component in the loading direction is affected by the magnitude of imposed displacement and shows more regular change. Large displacement levels in the compression direction are in good agreement with the imposed experimental displacement. The results presented here are promising in a sense of possible identification of local foam properties. New insights are expected to achieve better understanding of structural heterogeneities in the overall perception of the product. Industrial relevance: Texture evaluation of cereal product is an important aspect for testing consumer acceptability of new designed products. Mechanical evaluation of backed products is a systemic route for determining texture of cereal based product. From the industrial viewpoint, mechanical evaluation allows saving both time and cost compared to panel evaluation. We demonstrate that better understanding of structural changes during texture evaluation can be achieved in addition to texture evaluation. Sensing structural changes during bread crumb compression is achievable by combining novel imaging technique and processing based on image analysis. We present thus an efficient way to predict displacements during compression of freshly baked product. This method can be used in different

  15. Performance of a carbon nanotube field emission X-ray source array for stationary digital breast tomosynthesis

    Science.gov (United States)

    Gidcumb, Emily Morgan

    This work describes the performance of a stationary digital breast tomosynthesis (s-DBT) X-ray tube based on carbon nanotube (CNT) cathodes, and the imaging system developed around it. The s-DBT system has the potential to improve the detection and diagnosis of breast cancer over commercially available digital breast tomosynthesis (DBT) systems. DBT is growing in popularity in the United States, and around the world, as a potential replacement for traditional 2D mammography. The main advantage of DBT over 2D mammography lies in the pseudo-3D nature of the technique allowing the removal of overlapping breast tissue within the image. s-DBT builds on this advantage by removing blur from focal spot motion. Introductions to breast imaging techniques and the DBT modality are given, followed by an introduction to carbon nanotube field emission, the foundation of the s-DBT technology. Details of the s-DBT X-ray tube design and system integration are discussed including specific design parameters, system requirements, and the development process. Also included are summaries of the X-ray tube and system performance over time, and results from characterization measurements. Specific focus is given to the development and completion of a fabrication procedure for tungsten gate mesh, characterization of the CNT cathodes, and improving the system's spatial resolution with use of the focusing electrodes. The tungsten gate mesh is an essential component for extracting electrons from CNTs. A successful deep reactive ion etching fabrication procedure was developed, and the improved gate mesh allowed for higher cathode current and longer pulse widths to be employed in the s-DBT system. Characterization of the CNT cathodes revealed their high-current capacity and the ability to produce relatively long pulse widths, mimicking a 2D imaging modality. This work confirmed that the cathodes are well suited for the task of breast imaging, and explored possible improvements. Lastly, it was

  16. Spontaneous current sheets in magnetic fields with applications to stellar X-rays

    CERN Document Server

    Parker, Eugene N

    1994-01-01

    Expanding upon the ideas first proposed in his seminal book Cosmical Magnetic Fields, Eugene N. Parker here offers the first in-depth treatment of the magnetohydrodynamic theory of spontaneous magnetic discontinuities. In detailing his theory of the spontaneous formation of tangential discontinuities (current sheets) in a magnetic field embedded in highly conducting plasma, Parker shows how it can be used to explain the activity of the external magnetic fields of planets, stars, interstellar gas clouds, and galaxies, as well as the magnetic fields in laboratory plasmas. Provocative and fascinating, Spontaneous Current Sheets in Magnetic Fields presents a bold new theory that will excite interest and discussion throughout the space physics community.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kastner, J. H.; Montez, R. Jr.; Rapson, V. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois, Champagne-Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofisica de Astronomia, Glorieta de la Astronomia s/n, Granada 18008 (Spain); Lopez, J. A. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Behar, E. [Department of Physics, Technion (Israel); Bujarrabal, V. [Observatorio Astronomico Nacional, Apartado 112, E-28803, Alcala de Henares (Spain); Corradi, R. L. M. [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Nordhaus, J. [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Sandin, C., E-mail: jhk@cis.rit.edu, E-mail: soker@physics.technion.ac.il, E-mail: eva.villaver@uam.es [Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); and others

    2012-08-15

    We present an overview of the initial results from the Chandra Planetary Nebula Survey (CHANPLANS), the first systematic (volume-limited) Chandra X-Ray Observatory survey of planetary nebulae (PNe) in the solar neighborhood. The first phase of CHANPLANS targeted 21 mostly high-excitation PNe within {approx}1.5 kpc of Earth, yielding four detections of diffuse X-ray emission and nine detections of X-ray-luminous point sources at the central stars (CSPNe) of these objects. Combining these results with those obtained from Chandra archival data for all (14) other PNe within {approx}1.5 kpc that have been observed to date, we find an overall X-ray detection rate of {approx}70% for the 35 sample objects. Roughly 50% of the PNe observed by Chandra harbor X-ray-luminous CSPNe, while soft, diffuse X-ray emission tracing shocks-in most cases, 'hot bubbles'-formed by energetic wind collisions is detected in {approx}30%; five objects display both diffuse and point-like emission components. The presence (or absence) of X-ray sources appears correlated with PN density structure, in that molecule-poor, elliptical nebulae are more likely to display X-ray emission (either point-like or diffuse) than molecule-rich, bipolar, or Ring-like nebulae. All but one of the point-like CSPNe X-ray sources display X-ray spectra that are harder than expected from hot ({approx}100 kK) central stars emitting as simple blackbodies; the lone apparent exception is the central star of the Dumbbell nebula, NGC 6853. These hard X-ray excesses may suggest a high frequency of binary companions to CSPNe. Other potential explanations include self-shocking winds or PN mass fallback. Most PNe detected as diffuse X-ray sources are elliptical nebulae that display a nested shell/halo structure and bright ansae; the diffuse X-ray emission regions are confined within inner, sharp-rimmed shells. All sample PNe that display diffuse X-ray emission have inner shell dynamical ages {approx}< 5 Multiplication

  18. Note: Development of a compact x-ray particle image velocimetry for measuring opaque flows. II. Three-dimensional velocity field reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Yong [Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Pohang 790-784 (Korea, Republic of); Lee, Sang Joon [Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Pohang 790-784 (Korea, Republic of)

    2012-04-15

    An x-ray particle image velocimetry (PIV) system using a cone-beam type x-ray was developed. The field of view and the spatial resolution are 36 x 24.05 mm{sup 2} and 20 {mu}m, respectively. The three-dimensional velocity field was reconstructed by adopting the least squares minimum residue and simultaneous multiplicative algebraic reconstruction techniques. According to a simulation study with synthetic images, the reconstructions were acceptable with 7 projections and 50 iterations. The reconstructed and supplied flow rates differed by only about 6.49% in experimental verification. The x-ray tomographic PIV system would be useful for 3D velocity field information of opaque flows.

  19. Deepest View of AGN X-Ray Variability with the 7 Ms Chandra Deep Field-South Survey

    Science.gov (United States)

    Zheng, X. C.; Xue, Y. Q.; Brandt, W. N.; Li, J. Y.; Paolillo, M.; Yang, G.; Zhu, S. F.; Luo, B.; Sun, M. Y.; Hughes, T. M.; Bauer, F. E.; Vito, F.; Wang, J. X.; Liu, T.; Vignali, C.; Shu, X. W.

    2017-11-01

    We systematically analyze the X-ray variability of active galactic nuclei (AGNs) in the 7 Ms Chandra Deep Field-South survey. On the longest timescale (≈17 years), we find only a weak (if any) dependence of X-ray variability amplitudes on energy bands or obscuration. We use four different power spectral density (PSD) models to fit the anticorrelation between normalized excess variance ({σ }{nxv}2) and luminosity, and obtain a best-fit power-law index β ={1.16}-0.05+0.05 for the low-frequency part of the AGN PSD. We also divide the whole light curves into four epochs in order to inspect the dependence of {σ }{nxv}2 on these timescales, finding an overall increasing trend. The analysis of these shorter light curves also infers a β of ∼1.3 that is consistent with the above-derived β, which is larger than the frequently assumed value of β =1. We then investigate the evolution of {σ }{nxv}2. No definitive conclusion is reached because of limited source statistics, but if present, the observed trend goes in the direction of decreasing AGN variability at fixed luminosity toward high redshifts. We also search for transient events and find six notable candidate events with our considered criteria. Two of them may be a new type of fast transient events, one of which is reported here for the first time. We therefore estimate a rate of fast outbursts ={1.0}-0.7+1.1× {10}-3 {{galaxy}}-1 {{yr}}-1 and a tidal disruption event (TDE) rate ={8.6}-4.9+8.5× {10}-5 {{galaxy}}-1 {{yr}}-1 assuming the other four long outbursts to be TDEs.

  20. X-Ray Emissions from Accreting White Dwarfs: A Review

    Science.gov (United States)

    Mukai, K.

    2017-01-01

    Interacting binaries in which a white dwarf accretes material from a companion-cataclysmic variables (CVs) in which the mass donor is a Roche-lobe filling star on or near the main sequence, and symbiotic stars in which the mass donor is a late type giant-are relatively commonplace. They display a wide range of behaviors in the optical, X-rays, and other wavelengths, which still often baffle observers and theorists alike. Here I review the existing body of research on X-ray emissions from these objects for the benefits of both experts and newcomers to the field. I provide introductions to the past and current X-ray observatories, the types of known X-ray emissions from these objects, and the data analysis techniques relevant to this field. I then summarize of our knowledge regarding the X-ray emissions from magnetic CVs, non-magnetic CVs and symbiotic stars, and novae in eruption. I also discuss space density and the X-ray luminosity functions of these binaries and their contribution to the integrated X-ray emission from the Galaxy. I then discuss open questions and future prospects.

  1. Study of self-generated electric field at shock front by broadband proton probing and soft X-ray emission

    Science.gov (United States)

    Hua, Rui; Sio, Hong; Wilks, Scott; McGuffey, Christopher; Bailly-Grandvaux, Mathieu; Heeter, Bob; Beg, Farhat; Collins, Gilbert; Ping, Yuan; MIT Collaboration; LLNL Collaboration; UCSD Collaboration

    2017-10-01

    Self-generated electric fields arise from gradients in the electron pressure at shock fronts. We report observations of such E-fields from experiments conducted on OMEGA EP. In the experiments, strong shock waves were generated in low density gas under a quasi-planar geometry and diagnosed by broadband proton radiography. The broad proton spectrum allows energy-dependent measurements of deflection from which one can quantitatively constrain the electrical potential and field thickness. Three UV beams delivering up to 6.4 kJ energy in 2ns were used for shock generation and a short laser pulse of energy up to 850 J, 10 ps duration, was used to accelerate the broadband proton beam for point-projection radiography. Observations show the existence of electric fields with potential 300 V at the front of a Mach 9 shock in helium gas. A Mach 16 shock is also studied, from which both the field thickness and electric potential are reproduced. Simultaneous spatially resolved soft-x-ray spectroscopy provided additional measurements of shock velocity, particle velocity and thermal emission. This work was performed under DOE contract DE-AC52-07NA27 344 with support from OFES Early Career program and LLNL LDRD program. This work has been partially supported by the University of California Office of the President Lab Fee Grant Number LFR-17-449059.

  2. A deep X-ray spectroscopic survey of the ESO imaging survey fields

    DEFF Research Database (Denmark)

    Nørgaard-Nielsen, Hans Ulrik; Jørgensen, H.E.; Hansen, Lene

    1998-01-01

    V, we propose to perform a spectroscopic survey with SODART and push these telescopes to the limit at the high energies. By selecting the four ESO Imaging Survey fields EIS teach 6 deg(2)) we will take full advantage of the large, systematic effort ESO is putting into the optical survey of these fields...

  3. Multiscale 3D characterization with dark-field x-ray microscopy

    DEFF Research Database (Denmark)

    Simons, Hugh; Jakobsen, Anders Clemen; Ahl, Sonja Rosenlund

    2016-01-01

    of the technique are presented-mapping the evolution of subgrains during the processing of plastically deformed aluminum, mapping domains and strain fields in ferroelectric crystals, and the three-dimensional mapping of strain fields around individual dislocations. This ability to directly characterize complex...

  4. Observation of the traveling component of an x-ray standing wave field

    Energy Technology Data Exchange (ETDEWEB)

    Lai, B.; Yun, W.B.; Chrzas, J.; Viccaro, P.J.

    1994-03-01

    We present the first systematic experimental study of the traveling component of a standing wave field, formed by interference of an incident beam with its specularly reflected part from a plane interface. The traveling component of the standing wave field propagates parallel to the interface and its existence manifests the dynamical aspect of the standing wave field. In our experiment, a multilayer structure was used to aid in the observation of the traveling wave component. The data measured are explained using a finite thickness diffraction grating model.

  5. Crystal-field excitations in multiferroic TbMnO3 by Mn L3 and O K resonant inelastic X-ray scattering

    Science.gov (United States)

    Feng, Jiatai; Juhin, Amélie; Delaunay, Renaud; Jarrier, Romain; Jaouen, Nicolas; Nicolaou, Alessandro; Sinclair, Ryan; Zhou, Haidong; Mariot, Jean-Michel; Chiuzbǎian, Sorin G.

    2017-11-01

    d-d excitations in multiferroic TbMnO3 have been investigated by X-ray absorption spectroscopy and resonant inelastic X-ray scattering at the Mn L3,2 and O K edges. Confrontation between experimental data and multiplet crystal-field calculations performed for Mn3+ ions in D4h symmetry has enabled us to identify the origin of the observed excitations and has provided reliable manganese crystal-field parameters that enter the description of the antisymmetric exchange interaction responsible for the multiferroicity in this compound.

  6. Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies using X-ray Emission: Results from the CHANDRA Deep Fields

    Science.gov (United States)

    Lehmer, B.D; Brandt, W.N.; Schneider, D.P.; Steffen, A.T.; Alexander, D.M.; Bell, E.F.; Hornschemeier, A.E.; McIntosh, D.H.; Bauer, F.E.; Gilli, R.; hide

    2008-01-01

    We report on the X-ray evolution over the last approx.9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S. respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies. which were identified using rest-frame optical colors and HST morphologies. We utilized X-ray stacking analyses to investigate the X-ray emission from these galaxies, emphasizing the contributions from normal galaxies that are not dominated by active galactic nuclei (AGNs). Over this redshift range, we find significant increases (factors of approx. 5-10) in the X-ray-to-optical mean luminosity ratio (L(sub x)/L(sub B)) and the X-ray-to-stellar-mass mean ratio (L(sub x)/M(sub *)) for galaxy populations selected by L(sub B) and M(sub *), respectively. When analyzing galaxy samples selected via SFR, we find that the mean X-ray-to-SFR ratio (L(sub x)/SFR) is consistent with being constant over the entire redshift range for galaxies with SFR = 1-100 Solar Mass/yr, thus demonstrating that X-ray emission can be used as a robust indicator of star-formation activity out to z approx. 1.4. We find that the star-formation activity (as traced by X-ray luminosity) per unit stellar mass in a given redshift bin increases with decreasing stellar mass over the redshift range z = 0.2-1, which is consistent with previous studies of how star-formation activity depends on stellar mass. Finally, we extend our X-ray analyses to Lyman break galaxies at z approx. 3 and estimate that L(sub x)/L(sub B) at z approx. 3 is similar to its value at z = 1.4.

  7. Chest X-Ray

    Medline Plus

    Full Text Available ... the most commonly performed x-ray exams and use a very small dose of ionizing radiation to ... to your health. While a chest x-ray use a tiny dose of ionizing radiation, the benefit ...

  8. X-ray and H-alpha observations of a filament-disappearance flare - An empirical analysis of the magnetic field configuration

    Science.gov (United States)

    Kahler, S. W.; Webb, D. F.; Moore, R. L.

    1981-01-01

    On August, 29, 1973, a flare event occurred that involved the disappearance of a filament near central meridian. The event, well-observed in X-rays on Skylab and in H-alpha, was a four-ribbon flare involving both new and old magnetic inversion lines which were roughly parallel. The H-alpha, X-ray, and magnetic field data are used to deduce the magnetic polarities of the H-alpha brightening at the footpoints of the brightest X-ray loops. It is suggested that the event involved a reconnection of magnetic field lines rather than a brightening in place of preexisting loops. The simultaneity of the H-alpha brightening onsets in the four ribbons and the apparent lack of an eruption of the filament are consistent with this interpretation.

  9. Tracing the accretion history of supermassive black holes through X-ray variability: results from the ChandraDeep Field-South

    Science.gov (United States)

    Paolillo, M.; Papadakis, I.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Tozzi, P.; Shemmer, O.; Allevato, V.; Bauer, F. E.; Comastri, A.; Gilli, R.; Koekemoer, A. M.; Liu, T.; Vignali, C.; Vito, F.; Yang, G.; Wang, J. X.; Zheng, X. C.

    2017-11-01

    We study the X-ray variability properties of distant active galactic nuclei (AGNs) in the ChandraDeep Field-South region over 17 yr, up to z ˜ 4, and compare them with those predicted by models based on local samples. We use the results of Monte Carlo simulations to account for the biases introduced by the discontinuous sampling and the low-count regime. We confirm that variability is a ubiquitous property of AGNs, with no clear dependence on the density of the environment. The variability properties of high-z AGNs, over different temporal time-scales, are most consistent with a power spectral density (PSD) described by a broken (or bending) power law, similar to nearby AGNs. We confirm the presence of an anticorrelation between luminosity and variability, resulting from the dependence of variability on black hole (BH) mass and accretion rate. We explore different models, finding that our acceptable solutions predict that BH mass influences the value of the PSD break frequency, while the Eddington ratio λEdd affects the PSD break frequency and, possibly, the PSD amplitude as well. We derive the evolution of the average λEdd as a function of redshift, finding results in agreement with measurements based on different estimators. The large statistical uncertainties make our results consistent with a constant Eddington ratio, although one of our models suggest a possible increase of λEdd with lookback time up to z ˜ 2-3. We conclude that variability is a viable mean to trace the accretion history of supermassive BHs, whose usefulness will increase with future, wide-field/large effective area X-ray missions.

  10. Hand x-ray

    Science.gov (United States)

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  11. X-Ray

    Science.gov (United States)

    ... show up on chest X-rays. Breast cancer. Mammography is a special type of X-ray test used to examine breast tissue. Enlarged heart. This sign of congestive heart failure shows up clearly on X-rays. Blocked blood vessels. Injecting a contrast material that contains iodine can help highlight sections ...

  12. Genome-wide screen of DNA methylation changes induced by low dose X-ray radiation in mice.

    Directory of Open Access Journals (Sweden)

    Jingzi Wang

    Full Text Available Epigenetic mechanisms play a key role in non-targeted effects of radiation. The purpose of this study was to investigate global hypomethylation and promoter hypermethylation of particular genes induced by low dose radiation (LDR. Thirty male BALB/c mice were divided into 3 groups: control, acutely exposed (0.5 Gy X-rays, and chronic exposure for 10 days (0.05Gy/d×10d. High-performance liquid chromatography (HPLC and MeDIP-quantitative polymerase chain reaction (qPCR were used to study methylation profiles. DNMT1 and MBD2 expression was determined by qPCR and western blot assays. Methylation and expression of Rad23b and Ddit3 were determined by bisulfate sequencing primers (BSP and qPCR, respectively. The results show that LDR induced genomic hypomethylation in blood 2 h postirraditaion, but was not retained at 1-month. DNMT1 and MBD2 were downregulated in a tissue-specific manner but did not persist. Specific hypermethylation was observed for 811 regions in the group receiving chronic exposure, which covered almost all key biological processes as indicated by GO and KEGG pathway analysis. Eight hypermethylated genes (Rad23b, Tdg, Ccnd1, Ddit3, Llgl1, Rasl11a, Tbx2, Scl6a15 were verified by MeDIP-qPCR. Among them, Rad23b and Ddit3 gene displayed tissue-specific methylation and downregulation, which persisted for 1-month postirradiation. Thus, LDR induced global hypomethylation and tissue-specific promoter hypermethylation of particular genes. Promoter hypermethylation, rather than global hypomethylation, was relatively stable. Dysregulation of methylation might be correlated with down-regulation of DNMT1 and MBD2, but much better understanding the molecular mechanisms involved in this process will require further study.

  13. Macropore flow at the field scale: predictive performance of empirical models and X-ray CT analyzed macropore characteristics

    Science.gov (United States)

    Naveed, M.; Moldrup, P.; Schaap, M.; Tuller, M.; Kulkarni, R.; Vögel, H.-J.; Wollesen de Jonge, L.

    2015-11-01

    Predictions of macropore flow is important for maintaining both soil and water quality as it governs key related soil processes e.g. soil erosion and subsurface transport of pollutants. However, macropore flow currently cannot be reliably predicted at the field scale because of inherently large spatial variability. The aim of this study was to perform field scale characterization of macropore flow and investigate the predictive performance of (1) current empirical models for both water and air flow, and (2) X-ray CT derived macropore network characteristics. For this purpose, 65 cylindrical soil columns (6 cm diameter and 3.5 cm height) were extracted from the topsoil (5 to 8.5 cm depth) in a 15 m × 15 m grid from an agricultural loamy field located in Silstrup, Denmark. All soil columns were scanned with an industrial CT scanner (129 μm resolution) and later used for measurements of saturated water permeability, air permeability and gas diffusivity at -30 and -100 cm matric potentials. Distribution maps for both water and air permeabilities and gas diffusivity reflected no spatial correlation irrespective of the soil texture and organic matter maps. Empirical predictive models for both water and air permeabilities showed poor performance as they were not able to realistically capture macropore flow because of poor correlations with soil texture and bulk density. The tested empirical model predicted well gas diffusivity at -100 cm matric potential, but relatively failed at -30 cm matric potential particularly for samples with biopore flow. Image segmentation output of the four employed methods was nearly the same, and matched well with measured air-filled porosity at -30 cm matric potential. Many of the CT derived macropore network characteristics were strongly interrelated. Most of the macropore network characteristics were also strongly correlated with saturated water permeability, air permeability, and gas diffusivity. The correlations between macropore

  14. Mapping strain fields induced in Zr-based bulk metallic glasses during in-situ nanoindentation by X-ray nanodiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gamcová, J.; Bednarčík, J.; Franz, H. [DESY, Notkestraße 85, Hamburg 22547 (Germany); Mohanty, G.; Wehrs, J.; Michler, J. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Michalik, Š. [Institute of Physics ASCR, Na Slovance 2, Praha 18221 (Czech Republic); Krywka, C. [HZG, Institut für Werkstoffforschung, Notkestraße 85, Hamburg 22547 (Germany); Breguet, J. M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Alemnis GmbH, Feuerwerkerstraße 39, Thun 3602 (Switzerland)

    2016-01-18

    A pioneer in-situ synchrotron X-ray nanodiffraction approach for characterization and visualization of strain fields induced by nanoindentation in amorphous materials is introduced. In-situ nanoindentation experiments were performed in transmission mode using a monochromatic and highly focused sub-micron X-ray beam on 40 μm thick Zr-based bulk metallic glass under two loading conditions. Spatially resolved X-ray diffraction scans in the deformed volume of Zr-based bulk metallic glass covering an area of 40 × 40 μm{sup 2} beneath the pyramidal indenter revealed two-dimensional map of elastic strains. The largest value of compressive elastic strain calculated from diffraction data at 1 N load was −0.65%. The region of high elastic compressive strains (<−0.3%) is located beneath the indenter tip and has radius of 7 μm.

  15. Improved Diagnostics by Assessing the Micromorphology of Breast Calcifications via X-Ray Dark-Field Radiography

    Science.gov (United States)

    Scherer, Kai; Braig, Eva; Ehn, Sebastian; Schock, Jonathan; Wolf, Johannes; Birnbacher, Lorenz; Chabior, Michael; Herzen, Julia; Mayr, Doris; Grandl, Susanne; Sztrókay-Gaul, Anikó; Hellerhoff, Karin; Pfeiffer, Franz

    2016-11-01

    Breast microcalcifications play an essential role in the detection and evaluation of early breast cancer in clinical diagnostics. However, in digital mammography, microcalcifications are merely graded with respect to their global appearance within the mammogram, while their interior microstructure remains spatially unresolved and therefore not considered in cancer risk stratification. In this article, we exploit the sub-pixel resolution sensitivity of X-ray dark-field contrast for clinical microcalcification assessment. We demonstrate that the micromorphology, rather than chemical composition of microcalcification clusters (as hypothesised by recent literature), determines their absorption and small-angle scattering characteristics. We show that a quantitative classification of the inherent microstructure as ultra-fine, fine, pleomorphic and coarse textured is possible. Insights underlying the micromorphological nature of breast calcifications are verified by comprehensive high-resolution micro-CT measurements. We test the determined microtexture of microcalcifications as an indicator for malignancy and demonstrate its potential to improve breast cancer diagnosis, by providing a non-invasive tool for sub-resolution microcalcification assessment. Our results indicate that dark-field imaging of microcalcifications may enhance the diagnostic validity of current microcalcification analysis and reduce the number of invasive procedures.

  16. Magma mixing in the Yellowstone Plateau Volcanic Field brought to light by X-ray microtomography and chemical analysis

    Science.gov (United States)

    Morgavi, Daniele; Arzilli, Fabio; Pritchard, Chad; Perugini, Diego; Mancini, Lucia; Larson, Peter; Dingwell, Donald Bruce

    2015-04-01

    The Yellowstone Plateau Volcanic Field (YVF) hosts at least four mixed magma complexes (Wilcox, 1944; Christiansen et al. 2007; Pritchard et al., 2013). We focus on the well-exposed Grizzly Lake complex. The main evidence of mixing in igneous rocks is commonly found as textural heterogeneities, such as i) flow structures, ii) magmatic enclaves and iii) physico-chemical disequilibria in melt and crystals (e.g. Perugini and Poli, 2012). From the geochemical and mineralogical point of view, quantitative and qualitative analyses of chemical and textural heterogeneity in mixed rocks highlights the important role of mixing dynamics in producing geochemical complexities and heterogeneities (Kratzmann et al., 2009). Zoned crystals and complex mineralogical associations are also considered, in many cases, evidence for mixing (e.g., Murphy at al., 1998; Couch et al., 2001). The generation of such textures implies the development of large contact interfaces between interacting melts/solids through which chemical and crystals exchanges are strongly amplified, leading to highly variable degrees of homogenization depending on differing element mobility (e.g. Perugini et al., 2006; 2008; De Campos et al., 2011; Perugini et al., 2012; Perugini and Poli, 2012; Morgavi et al., 2013a, b, c). Despite the abundant literature regarding magma mixing processes, only a few studies are focused on describing and quantifying the inter-relationship between the morphological texture of mixing patterns and the geochemical variability in mixed rhyolitic and basaltic complexes. (Freundt and Schmincke 1992; Morgavi et al., 2013 a, b, c;). Here, we combine two analytical techniques; X-ray computed microtomography and microprobe analysis to study the texture and chemistry of mixed rocks. Since mixed rocks of Grizzly Lake in the YVF had a very complex history and evolution, a significant amount of chemical measurements were needed to characterize the phases. In addition, X-ray microtomography was

  17. Performance evaluation of currently used portable X ray fluorescence instruments for measuring the lead content of paint in field samples.

    Science.gov (United States)

    Muller, Yan; Favreau, Philippe; Kohler, Marcel

    2014-01-01

    Field-portable X-ray fluorescence (FP-XRF) instruments are important for non-destructive, rapid and convenient measurements of lead in paint, in view of potential remediation. Using real-life paint samples, we compared measurements from three FP-XRF instruments currently used in Switzerland with laboratory measurements using inductively coupled plasma mass spectrometry after complete sample dissolution. Two FP-XRF devices that functioned by lead L shell excitation frequently underestimated the lead concentration of samples. Lack of accuracy correlated with lead depth and/or the presence of additional metal elements (Zn, Ba or Ti). A radioactive source emitter XRF that enabled the additional K shell excitation showed higher accuracy and precision, regardless of the depth of the lead layer in the sample or the presence of other elements. Inspection of samples by light and electron microscopy revealed the diversity of real-life samples, with multi-layered paints showing various depths of lead and other metals. We conclude that the most accurate measurements of lead in paint are currently obtained with instruments that provide at least sufficient energy for lead K shell excitation.

  18. A preliminary investigation of the potential of phase contrast x-ray imaging in the field of homeland security

    Science.gov (United States)

    Olivo, A.; Chana, D.; Speller, R.

    2008-11-01

    A novel technique based on coded apertures which makes x-ray phase contrast imaging (XPCi) feasible with conventional sources has been recently developed at University College London. This technique is expected to enable for the first time real-world applications of XPCi in fields as diverse as medical, biological and scientific imaging, industrial inspections and security scans. This paper focuses on XPCi applications in homeland security. A simulation of coded-aperture XPCi, which was experimentally validated in a previous work, has been used to produce images of potential threat objects, and to quantitatively assess detail visibility improvements in terms of contrast and signal-to-noise ratio over conventional techniques based on absorption. Free-space propagation phase contrast images taken with synchrotron radiation (SR) are also presented. Although not directly related to the coded-aperture technique used in the simulation, these can be considered indicative of the image quality that would be made available through coded-aperture XPCi with conventional sources: previous studies have demonstrated that this technique provides image enhancements compatible with those obtained with free-space propagation phase contrast with SR. Substantial enhancements in image quality and improvement in detail detectability in cluttered environments are demonstrated in this way. The results presented in this study and the software used to generate them will provide the basis for the design and realization of a dedicated imaging prototype.

  19. Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function

    Science.gov (United States)

    Vijayan, Sarath; Xiong, Zhenyu; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

    2017-03-01

    Beam shaping devices like ROI attenuators and compensation filters modulate the intensity distribution of the xray beam incident on the patient. This results in a spatial variation of skin dose due to the variation of primary radiation and also a variation in backscattered radiation from the patient. To determine the backscatter component, backscatter point spread functions (PSF) are generated using EGS Monte-Carlo software. For this study, PSF's were determined by simulating a 1 mm beam incident on the lateral surface of an anthropomorphic head phantom and a 20 cm thick PMMA block phantom. The backscatter PSF's for the head phantom and PMMA phantom are curve fit with a Lorentzian function after being normalized to the primary dose intensity (PSFn). PSFn is convolved with the primary dose distribution to generate the scatter dose distribution, which is added to the primary to obtain the total dose distribution. The backscatter convolution technique is incorporated in the dose tracking system (DTS), which tracks skin dose during fluoroscopic procedures and provides a color map of the dose distribution on a 3D patient graphic model. A convolution technique is developed for the backscatter dose determination for the nonuniformly spaced graphic-model surface vertices. A Gafchromic film validation was performed for shaped x-ray beams generated with an ROI attenuator and with two compensation filters inserted into the field. The total dose distribution calculated by the backscatter convolution technique closely agreed with that measured with the film.

  20. Small Field of View Scintimammography Gamma Camera Integrated to a Stereotactic Core Biopsy Digital X-ray System

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Weisenberger; Fernando Barbosa; T. D. Green; R. Hoefer; Cynthia Keppel; Brian Kross; Stanislaw Majewski; Vladimir Popov; Randolph Wojcik

    2002-10-01

    A small field of view gamma camera has been developed for integration with a commercial stereotactic core biopsy system. The goal is to develop and implement a dual-modality imaging system utilizing scintimammography and digital radiography to evaluate the reliability of scintimammography in predicting the malignancy of suspected breast lesions from conventional X-ray mammography. The scintimammography gamma camera is a custom-built mini gamma camera with an active area of 5.3 cm /spl times/ 5.3 cm and is based on a 2 /spl times/ 2 array of Hamamatsu R7600-C8 position-sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is < 4 mm full-width at half-maximum and a sensitivity of /spl sim/ 4000 Hz/mCi. The system is also capable of acquiring dynamic scintimammographic data to allow for dynamic uptake studies. Sample images of preliminary clinical results are presented to demonstrate the performance of the system.

  1. Identification of strain fields in pure Al and hybrid Ni/Al metal foams using X-ray micro-tomography under loading

    Science.gov (United States)

    Fíla, T.; Jiroušek, O.; Jung, A.; Kumpová, I.

    2016-11-01

    Hybrid foams are materials formed by a core from a standard open cell metal foam that is during the process of electrodeposition coated by a thin layer of different nanocrystalline metals. The material properties of the base metal foam are in this way modified resulting in higher plateau stress and, more importantly, by introduction of strain-rate dependence to its deformation response. In this paper, we used time-lapse X-ray micro-tomography for the mechanical characterization of Ni/Al hybrid foams (aluminium open cell foams with nickel coating layer). To fully understand the effects of the coating layer on the material's effective properties, we compared the compressive response of the base uncoated foam to the response of the material with coating thickness of 50 and 75 μm. Digital volume correlation (DVC) was applied to obtain volumetric strain fields of the deforming micro-structure up to the densification region of the deforming cellular structure. The analysis was performed as a compressive mechanical test with simultaneous observation using X-ray radiography and tomography. A custom design experimental device was used for compression of the foam specimens in several deformation states directly in the X-ray setup. Planar X-ray images were taken during the loading phases and a X-ray tomography was performed at the end of each loading phase (up to engineering strain 22%). The samples were irradiated using micro-focus reflection type X-ray tube and images were taken using a large area flat panel detector. Tomography reconstructions were used for an identification of a strain distribution in the foam using digital volumetric correlation. A comparison of the deformation response of the coated and the uncoated foam in uniaxial quasi-static compression is summarized in the paper.

  2. The Evolution of Normal Galaxy X-Ray Emission Through Cosmic History: Constraints from the 6 MS Chandra Deep Field-South

    Science.gov (United States)

    Lehmer, B. D.; Basu-Zych, A. R.; Mineo, S.; Brandt, W. N.; Eurfrasio, R. T.; Fragos, T.; Hornschemeier, A. E.; Lou, B.; Xue, Y. Q.; Bauer, F. E.; hide

    2016-01-01

    We present measurements of the evolution of normal-galaxy X-ray emission from z (is) approx. 0-7 using local galaxies and galaxy samples in the approx. 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations; however, hot gas is expected to provide small contributions to the observed-frame (is) less than 1 keV emission at z (is) less than 1. We show that a single scaling relation between X-ray luminosity (L(sub x)) and star-formation rate (SFR) literature, is insufficient for characterizing the average X-ray emission at all redshifts. We establish that scaling relations involving not only SFR, but also stellar mass and redshift, provide significantly improved characterizations of the average X-ray emission from normal galaxy populations at z (is) approx. 0-7. We further provide the first empirical constraints on the redshift evolution of X-ray emission from both low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings with stellar mass and SFR, respectively. We find L2 -10 keV(LMXB)/stellar mass alpha (1+z)(sub 2-3) and L2 -10 keV(HMXB)/SFR alpha (1+z), and show that these relations are consistent with XRB population-synthesis model predictions, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. We discuss how emission from XRBs could provide an important source of heating to the intergalactic medium in the early universe, exceeding that of active galactic nuclei.

  3. Synchrotron-Radiation Induced X-Ray Emission (SRIXE)

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Keith W.

    1999-09-01

    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.

  4. Radio emission from the X-ray pulsar Her X-1: a jet launched by a strong magnetic field neutron star?

    Science.gov (United States)

    van den Eijnden, J.; Degenaar, N.; Russell, T. D.; Miller-Jones, J. C. A.; Wijnands, R.; Miller, J. M.; King, A. L.; Rupen, M. P.

    2018-01-01

    Her X-1 is an accreting neutron star (NS) in an intermediate-mass X-ray binary. Like low-mass X-ray binaries (LMXBs), it accretes via Roche lobe overflow, but similar to many high-mass X-ray binaries containing a NS; Her X-1 has a strong magnetic field and slow spin. Here, we present the discovery of radio emission from Her X-1 with the Very Large Array. During the radio observation, the central X-ray source was partially obscured by a warped disc. We measure a radio flux density of 38.7 ± 4.8 μJy at 9 GHz but cannot constrain the spectral shape. We discuss possible origins of the radio emission, and conclude that coherent emission, a stellar wind, shocks and a propeller outflow are all unlikely explanations. A jet, as seen in LMXBs, is consistent with the observed radio properties. We consider the implications of the presence of a jet in Her X-1 on jet formation mechanisms and on the launching of jets by NSs with strong magnetic fields.

  5. Fabrication of applicator system of miniature X-ray tube based on carbon nanotubes for a skin cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Han Beom; Kim, Hyun Jin; Lee, Ju Hyuk; Ha, Jun Mok; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    A miniature X-ray tube is a small X-ray generation device generally with a diameter of less than 10 mm. Because of the feasible installation in a spatially constrained area and the possibility of electrical on/off control, miniature X-ray tubes can be widely used for nondestructive X-ray radiography, hand held X-ray spectrometers, electric brachytherapy, and interstitial or intracavitary radiation therapy or imaging with the substitution of radioactive isotopes. Miniature X-ray tubes have been developed mostly using thermionic electron sources or secondary X-ray emission. The X-ray tube show excellent field emission properties and good X-ray spectrum. Also, the flattening filter was made to irradiate uniformly. The X-ray dose radial uniformities between installed flattening filter and non-installed flattening filter were measured. When flattening filter is equipped, X-ray uniformity was improved from higher than 20% to lower than 10%. As a result, the fabricated applicator system of the miniature X-ray tube using optimized flattening filter exhibited fairly excellent properties.

  6. Exploring transient X-ray sky with Einstein Probe

    Science.gov (United States)

    Yuan, W.; Zhang, C.; Ling, Z.; Zhao, D.; Chen, Y.; Lu, F.; Zhang, S.

    2017-10-01

    The Einstein Probe is a small satellite in time-domain astronomy to monitor the soft X-ray sky. It is a small mission in the space science programme of the Chinese Academy of Sciences. It will carry out systematic survey and characterisation of high-energy transients at unprecedented sensitivity, spatial resolution, Grasp and monitoring cadence. Its wide-field imaging capability is achieved by using established technology of micro-pore lobster-eye X-ray focusing optics. Complementary to this is X-ray follow-up capability enabled by a narrow-field X-ray telescope. It is capable of on-board triggering and real time downlink of transient alerts, in order to trigger fast follow-up observations at multi-wavelengths. Its scientific goals are concerned with discovering and characterising diverse types of X-ray transients, including tidal disruption events, supernova shock breakouts, high-redshift GRBs, and of particular interest, X-ray counterparts of gravitational wave events.

  7. X-ray Properties of the z ~ 4.5 Lyα Emitters in the Chandra Deep Field South Region

    Science.gov (United States)

    Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E.; Finkelstein, K. D.

    2010-07-01

    We report the first X-ray detection of Lyα emitters (LAEs) at redshift z ~ 4.5. One source (J033127.2-274247) is detected in the Extended Chandra Deep Field-South (ECDF-S) X-ray data and has been spectroscopically confirmed as a z = 4.48 quasar with LX = 4.2 × 1044 erg s-1. The single detection gives an Lyα quasar density of ~ 2.7+6.2 -2.2 × 10-6 Mpc-3, consistent with the X-ray luminosity function of quasars. Another 22 LAEs in the central Chandra Deep Field-South region are not detected individually, but their co-added counts yield an S/N = 2.4 (p = 99.83%) detection at soft band, with an effective exposure time of ~36 Ms. Further analysis of the equivalent width (EW) distribution shows that all the signals come from 12 LAE candidates with EWrestLAEs. If the average X-ray emission is due to star formation, it corresponds to a star formation rate (SFR) of 3%-10%. However, our upper limit on the SFR X is ~7 times larger than the upper limit on SFR X on z ~ 3.1 LAEs in the same field and at least 30 times higher than the SFR estimated from Lyα emission. From the average X-ray-to-Lyα line ratio, we estimate that fewer than 3.2% (6.3%) of our LAEs could be high-redshift type 1 (type 2) active galactic nuclei (AGNs) and those hidden AGNs likely show low rest-frame EWs.

  8. X-Ray Polarimetry

    OpenAIRE

    Kaaret, Philip

    2014-01-01

    We review the basic principles of X-ray polarimetry and current detector technologies based on the photoelectric effect, Bragg reflection, and Compton scattering. Recent technological advances in high-spatial-resolution gas-filled X-ray detectors have enabled efficient polarimeters exploiting the photoelectric effect that hold great scientific promise for X-ray polarimetry in the 2-10 keV band. Advances in the fabrication of multilayer optics have made feasible the construction of broad-band ...

  9. Nanoscale uniformity of pore architecture in diatomaceous silica : A combined small and wide angle X-ray scattering study

    NARCIS (Netherlands)

    Vrieling, EG; Beelen, TPM; van Santen, RA; Gieskes, WWC

    Combined small and wide angle IZ-ray scattering (SAXS and WAXS) analysis was applied to purified biogenic silica of cultured diatom frustules and of natural populations sampled on marine tidal flats. The overall WAXS patterns did not reveal crystalline phases (WAXS domain between 0.07 to 0.5 nm) in

  10. Handbook of X-Ray Data

    CERN Document Server

    Zschornack, Günter

    2007-01-01

    This sourcebook is intended as an X-ray data reference for scientists and engineers working in the field of energy or wavelength dispersive X-ray spectrometry and related fields of basic and applied research, technology, or process and quality controlling. In a concise and informative manner, the most important data connected with the emission of characteristic X-ray lines are tabulated for all elements up to Z = 95 (Americium). This includes X-ray energies, emission rates and widths as well as level characteristics such as binding energies, fluorescence yields, level widths and absorption edges. The tabulated data are characterized and, in most cases, evaluated. Furthermore, all important processes and phenomena connected with the production, emission and detection of characteristic X-rays are discussed. This reference book addresses all researchers and practitioners working with X-ray radiation and fills a gap in the available literature.

  11. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... evaluated). MRI can also detect subtle or occult fractures or bone bruises (also called bone contusions or microfractures) not visible on x-ray images. CT is being used widely to assess trauma patients in ... fractures, subtle fractures or dislocations. In elderly or patients ...

  12. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... for a physician to view and assess bone injuries, including fractures, and joint abnormalities, such as arthritis. X-ray equipment is relatively inexpensive and widely available in emergency rooms, physician offices, ambulatory care centers, nursing homes and other locations, making it ...

  13. X-ray diffraction study of the composition and strain fields in buried SiGe islands

    NARCIS (Netherlands)

    Hrauda, N.; Zhang, J.J.; Stoffel, M.; Stangl, J.; Bauer, G.; Rehman-Khan, A.; Holy, V.; Schmidt, O.G.; Jovanovic, V.; Nanver, L.K.

    2009-01-01

    We report on studies of strain and composition of two-dimensionally ordered SiGe islands grown by molecular beam epitaxy using high resolution x-ray diffraction. To ensure a small size distribution of the islands, pit-patterned 4 (001) Si wafers were used as substrates. The Si wafers were patterned

  14. Chest X-Ray

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... d like to talk with you about chest radiography also known as chest x-rays. Chest x- ...

  15. Chest X-Ray

    Medline Plus

    Full Text Available ... to consider the likelihood of benefit to your health. While a chest x-ray use a tiny dose of ionizing radiation, the benefit of an accurate diagnosis far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot ...

  16. 6 MV x-ray spectra obtained by small field size attenuation measurements in water and their use in small field size dosimetry

    Science.gov (United States)

    Lu, Cenney W.

    Direct measurement of x-ray spectra produced by medical linear accelerators is not possible because of high intensity and energy of the radiation involved. Knowledge of energy spectra are very useful in determination of parameters that convert from ionization chamber measurements to absorbed dose. Many indirect methods for determination of x-ray spectra in therapy beams have been developed. In the present work photon beams generated by a 6-MV Varian 6000 linear accelerator were used to obtain small field (0.5 x 0.5 to 4.0 x 4.0 cm 2 at 0.5 cm increments per side) attenuation values in water for the depths from 5 to 30 cm, at 5 cm increments. Attenuation values lying between those depths were interpolated using the Newton-Coates method and attenuation data of zero-field was obtained by extrapolation. Based on the measured attenuation curves, the relative air kerma and photon energy x-ray spectra were derived for all investigating fields using a user input parameter program and an iterative procedure. The attenuation curves of the radiation fields were calculated using the reconstructed spectrum. They were compared with the measured attenuation data at each iteration step until a satisfactory fit between the measured and calculated attenuation curves was obtained. In order for derived spectra to be of practical use in radiotherapy treatment planning, they must accurate reproduce measured dose distribution data. From the knowledge of the incident beam attenuation and the incident x-ray energy spectrum for the zero-field, the percentage depth dose of the zero-field was calculated at different points along the Central Axis. The percentage depth doses of larger fields were calculated by applying of the Relative Scatter Factor to the percentage depth dose of the zero-field. The agreement was within 1.11% for all fields, ranging from 0.5 x 0.5 to 4.0 x 4.0 cm2 at 0.5 cm increments per side. Further, the reconstructed spectrum for 4 x 4 cm2 field size was used in Monte

  17. X-ray microdiffraction of biominerals.

    Science.gov (United States)

    Tamura, Nobumichi; Gilbert, Pupa U P A

    2013-01-01

    Biominerals have complex and heterogeneous architectures, hence diffraction experiments with spatial resolutions between 500 nm and 10 μm are extremely useful to characterize them. X-ray beams in this size range are now routinely produced at many synchrotrons. This chapter provides a review of the different hard X-ray diffraction and scattering techniques, used in conjunction with efficient, state-of-the-art X-ray focusing optics. These include monochromatic X-ray microdiffraction, polychromatic (Laue) X-ray microdiffraction, and microbeam small-angle X-ray scattering. We present some of the most relevant discoveries made in the field of biomineralization using these approaches. © 2013 Elsevier Inc. All rights reserved.

  18. X-ray Observations of "Recycled" Pulsars

    Science.gov (United States)

    Bogdanov, Slavko

    2014-11-01

    The Chandra X-ray Observatory has been instrumental in establishing the X-ray properties of the Galactic population of rotation-powered ("recycled") millisecond pulsars. In this talk I will provide a summary of deep X-ray studies of globular cluster millisecond pulsars, as well as several nearby field millisecond pulsars. These include thermally-emitting recycled pulsars that may provide stringent constraints on the elusive neutron star equation of state, and so-called "redback" binary pulsars, which seem to sporadically revert to an X-ray binary-like state.

  19. Characterization of a synthetic single crystal diamond detector for dosimetry in spatially fractionated synchrotron x-ray fields.

    Science.gov (United States)

    Livingstone, Jayde; Stevenson, Andrew W; Butler, Duncan J; Häusermann, Daniel; Adam, Jean-François

    2016-07-01

    Modern radiotherapy modalities often use small or nonstandard fields to ensure highly localized and precise dose delivery, challenging conventional clinical dosimetry protocols. The emergence of preclinical spatially fractionated synchrotron radiotherapies with high dose-rate, sub-millimetric parallel kilovoltage x-ray beams, has pushed clinical dosimetry to its limit. A commercially available synthetic single crystal diamond detector designed for small field dosimetry has been characterized to assess its potential as a dosimeter for synchrotron microbeam and minibeam radiotherapy. Experiments were carried out using a synthetic diamond detector on the imaging and medical beamline (IMBL) at the Australian Synchrotron. The energy dependence of the detector was characterized by cross-referencing with a calibrated ionization chamber in monoenergetic beams in the energy range 30-120 keV. The dose-rate dependence was measured in the range 1-700 Gy/s. Dosimetric quantities were measured in filtered white beams, with a weighted mean energy of 95 keV, in broadbeam and spatially fractionated geometries, and compared to reference dosimeters. The detector exhibits an energy dependence; however, beam quality correction factors (kQ) have been measured for energies in the range 30-120 keV. The kQ factor for the weighted mean energy of the IMBL radiotherapy spectrum, 95 keV, is 1.05 ± 0.09. The detector response is independent of dose-rate in the range 1-700 Gy/s. The percentage depth dose curves measured by the diamond detector were compared to ionization chambers and agreed to within 2%. Profile measurements of microbeam and minibeam arrays were performed. The beams are well resolved and the full width at halfmaximum agrees with the nominal width of the beams. The peak to valley dose ratio (PVDR) calculated from the profiles at various depths in water agrees within experimental error with PVDR calculations from Gafchromic film data. The synthetic diamond detector is now well

  20. Evaluation of patient dose saving in grid-less x-ray mammography acquisition compared with full field digital mammography (FFDMG) acquisition

    DEFF Research Database (Denmark)

    Abdi, Ahmed Jibril; Mussmann, Bo Redder

    2017-01-01

    thicknesses were then converted to an equivalent compressed breast tissue thicknesses. The average glandular dose (AGD) is calculated. Results: Dose reduction in both the directly measured entrance exposure and the calculated AGD is between 13% and 32% in the grid-less mammography acquisition. The contrast......Purpose: To investigate the patient radiation dose saving of grid-less X-ray mammography acquisitions compared with conventional full-field digital X-ray mammography (FFDMG). Methods and materials: The Siemens Inspiration MAMMOMAT PRIME system with Software Based Scatter Correction (SBSC) was used...... to investigate the dose saving in grid-less acquisition compared with conventional full-field digital mammography (FFDMG) acquisitions. A Piranha 657 was used to measure the entrance exposure. The entrance exposure was directly measured on different PMMA thicknesses of 20-70mm in steps of 10mm. The PMMA block...

  1. Thermo-enhanced field emission from ZnO nanowires: Role of defects and application in a diode flat panel X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhipeng; Chen, Daokun; Chen, Wenqing; Chen, Yicong; Song, Xiaomeng; Zhan, Runze; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun, E-mail: stscjun@mail.sysu.edu.cn

    2017-03-31

    Highlights: • A thermo-enhanced field emission phenomenon was observed from dendritic ZnO nanowires under the temperature of 323–723 K. • Defect-assisted field emission mechanism was proposed and quantitative calculation fits well with the experiment results. • The mechanism was verified by the field emission from ZnO nanowires with different defect concentrations. • A diode X-ray source making use of thermo-enhanced field emission phenomenon was proposed for separate tuning of dose and energy. - Abstract: A thermo-enhanced field emission phenomenon was observed from ZnO nanowires. The field emission current increased by almost two orders of magnitude under a constant applied electric field, and the turn-on field decreased from 6.04 MV/m to 5.0 MV/m when the temperature increased from 323 to 723 K. The Poole–Frenkel electron excitation from the defect-induced trapping centers to the conduction band under high electric fields is believed to be the primary cause of the observed phenomenon. The experimental results fit well with the proposed physical model. The field emission from ZnO nanowires with different defect concentrations further confirmed the role of defects. Using the thermo-enhanced field emission phenomenon, a diode flat panel X-ray source was demonstrated, for which the energy and dose can be separately tuned. The thermo-enhanced field emission phenomenon observed from ZnO nanowires could be an effective way to realize a large area flat panel multi-energy X-ray source.

  2. Elemental analysis with a full-field X-ray fluorescence microscope and a CCD photon-counting system.

    Science.gov (United States)

    Ohigashi, Takuji; Watanabe, Norio; Yokosuka, Hiroki; Aota, Tatsuya; Takano, Hidekazu; Takeuchi, Akihisa; Aoki, Sadao

    2002-05-01

    The first result is presented of an X-ray fluorescence microscope with a Wolter mirror in combination with a CCD camera used as an energy-resolved two-dimensional detector in photon-counting mode. Two-dimensional elemental maps of metallic wires, such as Fe, Co, Ni and Cu, and inclusions of a synthesized diamond could be obtained with an energy resolution of 350 eV.

  3. Bone X-Ray (Radiography)

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    Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

  4. Bone X-Ray (Radiography)

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    Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  5. Abdomen X-Ray (Radiography)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a very small ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

  6. Experimental observation of temperature and magnetic-field evolution of the 4 f states in CeFe2 revealed by soft x-ray magnetic circular dichroism

    Science.gov (United States)

    Saitoh, Y.; Yasui, A.; Fuchimoto, H.; Nakatani, Y.; Fujiwara, H.; Imada, S.; Narumi, Y.; Kindo, K.; Takahashi, M.; Ebihara, T.; Sekiyama, A.

    2017-07-01

    We revisit the delocalized character of the 4 f states of CeFe2 in the ferromagnetically ordered phase by x-ray magnetic circular dichroism (XMCD) in x-ray absorption spectroscopy (XAS) with improved data quality using single crystals. Surprisingly, the Ce M4 ,5 XMCD spectral shape changes significantly as a function of temperature and applied magnetic field, with no concomitant changes in the spectral shape of the Ce M4 ,5 XAS as well as the Fe L2 ,3 XAS and XMCD. This unusual behavior is characterized by the J =7 /2 states in a 4 f1 configuration mixed into the J =5 /2 ground state. Such extreme sensitivity of the Ce 4 f states to the external perturbations can be related to the magnetic instability toward an antiferromagnetic phase in CeFe2. Our experimental data presented here provide valuable insights into the underlying physics in strongly hybridized ferromagnetic Ce compounds.

  7. Symbiotic Stars in X-rays

    Science.gov (United States)

    Luna, G. J. M.; Sokoloski, J. L.; Mukai, K.; Nelson, T.

    2014-01-01

    hard X-ray emission from the innermost accretion region. Since we have identified the elusive accretion component in the emission from a sample of symbiotic stars, our results have implications for the understanding of wind-fed mass transfer in wide binaries, and the accretion rate in one class of candidate progenitors of type Ia supernovae.

  8. Quantification of trace arsenic in soils by field-portable X-ray fluorescence spectrometry: considerations for sample preparation and measurement conditions.

    Science.gov (United States)

    Parsons, Chris; Margui Grabulosa, Eva; Pili, Eric; Floor, Geerke H; Roman-Ross, Gabriela; Charlet, Laurent

    2013-11-15

    Recent technological improvements have led to the widespread adoption of field portable energy dispersive X-ray fluorescence (FP-XRF) by governmental agencies, environmental consultancies and research institutions. FP-XRF units often include analysis modes specifically designed for the quantification of trace elements in soils. Using these modes, X-ray tube based FP-XRF units can offer almost "point and shoot" ease of use and results comparable to those of laboratory based instruments. Nevertheless, FP-XRF analysis is sensitive to spectral interferences as well as physical and chemical matrix effects which can result in decreased precision and accuracy. In this study, an X-ray tube-based FP-XRF analyser was used to determine trace (low ppm) concentrations of As in a floodplain soil. The effect of different sample preparation and analysis conditions on precision and accuracy were systematically evaluated. We propose strategies to minimise sources of error and maximise data precision and accuracy, achieving in situ limits of detection and precision of 6.8 ppm and 14.4%RSD, respectively for arsenic. We demonstrate that soil moisture, even in relatively dry soils, dramatically affects analytical performance with a signal loss of 37% recorded for arsenic at 20 wt% soil moisture relative to dry soil. We also highlight the importance of the use of certified reference materials and independent measurement methods to ensure accurate correction of field values. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. A search for the presence of magnetic fields in the two supergiant fast X-ray transients, IGR J08408-4503 and IGR J11215-5952

    Science.gov (United States)

    Hubrig, S.; Sidoli, L.; Postnov, K.; Schöller, M.; Kholtygin, A. F.; Järvinen, S. P.; Steinbrunner, P.

    2018-02-01

    A significant fraction of high-mass X-ray binaries are supergiant fast X-ray transients (SFXTs). The prime model for the physics governing their X-ray behaviour suggests that the winds of donor OB supergiants are magnetized. To investigate if magnetic fields are indeed present in the optical counterparts of such systems, we acquired low-resolution spectropolarimetric observations of the two optically brightest SFXTs, IGR J08408-4503 and IGR J11215-5952, with the ESO FORS 2 instrument during two different observing runs. No field detection at a significance level of 3σ was achieved for IGR J08408-4503. For IGR J11215-5952, we obtain 3.2σ and 3.8σ detections (⟨Bz⟩hydr = -978 ± 308 G and ⟨Bz⟩hydr = 416 ± 110 G) on two different nights in 2016. These results indicate that the model involving the interaction of a magnetized stellar wind with the neutron star magnetosphere can indeed be considered to characterize the behaviour of SFXTs. We detected long-term spectral variability in IGR J11215-5952, whereas for IGR J08408-4503, we find an indication of the presence of short-term variability on a time-scale of minutes.

  10. Optical Design for a Survey X-Ray Telescope

    Science.gov (United States)

    Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

    2014-01-01

    Optical design trades are underway at the Goddard Space Flight Center to define a telescope for an x-ray survey mission. Top-level science objectives of the mission include the study of x-ray transients, surveying and long-term monitoring of compact objects in nearby galaxies, as well as both deep and wide-field x-ray surveys. In this paper we consider Wolter, Wolter-Schwarzschild, and modified Wolter-Schwarzschild telescope designs as basic building blocks for the tightly nested survey telescope. Design principles and dominating aberrations of individual telescopes and nested telescopes are discussed and we compare the off-axis optical performance at 1.0 KeV and 4.0 KeV across a 1.0-degree full field-of-view.

  11. Chest X-Ray

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    Full Text Available ... Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey ...

  12. Chest X-Ray

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    Full Text Available ... Index A-Z Spotlight March is National Colorectal Cancer Awareness Month Recently posted: Carotid Intima-Media Thickness ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  13. Chest X-Ray

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    Full Text Available ... Site Index A-Z Spotlight February is American Heart Month Recently posted: Carotid Intima-Media Thickness Test ... x-ray is used to evaluate the lungs, heart and chest wall and may be used to ...

  14. Chest X-Ray

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    Full Text Available ... chest x-ray is used to evaluate the lungs, heart and chest wall and may be used ... diagnose and monitor treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A ...

  15. Chest X-Ray

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    Full Text Available ... breath, persistent cough, fever, chest pain or injury. It may also be useful to help diagnose and ... have some concerns about chest x-rays. However, it’s important to consider the likelihood of benefit to ...

  16. Chest X-Ray

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    Full Text Available ... accurate diagnosis far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot ... Inc. (RSNA). To help ensure current and accurate information, we do not permit copying but encourage linking ...

  17. Sinus x-ray

    Science.gov (United States)

    ... an infection and inflammation of the sinuses called sinusitis . A sinus x-ray is ordered when you have any of the following: Symptoms of sinusitis Other sinus disorders, such as a deviated septum ( ...

  18. Chest X-Ray

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    Full Text Available ... Index A-Z Spotlight November is National Lung Cancer Awareness Month Recently posted: Carotid Intima-Media Thickness ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  19. Chest X-Ray

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    Full Text Available ... exams and use a very small dose of ionizing radiation to produce pictures of the inside of the ... chest x-ray use a tiny dose of ionizing radiation, the benefit of an accurate diagnosis far outweighs ...

  20. Chest X-Ray

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    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  1. X-ray

    Science.gov (United States)

    ... X-ray References Geleijns J, Tack D. Medical physics: radiation risks. In: Adam A, Dixon AK, Gillard ... Updated by: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic ...

  2. Chest X-Ray

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    Full Text Available ... and use a very small dose of ionizing radiation to produce pictures of the inside of the ... x-ray use a tiny dose of ionizing radiation, the benefit of an accurate diagnosis far outweighs ...

  3. Chest X-Ray

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    Full Text Available ... Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. ... University in Durham, North Carolina. I’d like to talk with you about chest radiography also known ...

  4. Chest X-Ray

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    Full Text Available ... Index A-Z Spotlight October is National Breast Cancer Awareness Month Recently posted: Carotid Intima-Media Thickness ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  5. A multipurpose ultra-high vacuum-compatible chamber for in situ X-ray surface scattering studies over a wide range of temperature and pressure environment conditions

    Science.gov (United States)

    Ferrer, P.; Rubio-Zuazo, J.; Heyman, C.; Esteban-Betegón, F.; Castro, G. R.

    2013-03-01

    A low/high temperature (60-1000K) and pressure (10-10-3x103 mbar) "baby chamber", specially adapted to the grazing-incidence X-ray scattering station, has been designed, developed and installed at the Spanish CRG BM25 SpLine beamline at European Synchrotron Radiation Facility. The chamber has a cylindrical form with 100 mm of diameter, built on a 360° beryllium nipple of 150 mm height. The UHV equipment and a turbo pump are located on the upper part of the chamber to leave a wide solid angle for exploring reciprocal space. The chamber features 4 CF16 and 5 CF40 ports for electrical feed through and leak valves, ion gun, etc. The heat exchanger is a customized compact LN2 (or LHe) continuous flow cryostat. The sample is mounted on a Mo support on the heat exchanger, which has in the back side a BORALECTRIC® Heater Elements. Experiments of surfaces/interfaces/ multilayer materials, thin films or single crystals in a huge variety of environments can be performed, also in situ studies of growth or evolution of the samples. Data measurement can be collected with a punctual and a bi-dimensional detector, being possible to simultaneously use them.

  6. Structure of Poly(dialkylsiloxane) Melts: Comparisons of Wide-Angle X-ray Scattering, Molecular Dynamics Simualations, and Integral Equation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Habenschuss, Anton {Tony} [ORNL; Tsige, Mesfin [Southern Illinois University; Curro, John G. [Sandia National Laboratories (SNL); Grest, Gary S. [Sandia National Laboratories (SNL); Nath, Shyamal [CULGI Inc, Albuquerque, NM

    2007-01-01

    Wide-angle X-ray scattering, molecular dynamics (MD) simulations, and integral equation theory are used to study the structure of poly(diethylsiloxane) (PDES), poly(ethylmethylsiloxane) (PEMS), and poly(dimethylsiloxane) (PDMS) melts. The structure functions of PDES, PEMS, and PDMS are similar, but systematic trends in the intermolecular packing are observed. The local intramolecular structure is extracted from the experimental structure functions. The bond distances and bond angles obtained, including the large Si-O-Si angle, are in good agreement with the explicit atom (EA) and united atom (UA) potentials used in the simulations and theory and from other sources. Very good agreement is found between the MD simulations using the EA potentials and the experimental scattering results. Good agreement is also found between the polymer reference interaction site model (PRISM theory) and the UA MD simulations. The intermolecular structure is examined experimentally using an appropriately weighted radial distribution function and with theory and simulation using intermolecular site/site pair correlation functions. Experiment, simulation, and theory show systematic increases in the chain/chain packing distances in the siloxanes as the number of sites in the pendant side chains is increased.

  7. Structure of Poly(dialkylsiloxane) Melts: Comparisons of Wide Angle X-ray Scattering, Molecular Dynamics Simulations, and Integral Equation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Habenschuss, Anton {Tony} [ORNL; Tsige, Mesfin [Southern Illinois University; Curro, John G. [Sandia National Laboratories (SNL); Grest, Gary S. [Sandia National Laboratories (SNL); Nath, Shyamal [CULGI Inc, Albuquerque, NM

    2007-01-01

    Wide-angle X-ray scattering, molecular dynamics (MD) simulations, and integral equation theory are used to study the structure of poly(diethylsiloxane) (PDES), poly(ethylmethylsiloxane) (PEMS), and poly(dimethylsiloxane) (PDMS) melts. The structure functions of PDES, PEMS, and PDMS are similar, but systematic trends in the intermolecular packing are observed. The local intramolecular structure is extracted from the experimental structure functions. The bond distances and bond angles obtained, including the large Si-O-Si angle, are in good agreement with the explicit atom (EA) and united atom (UA) potentials used in the simulations and theory and from other sources. Very good agreement is found between the MD simulations using the EA potentials and the experimental scattering results. Good agreement is also found between the polymer reference interaction site model (PRISM theory) and the UA MD simulations. The intermolecular structure is examined experimentally using an appropriately weighted radial distribution function and with theory and simulation using intermolecular site/site pair correlation functions. Experiment, simulation, and theory show systematic increases in the chain/chain packing distances in the siloxanes as the number of sites in the pendant side chains is increased.

  8. Three-Dimensional Morphology Control Yielding Enhanced Hole Mobility in Air-Processed Organic Photovoltaics: Demonstration with Grazing-Incidence Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Levi M. J. [School of Polymers; Bhattacharya, Mithun [School of Polymers; Wu, Qi [School of Polymers; Youm, Sang Gil [Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States; Nesterov, Evgueni E. [Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States; Morgan, Sarah E. [School of Polymers

    2017-06-28

    Polymer organic photovoltaic (OPV) device performance is defined by the three-dimensional morphology of the phase-separated domains in the active layer. Here, we determine the evolution of morphology through different stages of tailored solvent vapor and thermal annealing techniques in air-processed poly(3-hexylthiophene-2,5-diyl)/phenyl-C61-butyric acid methyl ester-based OPV blends. A comparative evaluation of the effect of solvent type used for vapor annealing was performed using grazing-incidence wide-angle X-ray scattering, atomic force microscopy, and UV–vis spectroscopy to probe the active-layer morphology. A nonhalogenated orthogonal solvent was found to impart controlled morphological features within the exciton diffusion length scales, enhanced absorbance, greater crystallinity, increased paracrystalline disorder, and improved charge-carrier mobility. Low-boiling, fast-diffusing isopropanol allowed the greatest control over the nanoscale structure of the solvents evaluated and yielded a cocontinuous morphology with narrowed domains and enhanced paths for the charge carrier to reach the anode.

  9. Microscopic structures of tri-n-butyl phosphate/n-octane mixtures by X-ray and neutron scattering in a wide q range.

    Science.gov (United States)

    Motokawa, Ryuhei; Suzuki, Shinichi; Ogawa, Hiroki; Antonio, Mark R; Yaita, Tsuyoshi

    2012-02-02

    Tri-n-butyl phosphate (TBP) is an important extractant for separating hexavalent uranium and tetravalent plutonium from used nuclear fuel by solvent extraction. In such solvent extractions using TBP, the organic phase occasionally separates into two organic phases, namely, light and heavy organic phases. The latter one in particular is called the third phase. The purpose of this work is to elucidate the mechanism whereby the third phase forms in biphasic liquid-liquid solvent extraction of heavy metal ions. Toward this end, small- and wide-angle X-ray and neutron scattering (SWAXS and SWANS) experiments were conducted to examine the microscopic structures of TBP/octane mixtures. These investigations of solute associations in TBP-containing organic phases before extraction of heavy metal ions provide insights into system performance. After the extraction of heavy metal ions, for example, the microscopic structures formed in the organic phase are likely to be correlated with the initial microscopic structures, which are revealed here. SWAXS and SWANS, with accurate estimations of incoherent scattering intensities for all solution samples, revealed the following: (i) TBP self-associates in octane, and the average distance between two TBP molecules in the TBP assemblies is evaluated as 0.9-1.0 nm; (ii) the shape of the TBP assembly is ellipsoidal; and (iii) the attractive interaction among TBP assemblies in octane is miniscule, and thus, they tend to be dispersed homogeneously due to the excluded volume effect.

  10. Stellar X-Ray Polarimetry

    Science.gov (United States)

    Swank, J.

    2011-01-01

    Most of the stellar end-state black holes, pulsars, and white dwarfs that are X-ray sources should have polarized X-ray fluxes. The degree will depend on the relative contributions of the unresolved structures. Fluxes from accretion disks and accretion disk corona may be polarized by scattering. Beams and jets may have contributions of polarized emission in strong magnetic fields. The Gravity and Extreme Magnetism Small Explorer (GEMS) will study the effects on polarization of strong gravity of black holes and strong magnetism of neutron stars. Some part of the flux from compact stars accreting from companion stars has been reflected from the companion, its wind, or accretion streams. Polarization of this component is a potential tool for studying the structure of the gas in these binary systems. Polarization due to scattering can also be present in X-ray emission from white dwarf binaries and binary normal stars such as RS CVn stars and colliding wind sources like Eta Car. Normal late type stars may have polarized flux from coronal flares. But X-ray polarization sensitivity is not at the level needed for single early type stars.

  11. Bone X-Ray (Radiography)

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    Full Text Available ... drawer under the table holds the x-ray film or image recording plate . Sometimes the x-ray ... extended over the patient while an x-ray film holder or image recording plate is placed beneath ...

  12. Bone X-Ray (Radiography)

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    Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. ... x-rays. A Word About Minimizing Radiation Exposure Special care is taken during x-ray examinations to ...

  13. Bone X-Ray (Radiography)

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    Full Text Available ... position possible that still ensures x-ray image quality. top of page Who interprets the results and ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

  14. Bone X-Ray (Radiography)

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    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

  15. Bone X-Ray (Radiography)

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    Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. ... Media Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to X-ray (Radiography) - ...

  16. Bone X-Ray (Radiography)

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    Full Text Available ... of knee x-rays. A portable x-ray machine is a compact apparatus that can be taken ... of the body being examined, an x-ray machine produces a small burst of radiation that passes ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ... Safety page for more information about radiation dose. Women should always inform their physician or x-ray ...

  18. The First Wide-field X-ray Imaging Telescope for Observations of Charge Exchange Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We will demonstrate a full, end-to-end, lobster-eye optic instrument at GSFC. The STORM prototype is fully self-contained, including integrated pre-amps, HV power...

  19. Watching Nanoparticles Form: An In Situ (Small-/Wide-Angle X-ray Scattering/Total Scattering) Study of the Growth of Yttria-Stabilised Zirconia in Supercritical Fluids

    DEFF Research Database (Denmark)

    Tyrsted, Christoffer; Pauw, Brian; Jensen, Kirsten Marie Ørnsbjerg

    2012-01-01

    Understanding nanoparticle formation reactions requires multitechnique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/total-scattering study of nano...... of nanoparticle formation is presented. We report on the formation and growth of yttria-stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y2O3 equivalent molar fractions of 0, 4, 8, 12 and 25%....

  20. Crystal analyser-based X-ray phase contrast imaging in the dark field: implementation and evaluation using excised tissue specimens

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Masami [RIST, Tokyo University of Science, Noda, Chiba (Japan); Sunaguchi, Naoki [Gunma University, Graduate School of Engineering, Kiryu, Gunma (Japan); Wu, Yanlin [The Graduate University for Advanced Studies, Department of Materials Structure Science, School of High Energy Accelerator Science, Tsukuba, Ibaraki (Japan); Do, Synho; Sung, Yongjin; Gupta, Rajiv [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Louissaint, Abner [Massachusetts General Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Yuasa, Tetsuya [Yamagata University, Faculty of Engineering, Yonezawa, Yamagata (Japan); Ichihara, Shu [Nagoya Medical Center, Department of Pathology, Nagoya, Aichi (Japan)

    2014-02-15

    We demonstrate the soft tissue discrimination capability of X-ray dark-field imaging (XDFI) using a variety of human tissue specimens. The experimental setup for XDFI comprises an X-ray source, an asymmetrically cut Bragg-type monochromator-collimator (MC), a Laue-case angle analyser (LAA) and a CCD camera. The specimen is placed between the MC and the LAA. For the light source, we used the beamline BL14C on a 2.5-GeV storage ring in the KEK Photon Factory, Tsukuba, Japan. In the eye specimen, phase contrast images from XDFI were able to discriminate soft-tissue structures, such as the iris, separated by aqueous humour on both sides, which have nearly equal absorption. Superiority of XDFI in imaging soft tissue was further demonstrated with a diseased iliac artery containing atherosclerotic plaque and breast samples with benign and malignant tumours. XDFI on breast tumours discriminated between the normal and diseased terminal duct lobular unit and between invasive and in-situ cancer. X-ray phase, as detected by XDFI, has superior contrast over absorption for soft tissue processes such as atherosclerotic plaque and breast cancer. (orig.)

  1. Transition-edge sensor pixel parameter design of the microcalorimeter array for the x-ray integral field unit on Athena

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Bandler, S. R.; Betancourt-Martinez, G. L.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Miniussi, A. R.; Porter, F. S.; Sadleir, J. E.; Sakai, K.; Wakeham, N. A.; Wassell, E. J.; Yoon, W.; Bennett, D. A.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Morgan, K. M.; Pappas, C. G.; Reintsema, C. N.; Swetz, D. S.; Ullom, J. N.; Irwin, K. D.; Akamatsu, H.; Gottardi, L.; den Hartog, R.; Jackson, B. D.; van der Kuur, J.; Barret, D.; Peille, P.

    2016-07-01

    The focal plane of the X-ray integral field unit (X-IFU) for ESA's Athena X-ray observatory will consist of 4000 transition edge sensor (TES) x-ray microcalorimeters optimized for the energy range of 0.2 to 12 keV. The instrument will provide unprecedented spectral resolution of 2.5 eV at energies of up to 7 keV and will accommodate photon fluxes of 1 mCrab (90 cps) for point source observations. The baseline configuration is a uniform large pixel array (LPA) of 4.28" pixels that is read out using frequency domain multiplexing (FDM). However, an alternative configuration under study incorporates an 18 × 18 small pixel array (SPA) of 2" pixels in the central 36" region. This hybrid array configuration could be designed to accommodate higher fluxes of up to 10 mCrab (900 cps) or alternately for improved spectral performance (< 1.5 eV) at low count-rates. In this paper we report on the TES pixel designs that are being optimized to meet these proposed LPA and SPA configurations. In particular we describe details of how important TES parameters are chosen to meet the specific mission criteria such as energy resolution, count-rate and quantum efficiency, and highlight performance trade-offs between designs. The basis of the pixel parameter selection is discussed in the context of existing TES arrays that are being developed for solar and x-ray astronomy applications. We describe the latest results on DC biased diagnostic arrays as well as large format kilo-pixel arrays and discuss the technical challenges associated with integrating different array types on to a single detector die.

  2. Gold nanoparticle contrast agents in advanced X-ray imaging technologies.

    Science.gov (United States)

    Ahn, Sungsook; Jung, Sung Yong; Lee, Sang Joon

    2013-05-17

    Recently, there has been significant progress in the field of soft- and hard-X-ray imaging for a wide range of applications, both technically and scientifically, via developments in sources, optics and imaging methodologies. While one community is pursuing extensive applications of available X-ray tools, others are investigating improvements in techniques, including new optics, higher spatial resolutions and brighter compact sources. For increased image quality and more exquisite investigation on characteristic biological phenomena, contrast agents have been employed extensively in imaging technologies. Heavy metal nanoparticles are excellent absorbers of X-rays and can offer excellent improvements in medical diagnosis and X-ray imaging. In this context, the role of gold (Au) is important for advanced X-ray imaging applications. Au has a long-history in a wide range of medical applications and exhibits characteristic interactions with X-rays. Therefore, Au can offer a particular advantage as a tracer and a contrast enhancer in X-ray imaging technologies by sensing the variation in X-ray attenuation in a given sample volume. This review summarizes basic understanding on X-ray imaging from device set-up to technologies. Then this review covers recent studies in the development of X-ray imaging techniques utilizing gold nanoparticles (AuNPs) and their relevant applications, including two- and three-dimensional biological imaging, dynamical processes in a living system, single cell-based imaging and quantitative analysis of circulatory systems and so on. In addition to conventional medical applications, various novel research areas have been developed and are expected to be further developed through AuNP-based X-ray imaging technologies.

  3. Gold Nanoparticle Contrast Agents in Advanced X-ray Imaging Technologies

    Directory of Open Access Journals (Sweden)

    Sungsook Ahn

    2013-05-01

    Full Text Available Recently, there has been significant progress in the field of soft- and hard-X-ray imaging for a wide range of applications, both technically and scientifically, via developments in sources, optics and imaging methodologies. While one community is pursuing extensive applications of available X-ray tools, others are investigating improvements in techniques, including new optics, higher spatial resolutions and brighter compact sources. For increased image quality and more exquisite investigation on characteristic biological phenomena, contrast agents have been employed extensively in imaging technologies. Heavy metal nanoparticles are excellent absorbers of X-rays and can offer excellent improvements in medical diagnosis and X-ray imaging. In this context, the role of gold (Au is important for advanced X-ray imaging applications. Au has a long-history in a wide range of medical applications and exhibits characteristic interactions with X-rays. Therefore, Au can offer a particular advantage as a tracer and a contrast enhancer in X-ray imaging technologies by sensing the variation in X-ray attenuation in a given sample volume. This review summarizes basic understanding on X-ray imaging from device set-up to technologies. Then this review covers recent studies in the development of X-ray imaging techniques utilizing gold nanoparticles (AuNPs and their relevant applications, including two- and three-dimensional biological imaging, dynamical processes in a living system, single cell-based imaging and quantitative analysis of circulatory systems and so on. In addition to conventional medical applications, various novel research areas have been developed and are expected to be further developed through AuNP-based X-ray imaging technologies.

  4. Thermo-enhanced field emission from ZnO nanowires: Role of defects and application in a diode flat panel X-ray source

    Science.gov (United States)

    Zhang, Zhipeng; Chen, Daokun; Chen, Wenqing; Chen, Yicong; Song, Xiaomeng; Zhan, Runze; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

    2017-03-01

    A thermo-enhanced field emission phenomenon was observed from ZnO nanowires. The field emission current increased by almost two orders of magnitude under a constant applied electric field, and the turn-on field decreased from 6.04 MV/m to 5.0 MV/m when the temperature increased from 323 to 723 K. The Poole-Frenkel electron excitation from the defect-induced trapping centers to the conduction band under high electric fields is believed to be the primary cause of the observed phenomenon. The experimental results fit well with the proposed physical model. The field emission from ZnO nanowires with different defect concentrations further confirmed the role of defects. Using the thermo-enhanced field emission phenomenon, a diode flat panel X-ray source was demonstrated, for which the energy and dose can be separately tuned. The thermo-enhanced field emission phenomenon observed from ZnO nanowires could be an effective way to realize a large area flat panel multi-energy X-ray source.

  5. The Wide Field Imager instrument for Athena

    Science.gov (United States)

    Meidinger, Norbert; Barbera, Marco; Emberger, Valentin; Fürmetz, Maria; Manhart, Markus; Müller-Seidlitz, Johannes; Nandra, Kirpal; Plattner, Markus; Rau, Arne; Treberspurg, Wolfgang

    2017-08-01

    ESA's next large X-ray mission ATHENA is designed to address the Cosmic Vision science theme 'The Hot and Energetic Universe'. It will provide answers to the two key astrophysical questions how does ordinary matter assemble into the large-scale structures we see today and how do black holes grow and shape the Universe. The ATHENA spacecraft will be equipped with two focal plane cameras, a Wide Field Imager (WFI) and an X-ray Integral Field Unit (X-IFU). The WFI instrument is optimized for state-of-the-art resolution spectroscopy over a large field of view of 40 amin x 40 amin and high count rates up to and beyond 1 Crab source intensity. The cryogenic X-IFU camera is designed for high-spectral resolution imaging. Both cameras share alternately a mirror system based on silicon pore optics with a focal length of 12 m and large effective area of about 2 m2 at an energy of 1 keV. Although the mission is still in phase A, i.e. studying the feasibility and developing the necessary technology, the definition and development of the instrumentation made already significant progress. The herein described WFI focal plane camera covers the energy band from 0.2 keV to 15 keV with 450 μm thick fully depleted back-illuminated silicon active pixel sensors of DEPFET type. The spatial resolution will be provided by one million pixels, each with a size of 130 μm x 130 μm. The time resolution requirement for the WFI large detector array is 5 ms and for the WFI fast detector 80 μs. The large effective area of the mirror system will be completed by a high quantum efficiency above 90% for medium and higher energies. The status of the various WFI subsystems to achieve this performance will be described and recent changes will be explained here.

  6. Comparison of contrast-to-noise ratios of transmission and dark-field signal in grating-based X-ray imaging for healthy murine lung tissue.

    Science.gov (United States)

    Schwab, Felix; Schleede, Simone; Hahn, Dieter; Bech, Martin; Herzen, Julia; Auweter, Sigrid; Bamberg, Fabian; Achterhold, Klaus; Yildirim, Ali Ö; Bohla, Alexander; Eickelberg, Oliver; Loewen, Rod; Gifford, Martin; Ruth, Ronald; Reiser, Maximilian F; Nikolaou, Konstantin; Pfeiffer, Franz; Meinel, Felix G

    2013-09-01

    An experimental comparison of the contrast-to-noise ratio (CNR) between transmission and dark-field signals in grating-based X-ray imaging for ex-vivo murine lung tissue. Lungs from three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Background noise of transmission and dark-field signal was quantified by measuring the standard deviation in a region of interest (ROI) placed in a homogeneous area outside the specimen. Image contrast was quantified by measuring the signal range in rectangular ROIs placed in central and peripheral lung parenchyma. The relative contrast gain (RCG) of dark-field over transmission images was calculated as CNRDF / CNRT. In all images, there was a trend for contrast-to-noise ratios of dark-field images (CNRDF) to be higher than for transmission images (CNRT) for all ROIs (median 61 vs. 38, p=0.10), but the difference was statistically significant only for peripheral ROIs (61 vs. 32, p=0.03). Median RCG was >1 for all ROIs (1.84). RCG values were significantly smaller for central ROIs than for peripheral ROIs (1.34 vs. 2.43, p=0.03). The contrast-to-noise ratio of dark-field images compares more favorably to the contrast-to-noise ratio of transmission images for peripheral lung regions as compared to central regions. For any specific specimen, a calculation of the RCG allows comparing which X-ray modality (dark-field or transmission imaging) produces better contrast-to-noise characteristics in a well-defined ROI. Copyright © 2012. Published by Elsevier GmbH.

  7. Hybrid scintillators for x-ray imaging

    Science.gov (United States)

    Bueno, Clifford; Rairden, Richard L.; Betz, Robert A.

    1996-04-01

    The objective of this effort is to improve x-ray absorption and light production while maintaining high spatial resolution in x-ray imaging phosphor screens. Our current target is to improve screen absorption efficiency and screen brightness by factors of 2 or greater over existing screens that have 10-1p/mm resolution. In this program, commercial phosphor screens are combined with highly absorbing, high-resolution scintillating fiber-optic (SFO) face plates to provide a hybrid sensor that exhibits superior spatial resolution, x-ray absorption, and brightness values over the phosphor material alone. These characteristics of hybrid scintillators can be adjusted to meet specific x-ray imaging requirements over a wide range of x-ray energy. This paper discusses the design, fabrication, and testing of a new series of hybrid scintillators.

  8. Measurement of structural changes in tetragonal PZT ceramics under static and cyclic electric fields using a laboratory X-ray diffractometer.

    Science.gov (United States)

    Pramanick, Abhijit; Jones, Jacob L

    2009-08-01

    In situ structural characterization techniques that are capable of characterizing piezoelectric ceramics under different electrical loading conditions are important to understand the behavior of materials during their use. In this work, we report the use of a laboratory X-ray diffractometer for the measurement of various structural changes in tetragonal La-doped lead zirconate titanate (PZT) ceramics under the application of static and cyclic electric fields. The changes in the volume fractions of the 90 degrees domains parallel to the electric field direction are calculated from the intensities of the {002} diffraction peaks. In addition, the components of lattice strains are monitored from the changes in the (111) crystallographic planes. It is observed that, under the application of static electric fields, both 90 degrees domain switching and the 111 lattice strains showed similarity with the macroscopic strain-electric field hystersis loop. To measure the structural changes under cyclic electric fields, a time-resolved X-ray diffraction technique was used. Under application of a square-wave electric field of amplitude +/-650 V/mm and frequency 0.3 Hz, a change of approximately 5% in the volume fraction of the 90 degrees domains and approximately 0.07% strain of the 111 lattice planes are observed. Both the amount of 90 degrees domain switching and the 111 lattice strains are observed to increase with an increase in the amplitude of the cyclic electric field. The implications of the measured structural changes for the macroscopic piezoelectric properties of ceramics are discussed.

  9. Ultrafast X-ray diffraction probe of terahertz field-driven soft mode dynamics in SrTiO 3

    Energy Technology Data Exchange (ETDEWEB)

    Kozina, M.; Driel, T.van; Chollet, M.; Sato, T.; Glownia, J.M.; Wandel, S.; /SLAC; Radovic, M.; /PSI, SLS /PSI, Villigen; Staub, U.; /PSI, Villigen; Hoffmann, M.C.; /SLAC

    2017-09-01

    We use ultrafast X-ray pulses to characterize the lattice response of SrTiO3 when driven by strong terahertz fields. We observe transient changes in the diffraction intensity with a delayed onset with respect to the driving field. Fourier analysis reveals two frequency components corresponding to the two lowest energy zone-center optical modes in SrTiO3. The lower frequency mode exhibits clear softening as the temperature is decreased while the higher frequency mode shows slight temperature dependence.

  10. On Schwinger mechanics of electron-positron pair production from vacuum by the field of optical and x-ray laser

    CERN Document Server

    Popov, V S

    2001-01-01

    One calculated W probability of e sup + e sup - -pair production from vacuum under the effect of the intensive a-c field generated by optical or X-ray range lasers. One studied two peculiar ranges: gamma 1 and gamma 1, where gamma - parameter of adiabatic nature. It is shown that with rise of gamma, as well as, at transition from monochromatic radiation to finite duration laser pulse W probability increases abruptly (at similar value of field intensity). One discusses dependence of W probability and pulsed spectrum of electrons and positrons on the shape of laser pulse (the Schwinger dynamic effect)

  11. Analyzing the Spectra of Accreting X-Ray Pulsars

    Science.gov (United States)

    Wolff, Michael

    This proposal seeks funding for the analysis of accretion-powered X-ray pulsar spectra from NASA/ HEASARC archived X-ray data. Spectral modeling of accreting X-ray pulsars can tell us a great deal about the physical conditions in and near high mass X-ray binary systems. Such systems have accretion flows where plasma is initially channeled from an accretion disk by the strong neutron star magnetic field, eventually falling onto the magnetic polar cap of the neutron star compact object. Many of these accreting X-ray pulsars have X-ray spectra that consist of broad power-law continua with superposed cyclotron resonant scattering features indicating magnetic field strengths above 10^12 G. The energies of these cyclotron line features have recently been shown to vary with X-ray luminosity in a number of sources such as Her X-1 and V 0332+53, a phenomenon not well understood. Another recent development is the relatively new analytic model for the spectral continuum formation in accretion-powered pulsar systems developed by Becker & Wolff. In their formalism the accretion flows are assumed to go through radiation- dominated radiative shocks and settle onto the neutron star surface. The radiation field consists of strongly Comptonized bremsstrahlung emission from the entire plasma, Comptonized cyclotron emission from the de-excitations of Landau-excited electrons in the neutron star magnetic field, and Comptonized black-body emission from a thermal mound near the neutron star surface. We seek to develop the data analysis tools to apply this model framework to the X-ray data from a wide set of sources to make progress characterizing the basic accretion properties (e.g., magnetic field strength, plasma temperatures, polar cap size, accretion rate per unit area, dominance of bulk vs. thermal Comptonization) as well as understanding the variations of the cyclotron line energies with X-ray luminosity. The three major goals of our proposed work are as follows: In the first year

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

    Science.gov (United States)

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Bennett, N Robert; Pelc, Norbert; Fahrig, Rebecca

    2013-02-01

    Using hybrid x-ray∕MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine

  13. The wide field imager instrument for Athena

    Science.gov (United States)

    Meidinger, Norbert; Nandra, Kirpal; Plattner, Markus; Porro, Matteo; Rau, Arne; Santangelo, Andrea E.; Tenzer, Chris; Wilms, Jörn

    2014-07-01

    The "Hot and Energetic Universe" has been selected as the science theme for ESA's L2 mission, scheduled for launch in 2028. The proposed Athena X-ray observatory provides the necessary capabilities to achieve the ambitious goals of the science theme. The X-ray mirrors are based on silicon pore optics technology and will have a 12 m focal length. Two complementary camera systems are foreseen which can be moved in and out of the focal plane by an interchange mechanism. These instruments are the actively shielded micro-calorimeter spectrometer X-IFU and the Wide Field Imager (WFI). The WFI will combine an unprecedented survey power through its large field of view of 40 arcmin with a high countrate capability (approx. 1 Crab). It permits a state-of-the-art energy resolution in the energy band of 0.1 keV to 15 keV during the entire mission lifetime (e.g. FWHM serial analog output. The architecture of sensor and readout ASIC allows readout in full frame mode and window mode as well by addressing selectively arbitrary sub-areas of the sensor allowing time resolution in the order of 10 μs. The further detector electronics has mainly the following tasks: digitization, pre-processing and telemetry of event data as well as supply and control of the detector system. Although the sensor will already be equipped with an on-chip light blocking filter, a filter wheel is necessary to provide an additional external filter, an on-board calibration source, an open position for outgassing, and a closed position for protection of the sensor. The sensor concept provides high quantum efficiency over the entire energy band and we intend to keep the instrumental background as low as possible by designing a graded Z-shield around the sensor. All these properties make the WFI a very powerful survey instrument, significantly surpassing currently existing observatories and in addition allow high-time resolution of the brightest X-ray sources with low pile-up and high efficiency. This

  14. X-Ray Absorption with Transmission X-Ray Microscopes

    NARCIS (Netherlands)

    de Groot, F.M.F.|info:eu-repo/dai/nl/08747610X

    2016-01-01

    In this section we focus on the use of transmission X-ray microscopy (TXM) to measure the XAS spectra. In the last decade a range of soft X-ray and hard X-ray TXM microscopes have been developed, allowing the measurement of XAS spectra with 10–100 nm resolution. In the hard X-ray range the TXM

  15. Reabsorption of soft x-ray emission at high x-ray free-electron laser fluences.

    Science.gov (United States)

    Schreck, Simon; Beye, Martin; Sellberg, Jonas A; McQueen, Trevor; Laksmono, Hartawan; Kennedy, Brian; Eckert, Sebastian; Schlesinger, Daniel; Nordlund, Dennis; Ogasawara, Hirohito; Sierra, Raymond G; Segtnan, Vegard H; Kubicek, Katharina; Schlotter, William F; Dakovski, Georgi L; Moeller, Stefan P; Bergmann, Uwe; Techert, Simone; Pettersson, Lars G M; Wernet, Philippe; Bogan, Michael J; Harada, Yoshihisa; Nilsson, Anders; Föhlisch, Alexander

    2014-10-10

    We report on oxygen K-edge soft x-ray emission spectroscopy from a liquid water jet at the Linac Coherent Light Source. We observe significant changes in the spectral content when tuning over a wide range of incident x-ray fluences. In addition the total emission yield decreases at high fluences. These modifications result from reabsorption of x-ray emission by valence-excited molecules generated by the Auger cascade. Our observations have major implications for future x-ray emission studies at intense x-ray sources. We highlight the importance of the x-ray pulse length with respect to the core-hole lifetime.

  16. X-ray Optics for BES Light Source Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Dennis [Argonne National Lab. (ANL), Argonne, IL (United States); Padmore, Howard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lessner, Eliane [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2013-03-27

    Each new generation of synchrotron radiation sources has delivered an increase in average brightness 2 to 3 orders of magnitude over the previous generation. The next evolution toward diffraction-limited storage rings will deliver another 3 orders of magnitude increase. For ultrafast experiments, free electron lasers (FELs) deliver 10 orders of magnitude higher peak brightness than storage rings. Our ability to utilize these ultrabright sources, however, is limited by our ability to focus, monochromate, and manipulate these beams with X-ray optics. X-ray optics technology unfortunately lags behind source technology and limits our ability to maximally utilize even today’s X-ray sources. With ever more powerful X-ray sources on the horizon, a new generation of X-ray optics must be developed that will allow us to fully utilize these beams of unprecedented brightness. The increasing brightness of X-ray sources will enable a new generation of measurements that could have revolutionary impact across a broad area of science, if optical systems necessary for transporting and analyzing X-rays can be perfected. The high coherent flux will facilitate new science utilizing techniques in imaging, dynamics, and ultrahigh-resolution spectroscopy. For example, zone-plate-based hard X-ray microscopes are presently used to look deeply into materials, but today’s resolution and contrast are restricted by limitations of the current lithography used to manufacture nanodiffractive optics. The large penetration length, combined in principle with very high spatial resolution, is an ideal probe of hierarchically ordered mesoscale materials, if zone-plate focusing systems can be improved. Resonant inelastic X-ray scattering (RIXS) probes a wide range of excitations in materials, from charge-transfer processes to the very soft excitations that cause the collective phenomena in correlated electronic systems. However, although RIXS can probe high-energy excitations, the most exciting and

  17. X-ray monitoring for astrophysical applications on Cubesat

    Science.gov (United States)

    Pina, L.; Hudec, R.; Inneman, A.; Cerna, D.; Jakubek, J.; Sieger, L.; Dániel, V.; Cash, W.; Mikulickova, L.; Pavlica, R.; Belas, E.; Polak, J.

    2015-05-01

    The primary objective of the project VZLUSAT-1 is the development, manufacturing, qualification and experimental verification of products and technologies in Earth orbit (IOD - In-Orbit Demonstration). This work addresses the issue of X-ray monitoring for astrophysical applications. The proposed wide-field optical system has not been used in space yet. The proposed novel approach is based on the use of 1D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV. The proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is the only solution in cases the intensity of impinging X-ray radiation is below the sensitivity of the detector, e.g. while monitoring astrophysical objects in space, or phenomena in the Earth's atmosphere. On board the functions and features of Radiation Hardened Composite Housing (RHCH), Solar panels based on composite substrate and Hollow Retro Reflector Array based on composite (HRRA) will be verified. To verify the properties of the developed products the satellite is equipped by Health Monitoring system (HM). HM system includes temperature, volatiles, radiation and mechanical properties sensors. The custom ADCS algorithms are being developed within the project. Given the number of IOD experiments and the necessary power the 1U CubeSat is equipped with Composite Deployable Panels (CDP) where HM panels and additional Solar panels are located. Satellite platform is assembled from commercial parts. Mission VZLUSAT-1 is planned for 6 months with launch in 2016.

  18. Relationship between electrical properties and crystallization of indium oxide thin films using ex-situ grazing-incidence wide-angle x-ray scattering

    Science.gov (United States)

    González, G. B.; Okasinski, J. S.; Buchholz, D. B.; Boesso, J.; Almer, J. D.; Zeng, L.; Bedzyk, M. J.; Chang, R. P. H.

    2017-05-01

    Grazing-incidence, wide-angle x-ray scattering measurements were conducted on indium oxide thin films grown on silica substrates via pulsed laser deposition. Growth temperatures (TG) in this study ranged from -50 °C to 600 °C, in order to investigate the thermal effects on the film structure and its spatial homogeneity, as well as their relationship to electrical properties. Films grown below room temperature were amorphous, while films prepared at TG = 25 °C and above crystallized in the cubic bixbyite structure, and their crystalline fraction increased with deposition temperature. The electrical conductivity (σ) and electrical mobility (μ) were strongly enhanced at low deposition temperatures. For TG = 25 °C and 50 °C, a strong ⟨100⟩ preferred orientation (texture) occurred, but it decreased as the deposition temperature, and consequential crystallinity, increased. Higher variations in texture coefficients and in lattice parameters were measured at the film surface compared to the interior of the film, indicating strong microstructural gradients. At low crystallinity, the in-plane lattice spacing expanded, while the out-of-plane spacing contracted, and those values merged at TG = 400 °C, where high μ was measured. This directional difference in lattice spacing, or deviatoric strain, was linear as a function of both deposition temperature and the degree of crystallinity. The crystalline sample with TG = 100 °C had the lowest mobility, as well as film diffraction peaks which split into doublets. The deviatoric strains from these doublet peaks differ by a factor of four, supporting the presence of both a microstructure and strain gradient in this film. More isotropic films exhibit larger μ values, indicating that the microstructure directly correlates with electrical properties. These results provide valuable insights that can help to improve the desirable properties of indium oxide, as well as other transparent conducting oxides.

  19. X-ray magneto-optical polarization spectroscopy: an analysis from the visible region to the x-ray regime.

    Science.gov (United States)

    Tesch, M F; Gilbert, M C; Mertins, H-Ch; Bürgler, D E; Berges, U; Schneider, C M

    2013-06-20

    An ultra-high vacuum compatible multipurpose chamber for magneto-optical reflection and transmission experiments with polarization analysis on magnetic systems is introduced. It is applicable in a broad photon energy range from the visible to the soft x-ray regime and for a wide angular range from grazing to normal incidence. It exploits a novel magnetization device based on rotating permanent magnets, which generates tuneable magnetic fields up to 570 mT in longitudinal, transverse and polar geometry. The unique combination of these features enables the feasibility of all typical magneto-optical spectroscopy techniques as T-MOKE, L-MOKE, P-MOKE, x-ray magneto optical linear dichroism, x-ray magnetic circular dichroism in reflection and Kerr polarization-spectroscopy, which is demonstrated for Co with focus on the Co 3p edges.

  20. Subluminous X-ray binaries

    NARCIS (Netherlands)

    Armas Padilla, M.

    2013-01-01

    The discovery of the first X-ray binary, Scorpius X-1, by Giacconi et al. (1962), marked the birth of X-ray astronomy. Following that discovery, many additional X-ray sources where found with the first generation of X-ray rockets and observatories (e.g., UHURU and Einstein). The short-timescale

  1. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) ... top of page What are some common uses of the procedure? A bone x-ray is used ...

  2. Lumbosacral spine x-ray

    Science.gov (United States)

    X-ray - lumbosacral spine; X-ray - lower spine ... be placed over the lower part of your spine. You will be asked to hold your breath ... x-ray. The most common reason for lumbosacral spine x-ray is to look for the cause ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-01

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

  4. Non-destructive Analysis of Oil-Contaminated Soil Core Samples by X-ray Computed Tomography and Low-Field Nuclear Magnetic Resonance Relaxometry: a Case Study.

    Science.gov (United States)

    Nakashima, Yoshito; Mitsuhata, Yuji; Nishiwaki, Junko; Kawabe, Yoshishige; Utsuzawa, Shin; Jinguuji, Motoharu

    2011-01-01

    Non-destructive measurements of contaminated soil core samples are desirable prior to destructive measurements because they allow obtaining gross information from the core samples without touching harmful chemical species. Medical X-ray computed tomography (CT) and time-domain low-field nuclear magnetic resonance (NMR) relaxometry were applied to non-destructive measurements of sandy soil core samples from a real site contaminated with heavy oil. The medical CT visualized the spatial distribution of the bulk density averaged over the voxel of 0.31 × 0.31 × 2 mm(3). The obtained CT images clearly showed an increase in the bulk density with increasing depth. Coupled analysis with in situ time-domain reflectometry logging suggests that this increase is derived from an increase in the water volume fraction of soils with depth (i.e., unsaturated to saturated transition). This was confirmed by supplementary analysis using high-resolution micro-focus X-ray CT at a resolution of ∼10 μm, which directly imaged the increase in pore water with depth. NMR transverse relaxation waveforms of protons were acquired non-destructively at 2.7 MHz by the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence. The nature of viscous petroleum molecules having short transverse relaxation times (T2) compared to water molecules enabled us to distinguish the water-saturated portion from the oil-contaminated portion in the core sample using an M(0)-T2 plot, where M(0) is the initial amplitude of the CPMG signal. The present study demonstrates that non-destructive core measurements by medical X-ray CT and low-field NMR provide information on the groundwater saturation level and oil-contaminated intervals, which is useful for constructing an adequate plan for subsequent destructive laboratory measurements of cores.

  5. Chiral smectic transition phases appearing near the electric-field-induced phase transition observed by resonant microbeam x-ray scattering.

    Science.gov (United States)

    Iida, Atsuo; Nishiyama, Isa; Takanishi, Yoichi

    2014-03-01

    The electric-field-induced phase transition of a chiral liquid crystal containing Br revealed a transition phase between the three-layer periodicity ferrielectric phase and the synclinic ferroelectric phase in the electric field versus temperature phase diagram. Resonant x-ray scattering from the transition phase showed a diffuse streak or spotty weak reflections, which were composed of strong m/3-order (where m = 1 and 2) reflections and other weak peaks. The spotty reflections were found to be related to a 12-layer periodicity phase with a weak contribution from the 15-layer periodicity. An x-ray intensity analysis based on the Ising model suggested that the 12-layer periodicity phase was composed of two three-layer ferrielectric blocks and six synclinic layers. This model indicated that, in the transition phase, the three-layer ferrielectric molecular configuration gradually changed to the synclinic configuration. The diffuse streak appearing around m/3-order reflections near the field-induced transition from the four-layer periodicity phase to the synclinic ferroelectric phase is also discussed.

  6. Thin Films for X-ray Optics

    Science.gov (United States)

    Conley, Raymond

    Focusing x-rays with refraction requires an entire array of lens instead of a single element, each contributing a minute amount of focusing to the system. In contrast to their visible light counterparts, diffractive optics require a certain depth along the optical axis in order to provide sufficient phase shift. Mirrors reflect only at very shallow angles. In order to increase the angle of incidence, contribution from constructive interference within many layers needs to be collected. This requires a multilayer coating. Thin films have become a central ingredient for many x-ray optics due to the ease of which material composition and thickness can be controlled. Chapter 1 starts with a short introduction and survey of the field of x-ray optics. This begins with an explanation of reflective multilayers. Focusing optics are presented next, including mirrors, zone plates, refractive lenses, and multilayer Laue lens (MLL). The strengths and weaknesses of each "species" of optic are briefly discussed, alongside fabrication issues and the ultimate performance for each. Practical considerations on the use of thin-films for x-ray optics fabrication span a wide array of topics including material systems selection and instrumentation design. Sputter deposition is utilized exclusively for the work included herein because this method of thin-film deposition allows a wide array of deposition parameters to be controlled. This chapter also includes a short description of two deposition systems I have designed. Chapter 2 covers a small sampling of some of my work on reflective multilayers, and outlines two of the deposition systems I have designed and built at the Advanced Photon Source. A three-stripe double multilayer monochromator is presented as a case study in order to detail specifications, fabrication, and performance of this prolific breed of x-ray optics. The APS Rotary Deposition System was the first deposition system in the world designed specifically for multilayer

  7. Chest X-Ray

    Medline Plus

    Full Text Available ... of ionizing radiation, the benefit of an accurate diagnosis far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! Spotlight November is National Lung Cancer Awareness Month Recently posted: Carotid Intima-Media Thickness ...

  8. Chest X-Ray

    Medline Plus

    Full Text Available ... Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions ... Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey Rubin, ...

  9. Pelvis x-ray

    Science.gov (United States)

    The x-ray is used to look for: Fractures Tumors Degenerative conditions of bones in the hips, pelvis, and upper legs ... Abnormal results may suggest: Pelvic fractures Arthritis of the hip joint ... spondylitis (abnormal stiffness of the spine and joint) ...

  10. Chest X-Ray

    Medline Plus

    Full Text Available ... Radiology (IDoR) Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound November 8 is ...

  11. Versatile soft X-ray-optical cross-correlator for ultrafast applications

    Directory of Open Access Journals (Sweden)

    Daniel Schick

    2016-09-01

    eV up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50% total X-ray reflectivity and transient signal changes of more than 20%.

  12. Dual Energy X-Ray CT by Compton Scattering Hard X-Ray Source

    CERN Document Server

    Uesaka, Mitsuru; Kaneyasu, Tatsuo; Torikoshi, Masami

    2005-01-01

    We have developed a compact Compton scattering hard X-ray source at Nuclear Engineering Research Laboratory, University of Tokyo. The compact hard X-ray source can produce tunable monochromatic hard X-rays. The monochromatic hard X-rays are required in large field of medical and biological applications. We are planning to perform dual-energy X-ray CT, which enables us to measure atomic number Z distribution and electron density re distribution in a material. The hard X-ray source has an advantage to perform dual-energy X-ray CT. The X-ray energy can be changed quickly by introducing a fundamental frequency and a second harmonic frequency lasers. This quick energy change is indispensable to medical imaging and very difficult in a large SR light source and others. The information on the atomic number and electron density will be used for treatment plan in radiotherapy as well as for identification of materials in a nondestructive test. We examined applicability of the dual-energy X-ray CT for atomic number meas...

  13. Binary pseudo-random patterned structures for modulation transfer function calibration and resolution characterization of a full-field transmission soft x-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Yashchuk, V. V., E-mail: VVYashchuk@lbl.gov; Chan, E. R.; Lacey, I. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fischer, P. J. [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California Santa Cruz, Santa Cruz, California 94056 (United States); Conley, R. [Advance Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States); McKinney, W. R. [Diablo Valley College, 321 Golf Club Road, Pleasant Hill, California 94523 (United States); Artemiev, N. A. [KLA-Tencor Corp., 1 Technology Drive, Milpitas, California 95035 (United States); Bouet, N. [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States); Cabrini, S. [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Calafiore, G.; Peroz, C.; Babin, S. [aBeam Technologies, Inc., Hayward, California 94541 (United States)

    2015-12-15

    We present a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) one-dimensional sequences and two-dimensional arrays as an effective method for spectral characterization in the spatial frequency domain of a broad variety of metrology instrumentation, including interferometric microscopes, scatterometers, phase shifting Fizeau interferometers, scanning and transmission electron microscopes, and at this time, x-ray microscopes. The inherent power spectral density of BPR gratings and arrays, which has a deterministic white-noise-like character, allows a direct determination of the MTF with a uniform sensitivity over the entire spatial frequency range and field of view of an instrument. We demonstrate the MTF calibration and resolution characterization over the full field of a transmission soft x-ray microscope using a BPR multilayer (ML) test sample with 2.8 nm fundamental layer thickness. We show that beyond providing a direct measurement of the microscope’s MTF, tests with the BPRML sample can be used to fine tune the instrument’s focal distance. Our results confirm the universality of the method that makes it applicable to a large variety of metrology instrumentation with spatial wavelength bandwidths from a few nanometers to hundreds of millimeters.

  14. Gold Nanoparticle Contrast Agents in Advanced X-ray Imaging Technologies

    OpenAIRE

    Sungsook Ahn; Sung Yong Jung; Sang Joon Lee

    2013-01-01

    Recently, there has been significant progress in the field of soft- and hard-X-ray imaging for a wide range of applications, both technically and scientifically, via developments in sources, optics and imaging methodologies. While one community is pursuing extensive applications of available X-ray tools, others are investigating improvements in techniques, including new optics, higher spatial resolutions and brighter compact sources. For increased image quality and more exquisite investigatio...

  15. X-ray induced formation of γ-H2AX foci after full-field digital mammography and digital breast-tomosynthesis.

    Directory of Open Access Journals (Sweden)

    Siegfried A Schwab

    Full Text Available PURPOSE: To determine in-vivo formation of x-ray induced γ-H2AX foci in systemic blood lymphocytes of patients undergoing full-field digital mammography (FFDM and to estimate foci after FFDM and digital breast-tomosynthesis (DBT using a biological phantom model. MATERIALS AND METHODS: The study complies with the Declaration of Helsinki and was performed following approval by the ethic committee of the University of Erlangen-Nuremberg. Written informed consent was obtained from every patient. For in-vivo tests, systemic blood lymphocytes were obtained from 20 patients before and after FFDM. In order to compare in-vivo post-exposure with pre-exposure foci levels, the Wilcoxon matched pairs test was used. For in-vitro experiments, isolated blood lymphocytes from healthy volunteers were irradiated at skin and glandular level of a porcine breast using FFDM and DBT. Cells were stained against the phosphorylated histone variant γ-H2AX, and foci representing distinct DNA damages were quantified. RESULTS: Median in-vivo foci level/cell was 0.086 (range 0.067-0.116 before and 0.094 (0.076-0.126 after FFDM (p = 0.0004. In the in-vitro model, the median x-ray induced foci level/cell after FFDM was 0.120 (range 0.086-0.140 at skin level and 0.035 (range 0.030-0.050 at glandular level. After DBT, the median x-ray induced foci level/cell was 0.061 (range 0.040-0.081 at skin level and 0.015 (range 0.006-0.020 at glandular level. CONCLUSION: In patients, mammography induces a slight but significant increase of γ-H2AX foci in systemic blood lymphocytes. The introduced biological phantom model is suitable for the estimation of x-ray induced DNA damages in breast tissue in different breast imaging techniques.

  16. Oxidation process dependence of strain field under the SiO{sub 2}/Si(001) interface revealed by X-ray multiple-wave diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Yashiro, W [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Yoda, Y [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-gun, Sayo-cho, Hyogo 679-5198 (Japan); Takahashi, K [Department of Electrical and Electronic Engineering, Musashi Institute of Technology, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557 (Japan); Yamamoto, M [New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Hattori, T [New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Miki, K [National Research Institute of Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2007-10-15

    A multiple-wave X-ray diffraction phenomenon, i.e., interaction between Bragg reflection and crystal-truncation-rod (CTR) scattering, is applied to characterize strain field under SiO{sub 2}/Si(001) interface. Application of this phenomenon to strain characterization allows us to reveal that there is very small strain field extending over a mesoscopic-scale depth under the SiO{sub 2}/Si interface and having a static fluctuation in the lateral direction. It also allows us to obtain information on distribution of strain field. In this paper oxidation-process dependence of strain distribution is discussed: some recently obtained results of wet oxidations at 900 deg. C and 1100 deg. C are compared with those of dry oxidation and Kr/O{sub 2} plasma oxidation.

  17. AWARE Wide Field View

    Science.gov (United States)

    2016-04-29

    RGB colors to the standard sRGB to allow spectrally consistent colors on monitors for viewing . Finally, the images from each sensor are corrected based ...on the exposure time used and the calibrated sensitivity of each image sensor, again based on the flat field calibration, to allow viewing of imagery...prediction is scaled based on available bandwidth and the computational resources of the cluster. In addition to the interface described in the

  18. X-ray filter for x-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.; Dooryhee, Eric; Ghose, Sanjit

    2018-01-23

    Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and walls defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.

  19. AXIS - Advanced X-ray Imaging Sarellite

    Science.gov (United States)

    Loewenstein, Michael; AXIS Team

    2018-01-01

    We present an overview of the Advanced X-ray Imaging Satellite (AXIS), a probe mission concept under study to the 2020 Decadal survey. AXIS follows in the footsteps of the spectacularly successful Chandra X-ray Observatory with similar or higher angular resolution and an order of magnitude more collecting area in the 0.3-10 keV band over a 15' field of view. These capabilities are designed to attain a wide range of science goals such as (i) measuring the event horizon scale structure in AGN accretion disks and the spin of supermassive black holes through monitoring of gravitationally microlensed quasars; (ii) understanding AGN and starburst feedback in galaxies and galaxy clusters through direct imaging of winds and interaction of jets and via spatially resolved imaging of galaxies at high-z; (iii) probing the fueling of AGN by resolving the SMBH sphere of influence in nearby galaxies; (iv) investigating hierarchical structure formation and the SMBH merger rate through measurement of the occurrence rate of dual AGN and occupation fraction of SMBHs; (v) advancing SNR physics and galaxy ecology through large detailed samples of SNR in nearby galaxies; (vi) measuring the Cosmic Web through its connection to cluster outskirts. With a nominal 2028 launch, AXIS benefits from natural synergies with LSST, ELTs, ALMA, WFIRST and ATHENA, and will be a valuable precursor to Lynx. AXIS utilizes breakthroughs in the construction of light-weight X-ray optics from mono-crystalline silicon blocks, and developments in the fabrication of large format, small pixel, high readout detectors.

  20. High-pressure studies with x-rays using diamond anvil cells

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Guoyin; Mao, Ho Kwang

    2016-11-22

    Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

  1. High-pressure studies with x-rays using diamond anvil cells

    Science.gov (United States)

    Shen, Guoyin; Mao, Ho Kwang

    2017-01-01

    Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials’ properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

  2. Microfabrication of hard x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik

    This thesis deals with the development of silicon compound refractive lenses (Si-CRLs) for shaping hard x-ray beams. The CRLs are to be fabricated using state of the art microfabrication techniques. The primary goal of the thesis work is to produce Si-CRLs with considerably increased structure...... developed. Inverse replica molding in PDMS of the CRLs was established as an effective way to circumvent the limitations AFM probes have when concave surfaces need to be characterized, e.g. due to the finite lengths of AFM probes. Four different x-ray optical components have been designed, manufactured...... of space for sample surroundings and ensure low-divergent and wide x-ray beams with narrow waists. Both results are substantial improvements to what was available at the start of this thesis work. The challenge of making x-ray objectives in silicon by interdigitation of lenslets alternately focusing...

  3. The Energetic X-ray Imaging Survey Telescope (EXIST)

    Science.gov (United States)

    Grindlay, Jonathan E.

    2009-01-01

    The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed hard X-ray imaging all-sky deep survey mission recommended by the Report of the 2001 Decadal Survey. It is a strong candidate to be the Black Hole Finder Probe, one of the three "Einstein Probes" in the Beyond Einstein Program. In its new more evolved form, the EXIST mission now includes a simplified, but more sensitive, very large area and field of view imaging hard X-ray telescope as well as a 1.1m optical-NIR telescope (0.3-2.5microns) for rapid ( 100sec) followup imaging and spectra and thus prompt redshifts of high-z GRBs. The IRT will also permit identification and galaxy spectra for a significant fraction of the obscured AGNs detected in the EXIST full sky survey. The primary science objectives for EXIST are to: 1) study the earliest stars, re-ionization, and development of structure in the universe with prompt hard X-ray and prompt followup NIR measurements of GRBs at z >7, 2) constrain the accretion luminosity of the universe by measurements of high luminosity obscured AGN at z 0-2.5, low luminosity AGN at z 10X the area of Swift/BAT and much broader energy band, as well deep NIR coverage with a passively cooled mirror, EXIST greatly surpasses any previous or proposed mission for wide-field imaging and spectroscopy of GRBs and black holes on all scales.

  4. X-Ray Point-source Populations Constituting the Galactic Ridge X-Ray Emission

    Science.gov (United States)

    Morihana, Kumiko; Tsujimoto, Masahiro; Yoshida, Tessei; Ebisawa, Ken

    2013-03-01

    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 ≈10-14 erg cm-2 s-1, which is gradually taken over by Galactic sources in the fainter flux ranges. The Fe Kα emission is mostly from the group A thermal (WD binaries) and the group B (X-ray active stars) sources.

  5. Nonrelativistic quantum X-ray physics

    CERN Document Server

    Hau-Riege, Stefan P

    2015-01-01

    Providing a solid theoretical background in photon-matter interaction, Nonrelativistic Quantum X-Ray Physics enables readers to understand experiments performed at XFEL-facilities and x-ray synchrotrons. As a result, after reading this book, scientists and students will be able to outline and perform calculations of some important x-ray-matter interaction processes. Key features of the contents are that the scope reaches beyond the dipole approximation when necessary and that it includes short-pulse interactions. To aid the reader in this transition, some relevant examples are discussed in detail, while non-relativistic quantum electrodynamics help readers to obtain an in-depth understanding of the formalisms and processes. The text presupposes a basic (undergraduate-level) understanding of mechanics, electrodynamics, and quantum mechanics. However, more specialized concepts in these fields are introduced and the reader is directed to appropriate references. While primarily benefiting users of x-ray light-sou...

  6. Modeling the focusing efficiency of lobster-eye optics for image shifting depending on the soft x-ray wavelength.

    Science.gov (United States)

    Su, Luning; Li, Wei; Wu, Mingxuan; Su, Yun; Guo, Chongling; Ruan, Ningjuan; Yang, Bingxin; Yan, Feng

    2017-08-01

    Lobster-eye optics is widely applied to space x-ray detection missions and x-ray security checks for its wide field of view and low weight. This paper presents a theoretical model to obtain spatial distribution of focusing efficiency based on lobster-eye optics in a soft x-ray wavelength. The calculations reveal the competition mechanism of contributions to the focusing efficiency between the geometrical parameters of lobster-eye optics and the reflectivity of the iridium film. In addition, the focusing efficiency image depending on x-ray wavelengths further explains the influence of different geometrical parameters of lobster-eye optics and different soft x-ray wavelengths on focusing efficiency. These results could be beneficial to optimize parameters of lobster-eye optics in order to realize maximum focusing efficiency.

  7. Structure determination by X-ray crystallography

    CERN Document Server

    Ladd, M F C

    1995-01-01

    X-ray crystallography provides us with the most accurate picture we can get of atomic and molecular structures in crystals. It provides a hard bedrock of structural results in chemistry and in mineralogy. In biology, where the structures are not fully crystalline, it can still provide valuable results and, indeed, the impact here has been revolutionary. It is still an immense field for young workers, and no doubt will provide yet more striking develop­ ments of a major character. It does, however, require a wide range of intellectual application, and a considerable ability in many fields. This book will provide much help. It is a very straightforward and thorough guide to every aspect of the subject. The authors are experienced both as research workers themselves and as teachers of standing, and this is shown in their clarity of exposition. There are plenty of iliustrations and worked examples to aid the student to obtain a real grasp of the subject.

  8. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... and x-rays. A Word About Minimizing Radiation Exposure Special care is taken during x-ray examinations ... patient's body not being imaged receive minimal radiation exposure. top of page What are the limitations of ...

  9. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... foot. top of page What are some common uses of the procedure? A bone x-ray is ... care is taken during x-ray examinations to use the lowest radiation dose possible while producing the ...

  10. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... shades of gray and air appears black. Until recently, x-ray images were maintained on large film ... assist you in finding the most comfortable position possible that still ensures x-ray image quality. top ...

  11. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ... body. Once it is carefully aimed at the part of the body being examined, an x-ray ...

  12. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... Safety page for more information about radiation dose. Women should always inform their physician or x-ray ...

  13. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... tissues around or in bones. top of page How should I prepare? Most bone x-rays require ... is placed beneath the patient. top of page How does the procedure work? X-rays are a ...

  14. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... fracture. guide orthopedic surgery, such as spine repair/fusion, joint replacement and fracture reductions. look for injury, ... and Media Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to X-ray ( ...

  15. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ... and procedures may vary by geographic region. Discuss the fees associated with your prescribed ...

  16. Bone X-Ray (Radiography)

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    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... pregnancy and x-rays. top of page What does the equipment look like? The equipment typically used ... placed beneath the patient. top of page How does the procedure work? X-rays are a form ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures ...

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... that might interfere with the x-ray images. Women should always inform their physician and x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy ...

  20. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... wrist, arm, elbow, shoulder, spine, pelvis, hip, thigh, knee, leg (shin), ankle or foot. top of page ... the patient standing upright, as in cases of knee x-rays. A portable x-ray machine is ...

  1. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... position possible that still ensures x-ray image quality. top of page Who interprets the results and ...

  2. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures ...

  3. Bone X-Ray (Radiography)

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    Full Text Available ... tissue shows up in shades of gray and air appears black. Until recently, x-ray images were ... position possible that still ensures x-ray image quality. top of page Who interprets the results and ...

  4. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... of page What are some common uses of the procedure? A bone x-ray is used to: ... and x-rays. top of page What does the equipment look like? The equipment typically used for ...

  5. 14th International Conference on X-Ray Lasers

    CERN Document Server

    Menoni, Carmen; Marconi, Mario

    2016-01-01

    These proceedings comprise invited and contributed papers presented at the 14th International Conference on X-Ray Lasers (ICXRL 2014). This conference is part of a continuing series dedicated to recent developments and applications of x-ray lasers and other coherent x-ray sources with attention to supporting technologies and instrumentation. New results in the generation of intense, coherent x-rays and progress toward practical devices and their applications in numerous fields are reported. Areas of research in plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generation, and other x-ray generation schemes are covered.  The scope of ICXRL 2014 included, but was not limited to: Laser-pumped X-ray lasers Discharge excitation and other X-ray laser pumping methods Injection/seeding of X-ray amplifiers New lasing transitions and novel X-ray laser schemes High Harmonic sources-Free-electron laser generation in the XUV and X-ray range Novel schemes for coherent XUV and X-ray ge...

  6. A magnitude limited stellar X-ray survey and the F star X-ray luminosity function

    Science.gov (United States)

    Topka, K.; Golub, L.; Gorenstein, P.; Harnden, F. R., Jr.; Vaiana, G. S.; Avni, Y.; Rosner, R.

    1982-01-01

    An X-ray survey has been conducted of stars brighter than visual magnitude 8.5 that have serendipitously fallen into the fields of view of the Imaging Proportional Counter of the Einstein Observatory. The survey includes 227 separate 1 x 1 deg fields, containing 274 stars with a visual magnitude of no more than 8.5 and covering a wide range of spectral types and luminosity classes. X-ray emission was detected from 33 stars, and upper limits have been determined for the remainder of the sample. F type stars dominate the detected sample, and most of these are shown to be dwarfs. An X-ray luminosity function for dF stars has been deduced, and reveals that the average 0.2-4.0 keV luminosity of these stars is around 10 to the 29th erg/sec. Constraints have been placed on the high luminosity tails and medians of the X-ray luminosity functions for other types of stars.

  7. Evaluation of laboratory powder X-ray micro-diffraction for applications in the fields of cultural heritage and forensic science.

    Science.gov (United States)

    Svarcová, Silvie; Kocí, Eva; Bezdicka, Petr; Hradil, David; Hradilová, Janka

    2010-09-01

    The uniqueness and limited amounts of forensic samples and samples from objects of cultural heritage together with the complexity of their composition requires the application of a wide range of micro-analytical methods, which are non-destructive to the samples, because these must be preserved for potential late revision. Laboratory powder X-ray micro-diffraction (micro-XRD) is a very effective non-destructive technique for direct phase analysis of samples smaller than 1 mm containing crystal constituents. It compliments optical and electron microscopy with elemental micro-analysis, especially in cases of complicated mixtures containing phases with similar chemical composition. However, modification of X-ray diffraction to the micro-scale together with its application for very heterogeneous real samples leads to deviations from the standard procedure. Knowledge of both the limits and the phenomena which can arise during the analysis is crucial for the meaningful and proper application of the method. We evaluated basic limits of micro-XRD equipped with a mono-capillary with an exit diameter of 0.1 mm, for example the size of irradiated area, appropriate grain size, and detection limits allowing identification of given phases. We tested the reliability and accuracy of quantitative phase analysis based on micro-XRD data in comparison with conventional XRD (reflection and transmission), carrying out experiments with two-phase model mixtures simulating historic colour layers. Furthermore, we demonstrate the wide use of micro-XRD for investigation of various types of micro-samples (contact traces, powder traps, colour layers) and we show how to enhance data quality by proper choice of experiment geometry and conditions.

  8. Coherent methods in X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gorobtsov, Oleg

    2017-05-15

    X-ray radiation has been used to study structural properties of materials for more than a hundred years. Construction of extremely coherent and bright X-ray radiation sources such as free electron lasers (FELs) and latest generationstorage rings led to rapid development of experimental methods relying on high radiation coherence. These methods allow to perform revolutionary studies in a wide range of fields from solid state physics to biology. In this thesis I focus on several important problems connected with the coherent methods. The first part considers applications of dynamical diffraction theory on crystals to studies with coherent X-ray radiation. It presents the design of a high-resolution spectrometer for free electron lasers that should allow to resolve spectral structure of individual FEL pulses. The spectrometer is based on the principle of dynamical diffraction focusing. The knowledge of individual FEL pulse spectra is necessary for understanding FEL longitudinal coherence. In the same part I present quasi-kinematical approximation to dynamical theory which allows to treat analytically phase effects observed in X-ray coherent imaging on nanocrystals. These effects may play a big role when methods such as ptychography are used to study crystalline samples. The second part deals with measurements of FEL coherence properties using intensity - intensity interferometry. Results of several experiments performed at FELs FLASH and LCLS are revealed in this section. I have developed models and theories to explain the behavior observed in experiments on FLASH. These models allowed to extract information about external positional jitter of FEL pulses and secondary beams present in FEL radiation. In the LCLS experiment the Hanbury Brown and Twiss type interferometry was performed on Bragg peaks from colloidal crystal. This did not require additional measurements without the sample and information was extracted directly from diffraction patterns. Therefore intensity

  9. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... be taken to minimize radiation exposure to the baby. See the Safety page for more information about pregnancy and x-rays. top of page What does the equipment look like? The equipment typically used for bone x-rays consists of an x-ray tube suspended over a table on which the patient ...

  10. X-Ray Exam: Forearm

    Science.gov (United States)

    ... recorded on a computer or special X-ray film. This image shows the soft tissues and bones of the forearm. The X-ray image is black and white. Dense structures that block the passage of the X-ray beam through the body, such as the bones, appear white on the ...

  11. Jovian X-ray emissions

    Science.gov (United States)

    Waite, J. H.; Lewis, W. S.; Gladstone, G. R.; Fabian, A. C.; Brandt, W. N.

    1996-01-01

    The Einstein and Rosat observations of X-ray emissions from Jupiter are summarized. Jupiter's soft X-ray emission is observed to originate from the planet's auroral zones, and specifically, from its equatorial region. The processes responsible for these emissions are not established. The brightness distribution of the Jovian X-rays is characterized by the dependence on central meridian longitude and by north-south and morning-afternoon asymmetries. The X-rays observed during the impact of the comet Shoemaker-Levy 9 are believed to be impact-induced brightenings of the X-ray aurora.

  12. X-ray absorption spectroscopy of semiconductors

    CERN Document Server

    Ridgway, Mark

    2015-01-01

    X-ray Absorption Spectroscopy (XAS) is a powerful technique with which to probe the properties of matter, equally applicable to the solid, liquid and gas phases. Semiconductors are arguably our most technologically-relevant group of materials given they form the basis of the electronic and photonic devices that now so widely permeate almost every aspect of our society. The most effective utilisation of these materials today and tomorrow necessitates a detailed knowledge of their structural and vibrational properties. Through a series of comprehensive reviews, this book demonstrates the versatility of XAS for semiconductor materials analysis and presents important research activities in this ever growing field. A short introduction of the technique, aimed primarily at XAS newcomers, is followed by twenty independent chapters dedicated to distinct groups of materials. Topics span dopants in crystalline semiconductors and disorder in amorphous semiconductors to alloys and nanometric material as well as in-sit...

  13. X-ray polarimetry an upcoming 'new' tool in Astronomy

    Science.gov (United States)

    Soffitta, P.

    2017-10-01

    Sensitive X-ray polarimetry promises to solve many different issues in X-ray Astronomy: from disentangling physics from geometry removing degeneracies in models of magnetars and X-ray binaries hosting neutron stars, to mapping ordered magnetic fields in Supernova Remnants and Pulsar Wind Nebulae. It constrains emission mechanisms in blazars and solves the mistery of X-ray emission from cold molecular clouds in the galactic center. Moreover it can answer to questions of fundamental physics. XIPE the X-ray Imaging Polarimetry Explorer accomplished phase A as an ESA M4 candidate and IXPE the Imaging X-ray Polarimetry explorer was selected as next SMEX mission by NASA for a flight in late 2020. In this talk I will describe both missions and their ability to make energy, time and angle resolved polarimetry thanks to a detector developed at this aim and to X-ray optics with a large effective area.

  14. Visualizing and Quantifying Bioaccessible Pores in Field-Aged Petroleum Hydrocarbon-Contaminated Clay Soils Using Synchrotron-based X-ray Computed Tomography

    Science.gov (United States)

    Chang, W.; Kim, J.; Zhu, N.; McBeth, J. M.

    2015-12-01

    Microbial hydrocarbon degradation is environmentally significant and applicable to contaminated site remediation practices only when hydrocarbons (substrates) are physically bioaccessible to bacteria in soil matrices. Powerful X-rays are produced by synchrotron radiation, allowing for bioaccessible pores in soil (larger than 4 microns), where bacteria can be accommodated, colonize and remain active, can be visualized at a much higher resolution. This study visualized and quantified such bioaccessible pores in intact field-aged, oil-contaminated unsaturated soil fractions, and examined the relationship between the abundance of bioaccessible pores and hydrocarbon biodegradation. Using synchrotron-based X-ray Computed Tomography (CT) at the Canadian Light Source, a large dataset of soil particle characteristics, such as pore volumes, surface areas, number of pores and pore size distribution, was generated. Duplicate samples of five different soil fractions with different soil aggregate sizes and water contents (13, 18 and 25%) were examined. The method for calculating the number and distribution of bioaccessible pores using CT images was validated using the known porosity of Ottawa sand. This study indicated that the distribution of bioaccessible pore sizes in soil fractions are very closely related to microbial enhancement. A follow-up aerobic biodegradation experiment for the soils at 17 °C (average site temperature) over 90 days confirmed that a notable decrease in hydrocarbon concentrations occurred in soils fractions with abundant bioaccessible pores and with a larger number of pores between 10 and 100 μm. The hydrocarbon degradation in bioactive soil fractions was extended to relatively high-molecular-weight hydrocarbons (C16-C34). This study provides quantitative information about how internal soil pore characteristics can influence bioremediation performance.

  15. Dimyristoylphosphatidylcholine/C16 : 0-ceramide binary liposomes studied by differential scanning calorimetry and wide- and small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Holopainen, J. M.; Lemmich, Jesper; Richter, F.

    2000-01-01

    hysteresis in the thermal phase behavior of ceramide-containing membranes. A partial phase diagram was constructed based on results from a combination of these two methods. DSC heating scans show that with increased X-cer the pretransition temperature T-P first increases, whereafter at X-cer > 0.06 it can......Ceramide has recently been established as a central messenger in the signaling cascades controlling cell behavior. Physicochemical studies have revealed a strong tendency of this lipid toward phase separation in mixtures with phosphatidylcholines. The thermal phase behavior and structure of fully...... hydrated binary membranes composed of dimyristoylphosphatidylcholine (DMPC) and N-palmitoyl-ceramide (C16:0-ceramide, up to a mole fraction X-cer = 0.35) were resolved in further detail by high-sensitivity differential scanning calorimetry (DSC) and x-ray diffraction. Both methods reveal very strong...

  16. Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography

    Directory of Open Access Journals (Sweden)

    Lingtao Mao

    2015-04-01

    Full Text Available It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load. Few experimental techniques exist that can represent full-field three-dimensional (3D strain distribution inside a rock specimen. And yet it is crucial that this information is available for fully understanding the failure mechanism of rocks or other geomaterials. In this study, by using the newly developed digital volumetric speckle photography (DVSP technique in conjunction with X-ray computed tomography (CT and taking advantage of natural 3D speckles formed inside the rock due to material impurities and voids, we can probe the interior of a rock to map its deformation pattern under load and shed light on its failure mechanism. We apply this technique to the analysis of a red sandstone specimen under increasing uniaxial compressive load applied incrementally. The full-field 3D displacement fields are obtained in the specimen as a function of the load, from which both the volumetric and the deviatoric strain fields are calculated. Strain localization zones which lead to the eventual failure of the rock are identified. The results indicate that both shear and tension are contributing factors to the failure mechanism.

  17. Dosimetric characterization and behaviour in small X-ray fields of a microchamber and a plastic scintillator detector.

    Science.gov (United States)

    Pasquino, Massimo; Cutaia, Claudia; Radici, Lorenzo; Valzano, Serena; Gino, Eva; Cavedon, Carlo; Stasi, Michele

    2017-01-01

    The aim of this work was to investigate the main dosimetric characteristics and the performance of an A26 Exradin ionization microchamber (A26 IC) and a W1 Exradin plastic scintillation detector (W1 PSD) in small photon beam dosimetry for treatment planning system commissioning and quality assurance programme. Detector characterization measurements (short-term stability, dose linearity, angular dependence and energy dependence) were performed in water for field sizes up to 10 × 10 cm(2). Polarity effect (Ppol) was examined for the A26 IC. The behaviour of the detectors in small field relative dosimetry [percentage depth dose, dose profiles often called the off-axis ratio and output factors (OFs)] was investigated for field sizes ranging from 1 × 1 to 3 × 3 cm(2). Results were compared with those obtained with other detectors we already use for small photon beam dosimetry. A26 IC and W1 PSD showed a linear dose response. While the A26 IC showed no energy dependence, the W1 PSD showed energy dependence within 2%; no angular dependence was registered. Ppol values for A26 IC were below 0.9% (0.5% for field size >2 × 2 cm(2)). A26 IC and W1 PSD depth-dose curves and lateral profiles agreed with those obtained with an EDGE diode. No differences were observed among the detectors in OF measurement for field sizes larger than 1 × 1 cm(2), with average differences water equivalence of EDGE diode become significant. A26 IC OF values were significantly lower than EDGE diode and W1 PSD values, with percentage differences of about -23 and -13% for the smallest field, respectively. W1 PSD OF values lay between ion chambers and diode values, with a maximum percentage difference of about -10% with respect to the EDGE diode, for a 6 × 6-mm(2) field size. The results of our investigation confirm that A26 IC and W1 PSD could play an important role in small field relative dosimetry. Advances in knowledge: Dosimetric characteristics of Exradin A26

  18. X-ray Studies of Nano Composites

    Science.gov (United States)

    Hexemer, Alexander

    Nano composite materials are an exciting and fast expanding field. X-ray scattering has been used in order to study the structure properties relation. During the last few years the field has expanded more towards the field of thin films where there's been a dramatic increase in the use of grazing incidence small angle X-ray scattering (GISAXS). The main issue of GISAXS has been the complex analysis framework necessary for simulating and fitting. In addition, existing software has restricted the scientist in systems that can be simulated and the speed to analyze large amounts of data. Over the last few years we have worked closely with our computational research and supercomputer division to enable the use of supercomputers to simulate at scattering data. We have developed a comprehensive analysis framework to simulate and fit a wide variety of materials and morphologies. The framework is designed to supply scientists with close to real-time feedback during beam times. Therefore, HipGISAXS (High Performance GISAXS) has been developed to run simulations on massively parallel platforms such as the Oak Ridge Supercomputer Titan (OLCF). Further, with inverse modeling algorithms for fitting available in HipGISAXS, such as particle swarm optimization, it can handle a large number of parameters during the structure fitting process. In September of 2014, HipGISAXS was used in a real time demonstration that married the SAXS/WAXS beamline at the ALS with the data handling and processing capabilities at NERSC, and simulation capabilities of running at-scale simulations on Titan at OLCF. Doe Early Carrier Award, SPOT and CAMERA.

  19. Predicting Soil Physical Parameters and Copper Transport in a Polluted Field From X Ray CT-Images

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Naveed, Muhammad; Møldrup, Per

    2013-01-01

    in soils is strongly controlled by the soil structure, the capabilities of these visualization techniques could be used to predict the risk of pollutants leaching. This work was carried out using soils from a field site (Hygum) in Jutland, Denmark, a historical copper (Cu) polluted field cultivated for 80...... to the volume of each soil column. Leaching experiments were performed to analyze tritium transport, colloid leaching and dissolved organic carbon and Cu losses associated with particles or dissolved organic matter (DOM). Air permeability and saturated hydraulic conductivity were measured before and after...

  20. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis.

    Science.gov (United States)

    Habibi, Neda

    2015-02-05

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the NCH3 functional group about 2850cm(-1) is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. A comparison of surface doses for very small field size x-ray beams: Monte Carlo calculations and radiochromic film measurements.

    Science.gov (United States)

    Morales, J E; Hill, R; Crowe, S B; Kairn, T; Trapp, J V

    2014-06-01

    Stereotactic radiosurgery treatments involve the delivery of very high doses for a small number of fractions. To date, there is limited data in terms of the skin dose for the very small field sizes used in these treatments. In this work, we determine relative surface doses for small size circular collimators as used in stereotactic radiosurgery treatments. Monte Carlo calculations were performed using the BEAMnrc code with a model of the Novalis Trilogy linear accelerator and the BrainLab circular collimators. The surface doses were calculated at the ICRP skin dose depth of 70 μm all using the 6 MV SRS x-ray beam. The calculated surface doses varied between 15 and 12 % with decreasing values as the field size increased from 4 to 30 mm. In comparison, surface doses were measured using Gafchromic EBT3 film positioned at the surface of a Virtual Water phantom. The absolute agreement between calculated and measured surface doses was better than 2.0 % which is well within the uncertainties of the Monte Carlo calculations and the film measurements. Based on these results, we have shown that the Gafchromic EBT3 film is suitable for surface dose estimates in very small size fields as used in SRS.

  2. A model for electric field enhancement in lightning leader tips to levels allowing X-ray and γ ray emissions

    DEFF Research Database (Denmark)

    Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

    2015-01-01

    that the ionization channels of streamers limit the lateral expansion of the ionization wave, thereby enhancing the peak electric field to values allowing an acceleration of low-energy electrons into the runaway regime where electrons efficiently generate bremsstrahlung. The results suggest that the inhomogeneous...... ionization environment at the new leader tip amplifies the production rate of energetic electrons relative to a homogeneous environment considered in the past studies....

  3. Handbook of X-Ray Astronomy

    Science.gov (United States)

    Arnaud, Keith A. (Editor); Smith, Randall K.; Siemiginowska, Aneta

    2011-01-01

    X-ray astronomy was born in the aftermath of World War II as military rockets were repurposed to lift radiation detectors above the atmosphere for a few minutes at a time. These early flights detected and studied X-ray emission from the Solar corona. The first sources beyond the Solar System were detected during a rocket flight in 1962 by a team headed by Riccardo Giaccom at American Science and Engineering, a company founded by physicists from MIT. The rocket used Geiger counters with a system designed to reduce non-X-ray backgrounds and collimators limiting the region of sky seen by the counters. As the rocket spun, the field of view (FOV) happened to pass over what was later found to be the brightest non-Solar X-ray source; later designated See X-1. It also detected a uniform background glow which could not be resolved into individual sources. A follow-up campaign using X-ray detectors with better spatial resolution and optical telescopes identified See X-1 as an interacting binary with a compact (neutron star) primary. This success led to further suborbital rocket flights by a number of groups. More X-ray binaries were discovered, as well as X-ray emission from supernova remnants, the radio galaxies M87 and Cygnus-A, and the Coma cluster. Detectors were improved and Geiger counters were replaced by proportional counters, which provided information about energy spectra of the sources. A constant challenge was determining precise positions of sources as only collimators were available.

  4. Frontiers in x-ray components for high-resolution spectroscopy and imaging laminar type varied-line-spacing holographic gratings for soft x-ray

    CERN Document Server

    Sano, K

    2003-01-01

    Laminar-type varied-line-spacing gratings have been widely used for soft x-ray monochromator recently because of the features of low stray lights and higher order lights. We have developed and advanced holographic recording and an ion-beam etching methods for the laminar type varied-line spacing gratings. This report describes a short review of the soft x-ray spectrometers using varied-line-spacing gratings, the fabrication process of the laminar-type holographic gratings, and the performance of the flat field spectrographs equipped with the laminar type varied-line spacing gratings comparing with the mechanically ruled replica gratings. It is concluded that, for the sake of the advanced design and fabrication processes and excellent spectroscopic performance, laminar-type holographic gratings will be widely used for soft x-ray spectrometers for various purposes in the near future. (author)

  5. X-ray Emission Mechanisms in Herbig - Haro objects .

    Science.gov (United States)

    Bonito, R.; Orlando, S.; Peres, G.; Favata, F.; Rosner, R.

    X-ray emission in Herbig - Haro objects is a quite recent and uncommon finding still waiting full explanation. With the scope of explaining this X-ray emission, our project is devoted to model the interaction between a supersonic jet originating from a young stellar object and the ambient medium. We have performed a wide exploration of the parameter space to infer the configuration(s) which can give rise to X-ray emission very similar to what recently observed.

  6. X-ray instrumentation for SR beamlines

    CERN Document Server

    Kovalchuk, M V; Zheludeva, S I; Aleshko-Ozhevsky, O P; Arutynyan, E H; Kheiker, D M; Kreines, A Y; Lider, V V; Pashaev, E M; Shilina, N Y; Shishkov, V A

    2000-01-01

    The main possibilities and parameters of experimental X-ray stations are presented: 'Protein crystallography', 'X-ray structure analysis', 'High-precision X-ray optics', 'X-ray crystallography and material science', 'X-ray topography', 'Photoelectron X-ray standing wave' that are being installed at Kurchatov SR source by A.V. Shubnikov Institute of Crystallography.

  7. Simultaneous measurement of X-ray diffraction and ferroelectric polarization data as a function of applied electric field and frequency.

    Science.gov (United States)

    Wooldridge, Jenny; Ryding, Steph; Brown, Simon; Burnett, Tim L; Cain, Markys G; Cernik, Robert; Hino, Ricardo; Stewart, Mark; Thompson, Paul

    2012-09-01

    The characteristics of a new ferroelectric measurement system at the European Synchrotron Radiation Facility are presented. The electric-field-induced phase transitions of Pb(Mg(1/3)Nb(2/3))O(3)-xPbTiO(3) are determined via in situ measurements of electric polarization within the synchrotron diffraction beamline. Real-time data collection methods on single-crystal samples are employed as a function of frequency to determine the microstructural origin of piezoelectric effects within these materials, probing the dynamic ferroelectric response.

  8. X-ray optics of gold nanoparticles.

    Science.gov (United States)

    Letfullin, Renat R; Rice, Colin E W; George, Thomas F

    2014-11-01

    Gold nanoparticles have been investigated as contrast agents for traditional x-ray medical procedures, utilizing the strong absorption characteristics of the nanoparticles to enhance the contrast of the detected x-ray image. Here we use the Kramers-Kronig relation for complex atomic scattering factors to find the real and imaginary parts of the index of refraction for the medium composed of single-element materials or compounds in the x-ray range of the spectrum. These complex index of refraction values are then plugged into a Lorenz-Mie theory to calculate the absorption efficiency of various size gold nanoparticles for photon energies in the 1-100 keV range. Since the output from most medical diagnostic x-ray devices follows a wide and filtered spectrum of photon energies, we introduce and compute the effective intensity-absorption-efficiency values for gold nanoparticles of radii varying from 5 to 50 nm, where we use the TASMIP model to integrate over all spectral energies generated by typical tungsten anode x-ray tubes with kilovolt potentials ranging from 50 to 150 kVp.

  9. Soft X-ray optics

    CERN Document Server

    Spiller, Eberhard A

    1993-01-01

    This text describes optics mainly in the 10 to 500 angstrom wavelength region. These wavelengths are 50 to 100 times shorter than those for visible light and 50 to 100 times longer than the wavelengths of medical x rays or x-ray diffraction from natural crystals. There have been substantial advances during the last 20 years, which one can see as an extension of optical technology to shorter wavelengths or as an extension of x-ray diffraction to longer wavelengths. Artificial diffracting structures like zone plates and multilayer mirrors are replacing the natural crystals of x-ray diffraction.

  10. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    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.

  11. X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

    Directory of Open Access Journals (Sweden)

    Kumiko Morihana

    2014-12-01

    Full Text Available We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE. We extracted 2,002 X-ray point sources in the Chandra Bulge Field (l =0°.113, b = 1°.424 down to ~10-14.8 ergscm-2s-1 in 2-8 keV band with the longest observation (900 ks of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard, B (soft and broad spectrum, and C (soft and peaked spectrum. In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

  12. X-ray spectroscopy an introduction

    CERN Document Server

    Agarwal, Bipin K

    1979-01-01

    Rontgen's discovery of X-rays in 1895 launched a subject which became central to the development of modern physics. The verification of many of the predic­ tions of quantum theory by X-ray spectroscopy in the early part of the twen­ tieth century stimulated great interest in thi's area, which has subsequently influenced fields as diverse as chemical physics, nuclear physics, and the study of the electronic properties of solids, and led to the development of techniques such as Auger, Raman, and X-ray photoelectron spectroscopy. The improvement of the theoretical understanding of the physics underlying X-ray spectroscopy has been accompanied by advances in experimental techniques, and the subject provides an instructive example of how progress on both these fronts can be mutually beneficial. This book strikes a balance between his­ torical description, which illustrates this symbiosis, and the discussion of new developments. The application of X-ray spectroscopic methods to the in­ vestigation of chemical b...

  13. Wide-Field Plate Database

    Science.gov (United States)

    Tsvetkov, M. K.; Stavrev, K. Y.; Tsvetkova, K. P.; Semkov, E. H.; Mutatov, A. S.

    The Wide-Field Plate Database (WFPDB) and the possibilities for its application as a research tool in observational astronomy are presented. Currently the WFPDB comprises the descriptive data for 400 000 archival wide field photographic plates obtained with 77 instruments, from a total of 1 850 000 photographs stored in 269 astronomical archives all over the world since the end of last century. The WFPDB is already accessible for the astronomical community, now only in batch mode through user requests sent by e-mail. We are working on on-line interactive access to the data via INTERNET from Sofia and parallel from the Centre de Donnees Astronomiques de Strasbourg. (Initial information can be found on World Wide Web homepage URL http://www.wfpa.acad.bg.) The WFPDB may be useful in studies of a variety of astronomical objects and phenomena, andespecially for long-term investigations of variable objects and for multi-wavelength research. We have analysed the data in the WFPDB in order to derive the overall characteristics of the totality of wide-field observations, such as the sky coverage, the distributions by observation time and date, by spectral band, and by object type. We have also examined the totality of wide-field observations from point of view of their quality, availability and digitisation. The usefulness of the WFPDB is demonstrated by the results of identification and investigation of the photometrical behaviour of optical analogues of gamma-ray bursts.

  14. Effect of X-ray exposure on the pharmaceutical quality of drug tablets using X-ray inspection equipment.

    Science.gov (United States)

    Uehara, Kazuaki; Tagami, Tatsuaki; Miyazaki, Itaru; Murata, Norikazu; Takahashi, Yoshifumi; Ohkubo, Hiroshi; Ozeki, Tetsuya

    2015-06-01

    X-ray inspection equipment is widely used to detect missing materials and defective goods in opaque containers. Its application has been expanded to the pharmaceutical industry to detect the presence of drug tablets in aluminum foil press-through packaging. However, the effect of X-rays on the pharmaceutical quality of drug tablets is not well known. In this study, the effect of X-rays on the pharmaceutical quality of drug tablets was investigated. Exposure of acetaminophen, loxoprofen and mefenamic acid tablets to X-ray doses of 0.34 mGy (thrice the dose by X-ray scanning) to 300 Gy (maximum dose from our X-ray equipment) was demonstrated, and the samples were evaluated by formulation tests. Exposure to X-rays did not affect the pharmaceutical quality of the drug content. The samples exposed to X-rays exhibited almost the same profile in formulation tests (dissolution test, disintegrating test and hardness test) as control samples (0 Gy). The combination of X-ray exposure with accelerated temperature and humidity tests (six months) also did not affect the pharmaceutical quality. The color change of light-sensitive drugs (nifedipine and furosemide tablets) after X-ray exposure was negligible (drug tablets.

  15. X-Ray Calorimeter Arrays for Astrophysics

    Science.gov (United States)

    Kilbourne, Caroline A.

    2009-01-01

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

  16. XRASE: The X-Ray Spectroscopic Explorer

    DEFF Research Database (Denmark)

    Schnopper, H.W.; Silver, E.; Murray, S.

    2001-01-01

    The X-Ray Spectroscopic Explorer (XRASE) has a unique combination of features that will make it possible to address many of NASA's scientific goals. These include how galaxy clusters form, the physics and chemistry of the ISM, the heating of stellar coronae, the amount and content of intergalactic...... eV at 6 keV) and efficiency with a field-of-view of 26 arcmin(2) . A deep orbit allows for long, continuous observations. Monitoring instruments in the optical (WOM-X), UV (TAUVEX) and hard X-RAY (GRAM) bands will offer exceptional opportunities to make simultaneous multi-wavelength observations....

  17. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x-rays to pass through them. As a result, bones appear white on the x-ray, soft tissue shows up in shades of gray and air ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... diagnosis and treatment. No radiation remains in a patient's body after an x-ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... dose possible while producing the best images for evaluation. National and international radiology protection organizations continually review and update the technique standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

  20. Chandra's X-ray Vision

    Indian Academy of Sciences (India)

    1999-07-23

    Jul 23, 1999 ... GENERAL I ARTICLE. Chandra's X-ray Vision. K P Singh. Chandra X-ray Observatory (CXO) is a scientific satellite (moon/ chandra), named after the Indian-born Nobel laureate. Subrahmanyan Chandrasekhar - one of the foremost astro- physicists of the twentieth century and popularly known as. Chandra.

  1. X-Ray Exam: Ankle

    Science.gov (United States)

    ... radiation through the ankle, and black and white images of the bones and soft tissues are recorded on a computer or special X-ray film. Dense structures that block the passage of the X-ray beam through the body, such as bones, appear white. Softer body tissues, ...

  2. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... Info Images/Videos About Us News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ...

  3. On the nature of infrared-faint radio sources in the Subaru X-ray Deep and Very Large Array-VIMOS VLT Deep Survey fields

    Science.gov (United States)

    Singh, Veeresh; Wadadekar, Yogesh; Ishwara-Chandra, C. H.; Sirothia, Sandeep; Sievers, Jonathan; Beelen, Alexandre; Omont, Alain

    2017-10-01

    Infrared-faint radio sources (IFRSs) are an unusual class of objects that are relatively bright at radio wavelengths but have faint or undetected infrared counterparts, even in deep surveys. We identify and investigate the nature of IFRSs using deep radio (S1.4 GHz ˜ 100 μJy beam-1 at 5σ), optical (mr ˜ 26-27.7 at 5σ) and near-infrared (S3.6 μm ˜ 1.3-2.0 μJy beam-1 at 5σ) data that are available in two deep fields: the Subaru X-ray Deep Field (SXDF) and the Very Large Array-VIMOS VLT Deep Survey (VLA-VVDS) field. In 1.8 deg2 of the two fields, we identify a total of nine confirmed and ten candidate IFRSs. We find that our IFRSs are high-redshift radio-loud active galactic nuclei, with 12/19 sources having redshift estimates in the range of z ˜ 1.7-4.3, while a limit of z ≥ 2.0 is placed on the remaining seven sources. Notably, for the first time, our study finds IFRSs with measured redshift >3.0, and also redshift estimates for IFRSs in the faintest 3.6-μm flux regime (i.e. S3.6 μm colour (mr-m24 μm) suggest that a significant fraction of IFRSs are likely to be hosted in dusty obscured galaxies.

  4. Elemental sensitivity in soft x-ray imaging with a laser-plasma source and a color center detector.

    Science.gov (United States)

    Calegari, F; Valentini, G; Vozzi, C; Benedetti, E; Cabanillas-Gonzalez, J; Faenov, A; Gasilov, S; Pikuz, T; Poletto, L; Sansone, G; Villoresi, P; Nisoli, M; De Silvestri, S; Stagira, S

    2007-09-01

    Elemental sensitivity in soft x-ray imaging of thin foils with known thickness is observed using an ultrafast laser-plasma source and a LiF crystal as detector. Measurements are well reproduced by a simple theoretical model. This technique can be exploited for high spatial resolution, wide field of view imaging in the soft x-ray region, and it is suitable for the characterization of thin objects with thicknesses ranging from hundreds down to tens of nanometers.

  5. The Ooty Wide Field Array

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 38; Issue 1. The Ooty Wide Field Array. C. R. Subrahmanya P. K. Manoharan Jayaram N. Chengalur. Review Article Volume 38 Issue 1 March 2017 Article ID ... Keywords. Cosmology: large scale structure of Universe; intergalactic medium; diffuse radiation.

  6. X-Ray Tomographic Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  7. Compact stellar X-ray sources

    NARCIS (Netherlands)

    Lewin, W.H.G.; van der Klis, M.

    2006-01-01

    X-ray astronomy is the prime available window on astrophysical compact objects: black holes, neutron stars and white dwarfs. In the last ten years new observational opportunities have led to an explosion of knowledge in this field. This book provides a comprehensive overview of the astrophysics of

  8. Techniques in X-ray Astronomy

    Indian Academy of Sciences (India)

    Kulinder Pal Singh is in the Department of. Astronomy and Astro- physics of the Tata. Institute of Fundamental. Research, Mumbai. His primary fields of research are X-ray studies of hot plasmas in stars, super- nova remnants, galaxies, intergalactic medium in clusters of galaxies, active galactic nuclei, cataclys- mic variables ...

  9. The Beginnings of Stellar X-Ray Astronomy

    Science.gov (United States)

    Rosner, R.

    2000-09-01

    I review the beginnings of the field of stellar X-ray astronomy, concentrating on the period immediately preceeding, and immediately following, the launch of the Einstein Observatory. The wealth of data was such that, within the first two years following launch, major discoveries were made by scientists from both the Einstein Observatory PI groups and Einstein Observatory Guest Observers which established stellar X-ray astronomy as a new astronomical discipline: Discovery of early and late-type stars, as well as young protostars, as soft X-ray sources; discovery of the "dividing line" separating X-ray emitting and X-ray quiet giant and supergiant stars; and establishment of the "solar-stellar connection" as a paradigm for understanding X-ray emission from late-type stars.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-10

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

  11. Harnessing the full power of the widest Chandra field: average accretion rates of black holes in SDSS galaxies through X-ray stacking

    Science.gov (United States)

    Goulding, Andy D.; Greene, Jenny E.; Hickox, Ryan C.; Alexander, David M.; Forman, William R.; Jones, Christine; Lehmer, Bret

    2017-08-01

    Galaxy-scale bars are expected to provide an effective means for driving material towards the central region in spiral galaxies, and possibly feeding supermassive black holes (BHs). I will present our latest results on a statistically-complete study of the effect of bars on average BH accretion. From a well-selected sample of over 50,000 spiral galaxies extracted from the Sloan Digital Sky Survey, we separate those sources considered to contain galaxy-scale bars from those that do not. Using the first 16 years worth of data taken by the Chandra X-ray Observatory, we identify X-ray luminous AGN and perform the widest-area X-ray stacking analysis to date on the remaining X-ray undetected sources. Through our X-ray stacking, we derive a time-averaged look at accretion for galaxies at fixed stellar mass and star formation rate, finding that the average nuclear accretion rates of galaxies with bar structures are fully consistent with those lacking bars, and robustly concluding that large-scale bars have little or no effect on the average growth of BHs in nearby (z < 0.15) galaxies over gigayear timescales.

  12. X-RAY POLARIZATION FROM HIGH-MASS X-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Kallman, T. [NASA/GSFC, Code 662, Greenbelt, MD 20771 (United States); Dorodnitsyn, A. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Blondin, J. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

    2015-12-10

    X-ray astronomy allows study of objects that may be associated with compact objects, i.e., neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically nonspherical, and likely noncircular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. Potential targets for future X-ray polarization observations are the high-mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early-type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature that depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

  13. Diagnostic X-ray sources-present and future

    Science.gov (United States)

    Behling, Rolf; Grüner, Florian

    2018-01-01

    This paper compares very different physical principles of X-ray production to spur ideation. Since more than 120 years, bremsstrahlung from X-ray tubes has been the workhorse of medical diagnostics. Generated by X-ray segments comprised of X-ray tubes and high-voltage generators in the various medical systems, X-ray photons in the spectral range between about 16 keV and 150 keV deliver information about anatomy and function of human patients and in pre-clinical animal studies. Despite of strides to employ the wave nature of X-rays as phase sensitive means, commercial diagnostic X-ray systems available until the time of writing still rely exclusively on measuring the attenuation and scattering of X-rays by matter. Significant activities in research aim at building highly brilliant short pulse X-ray sources, based on e.g. synchrotron radiation, free electron lasers and/or laser wake-field acceleration of electrons followed by wiggling with magnetic structures or Thomson scattering in bunches of light. While both approaches, non-brilliant and brilliant sources, have different scope of application, we speculate that a combination may expand the efficacy in medical application. At this point, however, severe technical and commercial difficulties hinder closing this gap. This article may inspire further development and spark innovation in this important field.

  14. Microstructure selection in thin-sample directional solidification of an Al-Cu alloy: In situ X-ray imaging and phase-field simulations

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, A. J.; Tourret, D.; Song, Y.; Imhoff, S. D.; Gibbs, P. J.; Gibbs, J. W.; Fezzaa, K.; Karma, A.

    2017-05-01

    We study microstructure selection during directional solidification of a thin metallic sample. We combine in situ X-ray radiography of a dilute Al-Cu alloy solidification experiments with three-dimensional phase-field simulations. We explore a range of temperature gradient G and growth velocity V and build a microstructure selection map for this alloy. We investigate the selection of the primary dendritic spacing Lambda and tip radius rho. While rho shows a good agreement between experimental measurements and dendrite growth theory, with rho similar to V-1/2, Lambda is observed to increase with V (partial derivative Lambda/partial derivative V > 0), in apparent disagreement with classical scaling laws for primary dendritic spacing, which predict that partial derivative Lambda/partial derivative V <0. We show through simulations that this trend inversion for Lambda(V) is due to liquid convection in our experiments, despite the thin sample configuration. We use a classical diffusion boundary-layer approximation to semi-quantitatively incorporate the effect of liquid convection into phase-field simulations. This approximation is implemented by assuming complete solute mixing outside a purely diffusive zone of constant thickness that surrounds the solid-liquid interface. This simple method enables us to quantitatively match experimental measurements of the planar morphological instability threshold and primary spacings over an order of magnitude in V. We explain the observed inversion of partial derivative Lambda/partial derivative V by a combination of slow transient dynamics of microstructural homogenization and the influence of the sample thickness.

  15. A Semi-analytical Model for Wind-fed Black Hole High-mass X-Ray Binaries: State Transition Triggered by Magnetic Fields from the Companion Star

    Science.gov (United States)

    Yaji, Kentaro; Yamada, Shinya; Masai, Kuniaki

    2017-10-01

    We propose a mechanism of state transition in wind-fed black hole (BH) binaries (high-mass X-ray binaries) such as Cyg X-1 and LMC X-1. Modeling a line-driven stellar wind from the companion by two-dimensional hydrodynamical calculations, we investigate the processes of wind capture by, and accretion onto, the BH. We assume that the wind acceleration is terminated at the He ii ionization front because ions responsible for line-driven acceleration are ionized within the front, i.e., the He iii region. It is found that the mass accretion rate inferred from the luminosity is remarkably smaller than the capture rate. Considering the difference, we construct a model for the state transition based on the accretion flow being controlled by magnetorotational instability. The outer flow is torus-like, and plays an important role to trigger the transition. The model can explain why state transition does occur in Cyg X-1, while not in LMC X-1. Cyg X-1 exhibits a relatively low luminosity, and then the He ii ionization front is located and can move between the companion and BH, depending on its ionizing photon flux. On the other hand, LMC X-1 exhibits too high luminosity for the front to move considerably; the front is too close to the companion atmosphere. The model also predicts that each state of high-soft or low-hard would last fairly long because the luminosity depends weakly on the wind velocity. In the context of the model, the state transition is triggered by a fluctuation of the magnetic field when its amplitude becomes comparable to the field strength in the torus-like outer flow.

  16. Semiconductor X-ray detectors

    CERN Document Server

    Lowe, Barrie Glyn

    2014-01-01

    Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

  17. The LOFT (Large Observatory for X-ray Timing) background simulations

    DEFF Research Database (Denmark)

    Campana, R.; Feroci, M.; Del Monte, E.

    2012-01-01

    design. The two main contributions to the background are cosmic diffuse X-rays and high energy cosmic rays; also, albedo emission from the Earth is significant. These contributions to the background for both the Large Area Detector and the Wide Field Monitor are discussed, on the basis of extrensive...

  18. X-Ray Optics Research

    Science.gov (United States)

    1990-09-20

    OF FUNDING NUMBERS Building 410 PORM POET TS OKUI Bolig FBDC2032648ELEMENT NO. NO. NO ACCESiON NO 11. TITLE (include Security Classification) X - Ray Optics Research...by block number) This report describes work conducted during the period I October 1987 through 30 April 1990, under Contract AFOSR-88-00l0, " X - Ray Optics Research...growth and structure of multilayer interfaces. This capability is central to the development of future materials for multilayer x - ray optics , because

  19. Spectacular X-ray Jet Points Toward Cosmic Energy Booster

    Science.gov (United States)

    2000-06-01

    electromagnetic forces created by magnetized gas swirling toward a black hole. Although most of the material falls into the black hole, some can be ejected at extremely high speeds. Magnetic fields spun out by these forces can extend over vast distances and may help explain the narrowness of the jet. The Chandra observation of Pictor A was made on January 18, 2000 for eight hours using the Advanced CCD Imaging Spectrometer (ACIS). The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University, University Park. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF) are available at the Internet sites listed above. This image will be available on NASA Video File which airs at noon, 3:00 p.m., 6:00 p.m., 9:00 p.m. and midnight Eastern Time. NASA Television is available on GE-2, transponder 9C at 85 degrees West longitude, with vertical polarization. Frequency is on 3880.0 megahertz, with audio on 6.8 megahertz.

  20. Measuring and understanding ultrafast phenomena using X-rays

    DEFF Research Database (Denmark)

    Haldrup, Kristoffer; Nielsen, Martin Meedom

    2014-01-01

    Within the last decade, significant advances in X-ray sources and instrumentation as well as simultaneous developments in analysis methodology has allowed the field of fast- and ultrafast time-resolved X-ray studies of solution-state systems to truly come of age. We here describe some aspects...

  1. X-ray Microspectroscopy and Chemical Reactions in Soil Microsites

    Energy Technology Data Exchange (ETDEWEB)

    D Hesterberg; M Duff; J Dixon; M Vepraskas

    2011-12-31

    Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants.

  2. Rescuing Perishable Neuroanatomical Information from a Threatened Biodiversity Hotspot: Remote Field Methods for Brain Tissue Preservation Validated by Cytoarchitectonic Analysis, Immunohistochemistry, and X-Ray Microcomputed Tomography.

    Directory of Open Access Journals (Sweden)

    Daniel F Hughes

    Full Text Available Biodiversity hotspots, which harbor more endemic species than elsewhere on Earth, are increasingly threatened. There is a need to accelerate collection efforts in these regions before threatened or endangered species become extinct. The diverse geographical, ecological, genetic, morphological, and behavioral data generated from the on-site collection of an individual specimen are useful for many scientific purposes. However, traditional methods for specimen preparation in the field do not permit researchers to retrieve neuroanatomical data, disregarding potentially useful data for increasing our understanding of brain diversity. These data have helped clarify brain evolution, deciphered relationships between structure and function, and revealed constraints and selective pressures that provide context about the evolution of complex behavior. Here, we report our field-testing of two commonly used laboratory-based techniques for brain preservation while on a collecting expedition in the Congo Basin and Albertine Rift, two poorly known regions associated with the Eastern Afromontane biodiversity hotspot. First, we found that transcardial perfusion fixation and long-term brain storage, conducted in remote field conditions with no access to cold storage laboratory equipment, had no observable impact on cytoarchitectural features of lizard brain tissue when compared to lizard brain tissue processed under laboratory conditions. Second, field-perfused brain tissue subjected to prolonged post-fixation remained readily compatible with subsequent immunohistochemical detection of neural antigens, with immunostaining that was comparable to that of laboratory-perfused brain tissue. Third, immersion-fixation of lizard brains, prepared under identical environmental conditions, was readily compatible with subsequent iodine-enhanced X-ray microcomputed tomography, which facilitated the non-destructive imaging of the intact brain within its skull. In summary, we

  3. High energy X-ray diffraction study of a dental ceramics–titanium functional gradient material prepared by field assisted sintering technique

    Energy Technology Data Exchange (ETDEWEB)

    Witte, K., E-mail: kerstin.witte@uni-rostock.de [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany); Bodnar, W. [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany); Schell, N. [Institute of Materials Research, Helmholtz-Center Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Lang, H. [Department of Operative Dentistry and Periodontology, University of Rostock, Strempelstr. 13, 18057 Rostock (Germany); Burkel, E. [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany)

    2014-09-15

    A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is α-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. The crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1) Å, while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2) Å. The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable. - Highlights: • High energy XRD studies of dental ceramics–Ti gradient material consolidated by FAST. • Phase composition, crystallinity and lattice parameters are determined. • Crystallinity increases stepwisely along the gradient following weight fraction of Ti. • Lattice mismatch leading to internal stress is calculated over the whole gradient. • Internal stress in α-Ti embedded in the gradient is smaller than its yield strength.

  4. X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

    Science.gov (United States)

    Liu, Teng; Tozzi, Paolo; Wang, Jun-Xian; Brandt, William N.; Vignali, Cristian; Xue, Yongquan; Schneider, Donald P.; Comastri, Andrea; Yang, Guang; Bauer, Franz E.; Paolillo, Maurizio; Luo, Bin; Gilli, Roberto; Wang, Q. Daniel; Giavalisco, Mauro; Ji, Zhiyuan; Alexander, David M.; Mainieri, Vincenzo; Shemmer, Ohad; Koekemoer, Anton; Risaliti, Guido

    2017-09-01

    We present a detailed spectral analysis of the brightest active galactic nuclei (AGNs) identified in the 7Ms Chandra Deep Field-South (CDF-S) survey over a time span of 16 years. Using a model of an intrinsically absorbed power-law plus reflection, with possible soft excess and narrow Fe Kα line, we perform a systematic X-ray spectral analysis, both on the total 7Ms exposure and in four different periods with lengths of 2-21 months. With this approach, we not only present the power-law slopes, column densities {N}{{H}}, observed fluxes, and absorption-corrected 2-10 keV luminosities L X for our sample of AGNs, but also identify significant spectral variabilities among them on timescales of years. We find that the {N}{{H}} variabilities can be ascribed to two different types of mechanisms, either flux-driven or flux-independent. We also find that the correlation between the narrow Fe line EW and {N}{{H}} can be well explained by the continuum suppression with increasing {N}{{H}}. Accounting for the sample incompleteness and bias, we measure the intrinsic distribution of {N}{{H}} for the CDF-S AGN population and present reselected subsamples that are complete with respect to {N}{{H}}. The {N}{{H}}-complete subsamples enable us to decouple the dependences of {N}{{H}} on L X and on redshift. Combining our data with those from C-COSMOS, we confirm the anticorrelation between the average {N}{{H}} and L X of AGN, and find a significant increase of the AGN-obscured fraction with redshift at any luminosity. The obscured fraction can be described as {f}{obscured}≈ 0.42 {(1+z)}0.60.

  5. A tunable multicolour 'rainbow' filter for improved stress and dislocation density field mapping in polycrystals using X-ray Laue microdiffraction.

    Science.gov (United States)

    Robach, Odile; Micha, Jean Sébastien; Ulrich, Olivier; Geaymond, Olivier; Sicardy, Olivier; Härtwig, Jürgen; Rieutord, François

    2013-03-01

    White-beam X-ray Laue microdiffraction allows fast mapping of crystal orientation and strain fields in polycrystals, with a submicron spatial resolution in two dimensions. In the well crystallized parts of the grains, the analysis of Laue-spot positions provides the local deviatoric strain tensor. The hydrostatic part of the strain tensor may also be obtained, at the cost of a longer measuring time, by measuring the energy profiles of the Laue spots using a variable-energy monochromatic beam. A new `rainbow' method is presented, which allows measurement of the energy profiles of the Laue spots while remaining in the white-beam mode. It offers mostly the same information as the latter monochromatic method, but with two advantages: (i) the simultaneous measurement of the energy profiles and the Laue pattern; (ii) rapid access to energy profiles of a larger number of spots, for equivalent scans on the angle of the optical element. The method proceeds in the opposite way compared to a monochromator-based method, by simultaneously removing several sharp energy bands from the incident beam, instead of selecting a single one. It uses a diamond single crystal placed upstream of the sample. Each Laue diffraction by diamond lattice planes attenuates the corresponding energy in the incident spectrum. By rotating the crystal, the filtered-out energies can be varied in a controlled manner, allowing one to determine the extinction energies of several Laue spots of the studied sample. The energies filtered out by the diamond crystal are obtained by measuring its Laue pattern with another two-dimensional detector, at each rotation step. This article demonstrates the feasibility of the method and its validation through the measurement of a known lattice parameter.

  6. Comparison of field portable measurements of ultrafine TiO2: X-ray fluorescence, laser-induced breakdown spectroscopy, and Fourier-transform infrared spectroscopy.

    Science.gov (United States)

    LeBouf, Ryan F; Miller, Arthur L; Stipe, Christopher; Brown, Jonathan; Murphy, Nate; Stefaniak, Aleksandr B

    2013-06-01

    Laboratory measurements of ultrafine titanium dioxide (TiO2) particulate matter loaded on filters were made using three field portable methods (X-ray fluorescence (XRF), laser-induced breakdown spectroscopy (LIBS), and Fourier-transform infrared (FTIR) spectroscopy) to assess their potential for determining end-of-shift exposure. Ultrafine TiO2 particles were aerosolized and collected onto 37 mm polycarbonate track-etched (PCTE) filters in the range of 3 to 578 μg titanium (Ti). Limit of detection (LOD), limit of quantification (LOQ), and calibration fit were determined for each measurement method. The LOD's were 11.8, 0.032, and 108 μg Ti per filter, for XRF, LIBS, and FTIR, respectively and the LOQ's were 39.2, 0.11, and 361 μg Ti per filter, respectively. The XRF calibration curve was linear over the widest dynamic range, up to the maximum loading tested (578 μg Ti per filter). LIBS was more sensitive but, due to the sample preparation method, the highest loaded filter measurable was 252 μg Ti per filter. XRF and LIBS had good predictability measured by regressing the predicted mass to the gravimetric mass on the filter. XRF and LIBS produced overestimations of 4% and 2%, respectively, with coefficients of determination (R(2)) of 0.995 and 0.998. FTIR measurements were less dependable due to interference from the PCTE filter media and overestimated mass by 2% with an R(2) of 0.831.

  7. Synchrotron radiation and free-electron lasers principles of coherent X-ray generation

    CERN Document Server

    Kim, Kwang-Je; Lindberg, Ryan

    2017-01-01

    Learn about the latest advances in high-brightness X-ray physics and technology with this authoritative text. Drawing upon the most recent theoretical developments, pre-eminent leaders in the field guide readers through the fundamental principles and techniques of high-brightness X-ray generation from both synchrotron and free-electron laser sources. A wide range of topics is covered, including high-brightness synchrotron radiation from undulators, self-amplified spontaneous emission, seeded high-gain amplifiers with harmonic generation, ultra-short pulses, tapering for higher power, free-electron laser oscillators, and X-ray oscillator and amplifier configuration. Novel mathematical approaches and numerous figures accompanied by intuitive explanations enable easy understanding of key concepts, whilst practical considerations of performance-improving techniques and discussion of recent experimental results provide the tools and knowledge needed to address current research problems in the field. This is a comp...

  8. X-ray spectroscopy of highly-charged heavy ions at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Gumberidze, A. [Laboratoire Kastler Brossel, Universite P. et M. Curie, Paris (France)], E-mail: a.gumberidze@gsi.de; Stoehlker, Th. [Gesellschaft fur Schwerionenforschung mbh, 64291 GSI-Darmstadt (Germany); Physikalisches Institut, Universitt Heidelberg, D-69120 Heidelberg (Germany); Beyer, H.F.; Bosch, F.; Braeuning-Demian, A.; Hagmann, S.; Kozhuharov, C.; Kuehl, Th.; Mann, R. [Gesellschaft fur Schwerionenforschung mbh, 64291 GSI-Darmstadt (Germany); Indelicato, P. [Laboratoire Kastler Brossel, Universite P. et M. Curie, Paris (France); Quint, W. [Gesellschaft fur Schwerionenforschung mbh, 64291 GSI-Darmstadt (Germany); Schuch, R. [Stockholm University, Stockholm (Sweden); Warczak, A. [Institute of Physics, Jagiellonian University, Cracow (Poland)

    2009-01-15

    In the current contribution, we give an overview of the envisioned X-ray spectroscopy program within the atomic physics research collaboration SPARC (Stored Particle Atomic Research Collaboration) at FAIR (Facility for Antiproton and Ion Research). These activities comprise, among others, the investigation of relativistic collision dynamics, electron correlation in the presence of strong fields, the test of Quantum Electrodynamics in extremely strong electromagnetic fields, and ideas to test the predictions of fundamental theories besides Quantum Electrodynamics. The state of the art X-ray spectroscopy will be of key importance for realization of these challenging goals. The world-wide unique experimental conditions and opportunities offered by the future FAIR facility will be combined with advanced X-ray detection devices, i.e. large-area, segmented solid-state detectors, high-resolution crystal spectrometers, calorimetric detectors etc.

  9. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... for more information about pregnancy and x-rays. A Word About Minimizing Radiation Exposure Special care is ... code: Phone no: Thank you! Do you have a personal story about radiology? Share your patient story ...

  10. X-Ray Assembler Data

    Data.gov (United States)

    U.S. Department of Health & Human Services — Federal regulations require that an assembler who installs one or more certified components of a diagnostic x-ray system submit a report of assembly. This database...

  11. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... of any bone in the body, including the hand, wrist, arm, elbow, shoulder, spine, pelvis, hip, thigh, ... to current x-ray images for diagnosis and disease management. top of page How is the procedure ...

  12. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available Toggle navigation ... x-ray uses a very small dose of ionizing radiation to produce pictures of any bone in the body. It is commonly used to diagnose fractured bones or joint dislocation. Bone ...

  13. Bone X-Ray (Radiography)

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    Full Text Available ... x-ray machine is a compact apparatus that can be taken to the patient in a hospital ... so that any change in a known abnormality can be monitored over time. Follow-up examinations are ...

  14. Bone X-Ray (Radiography)

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    Full Text Available ... to produce pictures of any bone in the body. It is commonly used to diagnose fractured bones ... x-rays involves exposing a part of the body to a small dose of ionizing radiation to ...

  15. Bone X-Ray (Radiography)

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    Full Text Available ... or in bones. top of page How should I prepare? Most bone x-rays require no special ... to 10 minutes. top of page What will I experience during and after the procedure? A bone ...

  16. Bone X-Ray (Radiography)

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    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... examination may also be necessary so that any change in a known abnormality can be monitored over ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... position possible that still ensures x-ray image quality. top of page Who interprets the results and ... emergency rooms, physician offices, ambulatory care centers, nursing homes and other locations, making it convenient for both ...

  18. Bone X-Ray (Radiography)

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    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... taken of the unaffected limb, or of a child's growth plate (where new bone is forming), for ...

  19. Bone X-Ray (Radiography)

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    Full Text Available ... will analyze the images and send a signed report to your primary care or referring physician , who ... Medicine Radiation Safety How to Read Your Radiology Report Images related to X-ray (Radiography) - Bone Sponsored ...

  20. Bone X-Ray (Radiography)

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    Full Text Available ... fracture. guide orthopedic surgery, such as spine repair/fusion, joint replacement and fracture reductions. look for injury, ... CT Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology ...

  1. Bone X-Ray (Radiography)

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    Full Text Available ... here Images × Image Gallery Radiological technologist preparing to take an arm x-ray on a patient. View ... and/or your insurance provider to get a better understanding of the possible charges you will incur. ...

  2. Bone X-Ray (Radiography)

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    Full Text Available ... in evaluating the hips of children with congenital problems. top of page This page was reviewed on ... Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology Report ...

  3. Bone X-Ray (Radiography)

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    Full Text Available ... white on the x-ray, soft tissue shows up in shades of gray and air appears black. ... who will discuss the results with you. Follow-up examinations may be necessary. Your doctor will explain ...

  4. Bone X-Ray (Radiography)

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    Full Text Available ... the baby. See the Safety page for more information about pregnancy and x-rays. top of page ... procedure varies. See the Safety page for more information about radiation dose. Women should always inform their ...

  5. Bone X-Ray (Radiography)

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    Full Text Available ... a large photographic negative). Today, most images are digital files that are stored electronically. These stored images ... and places the x-ray film holder or digital recording plate under the table in the area ...

  6. Bone X-Ray (Radiography)

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    Full Text Available ... tissue shows up in shades of gray and air appears black. Until recently, x-ray images were ... imaged. When necessary, sandbags, pillows or other positioning devices will be used to help you maintain the ...

  7. Bone X-Ray (Radiography)

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    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... procedure varies. See the Safety page for more information about radiation dose. Women should always inform their ...

  8. Bone X-Ray (Radiography)

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    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... little information about muscles, tendons or joints. An MRI may be more useful in identifying bone and ...

  9. Bone X-Ray (Radiography)

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    Full Text Available ... The teddy bear denotes child-specific content. Related Articles and Media Arthritis X-ray, Interventional Radiology and ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  10. Bone X-Ray (Radiography)

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    Full Text Available ... very small dose of ionizing radiation to produce pictures of any bone in the body. It is ... a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays ...

  11. Bone X-Ray (Radiography)

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    Full Text Available ... pelvis, hip, thigh, knee, leg (shin), ankle or foot. top of page What are some common uses ... to current x-ray images for diagnosis and disease management. top of page How is the procedure ...

  12. Bone X-Ray (Radiography)

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    Full Text Available ... commonly used to diagnose fractured bones or joint dislocation. Bone x-rays are the fastest and easiest ... is used to: diagnose fractured bones or joint dislocation. demonstrate proper alignment and stabilization of bony fragments ...

  13. Bone X-Ray (Radiography)

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    Full Text Available ... Leave jewelry at home and wear loose, comfortable clothing. You may be asked to wear a gown. ... appliances, eye glasses and any metal objects or clothing that might interfere with the x-ray images. ...

  14. Bone X-Ray (Radiography)

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    Full Text Available ... in metabolic conditions. assist in the detection and diagnosis of bone cancer . locate foreign objects in soft ... frequently compared to current x-ray images for diagnosis and disease management. top of page How is ...

  15. Bone X-Ray (Radiography)

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    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  16. Bone X-Ray (Radiography)

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    Full Text Available ... a form of radiation like light or radio waves. X-rays pass through most objects, including the ... individual patient's condition. Ultrasound imaging, which uses sound waves instead of ionizing radiation to create diagnostic images, ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... for more information about pregnancy and x-rays. A Word About Minimizing Radiation Exposure Special care is ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  18. Bone X-Ray (Radiography)

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    Full Text Available ... pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to ... See the Safety page for more information about pregnancy and x-rays. top of page What does ...

  19. Bone X-Ray (Radiography)

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    Full Text Available ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ... radiology protection organizations continually review and update the technique standards used by radiology professionals. Modern x-ray ...

  20. Bone X-Ray (Radiography)

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    Full Text Available ... is commonly used to diagnose fractured bones or joint dislocation. Bone x-rays are the fastest and ... to view and assess bone fractures, injuries and joint abnormalities. This exam requires little to no special ...

  1. Bone X-Ray (Radiography)

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    Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... information you were looking for? Yes No Please type your comment or suggestion into the following text ...

  2. Bone X-Ray (Radiography)

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    Full Text Available ... small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different parts of the body absorb the x-rays in varying degrees. Dense ...

  3. Bone X-Ray (Radiography)

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    Full Text Available ... bone in the body, including the hand, wrist, arm, elbow, shoulder, spine, pelvis, hip, thigh, knee, leg ( ... x-ray tube is connected to a flexible arm that is extended over the patient while an ...

  4. Bone X-Ray (Radiography)

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Bone x-rays are the fastest and ... in the typical diagnostic range for this exam. Risks There is always a slight chance of cancer ...

  5. Bone X-Ray (Radiography)

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    Full Text Available ... pass through them. As a result, bones appear white on the x-ray, soft tissue shows up ... for a physician to view and assess bone injuries, including fractures, and joint abnormalities, such as arthritis. ...

  6. Bone X-Ray (Radiography)

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    Full Text Available ... abnormal bone growths and bony changes seen in metabolic conditions. assist in the detection and diagnosis of ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures ...

  7. Bone X-Ray (Radiography)

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    Full Text Available ... may also be asked to remove jewelry, removable dental appliances, eye glasses and any metal objects or clothing that might interfere with the x-ray images. Women should always inform their physician and ...

  8. Wide Field Imager for Athena

    Science.gov (United States)

    Meidinger, Norbert; Nandra, Kirpal; Rau, Arne; Plattner, Markus; WFI proto-Consortium

    2015-09-01

    The Wide Field Imager focal plane instrument on ATHENA will combine unprecedented survey power through its large field of view of 40 arcmin with a high count-rate capability (> 1 Crab). The energy resolution of the silicon sensor is state-of-the-art in the energy band of interest from 0.1 keV to 15 keV. At energy of 6 keV for example, the full width at half maximum of the line shall be not worse than 150 eV until the end of the mission. The performance is accomplished by a set of DEPFET active pixel sensor matrices with a pixel size well suited to the angular resolution of 5 arc sec (on-axis) of the mirror system.Each DEPFET pixel is a combined detector-amplifier structure with a MOSFET integrated onto a fully depleted 450 micron thick silicon bulk. Two different types of DEPFET sensors are planned for the WFI instrument: A set of large-area sensors to cover the physical size of 14 cm x 14 cm in the focal plane and a single gateable DEPFET sensor matrix optimized for the high count rate capability of the instrument. An overview will be given about the presently developed instrument concept and design, the status of the technology development, and the expected performance. An outline of the project organization, the model philosophy as well as the schedule will complete the presentation about the Wide Field Imager for Athena.

  9. RESOLVED COMPANIONS OF CEPHEIDS: TESTING THE CANDIDATES WITH X-RAY OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Nancy Remage; Pillitteri, Ignazio; Wolk, Scott; Karovska, Margarita; Tingle, Evan [Smithsonian Astrophysical Observatory, MS 4, 60 Garden St., Cambridge, MA 02138 (United States); Guinan, Edward; Engle, Scott [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Ave., Villanova, PA 19085 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Schaefer, Gail H. [The CHARA Array of Georgia State University, Mount Wilson, California 91023 (United States); Mason, Brian D., E-mail: nevans@cfa.harvard.edu, E-mail: heb11@psu.edu, E-mail: schaefer@chara-array.org [US Naval Observatory, 3450 Massachusetts Ave., NW, Washington, DC 20392-5420 (United States)

    2016-04-15

    We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M{sub ⊙}). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than 5″ (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥5″ or 4000 au.

  10. X-ray fluorescence holography

    CERN Document Server

    Hayashi, K; Takahashi, Y

    2003-01-01

    X-ray fluorescence holography (XFH) is a new structural analysis method of determining a 3D atomic arrangement around fluorescing atoms. We developed an XFH apparatus using advanced X-ray techniques and succeeded in obtaining high-quality hologram data. Furthermore, we introduced applications to the structural analysis of a thin film and the environment around dopants and, discussed the quantitative analysis of local lattice distortion. (author)

  11. Accelerator x-ray sources

    CERN Document Server

    Talman, Richard

    2007-01-01

    This first book to cover in-depth the generation of x-rays in particle accelerators focuses on electron beams produced by means of the novel Energy Recovery Linac (ERL) technology. The resulting highly brilliant x-rays are at the centre of this monograph, which continues where other books on the market stop. Written primarily for general, high energy and radiation physicists, the systematic treatment adopted by the work makes it equally suitable as an advanced textbook for young researchers.

  12. Why Do I Need X-Rays?

    Science.gov (United States)

    ... Child at Risk for Early Childhood Tooth Decay? Pacifiers Have Negative and Positive Effects The History of ... Sets the Record Straight on Dental X-Rays Types of X-Rays X-Rays Help Predict Permanent ...

  13. Nanometer x-ray lithography

    Science.gov (United States)

    Hartley, Frank T.; Khan Malek, Chantal G.

    1999-10-01

    New developments for x-ray nanomachining include pattern transfer onto non-planar surfaces coated with electrodeposited resists using synchrotron radiation x-rays through extremely high-resolution mask made by chemically assisted focused ion beam lithography. Standard UV photolithographic processes cannot maintain sub-micron definitions over large variation in feature topography. The ability of x-ray printing to pattern thin or thick layers of photoresist with high resolution on non-planar surfaces of large and complex topographies with limited diffraction and scattering effects and no substrate reflection is known and can be exploited for patterning microsystems with non-planar 3D geometries as well as multisided and multilayered substrates. Thin conformal coatings of electro-deposited positive and negative tone photoresist have been shown to be x-ray sensitive and accommodate sub-micro pattern transfer over surface of extreme topographical variations. Chemically assisted focused ion beam selective anisotropic erosion was used to fabricate x-ray masks directly. Masks with feature sizes less than 20 nm through 7 microns of gold were made on bulk silicon substrates and x-ray mask membranes. The technique is also applicable to other high density materials. Such masks enable the primary and secondary patterning and/or 3D machining of Nano-Electro-Mechanical Systems over large depths or complex relief and the patterning of large surface areas with sub-optically dimensioned features.

  14. The LOFT wide field monitor

    DEFF Research Database (Denmark)

    Brandt, Søren; Hernanz, M.; Alvarez, L.

    2012-01-01

    be able to address fundamental questions about strong gravity in the vicinity of black holes and the equation of state of nuclear matter in neutron stars. The prime goal of the WFM will be to detect transient sources to be observed by the LAD. However, with its wide field of view and good energy...... to the community of ~100 gamma ray burst positions per year with a ~1 arcmin location accuracy within 30 s of the burst. This paper provides an overview of the design, configuration, and capabilities of the LOFT WFM instrument....

  15. Center for X-Ray Optics, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    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.

  16. Harmonic lasing in X-ray FELs

    Energy Technology Data Exchange (ETDEWEB)

    Schneidmiller, E.A.; Yurkov, M.V.

    2012-05-15

    Harmonic lasing in a free electron laser with a planar undulator (under the condition that the fundamental frequency is suppressed) might be a cheap and efficient way of extension of wavelength ranges of existing and planned X-ray FEL facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam which is easier to handle due to the suppressed fundamental frequency. In this paper we perform a parametrization of the solution of the eigenvalue equation for lasing at odd harmonics, and present an explicit expression for FEL gain length, taking into account all essential effects. We propose and discuss methods for suppression of the fundamental harmonic. We also suggest a combined use of harmonic lasing and lasing at the retuned fundamental wavelength in order to reduce bandwidth and to increase brilliance of X-ray beam at saturation. Considering 3rd harmonic lasing as a practical example, we come to the conclusion that it is much more robust than usually thought, and can be widely used in the existing or planned X-ray FEL facilities. In particular, LCLS after a minor modification can lase to saturation at the 3rd harmonic up to the photon energy of 25-30 keV providing multi-gigawatt power level and narrow bandwidth. As for the European XFEL, harmonic lasing would allow to extend operating range (ultimately up to 100 keV), to reduce FEL bandwidth and to increase brilliance, to enable two-color operation for pump-probe experiments, and to provide more flexible operation at different electron energies. Similar improvements can be realized in other X-ray FEL facilities with gap-tunable undulators like FLASH II, SACLA, LCLS II, etc. Harmonic lasing can be an attractive option for compact X-ray FELs (driven by electron beams with a relatively low energy), allowing the use of the standard undulator technology instead of small-gap in-vacuum devices. Finally, in this paper we discover that in a part of the

  17. Combine TV-L1 model with guided image filtering for wide and faint ring artifacts correction of in-line x-ray phase contrast computed tomography.

    Science.gov (United States)

    Ji, Dongjiang; Qu, Gangrong; Hu, Chunhong; Zhao, Yuqing; Chen, Xiaodong

    2017-08-24

    In practice, mis-calibrated detector pixels give rise to wide and faint ring artifacts in the reconstruction image of the In-line phase-contrast computed tomography (IL-PC-CT). Ring artifacts correction is essential in IL-PC-CT. In this study, a novel method of wide and faint ring artifacts correction was presented based on combining TV-L1 model with guided image filtering (GIF) in the reconstruction image domain. The new correction method includes two main steps namely, the GIF step and the TV-L1 step. To validate the performance of this method, simulation data and real experimental synchrotron data are provided. The results demonstrate that TV-L1 model with GIF step can effectively correct the wide and faint ring artifacts for IL-PC-CT.

  18. The cosmological x-ray evolution of stars, AGN, and galaxies

    Science.gov (United States)

    Watson, Casey R.

    It is of great importance for our understanding of galaxy evolution to determine whether there is a break or a continuum in these processes from the powerful quasars and starbursts of the past, to the seemingly dormant, "normal" galaxies more typical of the present epoch. To help settle the question, we combined optical data from the NOAO Deep Wide-Field Survey (NDWFS), X-ray data from the XBootes survey, and spectral information from the AGN and Galaxy Evolution Survey (AGES) in order to simultaneously obtain deep and wide coverage of the normal galaxy population. In this manner, my collaborators and I were able to bridge the gap in normal galaxy X-ray coverage between large- area local surveys and high redshift, small volume deep fields. In particular, I present the X-ray evolution of normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0 [Special characters omitted.] z [Special characters omitted.] 0.5. We use radial emission profiles of low redshift galaxies, hardness ratios, and X-ray to optical luminosity ratios to estimate the relative contributions of stellar and nuclear sources. These tests suggest that the X-ray emission from spectroscopically late-type galaxies is dominated by star formation, while that from early-type galaxies is dominated by AGN. To extend our analysis of AGN to higher redshifts, we investigated the X-ray luminosity evolution of 3316 red galaxies selected over a wide range in redshift (0.3 global decline in accretion onto the central, supermassive black holes of early-type galaxies has proceeded in a similar manner at both the faint and the bright (individually detectable) ends of the AGN luminosity function. (Abstract shortened by UMI.)

  19. X-ray shout echoing through space

    Science.gov (United States)

    2004-01-01

    new gamma-ray satellite, called `Swift', will be launched as part of a collaboration between the USA, United Kingdom and Italy. Swift will add to the flotilla of satellites providing fast and accurate locations of gamma-ray bursts on the sky, which can then be followed with XMM-Newton. This will provide even more opportunities for new discoveries in this cutting-edge field. Notes to editors A scientific paper describing this discovery by Dr. Simon Vaughan and his collaborators has been accepted for publication in ``The Astrophysical Journal'' (see http://arxiv.org/abs/astro-ph/0312603). The other members in Vaughan's team are R. Willingale, P. O'Brien, J. Osborne, A. Levan, M. Watson and J. Tedds from the University of Leicester, United Kingdom; J. Reeves from NASA's Goddard Space Flight Center in Greenbelt, USA; D. Watson from the Neils Bohr Institute for Astronomy in Copenhagen, Denmark; M. Santos-Lleo, P. Rodriguez-Pascual and N. Schartel from ESA's XMM-Newton Science Operations Centre in Villafranca, Spain. Figure caption XMM-Newton's X-ray EPIC camera shows the expanding rings caused by a flash of X-rays scattered by dust in our Galaxy. The X-rays were produced by a powerful gamma-ray burst that took place on 3 December 2003. The slowly fading afterglow of the gamma-ray burst is at the centre of the expanding rings. Other, unrelated, X-ray sources can also be seen. The time since the gamma-ray explosion is shown in each panel in hours. At their largest size, the rings would appear in the sky about five times smaller than the full moon. Credit: ESA, S. Vaughan (University of Leicester) Video caption XMM-Newton's X-ray EPIC camera shows the expanding rings caused by a flash of X-rays scattered by dust in our Galaxy. The X-rays were produced by a powerful gamma-ray burst that took place on 3 December 2003. The slowly fading afterglow of the gamma-ray burst is at the centre of the expanding rings. Other, unrelated, X-ray sources can also be seen. The time since the

  20. Development of high resolution imaging detectors for x ray astronomy

    Science.gov (United States)

    Murray, S. S.; Schwartz, D. A.

    1992-01-01

    This final report summarizes our past activities and discusses the work performed over the period of 1 April 1990 through 1 April 1991 on x-ray optics, soft x-ray (0.1 - 10 KeV) imaging detectors, and hard x-ray (10 - 300 KeV) imaging detectors. If microchannel plates (MCPs) can be used to focus x-rays with a high efficiency and good angular resolution, they will revolutionize the field of x-ray optics. An x-ray image of a point source through an array of square MCP pores compared favorably with our ray tracing model for the MCP. Initial analysis of this image demonstrates the feasibility of MCPs for soft x-rays. Our work continues with optimizing the performance of our soft x-ray MCP imaging detectors. This work involves readout technology that should provide improved MCP readout devices (thin film crossed grid, curved, and resistive sheets), defect removal in MCPs, and photocathode optimization. In the area of hard x-ray detector development we have developed two different techniques for producing a CsI photocathode thickness of 10 to 100 microns, such that it is thick enough to absorb the high energy x-rays and still allow the photoelectrons to escape to the top MCP of a modified soft x-ray imaging detector. The methods involve vacuum depositing a thick film of CsI on a strong back, and producing a converter device that takes the place of the photocathode.

  1. The design of the wide field monitor for LOFT

    DEFF Research Database (Denmark)

    Brandt, Søren; Hernanz, M.; Alvarez, L.

    2014-01-01

    is designed to carry on-board two instruments with sensitivity in the 2-50 keV range: a 10 m 2 class Large Area Detector (LAD) with a ... will be to detect transient sources to be observed by the LAD. However, thanks to its unique combination of a wide field of view (FoV) and energy resolution (better than 500 eV), the WFM will be also an excellent monitoring instrument to study the long term variability of many classes of X-ray sources. The WFM...... consists of 10 independent and identical coded mask cameras arranged in 5 pairs to provide the desired sky coverage. We provide here an overview of the instrument design, configuration, and capabilities of the LOFT WFM. The compact and modular design of the WFM could easily make the instrument concept...

  2. Effect of the diaphragm of free-air ionisation chamber for X-ray air-kerma measurements.

    Science.gov (United States)

    Kurosawa, Tadahiro; Takata, Nobuhisa; Saito, Norio

    2011-07-01

    Free-air ionisation chambers are widely used at standards laboratories as primary standards for absolute measurements of air kerma in X-ray fields. The area of the diaphragm aperture of a free-air ionisation chambers is an important factor for absolute measurements because it defines the size of the X-ray beam incident on the free-air chamber. In this study, correction factors for the contribution of X rays transmitted through the diaphragm of a free-air ionisation chamber and those scattered from the surface of the diaphragm aperture are obtained by Monte Carlo simulation for two different sized free-air ionisation chambers and for various diaphragm aperture sizes, X-ray energies and source-to-chamber distances.

  3. Optoelectronic Picosecond Detection of Synchrotron X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Stephen M. [Purdue Univ., West Lafayette, IN (United States)

    2017-08-04

    The goal of this research program was to develop a detector that would measure x-ray time profiles with picosecond resolution. This was specifically aimed for use at x-ray synchrotrons, where x-ray pulse profiles have Gaussian time spreads of 50-100 ps (FWHM), so the successful development of such a detector with picosecond resolution would permit x-ray synchrotron studies to break through the pulse width barrier. That is, synchrotron time-resolved studies are currently limited to pump-probe studies that cannot reveal dynamics faster than ~50 ps, whereas the proposed detector would push this into the physically important 1 ps domain. The results of this research effort, described in detail below, are twofold: 1) the original plan to rely on converting electronic signals from a semiconductor sensor into an optical signal proved to be insufficient for generating signals with the necessary time resolution and sensitivity to be widely applicable; and 2) an all-optical method was discovered whereby the x-rays are directly absorbed in an optoelectronic material, lithium tantalate, which can then be probed by laser pulses with the desired picosecond sensitivity for detection of synchrotron x-rays. This research program has also produced new fundamental understanding of the interaction of x-rays and optical lasers in materials that has now created a viable path for true picosecond detection of synchrotron x-rays.

  4. Miniature x-ray tubes: current state and future prospects

    Science.gov (United States)

    Filip, V.; Filip, L. D.; Okuyama, F.

    2013-03-01

    Over the last decade, field emission miniature x-ray tubes emerged as cutting-edge applications of nanotechnology, possessing massive potential for use in various important fields, including that of precision medical therapy. The article essentially presents a review of such new devices reported in the literature. Additional discussions on the necessity of stabilizing the electron beam that generates x-rays are also included, and a simple technique for minimizing the current fluctuations is described. It is also pointed out that further miniaturization of field emission x-ray sources may need new concepts in designing the tube in shapes acting as ``self focusing'' structures for the electron beams.

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

    Science.gov (United States)

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

    2016-07-01

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

  6. High-Resolution Detector for At-Wavelength Metrology of X-Ray Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Since the launch of the first X-ray focusing telescope in 1963, the development of grazing incidence X-ray optics has been crucial to the development of the field of...

  7. Quantum effets in nonresonant X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Slowik, Jan Malte

    2015-11-15

    Due to their versatile properties, X rays are a unique tool to investigate the structure and dynamics of matter. X-ray scattering is the fundamental principle of many imaging techniques. Examples are X-ray crystallography, which recently celebrated one hundred years and is currently the leading method in structure determination of proteins, as well as X-ray phase contrast imaging (PCI), which is an imaging technique with countless applications in biology, medicine, etc. The technological development of X-ray free electron lasers (XFEL) has brought X-ray imaging at the edge of a new scientific revolution. XFELs offer ultrashort X-ray pulses with unprecedented high X-ray fluence and excellent spatial coherence properties. These properties make them an outstanding radiation source for X-ray scattering experiments, providing ultrafast temporal resolution as well as atomic spatial resolution. However, the radiation-matter interaction in XFEL experiments also advances into a novel regime. This demands a sound theoretical fundament to describe and explore the new experimental possibilities. This dissertation is dedicated to the theoretical study of nonresonant X-ray scattering. As the first topic, I consider the near-field imaging by propagation based X-ray phase contrast imaging (PCI). I devise a novel theory of PCI, in which radiation and matter are quantized. Remarkably, the crucial interference term automatically excludes contributions from inelastic scattering. This explains the success of the classical description thus far. The second topic of the thesis is the X-ray imaging of coherent electronic motion, where quantum effects become particularly apparent. The electron density of coherent electronic wave packets - important in charge transfer and bond breaking - varies in time, typically on femto- or attosecond time scales. In the near future, XFELs are envisaged to provide attosecond X-ray pulses, opening the possibility for time-resolved ultrafast X-ray scattering

  8. Measuring the X-ray Emission Impacting the Planets Orbiting Nearby Low-mass Stars

    Science.gov (United States)

    Brown, Alexander

    2013-09-01

    M dwarf planetary systems present a truly exciting opportunity to discover and study the first habitable extrasolar planets in the next 5-10 years. As part of our larger HST MUSCLES project, we propose ACIS-S observations of 4 low-mass exoplanet hosts (3 M dwarfs -- GJ581, GJ1214, GJ849, and 1 K dwarf -- HD97658) that have no existing measurements of their coronal X-ray emission. We will measure their X-ray luminosities and coronal temperatures, and derive the high energy radiation field to facilitate exoplanet atmospheric modeling. These planetary systems allow study of exoplanet atmospheric chemistry and evolution under a wide diversity of physical situations. X-ray heating enhances evaporation and atmospheric escape, which can impact the long-term stability of exoplanetary atmospheres.

  9. Theory of X-ray microcomputed tomography in dental research: application for the caries research

    Directory of Open Access Journals (Sweden)

    Young-Seok Park

    2011-03-01

    Full Text Available Caries remains prevalent throughout modern society and is the main disease in the field of dentistry. Although studies of this disease have used diverse methodology, recently, X-ray microtomography has gained popularity as a non-destructive, 3-dimensional (3D analytical technique, and has several advantages over the conventional methods. According to X-ray source, it is classified as monochromatic or polychromatic with the latter being more widely used due to the high cost of the monochromatic source despite some advantages. The determination of mineral density profiles based on changes in X-ray attenuation is the principle of this method and calibration and image processing procedures are needed for the better image and reproducible measurements. Using this tool, 3D reconstruction is also possible and it enables to visualize the internal structures of dental caries. With the advances in the computer technology, more diverse applications are being studied, such automated caries assessment algorithms.

  10. Identification of strain fields in pure Al and hybrid Ni/Al metal foams using X-ray micro-tomography under loading

    Czech Academy of Sciences Publication Activity Database

    Fíla, T.; Jiroušek, O.; Jung, A.; Kumpová, Ivana

    2016-01-01

    Roč. 11, November (2016), č. článku C11017. ISSN 1748-0221. [International Workshop on Radiation Imaging Detectors /18./. Barcelona, 03.07.2016-07.07.2016] R&D Projects: GA MŠk(CZ) LO1219 Keywords : computerized tomography (CT) * computed radiography (CR) * inspection with x-rays * X-ray radiography and digital radiography (DR) Subject RIV: JJ - Other Materials Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/11/11/C11017/meta;jsessionid=00BAD2D2C17907F1AF4F90CAFAB2A5D2.c1.iopscience.cld.iop.org

  11. Anecdotes about the Early Days of X-Ray Optics.

    Science.gov (United States)

    Baez, A V

    1997-01-01

    An anecdotal description of the trials and tribulations encountered by the first investigators in the field of x-ray optics starting in the late 1940s and how they managed to overcome them is provided. Some of the players, in addition to the author, included Paul Kirkpatrick, Hussein El Sum, and Howard Pattee of Stanford. At the University of Redlands we became interested in producing an x-ray microscope based on the concepts of holography which Dennis Gabor had demonstrated. This led to correspondence with Gabor and the opportunity to meet him and many other investigators at the first International Conference on X-Ray Microscopy and Microradiography held in Cambridge, England, in 1956. With the help of V.E. Cosslett and William Nixon, a point-focus x-ray tube was obtained by the University of Redlands for its experiments in x-ray holography in the1950s.

  12. A hard X-ray nanoprobe beamline for nanoscale microscopy.

    Science.gov (United States)

    Winarski, Robert P; Holt, Martin V; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G Brian; McNulty, Ian; Maser, Jörg

    2012-11-01

    The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals.

  13. Neutron and X-ray Spectroscopy

    CERN Document Server

    Hippert, Françoise; Hodeau, Jean Louis; Lelièvre-Berna, Eddy; Regnard, Jean-René

    2006-01-01

    Neutron and X-Ray Spectroscopy delivers an up-to-date account of the principles and practice of inelastic and spectroscopic methods available at neutron and synchrotron sources, including recent developments. The chapters are based on a course of lectures and practicals (the HERCULES course) delivered to young scientists who require these methods in their professional careers. Each chapter, written by a leading specialist in the field, introduces the basic concepts of the technique and provides an overview of recent work. This volume, which focuses on spectroscopic techniques in synchrotron radiation and inelastic neutron scattering, will be a primary source of information for physicists, chemists and materials scientists who wish to acquire a basic understanding of these techniques and to discover the possibilities offered by them. Emphasizing the complementarity of the neutron and X-ray methods, this tutorial will also be invaluable to scientists already working in neighboring fields who seek to extend thei...

  14. Discovery of X-ray pulsations from a massive star.

    Science.gov (United States)

    Oskinova, Lidia M; Nazé, Yael; Todt, Helge; Huenemoerder, David P; Ignace, Richard; Hubrig, Swetlana; Hamann, Wolf-Rainer

    2014-06-03

    X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star ξ(1) CMa. This star is a variable of β Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism.

  15. X-Ray-Scattering Measurements Of Strain In PEEK

    Science.gov (United States)

    Cebe, Peggy; Lowry, Lynn E.; Chung, Shirley Y.; Yavrouian, Andre H.; Gupta, Amitava

    1988-01-01

    Internal stress relieved by heating above glass-transition temperature. Report describes wide-angle x-ray scattering and differential scanning calorimetry of specimens of poly(etheretherketone) having undergone various thermal treatments. Wide-angle x-ray scattering particularly useful in determining distances between atoms, crystallinity, and related microstructurally generated phenomena, as thermal expansion and strain. Calorimetric measurements aid interpretation of scattering measurements by enabling correlation with thermal effects.

  16. Theoretical Calculation of coherent Laue-case conversion between X rays and ALPs for an X-ray LSW experiment

    OpenAIRE

    Yamaji, T.; Yamazaki, T; Tamasaku, K.; NAMBA, T

    2017-01-01

    Single crystals have high atomic electric fields as much as 10^{11} V/m, which correspond to magnetic fields of \\sim 10^3 T. These fields can be utilized to convert X rays into Axion Like Particles (ALPs) coherently similar to X-ray diffraction. In this paper, we perform the first theoretical calculation of the Laue-case conversion in crystals based on the Darwin dynamical theory of X-ray diffraction. The calculation shows that the Laue-case conversion has longer interaction length than the B...

  17. Clustering of X-Ray-Selected AGN

    Directory of Open Access Journals (Sweden)

    N. Cappelluti

    2012-01-01

    that galaxy mergers may constitute the main AGN-triggering mechanism. However, detailed analysis of observational data, acquired with modern telescopes, and the use of the new halo occupation formalism has revealed that the triggering of an AGN could also be attributed to phenomena-like tidal disruption or disk instability and to galaxy evolution. This paper reviews results from 1988 to 2011 in the field of X-ray-selected AGN clustering.

  18. Prospects of molybdenum and rhenium octahedral cluster complexes as X-ray contrast agents.

    Science.gov (United States)

    Krasilnikova, Anna A; Shestopalov, Michael A; Brylev, Konstantin A; Kirilova, Irina A; Khripko, Olga P; Zubareva, Kristina E; Khripko, Yuri I; Podorognaya, Valentina T; Shestopalova, Lidiya V; Fedorov, Vladimir E; Mironov, Yuri V

    2015-03-01

    Investigation of new X-ray contrast media for radiography is an important field of science since discovering of X-rays in 1895. Despite the wide diversity of available X-ray contrast media the toxicity, especially nephrotoxicity, is still a big problem to be solved. The octahedral metal-cluster complexes of the general formula [{M6Q8}L6] can be considered as quite promising candidates for the role of new radiocontrast media due to the high local concentration of heavy elements, high tuning ability of ligand environment and low toxicity. To exemplify this, the X-ray computed tomography experiments for the first time were carried out on some octahedral cluster complexes of molybdenum and rhenium. Based on the obtained data it was proposed to investigate the toxicological proprieties of cluster complex Na2H8[{Re6Se8}(P(CH2CH2CONH2)(CH2CH2COO)2)6]. Observed low cytotoxic and acute toxic effects along with rapid renal excretion of the cluster complex evidence its perspective as an X-ray contrast media for radiography. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. A flexible setup for angle-resolved X-ray fluorescence spectrometry with laboratory sources

    Energy Technology Data Exchange (ETDEWEB)

    Spanier, M., E-mail: mspanier@physik.tu-berlin.de; Herzog, C.; Grötzsch, D.; Kramer, F.; Mantouvalou, I.; Malzer, W.; Kanngießer, B. [Institute for Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin (Germany); Lubeck, J.; Weser, J.; Streeck, C.; Beckhoff, B. [Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin (Germany)

    2016-03-15

    X-ray fluorescence (XRF) analysis is one of the standard tools for the analysis of stratified materials and is widely applied for the investigation of electronics and coatings. The composition and thickness of the layers can be determined quantitatively and non-destructively. Recent work showed that these capabilities can be extended towards retrieving stratigraphic information like concentration depth profiles using angle-resolved XRF (ARXRF). This paper introduces an experimental sample chamber which was developed as a multi-purpose tool enabling different measurement geometries suited for transmission measurements, conventional XRF, ARXRF, etc. The chamber was specifically designed for attaching all kinds of laboratory X-ray sources for the soft and hard X-ray ranges as well as various detection systems. In detail, a setup for ARXRF using an X-ray tube with a polycapillary X-ray lens as source is presented. For such a type of setup, both the spectral and lateral characterizations of the radiation field are crucial for quantitative ARXRF measurements. The characterization is validated with the help of a stratified validation sample.

  20. Multiwavelength classification of Galactic X-ray sources using machine-learning

    Science.gov (United States)

    Hare, Jeremy; Kargaltsev, Oleg; Rangelov, Blagoy; Pavlov, George G.; Posselt, Bettina; Volkov, Igor

    2018-01-01

    Observations with Chandra and XMM-Newton X-ray observatories have detected a large number of Galactic sources serendipitously. The X-ray properties of these sources are extracted and placed into catalogs where they remain largely unexplored. These rich datasets hold excellent potential for population studies of various types of astrophysical sources and may also hide rare source types, which we are yet to discover. However, X-ray data alone is often not enough to classify these sources and multiwavelength data must be used. We have developed a multiwavelength machine-learning pipeline (MUWCLASS), which uses a rich training dataset (of about 10,000 sources of known types) to classify X-ray sources. We describe the pipeline, training dataset, and verification and validation procedures used to build the pipeline. We then present and discuss the results of the classifications of X-ray sources, as well as the code's performance in multiple example environments, including dwarf galaxies, stellar clusters, SNRs, unidentified TeV sources, and a wide Galactic disk field.

  1. Neutron and X-ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Carini, Gabriella [SLAC National Accelerator Lab., Menlo Park, CA (United States); Denes, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gruener, Sol [Cornell Univ., Ithaca, NY (United States); Lessner, Elianne [Dept. of Energy (DOE), Washington DC (United States). Office of Science Office of Basic Energy Sciences

    2012-08-01

    (and two computing hurdles that result from the corresponding increase in data volume) for the detector community to overcome in order to realize the full potential of BES neutron and X-ray facilities. Resolving these detector impediments will improve scientific productivity both by enabling new types of experiments, which will expand the scientific breadth at the X-ray and neutron facilities, and by potentially reducing the beam time required for a given experiment. These research priorities are summarized in the table below. Note that multiple, simultaneous detector improvements are often required to take full advantage of brighter sources. High-efficiency hard X-ray sensors: The fraction of incident particles that are actually detected defines detector efficiency. Silicon, the most common direct-detection X-ray sensor material, is (for typical sensor thicknesses) 100% efficient at 8 keV, 25%efficient at 20 keV, and only 3% efficient at 50 keV. Other materials are needed for hard X-rays. Replacement for 3He for neutron detectors: 3He has long been the neutron detection medium of choice because of its high cross section over a wide neutron energy range for the reaction 3He + n —> 3H + 1H + 0.764 MeV. 3He stockpiles are rapidly dwindling, and what is available can be had only at prohibitively high prices. Doped scintillators hold promise as ways to capture neutrons and convert them into light, although work is needed on brighter, more efficient scintillator solutions. Neutron detectors also require advances in speed and resolution. Fast-framing X-ray detectors: Today’s brighter X-ray sources make time-resolved studies possible. For example, hybrid X-ray pixel detectors, initially developed for particle physics, are becoming fairly mature X-ray detectors, with considerable development in Europe. To truly enable time-resolved studies, higher frame rates and dynamic range are required, and smaller pixel sizes are desirable. High-speed spectroscopic X-ray detectors

  2. X-Ray Polarimetry with GEMS

    Science.gov (United States)

    Strohmayer, Tod

    2011-01-01

    The polarization properties of cosmic X-ray sources are still largely unexplored. The Gravity and Extreme Magnetism SMEX (GEMS) will carry out the first sensitive X-ray polarization survey of a wide range of sources including; accreting compact objects (black holes and neutron stars), AGN, supernova remnants, magnetars and rotation-powered pulsars. GEMS employs grazing-incidence foil mirrors and novel time-projection chamber (TPC) polarimeters leveraging the photoelectric effect to achieve high polarization sensitivity in the 2 - 10 keV band. I will provide an update of the project status, illustrate the expected performance with several science examples, and provide a brief overview of the data analysis challenges

  3. Phototransistors use for dosimetric characteristics measurements of radiosurgery X-ray field; Uso de fototransistores para medida das caracteristicas dosimetricas de feixes de raios-X utilizados em radiocirurgia estereotaxica

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Walter M.; Hazin, Clovis A. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear; Souza, Cleber N. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Santos, Luiz Antonio P. dos [Centro Regional de Ciencias Nucleares (CRCN), Recife, PE (Brazil); Silva Junior, Eronildes F. da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Fisica

    2002-07-01

    Small X-ray beams are normally used in radiosurgery for the treatment of small intracranial lesions. The success of the treatment relies on the adequate planning, which in turn requires accurate evaluation of the radiation beam characteristics such as Percentage Depth Dose, Output Factor and Tissue-Maximum Ratio. However, the dosimetry of small X-ray fields is not a straightforward procedure, because the dimensions of the detectors normally used are not small enough so that their sensitive volumes are completely covered by the radiation beam, as well as to assure that electronic equilibrium conditions are attained. In this work, we have tested a transistor-type electronic device to be used as photodetector to determine some of the dosimetric parameters of a 6-MV linear accelerator used for radiosurgery. The results show that, under certain conditions, such a semiconductor device can be used for evaluating the dosimetric characteristics of small radiation beams used in radiosurgery. (author)

  4. Soft x-ray excitonics

    Science.gov (United States)

    Moulet, A.; Bertrand, J. B.; Klostermann, T.; Guggenmos, A.; Karpowicz, N.; Goulielmakis, E.

    2017-09-01

    The dynamic response of excitons in solids is central to modern condensed-phase physics, material sciences, and photonic technologies. However, study and control have hitherto been limited to photon energies lower than the fundamental band gap. Here we report application of attosecond soft x-ray and attosecond optical pulses to study the dynamics of core-excitons at the L2,3 edge of Si in silicon dioxide (SiO2). This attosecond x-ray absorption near-edge spectroscopy (AXANES) technique enables direct probing of the excitons’ quasiparticle character, tracking of their subfemtosecond relaxation, the measurement of excitonic polarizability, and observation of dark core-excitonic states. Direct measurement and control of core-excitons in solids lay the foundation of x-ray excitonics.

  5. X-ray tensor tomography

    Science.gov (United States)

    Malecki, A.; Potdevin, G.; Biernath, T.; Eggl, E.; Willer, K.; Lasser, T.; Maisenbacher, J.; Gibmeier, J.; Wanner, A.; Pfeiffer, F.

    2014-02-01

    Here we introduce a new concept for x-ray computed tomography that yields information about the local micro-morphology and its orientation in each voxel of the reconstructed 3D tomogram. Contrary to conventional x-ray CT, which only reconstructs a single scalar value for each point in the 3D image, our approach provides a full scattering tensor with multiple independent structural parameters in each volume element. In the application example shown in this study, we highlight that our method can visualize sub-pixel fiber orientations in a carbon composite sample, hence demonstrating its value for non-destructive testing applications. Moreover, as the method is based on the use of a conventional x-ray tube, we believe that it will also have a great impact in the wider range of material science investigations and in future medical diagnostics. The authors declare no competing financial interests.

  6. Generation of circularly polarized XUV and soft-x-ray high-order harmonics by homonuclear and heteronuclear diatomic molecules subject to bichromatic counter-rotating circularly polarized intense laser fields

    Science.gov (United States)

    Heslar, John; Telnov, Dmitry A.; Chu, Shih-I.

    2017-12-01

    Recently, studies of bright circularly polarized high-harmonic beams from atoms in the soft-x-ray region as a source for x-ray magnetic circular dichroism measurement in a tabletop-scale setup have received considerable attention. In this paper, we address the problem with molecular targets and perform a detailed quantum study of H2 +, CO, and N2 molecules in bichromatic counter-rotating circularly polarized laser fields where we adopt wavelengths (1300 and 790 nm) and intensities (2 ×1014W /cm2 ) reported in a recent experiment [Proc. Natl. Acad. Sci. USA 112, 14206 (2015), 10.1073/pnas.1519666112]. Our treatment of multiphoton processes in homonuclear and heteronuclear diatomic molecules is nonperturbative and based on the time-dependent density-functional theory for multielectron systems. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics with high-energy photons in the XUV and soft-x-ray ranges. Our results reveal intriguing and substantially different nonlinear optical responses for homonuclear and heteronuclear diatomic molecules subject to circularly polarized intense laser fields. We study in detail the below- and above-threshold harmonic regions and analyze the ellipticity and phase of the generated harmonic peaks.

  7. X-ray and synchrotron methods in studies of cultural heritage sites

    Energy Technology Data Exchange (ETDEWEB)

    Koval’chuk, M. V.; Yatsishina, E. B.; Blagov, A. E.; Tereshchenko, E. Yu., E-mail: elenatereschenko@yandex.ru; Prosekov, P. A.; Dyakova, Yu. A. [National Research Centre “Kurchatov Institute” (Russian Federation)

    2016-09-15

    X-ray and synchrotron methods that are most widely used in studies of cultural heritage objects (including archaeological sites)—X-ray diffraction analysis, X-ray spectroscopy, and visualization techniques— have been considered. The reported examples show high efficiency and informativeness of natural science studies when solving most diverse problems of archaeology, history, the study of art, museology, etc.

  8. X-ray and synchrotron methods in studies of cultural heritage sites

    Science.gov (United States)

    Koval'chuk, M. V.; Yatsishina, E. B.; Blagov, A. E.; Tereshchenko, E. Yu.; Prosekov, P. A.; Dyakova, Yu. A.

    2016-09-01

    X-ray and synchrotron methods that are most widely used in studies of cultural heritage objects (including archaeological sites)—X-ray diffraction analysis, X-ray spectroscopy, and visualization techniques— have been considered. The reported examples show high efficiency and informativeness of natural science studies when solving most diverse problems of archaeology, history, the study of art, museology, etc.

  9. X-ray Lobster Eye all-sky monitor for rocket experiment

    Science.gov (United States)

    Dániel, V.; Inneman, A.; Pína, L.; Zadražil, V.; Báča, T.; Stehlíková, V.; Nentvich, O.; Urban, M.; Maršíková, V.; McEntaffer, R.; Tutt, J.; Schulz, T.

    2017-05-01

    This paper presents a Lobster Eye (LE) X-ray telescope developed for the Water Recovery X-ray Rocket (WRX-R) experiment. The primary payload of the rocket experiment is a soft X-ray spectroscope developed by the Pennsylvania State University (PSU), USA. The Czech team participates by hard LE X-ray telescope as a secondary payload. The astrophysical objective of the rocket experiment is the Vela Supernova of size about 8deg x 8deg. In the center of the nebula is a neutron star with a strong magnetic field, roughly the mass of the Sun and a diameter of about 20 kilometers forming the Vela pulsar. The primary objective of WRX-R is the spectral measurement of the outer part of the nebula in soft X-ray and FOV of 3.25deg x 3.25deg. The secondary objective (hard LE X-ray telescope) is the Vela neutron star observation. The hard LE telescope consists of two X-ray telescopes with the Timepix detector. First telescope uses 2D LE Schmidt optics (2DLE- REX) with focal length over 1m and 4 Timepix detectors (2x2 matrix). The telescope FOV is 1.5deg x 1.5deg with spectral range from 3keV to 60keV. The second telescope uses 1D LE Schmidt optics (1D-LE-REX) with focal length of 25 cm and one Timepix detector. The telescope is made as a wide field with FOV 4.5deg x 3.5deg and spectral range from 3keV to 40keV. The rocket experiment serves as a technology demonstration mission for the payloads. The LE X-ray telescopes can be in the future used as all-sky monitor/surveyor. The astrophysical observation can cover the hard X-ray observation of astrophysical sources in time-domain, the GRBs surveying or the exploration of the gravitational wave sources.

  10. Spectral and Timing Nature of the Symbiotic X-Ray Binary 4U 1954+319: The Slowest Rotating Neutron Star in AN X-Ray Binary System

    Science.gov (United States)

    Enoto, Teruaki; Sasano, Makoto; Yamada, Shin'Ya; Tamagawa, Toru; Makishima, Kazuo; Pottschmidt, Katja; Marcu, Diana; Corbet, Robin H. D.; Fuerst, Felix; Wilms, Jorn

    2014-01-01

    The symbiotic X-ray binary (SyXB) 4U 1954+319 is a rare system hosting a peculiar neutron star (NS) and an M-type optical companion. Its approx. 5.4 hr NS spin period is the longest among all known accretion-powered pulsars and exhibited large (is approx. 7%) fluctuations over 8 yr. A spin trend transition was detected with Swift/BAT around an X-ray brightening in 2012. The source was in quiescent and bright states before and after this outburst based on 60 ks Suzaku observations in 2011 and 2012. The observed continuum is well described by a Comptonized model with the addition of a narrow 6.4 keV Fe-K alpha line during the outburst. Spectral similarities to slowly rotating pulsars in high-mass X-ray binaries, its high pulsed fraction (approx. 60%-80%), and the location in the Corbet diagram favor high B-field (approx. greater than 10(exp12) G) over a weak field as in low-mass X-ray binaries. The observed low X-ray luminosity (10(exp33)-10(exp35) erg s(exp-1)), probable wide orbit, and a slow stellar wind of this SyXB make quasi-spherical accretion in the subsonic settling regime a plausible model. Assuming a approx. 10(exp13) G NS, this scheme can explain the approx. 5.4 hr equilibrium rotation without employing the magnetar-like field (approx. 10(exp16) G) required in the disk accretion case. The timescales of multiple irregular flares (approx. 50 s) can also be attributed to the free-fall time from the Alfv´en shell for a approx. 10(exp13) G field. A physical interpretation of SyXBs beyond the canonical binary classifications is discussed.

  11. Nanofocusing refractive X-ray lenses

    Energy Technology Data Exchange (ETDEWEB)

    Boye, Pit

    2010-02-05

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  12. X-raying galaxies: a Chandra legacy.

    Science.gov (United States)

    Wang, Q Daniel

    2010-04-20

    This presentation reviews Chandra's major contribution to the understanding of nearby galaxies. After a brief summary on significant advances in characterizing various types of discrete x-ray sources, the presentation focuses on the global hot gas in and around galaxies, especially normal ones like our own. The hot gas is a product of stellar and active galactic nuclear feedback--the least understood part in theories of galaxy formation and evolution. Chandra observations have led to the first characterization of the spatial, thermal, chemical, and kinetic properties of the gas in our galaxy. The gas is concentrated around the galactic bulge and disk on scales of a few kiloparsec. The column density of chemically enriched hot gas on larger scales is at least an order magnitude smaller, indicating that it may not account for the bulk of the missing baryon matter predicted for the galactic halo according to the standard cosmology. Similar results have also been obtained for other nearby galaxies. The x-ray emission from hot gas is well correlated with the star formation rate and stellar mass, indicating that the heating is primarily due to the stellar feedback. However, the observed x-ray luminosity of the gas is typically less than a few percent of the feedback energy. Thus the bulk of the feedback (including injected heavy elements) is likely lost in galaxy-wide outflows. The results are compared with simulations of the feedback to infer its dynamics and interplay with the circumgalactic medium, hence the evolution of galaxies.

  13. Healing X-ray scattering images.

    Science.gov (United States)

    Liu, Jiliang; Lhermitte, Julien; Tian, Ye; Zhang, Zheng; Yu, Dantong; Yager, Kevin G

    2017-07-01

    X-ray scattering images contain numerous gaps and defects arising from detector limitations and experimental configuration. We present a method to heal X-ray scattering images, filling gaps in the data and removing defects in a physically meaningful manner. Unlike generic inpainting methods, this method is closely tuned to the expected structure of reciprocal-space data. In particular, we exploit statistical tests and symmetry analysis to identify the structure of an image; we then copy, average and interpolate measured data into gaps in a way that respects the identified structure and symmetry. Importantly, the underlying analysis methods provide useful characterization of structures present in the image, including the identification of diffuse versus sharp features, anisotropy and symmetry. The presented method leverages known characteristics of reciprocal space, enabling physically reasonable reconstruction even with large image gaps. The method will correspondingly fail for images that violate these underlying assumptions. The method assumes point symmetry and is thus applicable to small-angle X-ray scattering (SAXS) data, but only to a subset of wide-angle data. Our method succeeds in filling gaps and healing defects in experimental images, including extending data beyond the original detector borders.

  14. Healing X-ray scattering images

    Directory of Open Access Journals (Sweden)

    Jiliang Liu

    2017-07-01

    Full Text Available X-ray scattering images contain numerous gaps and defects arising from detector limitations and experimental configuration. We present a method to heal X-ray scattering images, filling gaps in the data and removing defects in a physically meaningful manner. Unlike generic inpainting methods, this method is closely tuned to the expected structure of reciprocal-space data. In particular, we exploit statistical tests and symmetry analysis to identify the structure of an image; we then copy, average and interpolate measured data into gaps in a way that respects the identified structure and symmetry. Importantly, the underlying analysis methods provide useful characterization of structures present in the image, including the identification of diffuse versus sharp features, anisotropy and symmetry. The presented method leverages known characteristics of reciprocal space, enabling physically reasonable reconstruction even with large image gaps. The method will correspondingly fail for images that violate these underlying assumptions. The method assumes point symmetry and is thus applicable to small-angle X-ray scattering (SAXS data, but only to a subset of wide-angle data. Our method succeeds in filling gaps and healing defects in experimental images, including extending data beyond the original detector borders.

  15. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  16. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... dislocations. In elderly or patients with osteoporosis, a hip fracture may be clearly seen on a CT scan, while it may be barely seen, if at all, on a hip x-ray. For suspected spine injury or other ...

  17. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... to current x-ray images for diagnosis and disease management. top of page How is the procedure ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different ... This ensures that those parts of a patient's body not being imaged receive minimal radiation ... x-ray images are among the clearest, most detailed views of ...

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... may be placed over your pelvic area or breasts when feasible to protect from ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  20. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... is commonly used to diagnose fractured bones or joint dislocation. Bone x-rays are the fastest and easiest way for your doctor ... shin), ankle or foot. top of page What are some common uses of the ... bones or joint dislocation. demonstrate proper alignment and stabilization of bony ...

  1. X-rays and magnetism.

    Science.gov (United States)

    Fischer, Peter; Ohldag, Hendrik

    2015-09-01

    Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.

  2. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different ... bear denotes child-specific content. Related Articles and Media ... Images related to X-ray (Radiography) - Bone Sponsored by ...

  3. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone ...

  4. X-Ray Exam: Pelvis

    Science.gov (United States)

    ... pelvis and an image is recorded on special film or a computer. This image shows the bones of the pelvis, which include the two hip bones, plus the sacrum and the coccyx (tailbone). The X-ray image is black and white. Dense body parts that block the passage of the X- ...

  5. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to ... See the Safety page for more information about pregnancy and x-rays. A Word About Minimizing ... imaging tests and treatments have special pediatric considerations. The teddy ...

  6. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... way for your doctor to view and assess bone fractures, injuries and joint abnormalities. This exam requires little ... way for a physician to view and assess bone injuries, including fractures, and joint abnormalities, such as arthritis. X-ray ...

  7. Mapping strain fields induced in Zr-based bulk metallic glasses during in-situ nanoindentation by X-ray nanodiffraction

    Czech Academy of Sciences Publication Activity Database

    Gamcová, J.; Mohanty, G.; Michalik, Štefan; Wehrs, J.; Bednarčík, J.; Krywka, C.; Breguet, J.M.; Michler, J.; Franz, H.

    2016-01-01

    Roč. 108, č. 3 (2016), 1-4, č. článku 031907. ISSN 0003-6951 R&D Projects: GA MŠk EE2.3.30.0057 Grant - others:OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057; AVČR(CZ) M100101221 Institutional support: RVO:68378271 Keywords : X-ray diffraction * hardness * elasticity * nanotechnology * amorphous metals Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.411, year: 2016

  8. The wide field imager instrument for Athena

    Science.gov (United States)

    Meidinger, Norbert; Eder, Josef; Eraerds, Tanja; Nandra, Kirpal; Pietschner, Daniel; Plattner, Markus; Rau, Arne; Strecker, Rafael

    2016-07-01

    The WFI (Wide Field Imager) instrument is planned to be one of two complementary focal plane cameras on ESA's next X-ray observatory Athena. It combines unprecedented survey power through its large field of view of 40 amin x 40 amin together with excellent count rate capability (>= 1 Crab). The energy resolution of the silicon sensor is state-of-the-art in the energy band of interest from 0.2 keV to 15 keV, e.g. the full width at half maximum of a line at 7 keV will be MOSFET integrated onto a fully depleted 450 μm thick silicon bulk. Two detectors are planned for the WFI instrument: A large-area detector comprising four sensors with a total of 1024 x 1024 pixels and a fast detector optimized for high count rate observations. This high count rate capable detector permits for bright point sources with an intensity of 1 Crab a throughput of more than 80% and a pile-up of less than 1%. The fast readout of the DEPFET pixel matrices is facilitated by an ASIC development, called VERITAS-2. Together with the Switcher-A, a control ASIC that allows for operation of the DEPFET in rolling shutter mode, these elements form the key components of the WFI detectors. The detectors are surrounded by a graded-Z shield, which has in particular the purpose to avoid fluorescence lines that would contribute to the instrument background. Together with ultra-thin coating of the sensor and particle identification by the detector itself, the particle induced background shall be minimized in order to achieve the scientific requirement of a total instrumental background value smaller than 5 x 10-3 cts/cm2/s/keV. Each detector has its dedicated detector electronics (DE) for supply and data acquisition. Due to the high frame rate in combination with the large pixel array, signal correction and event filtering have to be done on-board and in real-time as the raw data rate would by far exceed the feasible telemetry rate. The data streams are merged and compressed in the Instrument Control and

  9. High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

    NARCIS (Netherlands)

    Groot, F.M.F. de

    2000-01-01

    In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

  10. Shining X-rays on catalysts at work

    DEFF Research Database (Denmark)

    Grunwaldt, Jan-Dierk

    2009-01-01

    excitation spectroscopy). In order to obtain spectroscopic information on the oxidation state inside a microreactor, scanning and full field X-ray microscopy with X-ray absorption spectroscopic contrast were achieved under reaction conditions. If a microbeam is applied, fast scanning techniques like QEXAFS...... are required. In this way, even X-ray absorption spectroscopic tomographic images of a slice of a microreactor were obtained. The studies were recently extended to spatiotemporal studies that give important insight into the dynamics of the catalyst structure in a spatial manner with subsecond time-resolution....

  11. Simulation of high currents in x-ray flash tubes

    Science.gov (United States)

    Germer, R.; Sato, E.

    2008-11-01

    The discharge in linear plasma X-ray flash tubes ( Sato tubes ) is simulated. For the geometry of a cylinder cathode outside and an anode in the centre, the electrical fields and potentials are calculated and the propagation of electrons are studied. Space charge limits the current in the initial phase strongly. Replacing the vacuum by plasma from the anode evaporation, it is possible to get increasing current and strong X-ray pulses. Space charge is important for the high intensity X-ray production up to the end of the emission.

  12. [Radiobiological aspects of diagnostic X-ray use in dentistry].

    Science.gov (United States)

    Hoogeveen, R C; van den Aardweg, G J M J

    2015-05-01

    Soon after the discovery of X-rays, it became clear that their use can cause detrimental effects. The field of radiobiology deals with these detrimental effects. In this article, the theoretical concepts of radiobiology relevant to diagnostic X-ray use are presented. The effects of radiation on living tissues, the relationship between dose and effect, and a translation of these effects into the dental application are discussed. X-rays cannot be considered to be harmless even when used at the relatively low doses as in dentistry. If applied with justification and optimization, the risk to the patient will, however, be small.

  13. The X-ray Telescope of CAST

    CERN Document Server

    Kuster, M.; Cebrian, S.; Davenport, M.; Elefteriadis, C.; Englhauser, J.; Fischer, H.; Franz, J.; Friedrich, P.; Hartmann, R.; Heinsius, F.H.; Hoffmann, D.H.H.; Hoffmeister, G.; Joux, J.N.; Kang, D.; Konigsmann, Kay; Kotthaus, R.; Papaevangelou, T.; Lasseur, C.; Lippitsch, A.; Lutz, G.; Morales, J.; Rodriguez, A.; Struder, L.; Vogel, J.; Zioutas, K.

    2007-01-01

    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.

  14. Axion mass limits from pulsar x rays

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.E.

    1984-12-01

    Axions thermally emitted by a neutron star would be converted into x rays in the strong magnetic field surrounding the star. An improvement in the observational upper limit of pulsed x rays from the Vela pulsar (PSR 0833-45) by a factor of 12 would constrain the axion mass M/sub a/ < 2 x 10/sup -3/eV if the core is non-superfluid and at temperature T/sub c/ greater than or equal to 2 x 10/sup 8/K. If the core is superfluid throughout, an improvement factor of 240 would be needed to provide the same constraint on the axion mass, while in the absence of superfluidity, an improvement factor of 200 could constrain M/sub a/ < 6 x 10/sup -4/eV. A search for modulated hard x rays from PSR 1509-58 or other young pulsars at presently attainable sensitivities may enable the setting of an upper limit for the axion mass. Observation of hard x rays from a very young hot pulsar with T/sub c/ greater than or equal to 7 x 10/sup 8/K could set a firm bound on the axion mass, since neutron superfluidity is not expected above this temperature. The remaining axion mass range 6 x 10/sup -4/eV > M/sub a/ > 10/sup -5/eV (the cosmological lower bound) can be covered by an improved Sikivie type laboratory cavity detector for relic axions constituting the galactic halo. 48 refs.

  15. A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection

    Science.gov (United States)

    Xu, Jie; Wang, Xin; Zhan, Qi; Huang, Shengling; Chen, Yifan; Mu, Baozhong

    2016-07-01

    This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system based on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.

  16. A simple X-ray emitter.

    Science.gov (United States)

    Murakami, Hiroaki; Ono, Ryoichi; Hirai, Atsuhiko; Hosokawa, Yoshinori; Kawai, Jun

    2005-07-01

    A compact X-ray emission instrument is made, and the X-ray spectra are measured by changing the applied electric potential. Strong soft X-rays are observed when evacuating roughly and applying a high voltage to an insulator settled in this device. The X-ray intensity is higher as the applied voltage is increased. A light-emitting phenomenon is observed when this device emits X-rays. The present X-ray emitter is made of a small cylinder with a radius of 20 mm and a height of 50 mm. This X-ray generator has a potential to be used as an X-ray source in an X-ray fluorescence spectrometer.

  17. X-rays from comets - a surprising discovery

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    Comets are kilometre-size aggregates of ice and dust, which remained from the formation of the solar system. It was not obvious to expect X-ray emission from such objects. Nevertheless, when comet Hyakutake (C/1996 B2) was observed with the ROSAT X-ray satellite during its close approach to Earth in March 1996, bright X-ray emission from this comet was discovered. This finding triggered a search in archival ROSAT data for comets, which might have accidentally crossed the field of view during observations of unrelated targets. To increase the surprise even more, X-ray emission was detected from four additional comets, which were optically 300 to 30 000 times fainter than Hyakutake. For one of them, comet Arai (C/1991 A2), X-ray emission was even found in data which were taken six weeks before the comet was optically discovered. These findings showed that comets represent a new class of celestial X-ray sources. The subsequent detection of X-ray emission from several other comets in dedicated observations confir...

  18. Observing GRBs with the LOFT Wide Field Monitor

    DEFF Research Database (Denmark)

    Brandt, Søren; Hernanz, M.; Feroci, M.

    2013-01-01

    field of view and good energy resolution of GRBs and X-ray flashes. The WFM will be able to detect ~150 gamma ray bursts per year, and a burst alert system will enable the distribution of ~100 GRB positions per year with a ~1...

  19. Modeling the amorphous structure of mechanically alloyed Ti{sub 50}Ni{sub 25}Cu{sub 25} using anomalous wide-angle x-ray scattering and reverse Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.br [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Poffo, C.M. [Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Souza, S.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Machado, K.D. [Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná (Brazil); Trichês, D.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Grandi, T.A. [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Biasi, R.S. de [Seção de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

    2013-09-01

    An amorphous Ti{sub 50}Ni{sub 25}Cu{sub 25} alloy was produced by 19 h of mechanical alloying. Anomalous wide angle x-ray scattering data were collected at six energies and six total scattering factors were obtained. By considering the data collected at two energies close to the Ni and Cu K edges, two differential anomalous scattering factors about the Ni and Cu atoms were obtained, showing that the chemical environments around these atoms are different. Eight factors were used as input data to the reverse Monte Carlo method used to compute the partial structure factors S{sub Ti3Ti}(K), S{sub Ti–Cu}(K), S{sub Ti–Ni}(K), S{sub Cu3Cu}(K), S{sub Cu–Ni}(K) and S{sub Ni–Ni}(K) and the partial pair distribution functions G{sub Ti3Ti}(r), G{sub Ti–Cu}(r), G{sub Ti–Ni}(r), G{sub Cu3Cu}(r), G{sub Cu–Ni}(r) and G{sub Ni–Ni}(r). From the RMC final atomic configuration and G{sub ij}(r) functions, the coordination numbers and interatomic atomic distances for the first neighbors were determined.

  20. A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography.