WorldWideScience

Sample records for rotational x-ray angiography

  1. On the ultimate x-ray detector for angiography

    NARCIS (Netherlands)

    Slump, Cornelis H.; Flynn, M.J.; Kauffman, J.A.

    2005-01-01

    The purpose of our research is to describe the ultimate X-ray detector for angiography. Angiography is a well established X-ray imaging technique for the examination of blood vessels. Contrast agent is injected followed by X-ray exposures and possible obstructions in the blood vessels can be

  2. On the ultimate x-ray detector for angiography

    Science.gov (United States)

    Slump, Cornelis H.; Kauffman, Joost A.

    2005-04-01

    The purpose of our research is to describe the ultimate X-ray detector for angiography. Angiography is a well established X-ray imaging technique for the examination of blood vessels. Contrast agent is injected followed by X-ray exposures and possible obstructions in the blood vessels can be visualized. Standard angiography primarily inspects for possible occlusions and views the vessels as rigid pipes. However, due to the beating heart the flow in arteries is pulsatile. Healthy arteries are not rigid tubes but adapt to various pressure and flow conditions. Our interest is in the (small) response of the artery on the pulse flow. If the arteries responses elastically on the pulse flow, we can expect that it is still healthy. So the detection of artery diameter variations is of interest for the detection of atherosclerosis in an early stage. In this contribution we specify and test a model X-ray detector for its abilities to record the responses of arteries on pulsatile propagating flow distributions. Under normal physiological conditions vessels respond with a temporal increase in arterial internal cross-sectional area of order 10%. This pulse flow propagates along the arteries in response of the left ventricle ejections. We show results of the detection of simulated vessel distensabilities for the model detector and discuss salient parameters features.

  3. Rotational X-ray angiography: a method for intra-operative volume imaging of the left-atrium and pulmonary veins for atrial fibrillation ablation guidance

    Science.gov (United States)

    Manzke, R.; Zagorchev, L.; d'Avila, A.; Thiagalingam, A.; Reddy, V. Y.; Chan, R. C.

    2007-03-01

    Catheter-based ablation in the left atrium and pulmonary veins (LAPV) for treatment of atrial fibrillation in cardiac electrophysiology (EP) are complex and require knowledge of heart chamber anatomy. Electroanatomical mapping (EAM) is typically used to define cardiac structures by combining electromagnetic spatial catheter localization with surface models which interpolate the anatomy between EAM point locations in 3D. Recently, the incorporation of pre-operative volumetric CT or MR data sets has allowed for more detailed maps of LAPV anatomy to be used intra-operatively. Preoperative data sets are however a rough guide since they can be acquired several days to weeks prior to EP intervention. Due to positional and physiological changes, the intra-operative cardiac anatomy can be different from that depicted in the pre-operative data. We present an application of contrast-enhanced rotational X-ray imaging for CT-like reconstruction of 3D LAPV anatomy during the intervention itself. Depending on the heart size a single or two selective contrastenhanced rotational acquisitions are performed and CT-like volumes are reconstructed with 3D filtered back projection. In case of dual injection, the two volumes depicting the left and right portions of the LAPV are registered and fused. The data sets are visualized and segmented intra-procedurally to provide anatomical data and surface models for intervention guidance. Our results from animal and human experiments indicate that the anatomical information from intra-operative CT-like reconstructions compares favorably with preacquired imaging data and can be of sufficient quality for intra-operative guidance.

  4. K-Edge Subtraction Angiography with Synchrotron X-Rays

    CERN Document Server

    Giacomini, J C

    1996-01-01

    The purpose of this project was to utilize dual energy, monochromatic X-rays produced from synchrotrons radiation in order to obtain noninvasive medical imaging. The application of synchrotrons radiation to medical imaging is based on the principle of iodine dichromography, first described by Bertil Jacobson of the Karolinska Institute in 1953. Medical imaging using synchrotrons radiation and K-edge dichromography was pioneered at Stanford University under the leadership of Dr. Ed Rubenstein, and the late Nobel Laureate in Physics, Dr. Robert Hofstadter. With progressive refinements in hardware, clinical-quality images were obtained of human coronary arteries utilizing peripheral injections of iodinated contrast agent. These images even now are far superior to those being presented by investigators using MRI as an imaging tool for coronary arteries. However, new supplies and instruments in the cardiac catheterization laboratory have served to transform coronary angiography into an outpatient procedure, with r...

  5. 3D Rotational X-Ray guidance for surgical interventions

    NARCIS (Netherlands)

    Kraats, Everine Brenda van de

    2005-01-01

    The research described in this thesis is aimed at increasing the accuracy and decreasing the invasiveness of surgical procedures, with a focus on spine procedures, by using a combination of multi-modality images, computer-assisted navigation, intraoperative 3D rotational X-ray (3DRX) imaging, and

  6. Rotation powered pulsars in the x-rays

    Science.gov (United States)

    Arumugasamy, Prakash

    The dissertation focuses on the study of rotation-powered pulsars, the primary observational manifestation of neutron stars. These objects are powerful sources of electromagnetic radiation and relativistic particles whose emission is provided by the loss of pulsar rotational energy. Understanding the evolution of pulsars, which happens over billion year timescales, requires detection and study of pulsars at different stages of evolution. I present detailed X-ray analyses of pulsars at four distinct stages of evolution and compare their emission behavior with that of other pulsars expected to be in similar evolutionary stages. I also show key characteristics of the pulsars that make them unique in their group. I start with a young and energetic pulsar, PSR J2022+3842 (characteristic age tauc ≈ 9 kyr, spin-down power E = 3 x 1037 erg s-1), with powerful non-thermal emission. X-ray timing of the pulsar revealed double-peaked X-ray profile with a period twice the previously established value. Our analysis allowed us to update the pulsar's spin-down power and X-ray efficiency using the correct timing results, which brought the pulsar more in-line with other young X-ray pulsars. I also provide the phase-dependent behavior of the pulsar's non-thermal emission. Pulsars with true ages, often substituted by characteristic age, below tauc ˜100 kyr are considered young and ones with tau c ≥ 1 Myr are considered old, with the 'middle-aged' pulsars in the middle. My next pulsar is a tauc = 1.8 Myr old J1836+5925 (E = 1 x 1034 erg s-1), which is perhaps the brightest X-ray source among the oldest pulsars still observable in the gamma-rays. Detailed timing and spectral analyses show strong evidence of an absorption feature (perhaps an electron cyclotron line) in the pulsar's spectrum. Characterizing its thermal emission might have important implications for the neutron star cooling models. Moving another two orders of magnitude up in tauc, we arrive at one of the oldest known

  7. Design study of Thomson Laser-Electron X-ray Generator (LEX) for Millisecond Angiography

    Science.gov (United States)

    Artyukov, I. A.; Bessonov, E. G.; Feshchenko, R. M.; Gorbunkov, M. V.; Maslova, Yu Ya; Popov, N. L.; Dyachkov, N. V.; Postnov, A. A.; Vinogradov, S. L.; Vinogradov, A. V.

    2017-01-01

    In this concept study a laser-electron X-ray generator (LEX) is considered for the medical imaging of the inner vessel structure. It is demonstrated that the modern lasers and linear electron accelerators are suitable for the design of the new generation of angiography medical equipment combining higher spatial and time resolution with the reduced patient dose. Angiography setup based on LEXG can make use of different contrast media (iodine, gadolinium) working on absorption edge due to the narrow tuneable spectrum which is not possible with conventional X-ray tubes. In the present study all estimations are made for iodine-based contrast agents. The conclusion is that modern technologies allow practical implementation of LEX for angiography based on multibunch linear accelerator and photon storage device.

  8. Exotic sources of x-rays for iodine K-edge angiography

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.

    1993-08-01

    Digital Subtractive Angiography (DSA) has been performed to image human coronary arteries using wiggler radiation from electron storage rings. The significant medical promise of this procedure motivates the development of smaller and less costly x-ray sources. Several exotic sources are candidates for consideration, using effects such as Cherenkov, channeling, coherent bremsstrahlung, laser backscattering, microundulator, parametric, Smith-Purcell, and transition radiation. In this work we present an analysis of these effects as possible sources of intense x-rays at the iodine K-edge at 33.169 key. The criteria we use are energy, efficiency, flux, optical properties, and technical realizability. For each of the techniques, we find that they suffer either from low flux, a low energy cutoff, target materials heating, too high electron beam energy requirement, optical mismatch to angiography, or a combination of these. We conclude that the foreseeable state-of-the-art favors a compact storage ring design.

  9. A compact Compton backscatter X-ray source for mammography and coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, D.C.; Kinross-Wright, J.M.; Weber, M.E.; Volz, S.K. [Los Alamos National Lab., NM (United States); Gierman, S.M.; Hayes, K.; Vernon, W. [Univ. of California, San Diego, CA (United States); Goldstein, D.J. [Univ. of California, Los Angeles, CA (United States)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The project objective is to generate a large flux of tunable, monochromatic x-rays for use in mammography and coronary angiography. The approach is based on Compton backscattering of an ultraviolet solid-state laser beam against the high-brightness 20-MeV electron beams from a compact linear accelerator. The direct Compton backscatter approach failed to produce a large flux of x-rays due to the low photon flux of the scattering solid-state laser. The authors have modified the design of a compact x-ray source to the new Compton backscattering geometry with use of a regenerative amplifier free-electron laser. They have successfully demonstrated the production of a large flux of infrared photons and a high-brightness electron beam focused in both dimensions for performing Compton backscattering in a regenerative amplifier geometry.

  10. Relations among stellar X-ray emission observed from Einstein, stellar rotation and bolometric luminosity

    Science.gov (United States)

    Pallavicini, R.; Golub, L.; Rosner, R.; Vaiana, G. S.; Ayres, T.; Linsky, J. L.

    1981-01-01

    The correlation between observed stellar X-ray luminosities, bolometric luminosities, and projected rotational velocities for stars of various spectral types and luminosity classes are determined. Early type stars (O3 to A5) have X-ray luminosities independent of rotational velocities, and correlating with bolometric luminosities. Late type stars of spectral type G to M have luminosities well correlated to equatorial rotational velocities, and are independent of luminosity class. The dependence of late type stars is found to be equivalent to a relation between the X-ray surface flux and the stellar angular velocity. F stars are intermediate with X-ray luminosities higher than would be predicted on the basis of the early type star relation, although lower than expected from the late type velocity dependence. The location of RS CVn stars as a class is also discussed, and it is found that the heating of late type stellar coronas does not result from direct conversion of ratational energy.

  11. General relativistic x ray (UV) polarization rotations as a quantitative test for black holes

    Science.gov (United States)

    Stark, Richard F.

    1989-01-01

    It is now 11 years since a potentially easily observable and quantitative test for black holes using general relativistic polarization rotations was proposed (Stark and Connors 1977, and Connors and Stark 1977). General relativistic rotations of the x ray polarization plane of 10 to 100 degrees with x ray energy (between 1 and 100 keV) are predicted for black hole x ray binaries. (Classically, by symmetry, there is no rotation.) Unfortunately, x ray polarimetry has not been taken sufficiently seriously during this period, and this test has not yet been performed. A similar (though probably less clean) effect is expected in the UV for supermassive black holes in some quasars active galactic nuclei. Summarizing: (1) a quantitative test (proposed in 1977) for black holes exists; (2) x ray polarimetry of galactic x ray binaries sensitive to at least 1/2 percent between 1 keV and 100 keV is needed (polarimetry in the UV of quasars and AGN will also be of interest); and (3) proportional counters using timerise discrimination were shown in laboratory experiments able to perform x ray polarimetry and this and other methods need to be developed.

  12. Detectability of rotation-powered pulsars in future hard X-ray surveys

    Science.gov (United States)

    Wang, Wei

    2009-11-01

    Recent INTEGRAL/IBIS hard X-ray surveys have detected about 10 young pulsars. We show hard X-ray properties of these 10 young pulsars, which have a luminosity of 1033-1037 erg s-1 and a photon index of 1.6-2.1 in the energy range of 20-100 keV. The correlation between X-ray luminosity and spin-down power of LX propto Lsd1.31suggests that the hard X-ray emission in rotation-powered pulsars is dominated by the pulsar wind nebula (PWN) component. Assuming spectral properties are similar in 20-100 keV and 2-10 keV for both the pulsar and PWN components, the hard X-ray luminosity and flux of 39 known young X-ray pulsars and 8 millisecond pulsars are obtained, and a correlation of LX propto Lsd1.5 is derived. About 20 known young X-ray pulsars and 1 millisecond pulsars could be detected with future INTEGRAL and HXMT surveys. We also carry out Monte Carlo simulations of hard X-ray pulsars in the Galaxy and the Gould Belt, assuming values for the pulsar birth rate, initial position, proper motion velocity, period, and magnetic field distribution and evolution based on observational statistics and the LX - Lsd relations: LX propto Lsd1.31 and LX propto Lsd1.5. More than 40 young pulsars (mostly in the Galactic plane) could be detected after ten years of INTEGRAL surveys and the launch of HXMT. So, the young pulsars would be a significant part of the hard X-ray source population in the sky, and will contribute to unidentified hard X-ray sources in present and future hard X-ray surveys by INTEGRAL and HXMT.

  13. [Study on spectrum analysis of X-ray based on rotational mass effect in special relativity].

    Science.gov (United States)

    Yu, Zhi-Qiang; Xie, Quan; Xiao, Qing-Quan

    2010-04-01

    Based on special relativity, the formation mechanism of characteristic X-ray has been studied, and the influence of rotational mass effect on X-ray spectrum has been given. A calculation formula of the X-ray wavelength based upon special relativity was derived. Error analysis was carried out systematically for the calculation values of characteristic wavelength, and the rules of relative error were obtained. It is shown that the values of the calculation are very close to the experimental values, and the effect of rotational mass effect on the characteristic wavelength becomes more evident as the atomic number increases. The result of the study has some reference meaning for the spectrum analysis of characteristic X-ray in application.

  14. Probing the gravitational Faraday rotation using quasar X-ray microlensing.

    Science.gov (United States)

    Chen, Bin

    2015-11-17

    The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission.

  15. X-ray wavefront characterization using a rotating shearing interferometer technique.

    Science.gov (United States)

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sébastien; Ziegler, Eric; Rutishauser, Simon; David, Christian

    2011-08-15

    A fast and accurate method to characterize the X-ray wavefront by rotating one of the two gratings of an X-ray shearing interferometer is described and investigated step by step. Such a shearing interferometer consists of a phase grating mounted on a rotation stage, and an absorption grating used as a transmission mask. The mathematical relations for X-ray Moiré fringe analysis when using this device are derived and discussed in the context of the previous literature assumptions. X-ray beam wavefronts without and after X-ray reflective optical elements have been characterized at beamline B16 at Diamond Light Source (DLS) using the presented X-ray rotating shearing interferometer (RSI) technique. It has been demonstrated that this improved method allows accurate calculation of the wavefront radius of curvature and the wavefront distortion, even when one has no previous information on the grating projection pattern period, magnification ratio and the initial grating orientation. As the RSI technique does not require any a priori knowledge of the beam features, it is suitable for routine characterization of wavefronts of a wide range of radii of curvature. © 2011 Optical Society of America

  16. Highly bright X-ray generator using heat of fusion with a specially designed rotating anticathode

    Energy Technology Data Exchange (ETDEWEB)

    Sakabe, N., E-mail: nsakabe@sbsp.jp [PF, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Foundation for Advancement of International Science, 586-9 Akatsuka, Tsukuba, Ibaraki 305-0062 (Japan); Ohsawa, S.; Sugimura, T.; Ikeda, M.; Tawada, M. [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Watanabe, N. [Synchrotron Radiation Research Center, Nagoya University, Chikusa, Nagoya, Aichi 464-8603 (Japan); Sasaki, K. [Nagoya University, Chikusa, Nagoya, Aichi 464-8601 (Japan); Ohshima, K. [Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573 (Japan); Wakatsuki, M. [AIST, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Sakabe, K. [Foundation for Advancement of International Science, 586-9 Akatsuka, Tsukuba, Ibaraki 305-0062 (Japan)

    2008-05-01

    A very compact X-ray generator, 4.3 times more brilliant than can be attained by a conventional rotating-anticathode X-ray generator, has been developed using a U-shaped rotating anticathode and a high-flux electron gun with focusing bending magnet. A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode (Cu). A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a strong centrifugal force fixes the melted part on the inner surface. When the irradiated part is melted, a large amount of energy is stored as the heat of fusion, resulting in emission of X-rays 4.3 times more brilliant than can be attained by a conventional rotating anticathode. Oscillating translation of the irradiated position on the inner surface during use is expected to be very advantageous for extending the target life. A carbon film coating on the inner surface is considered to suppress evaporation of the target metal and will be an important technique in further realization of highly bright X-ray generation.

  17. GIANT CORONAL LOOPS DOMINATE THE QUIESCENT X-RAY EMISSION IN RAPIDLY ROTATING M STARS

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, O.; Yadav, R.; Garraffo, C.; Saar, S. H.; Wolk, S. J.; Kashyap, V. L.; Drake, J. J.; Pillitteri, I. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2017-01-01

    Observations indicate that magnetic fields in rapidly rotating stars are very strong, on both small and large scales. What is the nature of the resulting corona? Here we seek to shed some light on this question. We use the results of an anelastic dynamo simulation of a rapidly rotating fully convective M star to drive a physics-based model for the stellar corona. We find that due to the several kilo Gauss large-scale magnetic fields at high latitudes, the corona, and its X-ray emission are dominated by star-size large hot loops, while the smaller, underlying colder loops are not visible much in the X-ray. Based on this result, we propose that, in rapidly rotating stars, emission from such coronal structures dominates the quiescent, cooler but saturated X-ray emission.

  18. 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...

  19. Nanofocusing with aberration-corrected rotationally parabolic refractive X-ray lenses.

    Science.gov (United States)

    Seiboth, Frank; Wittwer, Felix; Scholz, Maria; Kahnt, Maik; Seyrich, Martin; Schropp, Andreas; Wagner, Ulrich; Rau, Christoph; Garrevoet, Jan; Falkenberg, Gerald; Schroer, Christian G

    2018-01-01

    Wavefront errors of rotationally parabolic refractive X-ray lenses made of beryllium (Be CRLs) have been recovered for various lens sets and X-ray beam configurations. Due to manufacturing via an embossing process, aberrations of individual lenses within the investigated ensemble are very similar. By deriving a mean single-lens deformation for the ensemble, aberrations of any arbitrary lens stack can be predicted from the ensemble with \\bar{\\sigma} = 0.034λ. Using these findings the expected focusing performance of current Be CRLs are modeled for relevant X-ray energies and bandwidths and it is shown that a correction of aberrations can be realised without prior lens characterization but simply based on the derived lens deformation. The performance of aberration-corrected Be CRLs is discussed and the applicability of aberration-correction demonstrated over wide X-ray energy ranges.

  20. Multiscale adaptive method for blood vessel enhancement in x-ray angiography

    Science.gov (United States)

    Wu, Zhenyu; Fang, Ming; Qian, JianZhong; Schramm, Helmut F.

    1997-04-01

    The goal of this work is to provide a powerful computer- aided-perception tool for physicians to visualize low- contrast blood vessel structures with exquisite details and hence to facilitate the extraction of valuable diagnostic information from angiographic images. In x-ray angiography, blood vessels often exhibit low intensity contrast with respect to their surrounding soft tissues. The problem is particularly severe for fine vessel structures. A major challenge for enhancement is the ability to emphasize vessel structures without creating artifacts such as edge overshot and noise magnification. In this work, a multi-scale adaptive contrast enhancement algorithm is developed. A pyramid of intensity images is generated using wavelet decomposition. At each pyramid level, an enhancement mask is computed which captures the fine vessel structures in the image at that scale. To generate this mask, we first compute directional sensitive Laplacian which is capable of extracting fine lines with very low contrast to its surroundings. An adaptive non-linear weighting function is then applied to the Laplacian to form an enhancement mask. The non-linearity is crucial for virtually eliminating edge overshots. These masks are then combined recursively to form a single composite mask of full resolution. Finally, the enhanced image is obtained by adding this composite mask to the original image. Extensive testing demonstrates remarkable contrast improvement in blood vessels without noticeable artifacts.

  1. The Radiative X-ray and Gamma-ray Efficiencies of Rotation-powered Pulsars

    NARCIS (Netherlands)

    Vink, J.|info:eu-repo/dai/nl/182880559; Bamba, A.; Yamazaki, R.

    2011-01-01

    We present a statistical analysis of the X-ray luminosity of rotation-powered pulsars and their surrounding nebulae using the sample of Kargaltsev & Pavlov, and we complement this with an analysis of the γ -ray emission of Fermi-detected pulsars. We report a strong trend in the efficiency with which

  2. Soft x-ray magneto-optic Kerr rotation and element-specific hysteresis measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Rice, M.

    1996-03-01

    Soft x-ray magneto-optic Kerr rotation has been measured using a continuously tunable multilayer linear polarizer in the beam reflected form samples in applied magnetic fields. Like magnetic circular dichroism, Kerr rotation in the soft x-ray can be element - specific and much larger than in the visible spectral range when the photon energy is tuned near atomic core resonances. Thus sensitive element-specific hysteresis measurements are possible with this technique. Examples showing large Kerr rotation from an Fe film and element-specific hysteresis loops of the Fe and Cr in an Fe/Cr multilayer demonstrate these new capabilities. Some consequences of the strong anomalous dispersion near the FeL{sub 2,3} edges to the Kerr rotation are discussed.

  3. Dynamic crystal rotation resolved by high-speed synchrotron X-ray Laue diffraction

    OpenAIRE

    Huang, J.W.; E, J. C.; Huang, J. Y.; Sun, T.; Fezzaa, K.; Luo, S.N.

    2016-01-01

    Dynamic compression experiments are performed on single-crystal Si under split Hopkinson pressure bar loading, together with simultaneous high-speed (250?350?ns resolution) synchrotron X-ray Laue diffraction and phase-contrast imaging. A methodology is presented which determines crystal rotation parameters, i.e. instantaneous rotation axes and angles, from two unindexed Laue diffraction spots. Two-dimensional translation is obtained from dynamic imaging by a single camera. High-speed motion o...

  4. Experimental and theoretical studies of dual energy subtraction angiography (DESA) performed using laser-based x-ray source

    Science.gov (United States)

    Krol, Andrzej; Kieffer, Jean-Claude; Ichalalene, Zahia; Jiang, Zhiming; Chamberlain, Charles C.; Scalzetti, Ernest M.

    2001-11-01

    Two types of x-ray sources for dual energy subtraction angiography (DESA), laser-based and conventional, were investigated. A Tabletop Terawatt laser was used to create x-ray source with Ba, La, Nd, Gd, and Ce targets. A theoretical model of image quality was developed. A Figure of Merit, FOM equals SNR./(integral dose)1/2, was obtained. Images of an angiographic contrast detail phantom were obtained using laser-driven x-ray source in DESA regime and a standard angiography unit in DSA regime. The log-signals due to Iodine contrast agent in the images were measured and compared with the theoretical model predictions. The integral dose was estimated. We found that the La and Ba lines extracted by a monochromator are optimal for imaging Iodine contrast with laser-based DESA. In this case, SNR exhibits three- to five-fold improvement, as compared to SNR expected for a tube-based DESA system. Consequently, dose utilization, as defined by FOM, improves by factor of two to three, depending on patient thickness and scatter conditions. When only filters are used, SNR and FOM due to laser-based system are comparable to those due to tube-based DESA. In this case, preferable target/filter combination for the laser system is Ba/I and Ce/Nd for the low- and high-beam, respectively.

  5. Dynamic crystal rotation resolved by high-speed synchrotron X-ray Laue diffraction.

    Science.gov (United States)

    Huang, J W; E, J C; Huang, J Y; Sun, T; Fezzaa, K; Luo, S N

    2016-05-01

    Dynamic compression experiments are performed on single-crystal Si under split Hopkinson pressure bar loading, together with simultaneous high-speed (250-350 ns resolution) synchrotron X-ray Laue diffraction and phase-contrast imaging. A methodology is presented which determines crystal rotation parameters, i.e. instantaneous rotation axes and angles, from two unindexed Laue diffraction spots. Two-dimensional translation is obtained from dynamic imaging by a single camera. High-speed motion of crystals, including translation and rotation, can be tracked in real time via simultaneous imaging and diffraction.

  6. Dynamic crystal rotation resolved by high-speed synchrotron X-ray Laue diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J. W.; E, J. C.; Huang, J. Y.; Sun, T.; Fezzaa, K.; Luo, S. N.

    2016-03-30

    Dynamic compression experiments are performed on single-crystal Si under split Hopkinson pressure bar loading, together with simultaneous high-speed (250–350 ns resolution) synchrotron X-ray Laue diffraction and phase-contrast imaging. A methodology is presented which determines crystal rotation parameters,i.e.instantaneous rotation axes and angles, from two unindexed Laue diffraction spots. Two-dimensional translation is obtained from dynamic imaging by a single camera. High-speed motion of crystals, including translation and rotation, can be tracked in real timeviasimultaneous imaging and diffraction.

  7. Thomson scattering laser-electron X-ray source for reduction of patient radiation dose in interventional coronary angiography

    Science.gov (United States)

    Artyukov, I. A.; Dyachkov, N. V.; Feshchenko, R. M.; Polunina, A. V.; Popov, N. L.; Shvedunov, V. I.; Vinogradov, A. V.

    2017-05-01

    It was medical applications that stimulated F. Carrol in the early 1990s to start the research of on relativistic Thomson scattering X-ray sources, as a part of the infrastructure of the future society. The possibility to use such a source in interventional cardiology is discussed in this paper. The replacement of X-ray tube by relativistic Thomson scattering Xray source is predicted to lower the patient radiation dose by a factor of 3 while image quality remains the same. The required general characteristics of accelerator and laser units are found. They can be reached by existing technology. A semiempirical method for simulation of medical and technical parameters of interventional coronary angiography systems is suggested.

  8. 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.

  9. QPOs from Random X-ray Bursts around Rotating Black Holes

    Science.gov (United States)

    Kukumura, Keigo; Kazanas, Demosthenes; Stephenson, Gordon

    2009-01-01

    We continue our earlier studies of quasi-periodic oscillations (QPOs) in the power spectra of accreting, rapidly-rotating black holes that originate from the geometric 'light echoes' of X-ray flares occurring within the black hole ergosphere. Our present work extends our previous treatment to three-dimensional photon emission and orbits to allow for arbitrary latitudes in the positions of the distant observers and the X-ray sources in place of the mainly equatorial positions and photon orbits of the earlier consideration. Following the trajectories of a large number of photons we calculate the response functions of a given geometry and use them to produce model light curves which we subsequently analyze to compute their power spectra and autocorrelation functions. In the case of an optically-thin environment, relevant to advection-dominated accretion flows, we consistently find QPOs at frequencies of order of approximately kHz for stellar-mass black hole candidates while order of approximately mHz for typical active galactic nuclei (approximately equal to 10(exp 7) solar mass) for a wide range of viewing angles (30 degrees to 80 degrees) from X-ray sources predominantly concentrated toward the equator within the ergosphere. As in out previous treatment, here too, the QPO signal is produced by the frame-dragging of the photons by the rapidly-rotating black hole, which results in photon 'bunches' separated by constant time-lags, the result of multiple photon orbits around the hole. Our model predicts for various source/observer configurations the robust presence of a new class of QPOs, which is inevitably generic to curved spacetime structure in rotating black hole systems.

  10. Quantitative characterization of the x-ray imaging capability of rotating modulation collimators with laser light

    Science.gov (United States)

    Gaither, C. C., III; Schmahl, E. J.; Crannell, C. J.; Dennis, B. R.; Lang, F. L.; Orwig, L. E.; Hartman, C. N.; Hurford, G. J.

    1996-12-01

    We developed a method for making quantitative characterizations of bi-grid rotating modulation collimators (RMC's) that are used in a Fourier transform x-ray imager. With appropriate choices of the collimator spacings, this technique can be implemented with a beam-expanded He-Ne laser to simulate the plane wave produced by a point source at infinity even though the RMC's are diffraction limited at the He-Ne wavelength of 632.8 nm. The expanded beam passes through the grid pairs at a small angle with respect to their axis of rotation, and the modulated transmission through the grids as the RMC's rotate is detected with a photomultiplier tube. In addition to providing a quantitative characterization of the RMC's, the method also produces a measured point response function and provides an end-to-end check of the imaging system. We applied our method to the RMC's on the high-energy imaging device (HEIDI) balloon payload in its preflight configuration. We computed the harmonic ratios of the modulation time profile from the laser measurements and compared them with theoretical calculations, including the diffraction effects on irregular grids. Our results indicate the 25-in. (64-cm) x-ray imaging optics on HEIDI are capable of achieving images near the theoretical limit and are not seriously compromised by imperfections in the grids.

  11. In situ azimuthal rotation device for linear dichroism measurements in scanning transmission x-ray microscopy

    Science.gov (United States)

    Hernández-Cruz, D.; Hitchcock, A. P.; Tyliszczak, T.; Rousseau, M.-E.; Pézolet, M.

    2007-03-01

    A novel miniature rotation device used in conjunction with a scanning transmission x-ray microscope is described. It provides convenient in situ sample rotation to enable measurements of linear dichroism at high spatial resolution. The design, fabrication, and mechanical characterization are presented. This device has been used to generate quantitative maps of the spatial distribution of the orientation of proteins in several different spider and silkworm silks. Specifically, quantitative maps of the dichroic signal at the C 1s→π*amide transition in longitudinal sections of the silk fibers give information about the spatial orientation, degree of alignment, and spatial distribution of protein peptide bonds. A new approach for analyzing the dichroic signal to extract orientation distributions, in addition to magnitudes of aligned components, is presented and illustrated with results from Nephila clavipes dragline spider silk measured using the in situ rotation device.

  12. Lattice rotations of individual bulk grains. Part 1: 3D X-ray characterization

    DEFF Research Database (Denmark)

    Poulsen, H.F.; Margulies, L.; Schmidt, S.

    2003-01-01

    dependence on the initial orientation, while the influence of grain interaction is relatively small. All grains deform plastically. Averaged over grains and reflections the rotation of the tensile axis and the FWHM of the internal spread is 2.0 and 0.8°, respectively, at 6% strain.......Three-dimensional X-ray diffraction has been applied to characterise the plastic deformation of individualgrains deeply embedded in a 99.6% pure aluminium specimen. The specimen is 4 mm thick with an average grain size of 75 μm. The average latticerotation for each grain as well as the degree...

  13. Design optimization of MR-compatible rotating anode x-ray tubes for stable operation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Mihye [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Lillaney, Prasheel [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Hinshaw, Waldo; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2013-11-15

    Purpose: Hybrid x-ray/MR systems can enhance the diagnosis and treatment of endovascular, cardiac, and neurologic disorders by using the complementary advantages of both modalities for image guidance during interventional procedures. Conventional rotating anode x-ray tubes fail near an MR imaging system, since MR fringe fields create eddy currents in the metal rotor which cause a reduction in the rotation speed of the x-ray tube motor. A new x-ray tube motor prototype has been designed and built to be operated close to a magnet. To ensure the stability and safety of the motor operation, dynamic characteristics must be analyzed to identify possible modes of mechanical failure. In this study a 3D finite element method (FEM) model was developed in order to explore possible modifications, and to optimize the motor design. The FEM provides a valuable tool that permits testing and evaluation using numerical simulation instead of building multiple prototypes.Methods: Two experimental approaches were used to measure resonance characteristics: the first obtained the angular speed curves of the x-ray tube motor employing an angle encoder; the second measured the power spectrum using a spectrum analyzer, in which the large amplitude of peaks indicates large vibrations. An estimate of the bearing stiffness is required to generate an accurate FEM model of motor operation. This stiffness depends on both the bearing geometry and adjacent structures (e.g., the number of balls, clearances, preload, etc.) in an assembly, and is therefore unknown. This parameter was set by matching the FEM results to measurements carried out with the anode attached to the motor, and verified by comparing FEM predictions and measurements with the anode removed. The validated FEM model was then used to sweep through design parameters [bearing stiffness (1×10{sup 5}–5×10{sup 7} N/m), shaft diameter (0.372–0.625 in.), rotor diameter (2.4–2.9 in.), and total length of motor (5.66–7.36 in.)] to

  14. 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.

  15. Brain and arterial abnormalities following prenatal X-ray irradiation in mice assessed by magnetic resonance imaging and angiography.

    Science.gov (United States)

    Saito, Shigeyoshi; Sawada, Kazuhiko; Mori, Yuki; Yoshioka, Yoshichika; Murase, Kenya

    2015-05-01

    The present study aimed to quantitatively characterize changes in the whole brain and arterial morphology in response to prenatal ionizing irradiation. Magnetic resonance imaging (MRI) and angiography (MRA) were used to evaluate brain and arterial abnormalities in 8-week-old male mice prenatally exposed to X-ray radiation at a dose of 0.5 or 1.0 Gy on embryonic day (E) 13. Irradiated mice demonstrated decreased brain volume, increased ventricular volume, and arterial malformation. Additionally, MRA signal intensity and arterial thickness in the anterior cerebral artery, middle cerebral artery, and basilar artery were lower in radiation-exposed mice than in control mice. MRI and MRA are useful tools for assessing brain and arterial abnormalities after prenatal exposure to radiation. © 2014 Japanese Teratology Society.

  16. Reduced Patient Radiation Exposure during Neurodiagnostic and Interventional X-Ray Angiography with a New Imaging Platform.

    Science.gov (United States)

    van der Marel, K; Vedantham, S; van der Bom, I M J; Howk, M; Narain, T; Ty, K; Karellas, A; Gounis, M J; Puri, A S; Wakhloo, A K

    2017-03-01

    Advancements in medical device and imaging technology as well as accruing clinical evidence have accelerated the growth of the endovascular treatment of cerebrovascular diseases. However, the augmented role of these procedures raises concerns about the radiation dose to patients and operators. We evaluated patient doses from an x-ray imaging platform with radiation dose-reduction technology, which combined image noise reduction, motion correction, and contrast-dependent temporal averaging with optimized x-ray exposure settings. In this single-center, retrospective study, cumulative dose-area product inclusive of fluoroscopy, angiography, and 3D acquisitions for all neurovascular procedures performed during a 2-year period on the dose-reduction platform were compared with a reference platform. Key study features were the following: The neurointerventional radiologist could select the targeted dose reduction for each patient with the dose-reduction platform, and the statistical analyses included patient characteristics and the neurointerventional radiologist as covariates. The analyzed outcome measures were cumulative dose (kerma)-area product, fluoroscopy duration, and administered contrast volume. A total of 1238 neurointerventional cases were included, of which 914 and 324 were performed on the reference and dose-reduction platforms, respectively. Over all diagnostic and neurointerventional procedures, the cumulative dose-area product was significantly reduced by 53.2% (mean reduction, 160.3 Gy × cm2; P technology with a minimal impact on workflow. © 2017 by American Journal of Neuroradiology.

  17. Patient radiation dose reduction using an X-ray imaging noise reduction technology for cardiac angiography and intervention.

    Science.gov (United States)

    Nakamura, Shigeru; Kobayashi, Tomoko; Funatsu, Atsushi; Okada, Tadahisa; Mauti, Maria; Waizumi, Yuki; Yamada, Shinichi

    2016-05-01

    Coronary angiography and intervention can expose patients to high radiation dose. This retrospective study quantifies the patient dose reduction due to the introduction of a novel X-ray imaging noise reduction technology using advanced real-time image noise reduction algorithms and optimized acquisition chain for fluoroscopy and exposure in interventional cardiology. Patient, procedure and radiation dose data were retrospectively collected in the period August 2012-August 2013 for 883 patients treated with the image noise reduction technology (referred as "new system"). The same data were collected for 1083 patients in the period April 2011-July 2012 with a system using state-of-the-art image processing and reference acquisition chain (referred as "reference system"). Procedures were divided into diagnostic (CAG) and intervention (PCI). Acquisition parameters such as fluoroscopy time, volume of contrast medium, number of exposure images and number of stored fluoroscopy images were collected to classify procedure complexity. The procedural dose reduction was investigated separately for three main cardiologists. The new system provides significant dose reduction compared to the reference system. Median DAP values decreased for all procedures (p X-ray imaging technology combining advanced real-time image noise reduction algorithms and anatomy-specific optimized fluoroscopy and cine acquisition chain provides 66 % patient dose reduction in interventional cardiology.

  18. Rotation of X-ray polarization in the glitches of a silicon crystal monochromator.

    Science.gov (United States)

    Sutter, John P; Boada, Roberto; Bowron, Daniel T; Stepanov, Sergey A; Díaz-Moreno, Sofía

    2016-08-01

    EXAFS studies on dilute samples are usually carried out by collecting the fluorescence yield using a large-area multi-element detector. This method is susceptible to the 'glitches' produced by all single-crystal monochromators. Glitches are sharp dips or spikes in the diffracted intensity at specific crystal orientations. If incorrectly compensated, they degrade the spectroscopic data. Normalization of the fluorescence signal by the incident flux alone is sometimes insufficient to compensate for the glitches. Measurements performed at the state-of-the-art wiggler beamline I20-scanning at Diamond Light Source have shown that the glitches alter the spatial distribution of the sample's quasi-elastic X-ray scattering. Because glitches result from additional Bragg reflections, multiple-beam dynamical diffraction theory is necessary to understand their effects. Here, the glitches of the Si(111) four-bounce monochromator of I20-scanning just above the Ni  K edge are associated with their Bragg reflections. A fitting procedure that treats coherent and Compton scattering is developed and applied to a sample of an extremely dilute (100 micromolal) aqueous solution of Ni(NO 3 ) 2 . The depolarization of the wiggler X-ray beam out of the electron orbit is modeled. The fits achieve good agreement with the sample's quasi-elastic scattering with just a few parameters. The X-ray polarization is rotated up to ±4.3° within the glitches, as predicted by dynamical diffraction. These results will help users normalize EXAFS data at glitches.

  19. Rotation of X-ray polarization in the glitches of a silicon crystal monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, John P.; Boada, Roberto; Bowron, Daniel T.; Stepanov, Sergey A.; Díaz-Moreno, Sofía

    2016-07-06

    EXAFS studies on dilute samples are usually carried out by collecting the fluorescence yield using a large-area multi-element detector. This method is susceptible to the `glitches' produced by all single-crystal monochromators. Glitches are sharp dips or spikes in the diffracted intensity at specific crystal orientations. If incorrectly compensated, they degrade the spectroscopic data. Normalization of the fluorescence signal by the incident flux alone is sometimes insufficient to compensate for the glitches. Measurements performed at the state-of-the-art wiggler beamline I20-scanning at Diamond Light Source have shown that the glitches alter the spatial distribution of the sample's quasi-elastic X-ray scattering. Because glitches result from additional Bragg reflections, multiple-beam dynamical diffraction theory is necessary to understand their effects. Here, the glitches of the Si(111) four-bounce monochromator of I20-scanning just above the Ni Kedge are associated with their Bragg reflections. A fitting procedure that treats coherent and Compton scattering is developed and applied to a sample of an extremely dilute (100 micromolal) aqueous solution of Ni(NO3)2. The depolarization of the wiggler X-ray beam out of the electron orbit is modeled. The fits achieve good agreement with the sample's quasi-elastic scattering with just a few parameters. The X-ray polarization is rotated up to ±4.3° within the glitches, as predicted by dynamical diffraction. These results will help users normalize EXAFS data at glitches.

  20. Automatic segmentation of rotational x-ray images for anatomic intra-procedural surface generation in atrial fibrillation ablation procedures.

    Science.gov (United States)

    Manzke, Robert; Meyer, Carsten; Ecabert, Olivier; Peters, Jochen; Noordhoek, Niels J; Thiagalingam, Aravinda; Reddy, Vivek Y; Chan, Raymond C; Weese, Jürgen

    2010-02-01

    Since the introduction of 3-D rotational X-ray imaging, protocols for 3-D rotational coronary artery imaging have become widely available in routine clinical practice. Intra-procedural cardiac imaging in a computed tomography (CT)-like fashion has been particularly compelling due to the reduction of clinical overhead and ability to characterize anatomy at the time of intervention. We previously introduced a clinically feasible approach for imaging the left atrium and pulmonary veins (LAPVs) with short contrast bolus injections and scan times of approximately 4 -10 s. The resulting data have sufficient image quality for intra-procedural use during electro-anatomic mapping (EAM) and interventional guidance in atrial fibrillation (AF) ablation procedures. In this paper, we present a novel technique to intra-procedural surface generation which integrates fully-automated segmentation of the LAPVs for guidance in AF ablation interventions. Contrast-enhanced rotational X-ray angiography (3-D RA) acquisitions in combination with filtered-back-projection-based reconstruction allows for volumetric interrogation of LAPV anatomy in near-real-time. An automatic model-based segmentation algorithm allows for fast and accurate LAPV mesh generation despite the challenges posed by image quality; relative to pre-procedural cardiac CT/MR, 3-D RA images suffer from more artifacts and reduced signal-to-noise. We validate our integrated method by comparing 1) automatic and manual segmentations of intra-procedural 3-D RA data, 2) automatic segmentations of intra-procedural 3-D RA and pre-procedural CT/MR data, and 3) intra-procedural EAM point cloud data with automatic segmentations of 3-D RA and CT/MR data. Our validation results for automatically segmented intra-procedural 3-D RA data show average segmentation errors of 1) approximately 1.3 mm compared with manual 3-D RA segmentations 2) approximately 2.3 mm compared with automatic segmentation of pre-procedural CT/MR data and 3

  1. Co-registration of optical coherence tomography and X-ray angiography in percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Hebsgaard, Lasse; Nielsen, Troels Munck; Tu, Shengxian

    2014-01-01

    Background Intracoronary imaging provides accurate lesion delineation and precise measurements for sizing and positioning of coronary stents. During percutaneous coronary intervention (PCI), it may be challenging to identify corresponding segments between intracoronary imaging and angiography....... Computer based online co-registration may aid the target segment identification. Methods The DOCTOR fusion study was a prospective, single arm, observational study including patients admitted for elective PCI. Optical coherence tomography (OCT) was acquired pre-stent implantation for sizing of stents...... to the computer-based co-registration, segments of the target lesion indicated on OCT were left uncovered by stent in 14 patients (70%). Conclusion Computer based online co-registration of OCT and angiography is feasible. Frequent inaccuracies in operator based registration indicate that computer aided co...

  2. X-ray spectra and the rotation-activity connection of RS Canum Venaticorum binaries

    Science.gov (United States)

    Majer, P.; Schmitt, J. H. M. M.; Golub, L.; Harnden, F. R., Jr.; Rosner, R.

    1986-01-01

    Results are presented from a survey of RS CVn binaries which were observed with the imaging proportional counter (IPC) on board the Einstein Observatory. Spectral analyses of the IPC pulse height spectra show that the coronae of RS CVn binaries always contain hot gas with temperatures in excess of 10 to the 7th K, similar to active late-type main-sequence stars, and that at least two temperature components are necessary to account for the higher quality IPC spectra (when absorption is unimportant). It is argued that these bimodal temperature distributions found by the IPC are indicative of true distributions of emission measure versus temperature that are continuous (just as is the case of magnetically confined coronal plasma loops observed on the sun). It is further shown that none of the derivable X-ray characteristics of RS CVn binaries depend on rotation period, implying that previous claims of period-activity relationships in RS CVn binaries were unfounded.

  3. Rotational coherence as an alternative to coincidence techniques at x-ray free electron lasers

    Science.gov (United States)

    Coffee, Ryan; Hegazy, Kareem; Hartmann, Nick; Walter, Peter; Osipov, Timur; Lindahl, Anton; Helml, Wolfram; Ilchen, Markus; Galler, Andreas; Liu, Jia; Buck, Jens; Shevchuk, Ivan; Viefhaus, Jens; Hartmann, Gregor; Knie, Andre; Demekhin, Philipp; Inhester, Ludger; Li, Zheng; Ziaja-Motyka, Beata; Medvedev, Nikita; Bostedt, Christoph; Guillemin, Renaud; Simon, Marc; Novella-Piancastelli, Maria; Miron, Catalin; LCLS-AMOI0314 Team

    2017-04-01

    We demonstrate an alternative approach to coincidence particle detection, based on impulsive rotational Raman excitation, for molecular frame measurements at x-ray FELs. A train of 8 infrared laser pulses induces the lab-frame observable coherence. At a field-free alignment revival, we register the angle-resolved laboratory frame Auger and photo-electron spectral feature variations with the tumbling molecular body frame. The time and angle dependence of the electron emission patterns that constrain theory are amenable to large numbers of interactions per pulse and, more importantly, has no axial recoil requirement for kinematic reconstruction. We see this as a method to bypass experimental challenges at XFELs by accepting The Linac Coherent Light Source (LCLS) is supported by the U.S. DoE-BES Contract No. DE-AC02-76SF0051.

  4. A convolutional neural network approach to calibrating the rotation axis for X-ray computed tomography.

    Science.gov (United States)

    Yang, Xiaogang; De Carlo, Francesco; Phatak, Charudatta; Gürsoy, Dogˇa

    2017-03-01

    This paper presents an algorithm to calibrate the center-of-rotation for X-ray tomography by using a machine learning approach, the Convolutional Neural Network (CNN). The algorithm shows excellent accuracy from the evaluation of synthetic data with various noise ratios. It is further validated with experimental data of four different shale samples measured at the Advanced Photon Source and at the Swiss Light Source. The results are as good as those determined by visual inspection and show better robustness than conventional methods. CNN has also great potential for reducing or removing other artifacts caused by instrument instability, detector non-linearity, etc. An open-source toolbox, which integrates the CNN methods described in this paper, is freely available through GitHub at tomography/xlearn and can be easily integrated into existing computational pipelines available at various synchrotron facilities. Source code, documentation and information on how to contribute are also provided.

  5. The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

    Science.gov (United States)

    Coelho, Jaziel G.; Cáceres, D. L.; de Lima, R. C. R.; Malheiro, M.; Rueda, J. A.; Ruffini, R.

    2017-03-01

    Context. Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slow rotating isolated pulsars whose energy reservoir is still matter of debate. Adopting neutron star (NS) fiducial parameters; mass M = 1.4 M⊙, radius R = 10 km, and moment of inertia, I = 1045 g cm2, the rotational energy loss, Ėrot, is lower than the observed luminosity (dominated by the X-rays) LX for many of the sources. Aims: We investigate the possibility that some members of this family could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. Methods: We compute the NS mass, radius, moment of inertia and angular momentum from numerical integration of the axisymmetric general relativistic equations of equilibrium. We then compute the entire range of allowed values of the rotational energy loss, Ėrot, for the observed values of rotation period P and spin-down rate Ṗ. We also estimate the surface magnetic field using a general relativistic model of a rotating magnetic dipole. Results: We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, LX/Ėrot, with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for LX computed in the soft (2-10 keV) X-ray band. We compute the range of NS masses for which LX/Ėrotpowered NSs. This additional hard X-ray component dominates over the soft one leading to LX/Ėrot > 1 in two of them. Conclusions: We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2-10 keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give additional support to our results of a natural explanation of these sources in terms of ordinary pulsars

  6. Conventional digital subtraction x-ray angiography versus magnetic resonance angiography in the evaluation of carotid disease: patient satisfaction and preferences

    Energy Technology Data Exchange (ETDEWEB)

    U-King-Im, J.M. E-mail: jhg21@cam.ac.uk; Trivedi, R.; Cross, J.; Higgins, N.; Graves, M.; Kirkpatrick, P.; Antoun, N.; Gillard, J.H

    2004-04-01

    AIM: To compare conventional digital subtraction x-ray angiography (DSA) and contrast-enhanced magnetic resonance angiography (MRA) of the carotid arteries in terms of patient satisfaction and preferences. METHODS: One hundred and sixty-seven patients with symptomatic carotid artery disease, who underwent both DSA and MRA, were prospectively recruited in this study. Patients' perceptions of each method were assessed by the use of a questionnaire after each procedure. Main outcome measures were anxiety, pain, satisfaction rate and patient preferences. RESULTS: DSA generated more anxiety and pain during the procedure, but the severity of these ill-effects was mild. Satisfaction rates for each method were similar. More patients were, however, willing to have a repeat MRA compared with DSA (67 versus 41%). The majority of patients (62%) preferred MRA over DSA (31%). The shorter MRA imaging time was found to be a significant factor in patients' acceptance of the technique. The main reasons cited by patients for their dislike of a particular procedure was noise and claustrophobia for MRA and invasiveness, pain and post-procedural bed rest for DSA. CONCLUSIONS: MRA is the method that is preferred by the majority of patients, although the actual disutility of DSA may be small. Assuming equal diagnostic accuracy, our data supports replacement of DSA by MRA for routine carotid imaging.

  7. Real-time fusion of coronary CT angiography with X-ray fluoroscopy during chronic total occlusion PCI

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshhajra, Brian B.; Takx, Richard A.P. [Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Department of Radiology and Division of Cardiology, Boston, MA (United States); Stone, Luke L.; Yeh, Robert W.; Jaffer, Farouc A. [Harvard Medical School, Cardiac Cathetrization Laboratory, Cardiology Division, Massachusetts General Hospital, Boston, MA (United States); Girard, Erin E. [Siemens Healthcare, Princeton, NJ (United States); Brilakis, Emmanouil S. [Cardiology Division, Dallas VA Medical Center and UT Southwestern Medical Center, Dallas, TX (United States); Lombardi, William L. [University of Washington, Cardiology Division, Seattle, WA (United States)

    2017-06-15

    The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with X-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. (orig.)

  8. An angle-dependent estimation of CT x-ray spectrum from rotational transmission measurements.

    Science.gov (United States)

    Lin, Yuan; Ramirez-Giraldo, Juan Carlos; Gauthier, Daniel J; Stierstorfer, Karl; Samei, Ehsan

    2014-06-01

    Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors propose an angle-dependent estimation technique, where the incident spectra across a wide range of angular trajectories can be estimated accurately with only a single phantom and a single axial scan in the absence of the knowledge of the bowtie filter. The proposed technique uses a uniform cylindrical phantom, made of ultra-high-molecular-weight polyethylene and positioned in an off-centered geometry. The projection data acquired with an axial scan have a twofold purpose. First, they serve as a reflection of the transmission measurements across different angular trajectories. Second, they are used to reconstruct the cross sectional image of the phantom, which is then utilized to compute the intersection length of each transmission measurement. With each CT detector element recording a range of transmission measurements for a single angular trajectory, the spectrum is estimated for that trajectory. A data conditioning procedure is used to combine information from hundreds of collected transmission measurements to accelerate the estimation speed, to reduce noise, and to improve estimation stability. The proposed spectral estimation technique was validated experimentally using a clinical scanner (Somatom Definition Flash, Siemens Healthcare, Germany) with spectra provided by the manufacturer serving as the comparison standard. Results obtained with the proposed technique were compared against those obtained from a second conventional transmission measurement technique with two materials (i.e., Cu and Al). After validation, the proposed technique was applied to measure spectra from the

  9. A convolutional neural network approach to calibrating the rotation axis for X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaogang; De Carlo, Francesco; Phatak, Charudatta; Gürsoy, Dogˇa

    2017-01-24

    This paper presents an algorithm to calibrate the center-of-rotation for X-ray tomography by using a machine learning approach, the Convolutional Neural Network (CNN). The algorithm shows excellent accuracy from the evaluation of synthetic data with various noise ratios. It is further validated with experimental data of four different shale samples measured at the Advanced Photon Source and at the Swiss Light Source. The results are as good as those determined by visual inspection and show better robustness than conventional methods. CNN has also great potential forreducing or removingother artifacts caused by instrument instability, detector non-linearity,etc. An open-source toolbox, which integrates the CNN methods described in this paper, is freely available through GitHub at tomography/xlearn and can be easily integrated into existing computational pipelines available at various synchrotron facilities. Source code, documentation and information on how to contribute are also provided.

  10. A rotational and axial motion system load frame insert for in situ high energy x-ray studies

    Energy Technology Data Exchange (ETDEWEB)

    Shade, Paul A., E-mail: paul.shade.1@us.af.mil; Schuren, Jay C.; Turner, Todd J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Blank, Basil [PulseRay, Beaver Dams, New York 14812 (United States); Kenesei, Peter; Goetze, Kurt; Lienert, Ulrich; Almer, Jonathan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Suter, Robert M. [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Bernier, Joel V.; Li, Shiu Fai [Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Lind, Jonathan [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-09-15

    High energy x-ray characterization methods hold great potential for gaining insight into the behavior of materials and providing comparison datasets for the validation and development of mesoscale modeling tools. A suite of techniques have been developed by the x-ray community for characterizing the 3D structure and micromechanical state of polycrystalline materials; however, combining these techniques with in situ mechanical testing under well characterized and controlled boundary conditions has been challenging due to experimental design requirements, which demand new high-precision hardware as well as access to high-energy x-ray beamlines. We describe the design and performance of a load frame insert with a rotational and axial motion system that has been developed to meet these requirements. An example dataset from a deforming titanium alloy demonstrates the new capability.

  11. Targeted ROTational magnetic resonance angiography (TROTA).

    Science.gov (United States)

    Goldfarb, James W

    2007-09-01

    An MR angiographic method is presented in which a rotating 2D slice is centered on and targets a region or vessel of interest. Collecting a series of slices rotating about the center of the targeted region yields projection data sufficient for the calculation of 3D volumetric data of the region using conventional backprojection reconstruction techniques. These volumetric data depict the internal structure of the vessel and can be processed and displayed with multiplanar reformation, maximum intensity projections, and 3D rendering algorithms. The rotational angiographic acquisition preserves the high temporal resolution of 2D-MR digital subtraction angiography with the added benefit of 3D reformatting and display. The method is explained in detail and results from phantom and human experiments are presented. Copyright (c) 2007 Wiley-Liss, Inc.

  12. Laser-produced plasma (LPP) x-ray source with BaF2 and rare-earth targets for application in dual-energy subtraction angiography (DESA)

    Science.gov (United States)

    Krol, Andrzej; Kieffer, Jean-Claude; Jiang, Zhiming; Yu, Jianfan; Chamberlain, Charles C.; Bassano, Daniel A.; Gallant, Pascal

    1999-05-01

    A laser produced plasma (LPP) x-ray source utilizing ultra- fast laser was investigated in the context of its utility for dual energy subtraction angiography. Experiments were performed with a Table Top Terawatt (TTT) laser using BaF2 and rare-earth metal targets including La, Ce, Nd and Gd. The laser was operated in a single-pulse or in a dual pulse mode with surface power density in the 1018 - 1019 Wcm-2 range with pulse duration of 150 or 450 fs. Infrared and/or green beams were utilized. Hot electrons' temperature was in the 35 - 50 keV range. The obtained LPP x- ray spectra were comprised of a continuous bremsstrahlung component as well as discrete characteristic lines. The bremsstrahlung extended to high energies with no evident cutoff energy below 100 keV. Its shape was best described by exp(-E/kTe), where Te is the hot electron temperature. The overall efficiency was equal to approximately 9 X 10-4 for 450 fs pulse and approximately 6 X 10-4 for 150 fs pulses. The x-ray focal spot size was in the range 13 to 50 microns. We have found that the LPP x- ray source with BaF2 and rare-earth targets provide x-ray spectra that might be suitable for DESA.

  13. Individual selection of X-ray tube settings in computed tomography coronary angiography: Reliability of an automated software algorithm to maintain constant image quality.

    Science.gov (United States)

    Durmus, Tahir; Luhur, Reny; Daqqaq, Tareef; Schwenke, Carsten; Knobloch, Gesine; Huppertz, Alexander; Hamm, Bernd; Lembcke, Alexander

    2016-05-01

    To evaluate a software tool that claims to maintain a constant contrast-to-noise ratio (CNR) in high-pitch dual-source computed tomography coronary angiography (CTCA) by automatically selecting both X-ray tube voltage and current. A total of 302 patients (171 males; age 61±12years; body weight 82±17kg, body mass index 27.3±4.6kg/cm(2)) underwent CTCA with a topogram-based, automatic selection of both tube voltage and current using dedicated software with quality reference values of 100kV and 250mAs/rotation (i.e., standard values for an average adult weighing 75kg) and an injected iodine load of 222mg/kg. The average radiation dose was estimated to be 1.02±0.64mSv. All data sets had adequate contrast enhancement. Average CNR in the aortic root, left ventricle, and left and right coronary artery was 15.7±4.5, 8.3±2.9, 16.1±4.3 and 15.3±3.9 respectively. Individual CNR values were independent of patients' body size and radiation dose. However, individual CNR values may vary considerably between subjects as reflected by interquartile ranges of 12.6-18.6, 6.2-9.9, 12.8-18.9 and 12.5-17.9 respectively. Moreover, average CNR values were significantly lower in males than females (15.1±4.1 vs. 16.6±11.7 and 7.9±2.7 vs. 8.9±3.0, 15.5±3.9 vs. 16.9±4.6 and 14.7±3.6 vs. 16.0±4.1 respectively). A topogram-based automatic selection of X-ray tube settings in CTCA provides diagnostic image quality independent of patients' body size. Nevertheless, considerable variation of individual CNR values between patients and significant differences of CNR values between males and females occur which questions the reliability of this approach. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. X-ray micro-beam characterization of lattice rotations and distortions due to an individual dislocation.

    Science.gov (United States)

    Hofmann, Felix; Abbey, Brian; Liu, Wenjun; Xu, Ruqing; Usher, Brian F; Balaur, Eugeniu; Liu, Yuzi

    2013-01-01

    Understanding and controlling the behaviour of dislocations is crucial for a wide range of applications, from nano-electronics and solar cells to structural engineering alloys. Quantitative X-ray diffraction measurements of the strain fields due to individual dislocations, particularly in the bulk, however, have thus far remained elusive. Here we report the first characterization of a single dislocation in a freestanding GaAs/In0.2Ga0.8As/GaAs membrane by synchrotron X-ray micro-beam Laue diffraction. Our experimental X-ray data agrees closely with textbook anisotropic elasticity solutions for dislocations, providing one of few experimental validations of this fundamental theory. On the basis of the experimental uncertainty in our measurements, we predict the X-ray beam size required for three-dimensional measurements of lattice strains and rotations due to individual dislocations in the material bulk. These findings have important implications for the in situ study of dislocation structure formation, self-organization and evolution in the bulk.

  15. Catheter Angiography

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography uses a catheter, x-ray imaging ... the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive medical test that ...

  16. 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.

  17. Development and assessment of a digital X-ray software tool to determine vertebral rotation in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Eijgenraam, Susanne M; Boselie, Toon F M; Sieben, Judith M; Bastiaenen, Caroline H G; Willems, Paul C; Arts, Jacobus J; Lataster, Arno

    2017-02-01

    The amount of vertebral rotation in the axial plane is of key importance in the prognosis and treatment of adolescent idiopathic scoliosis (AIS). Current methods to determine vertebral rotation are either designed for use in analogue plain radiographs and not useful in digital images, or lack measurement precision and are therefore less suitable for the follow-up of rotation in AIS patients. This study aimed to develop a digital X-ray software tool with high measurement precision to determine vertebral rotation in AIS, and to assess its (concurrent) validity and reliability. In this study a combination of basic science and reliability methodology applied in both laboratory and clinical settings was used. Software was developed using the algorithm of the Perdriolle torsion meter for analogue AP plain radiographs of the spine. Software was then assessed for (1) concurrent validity and (2) intra- and interobserver reliability. Plain radiographs of both human cadaver vertebrae and outpatient AIS patients were used. Concurrent validity was measured by two independent observers, both experienced in the assessment of plain radiographs. Reliability-measurements were performed by three independent spine surgeons. Pearson correlation of the software compared with the analogue Perdriolle torsion meter for mid-thoracic vertebrae was 0.98, for low-thoracic vertebrae 0.97 and for lumbar vertebrae 0.97. Measurement exactness of the software was within 5° in 62% of cases and within 10° in 97% of cases. Intraclass correlation coefficient (ICC) for inter-observer reliability was 0.92 (0.91-0.95), ICC for intra-observer reliability was 0.96 (0.94-0.97). We developed a digital X-ray software tool to determine vertebral rotation in AIS with a substantial concurrent validity and reliability, which may be useful for the follow-up of vertebral rotation in AIS patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. X-Raying the Beating Heart of a Newborn Star: Rotational Modulation of High-Energy Radiation from V1647 Ori

    Science.gov (United States)

    Hamaguchi, Kenji; Grosso, Nicolas; Kastner, Joel H.; Weintraub, David A.; Richmond, Michael; Petre, Robert; Teets, William K.; Principe, David

    2012-01-01

    We report a periodicity of approx.1 day in the highly elevated X-ray emission from the protostar V1647 Ori during its two recent multiple-year outbursts of mass accretion. This periodicity is indicative of protostellar rotation at near-breakup speed. Modeling of the phased X-ray light curve indicates the high-temperature ( 50 MK), X-ray-emitting plasma, which is most likely heated by accretion-induced magnetic reconnection, resides in dense ( 5 1010 cm.3), pancake-shaped magnetic footprints where the accretion stream feeds the newborn star. The sustained X-ray periodicity of V1647 Ori demonstrates that such protostellar magnetospheric accretion configurations can be stable over timescales of years. Subject headings: stars: formation stars: individual (V1647 Ori) stars: pre-main sequence X-rays: stars

  19. Catheter Angiography

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    Full Text Available ... far outweighs the risk. If you have a history of allergy to x-ray contrast material, your ... Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Catheter Angiography Sponsored ...

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, ... a tumor; this is called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of ...

  1. Calculation Of Correction Angles Of 3-Dimensional Vertebral Rotations Based On Bi-Plane X-Ray Photogrammetry

    Science.gov (United States)

    Tamaki, Tamotsu; Umezaki, Eisaku; Yamagata, Masatsune; Inoue, Shun-ichi

    1984-10-01

    For the therapy of diseases of spinal deformity such as scoliosis, the data of 3-dimensional and correct spinal configuration are needed. Authors developed the system of spinal configuration analysis using bi-plane X-ray photogrammetry which is strong aid for this subject. The idea of correction angle of rotation of vertebra is introduced for this system. Calculated result under this idea has the clinical meaning because the correction angle is the angle which should be corrected on the treatment such as operation or wearing the equipment. Method of 30° oblique projection which gives the apparent X-ray image and eases the measurement of the anatomically characteristic points is presented. The anatomically characteristic bony points whose images should be measured on a- or b-film are of four points. These are centers of upper and lower end plates of each vertebra the center is calculated from two points which are most distant each other on the contour of vertebral end plate ), the lower end points of root of right and left pedicles. Some clinical applications and the effectiveness of this system are presented.

  2. The Formation of Rapidly Rotating Black Holes in High-mass X-Ray Binaries

    Science.gov (United States)

    Batta, Aldo; Ramirez-Ruiz, Enrico; Fryer, Chris

    2017-09-01

    High-mass X-ray binaries (HMXRBs), such as Cygnus X-1, host some of the most rapidly spinning black holes (BHs) known to date, reaching spin parameters a≳ 0.84. However, there are several effects that can severely limit the maximum BH spin parameter that could be obtained from direct collapse, such as tidal synchronization, magnetic core-envelope coupling, and mass loss. Here, we propose an alternative scenario where the BH is produced by a failed supernova (SN) explosion that is unable to unbind the stellar progenitor. A large amount of fallback material ensues, whose interaction with the secondary naturally increases its overall angular momentum content, and therefore the spin of the BH when accreted. Through SPH hydrodynamic simulations, we studied the unsuccessful explosion of an 8 {M}⊙ pre-SN star in a close binary with a 12 {M}⊙ companion with an orbital period of ≈1.2 days, finding that it is possible to obtain a BH with a high spin parameter a≳ 0.8 even when the expected spin parameter from direct collapse is a≲ 0.3. This scenario also naturally explains the atmospheric metal pollution observed in HMXRB stellar companions.

  3. Automated coronary artery tree segmentation in X-ray angiography using improved Hessian based enhancement and statistical region merging.

    Science.gov (United States)

    Wan, Tao; Shang, Xiaoqing; Yang, Weilin; Chen, Jianhui; Li, Deyu; Qin, Zengchang

    2018-04-01

    Coronary artery segmentation is a fundamental step for a computer-aided diagnosis system to be developed to assist cardiothoracic radiologists in detecting coronary artery diseases. Manual delineation of the vasculature becomes tedious or even impossible with a large number of images acquired in the daily life clinic. A new computerized image-based segmentation method is presented for automatically extracting coronary arteries from angiography images. A combination of a multiscale-based adaptive Hessian-based enhancement method and a statistical region merging technique provides a simple and effective way to improve the complex vessel structures as well as thin vessel delineation which often missed by other segmentation methods. The methodology was validated on 100 patients who underwent diagnostic coronary angiography. The segmentation performance was assessed via both qualitative and quantitative evaluations. Quantitative evaluation shows that our method is able to identify coronary artery trees with an accuracy of 93% and outperforms other segmentation methods in terms of two widely used segmentation metrics of mean absolute difference and dice similarity coefficient. The comparison to the manual segmentations from three human observers suggests that the presented automated segmentation method is potential to be used in an image-based computerized analysis system for early detection of coronary artery disease. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Direct navigation on 3D rotational x-ray data acquired with a mobile propeller C-arm: accuracy and application in functional endoscopic sinus surgery

    NARCIS (Netherlands)

    van de Kraats, Everine B.; Carelsen, Bart; Fokkens, Wytske J.; Boon, Sjirk N.; Noordhoek, Niels; Niessen, Wiro J.; van Walsum, Theo

    2005-01-01

    Recently, three-dimensional (3D) rotational x-ray imaging has been combined with navigation technology, enabling direct 3D navigation for minimally invasive image guided interventions. In this study, phantom experiments are used to determine the accuracy of such a navigation set-up for a mobile

  5. A study of the performance characteristics of an X-ray detector for region-of-interest angiography

    Science.gov (United States)

    Ganguly, Arundhuti

    Minimally invasive image-guided neuro-vascular interventions require very high image resolution and quality, specifically over regions-of-interest (ROI) crucial to the procedure. ROI images allow limited patient integral radiation dose while permitting rapid frame transfer of high-resolution images. The design and performance of a CCD based x-ray detector was assessed for neuro-vascular procedures. The detector consists of a 250 mum thick CsI(Tl) phosphor fiber-optically coupled through a 2:1 taper to a CCD chip, with an effective image pixel size of 50 mum and a frame rate of 5 fps in the 2:1 pixel-binned mode. The characteristics of the camera including the MTF, NEQ, DQE and observer performance were evaluated experimentally and through theoretical modeling. The MTF was non-zero (>1%), at the Nyquist frequency of 10 cycles/mm while the DQE(0) had a value of ˜54%. All values were measured using head equivalent attenuating material in the beam at 80 kVp. Observer studies performed using the 2 Alternative Forced Choice (2AFC) method, revealed that 100 mum diameter iodinated vessels with 2 cm length could be seen with greater than 75% confidence level. The theoretical modeling included parallel cascade calculations for the signal and noise characteristics of the detector chain. The observer studies included an ideal observer performance calculation based on the integral signal to noise ratio in the image. Probabilities of visualization of various objects of interest in a neuro-intervention were assessed. There was good agreement between experiment and theory and the results suggest ways for further performance improvement for the ROI CCD camera. Additionally, possible direct flat panel ROI detectors designs were also considered for the future.

  6. Dispersion Relations for X-Ray Faraday Rotation and Magnetic Circular Dichroism

    Science.gov (United States)

    Smith, D. Y.

    2003-03-01

    Experimental demonstration of Kramers-Kronig relations between XFR and XMCD has recently been reported. This is at variance with predictions^1 of a more complex relationship because of the lack of time-reversal symmetry in a magnetic field. Qualitatively, this corresponds to recognizing that real EM waves contain Fourier components with positive and negative frequencies, but that right-hand modes for positive frequencies are left-hand modes for negative frequencies, and vice versa. Formally, circular modes mix real and imaginary parts of dielectric tensor elements (which individually obey the K-K relations) so that symmetric and antisymmetric combinations of optical constants must be used in forming their dispersion relations. The difference between dispersion relations for the magnetic and magnetic-field-free cases should be most readily observed in the tails of the Faraday rotation. Reanalysis of published data shows that the difference is small and comparable to experimental uncertainty in the materials studied; hence, the experiments do not distinguish between the two forms. However, there is a slight statistical preference for the magnetic relations in one set of measurements. ^1 D. Y. Smith, J. Opt. Soc. Am. 66, 454 (1967).

  7. Catheter Angiography

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    Full Text Available ... x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin plastic ... superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes it ...

  8. Catheter Angiography

    Medline Plus

    Full Text Available ... using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin ... called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes ...

  9. Catheter Angiography

    Medline Plus

    Full Text Available ... risks? What are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive ... of ionizing radiation ( x-rays ). top of page What are some common uses of the procedure? Catheter ...

  10. Coregistration of preoperative computed tomography and intraoperative three-dimensional rotational x-ray images for cochlear implant surgical evaluation.

    Science.gov (United States)

    Pearlman, Paul C; van Deurzen, Martinus H W; Pluim, Josien P W; Grolman, Wilko

    2014-12-01

    A registration procedure of intraoperative three-dimensional rotational x-ray (3DRX) imaging and preoperative computed tomography (CT) imaging so that intraoperative CT quality imaging is available during cochlear implant surgery, providing detailed information concerning electrode position in the cochlea and its relation to surrounding bony structures. Retrospective case series Tertiary referral center The imaging of five patients who had undergone cochlear implant surgery is used to develop a semiautomatic registration procedure to integrate intraoperative 3DRX and preoperative CT. The method is implemented in advanced medical imaging software to compute the transformations. The electrode is segmented from the registered 3DRX images using a semiautomated approach. The segmented electrode is superimposed onto the CT data. The methods are quantitatively validated based on expert-labeled anatomical landmarks. These landmarks are identified in the CT and 3DRX images by an expert. Mean error of the registration procedure for five anatomical landmarks in millimeters. Quantitative analysis showed a mean error of between 0.5 and 1 mm for all anatomical landmarks, suggesting that the results are trustworthy. We developed a reliable procedure for the registration of intraoperative 3DRX imaging and preoperative CT imaging for cochlear implant surgery. This registration procedure provides the ENT surgeon intraoperative high-quality CT imaging during cochlear implant surgery.

  11. Evaluation of 2 different x-ray digital systems designed for cardiovascular angiography: patient dosimetry data and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Octavian Dragusin; Kristien Smans; Hilde Bosmans [Department of Radiology, Gasthuisberg Hospital, Leuven (Belgium); Walter Desmet [Department of Cardiology, Gasthuisberg Hospital, Leuven (Belgium)

    2006-07-01

    The goal of this study was the comparative assessment of dose and image quality performance of a new flat-panel detector (F.D.) and an image intensifier (II) charge coupled device (C.C.D.) installed in a Catheterization laboratory (Cathlab). Poly-methyl methacrylate (PMMA) plates were used to simulate different patient size (10,15,20,25,30 cm). Entrance dose to the phantom and image quality of a test object (Leeds T.O.R. 18-F.G.) were measured. For analysis of image quality, two methods were used. Firstly, images were evaluated directly on the monitor (low contrast resolution and high spatial resolution). Secondly, a numerical method was used (noise and signal-to-noise ratio). Finally a preliminary patient dose survey for the two most common interventional cardiology procedures (coronary angiography C.A. and percutaneous transluminal coronary angioplasty - P.T.C.A.) was performed. Dose area product (D.A.P.), fluoroscopy time (F.T.) and total number of frames (No. frames) were collected. The results showed that both systems performed within international recommendations; the F.D. system seems superior to the II system, in terms of entrance doses of the phantom and image quality. Surprisingly, however, this potential dose reduction is not reflected in the patient data; D.A.P. values of patient data were not significantly reduced with the new system. This underlines the need for a careful set-up of the system and a more detailed analysis of the procedure. (authors)

  12. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ...

  13. Catheter Angiography

    Medline Plus

    Full Text Available ... is suspended over a table on which the patient lies. The catheter used in angiography is a ... other noninvasive procedures. No radiation remains in a patient's body after an x-ray examination. X-rays ...

  14. Catheter Angiography

    Medline Plus

    Full Text Available ... Z Catheter Angiography Catheter angiography uses a catheter, x-ray imaging guidance and an injection of contrast material ... vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging ( ...

  15. SU-E-I-10: Automatic Monitoring of Accumulated Dose Indices From DICOM RDSR to Improve Radiation Safety in X-Ray Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Omar, A; Bujila, R; Nowik, P; Karambatsakidou, A [Karolinska University Hospital, Stockholm (Sweden)

    2014-06-01

    Purpose: To investigate the potential benefits of automatic monitoring of accumulated patient and staff dose indicators, i.e., CAK and KAP, from DICOM Radiation Dose Structured Reports (RDSR) in x-ray angiography (XA). Methods: Recently RDSR has enabled the convenient aggregation of dose indices and technique parameters for XA procedures. The information contained in RDSR objects for three XA systems, dedicated to different types of clinical procedures, has been collected and aggregated in a database for over one year using a system developed with open-source software at the Karolinska University Hospital. Patient weight was complemented to the RDSR data via an interface with the Hospital Information System (HIS). Results: The linearly approximated trend in KAP over a time period of a year for cerebrovascular, pelvic/peripheral vascular, and cardiovascular procedures showed a decrease of 12%, 20%, and 14%, respectively. The decrease was mainly due to hardware/software upgrades and new low-dose imaging protocols, and partially due to ongoing systematic radiation safety education of the clinical staff. The CAK was in excess of 3 Gy for 15 procedures, and exceeded 5 Gy for 3 procedures. The dose indices have also shown a significant dependence on patient weight for cardiovascular and pelvic/peripheral vascular procedures; a 10 kg shift in mean patient weight can result in a dose index increase of 25%. Conclusion: Automatic monitoring of accumulated dose indices can be utilized to notify the clinical staff and medical physicists when the dose index has exceeded a predetermined action level. This allows for convenient and systematic follow-up of patients in risk of developing deterministic skin injuries. Furthermore, trend analyses of dose indices over time is a valuable resource for the identification of potential positive or negative effects (dose increase/decrease) from changes in hardware, software, and clinical work habits.

  16. Catheter Angiography

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    Full Text Available ... Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation ... costs for specific medical imaging tests, treatments and procedures may vary by geographic region. ...

  17. X-ray diffraction contrast tomography (DCT) system, and an X-ray diffraction contrast tomography (DCT) method

    DEFF Research Database (Denmark)

    2012-01-01

    Source: US2012008736A An X-ray diffraction contrast tomography system (DCT) comprising a laboratory X-ray source (2), a staging device (5) rotating a polycrystalline material sample in the direct path of the X-ray beam, a first X-ray detector (6) detecting the direct X-ray beam being transmitted...

  18. 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

  19. Cryotomography x-ray microscopy state

    Science.gov (United States)

    Le Gros, Mark; Larabell, Carolyn A.

    2010-10-26

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

  20. Catheter Angiography

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    Full Text Available ... heart chest abdomen (such as the kidneys and liver) pelvis legs and feet arms and hands Physicians ... Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Catheter Angiography Sponsored ...

  1. Applications and measurements of polycapillary x-ray optics.

    Science.gov (United States)

    Macdonald, C A

    1996-01-01

    The recent invention of Kumakhov polycapillary x-ray and neutron optics has expanded the ways x-ray beams can be controlled. X rays incident on the interior of glass tubes at small angles can be guided down the tubes by total external reflection. Now, arrays of curved tapered capillaries can be used to focus, collimate, and filter x-ray radiation. Extensive research is being conducted on the performance and potential applications of these optics. Potential medical applications include mammography, digital energy subtraction angiography, and focused beam therapy. Other applications are x-ray lithography, x-ray astronomy, crystal diffraction, x-ray fluorescence, and neutron prompt gamma analysis.

  2. 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 ...

  3. Interfraction rotation of the prostate as evaluated by kilovoltage X-ray fiducial marker imaging in intensity-modulated radiotherapy of localized prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Reinhold; Boehmer, Dirk; Budach, Volker [Charite Universitaetsmedizin Berlin, Department of Radiation Oncology, Campus Virchow-Klinikum, Berlin (Germany); Wust, Peter, E-mail: peter.wust@charite.de [Charite Universitaetsmedizin Berlin, Department of Radiation Oncology, Campus Virchow-Klinikum, Berlin (Germany)

    2012-01-01

    To quantify the daily rotation of the prostate during a radiotherapy course using stereoscopic kilovoltage (kV) x-ray imaging and intraprostatic fiducials for localization and positioning correction. From 2005 to 2009, radio-opaque fiducial markers were inserted into 38 patients via perineum into the prostate. The ExacTrac/Novalis Body X-ray 6-day image acquisition system (ET/NB; BrainLab AG, Feldkirchen, Germany) was used to determine and correct the target position. During the first period in 10 patients we recorded all rotation errors but used only Y (table) for correction. For the next 28 patients we used for correction all rotational coordinates, i.e., in addition Z (superior-inferior [SI] or roll) and X (left-right [LR] or tilt/pitch) according to the fiducial marker position by use of the Robotic Tilt Module and Varian Exact Couch. Rotation correction was applied above a threshold of 1 Degree-Sign displacement. The systematic and random errors were specified. Overall, 993 software-assisted rotational corrections were performed. The interfraction rotation errors of the prostate as assessed from the radiodense surrogate markers around the three axes Y, Z, and X were on average 0.09, -0.52, and -0.01 Degree-Sign with standard deviations of 2.01, 2.30, and 3.95 Degree-Sign , respectively. The systematic uncertainty per patient for prostate rotation was estimated with 2.30, 1.56, and 4.13 Degree-Sign and the mean random components with 1.81, 2.02, and 3.09 Degree-Sign . The largest rotational errors occurred around the X-axis (pitch), but without preferring a certain orientation. Although the error around Z (roll) can be compensated on average by a transformation with 4 coordinates, a significant error around X remains and advocates the full correction with 6 coordinates. Rotational errors as assessed via daily stereoscopic online imaging are significant and dominate around X. Rotation possibly degrades the dosimetric coverage of the target volume and may require

  4. CT angiography versus 3D rotational angiography in patients with subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Bechan, R.S.; Peluso, J.P.; Sluzewski, M.; Rooij, W.J. van [Sint Elisabeth Ziekenhuis Tilburg, Department of Radiology, Tilburg (Netherlands); Rooij, S.B. van [Medisch Centrum Alkmaar, Department of Radiology, Alkmaar (Netherlands); Sprengers, M.E.; Majoie, C.B. [Academisch Medisch Centrum, Department of Radiology, Amsterdam (Netherlands)

    2015-12-15

    CT angiography (CTA) is increasingly used as primary diagnostic tool to replace digital subtraction angiography (DSA) in patients with subarachnoid hemorrhage (SAH). However, 3D rotational angiography (3DRA) has substituted DSA as a reference standard. In this prospective observational study, we compare CTA with 3DRA of all cerebral vessels in a large cohort of patients with SAH. Of 179 consecutive patients with SAH admitted between March 2013 and July 2014, 139 underwent 64- to 256-detector row CTA followed by complete cerebral 3DRA within 24 h. In 86 patients (62 %), 3DRA was performed under general anesthesia. Two observers from outside hospitals reviewed CTA data. In 118 of 139 patients (85 %), 3DRA diagnosed the cause of hemorrhage: 113 ruptured aneurysms, three arterial dissections, one micro-arteriovenous malformation (AVM), and one reversible vasoconstriction syndrome. On CTA, both observers missed all five non-aneurysmal causes of SAH. Sensitivity of CTA in depicting ruptured aneurysms was 0.88-0.91, and accuracy was 0.88-0.92. Of 113 ruptured aneurysms, 28 were ≤3 mm (25 %) and of 95 additional aneurysms, 71 were ≤3 mm (75 %). Sensitivity of depicting aneurysms ≤3 mm was 0.28-0.43. Of 95 additional aneurysms, the two raters missed 65 (68 %) and 58 (61 %). Sensitivity in detection was lower in aneurysms of the internal carotid artery than in other locations. CTA had some limitations as primary diagnostic tool in patients with SAH. All non-aneurysmal causes for SAH and one in ten ruptured aneurysms were missed. Performance of CTA was poor in aneurysms ≤3 mm. The majority of additional aneurysms were not depicted on CTA. (orig.)

  5. When is rotational angiography superior to conventional single‐plane angiography for planning coronary angioplasty?

    Science.gov (United States)

    Taylor, Jane; Boutong, Sara; Brett, Sarah; Louis, Amal; Heppenstall, James; Morton, Allison C.; Gunn, Julian P.

    2015-01-01

    Objectives To investigate the value of rotational coronary angiography (RoCA) in the context of percutaneous coronary intervention (PCI) planning. Background As a diagnostic tool, RoCA is associated with decreased patient irradiation and contrast use compared with conventional coronary angiography (CA) and provides superior appreciation of three‐dimensional anatomy. However, its value in PCI remains unknown. Methods We studied stable coronary artery disease assessment and PCI planning by interventional cardiologists. Patients underwent either RoCA or conventional CA pre‐PCI for planning. These were compared with the referral CA (all conventional) in terms of quantitative lesion assessment and operator confidence. An independent panel reanalyzed all parameters. Results Six operators performed 127 procedures (60 RoCA, 60 conventional CA, and 7 crossed‐over) and assessed 212 lesions. RoCA was associated with a reduction in the number of lesions judged to involve a bifurcation (23 vs. 30 lesions, P RoCA improved confidence assessing lesion length (P = 0.01), percentage stenosis (P = 0.02), tortuosity (P RoCA augments quantitative lesion assessment, enhances confidence in the assessment of coronary artery disease and the precise details of the proposed procedure, but does not affect X‐ray dose, contrast agent volume, or procedure duration. © 2015 Wiley Periodicals, Inc. PMID:26012725

  6. Development of a Spatially Resolving X-Ray Crystal Spectrometer (XCS) for Measurement of Ion-Temperature (Ti) and Rotation-Velocity (v) Profiles in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hill, K W; Delgado-Aprico, L; Johnson, D; Feder, R; Beiersdorfer,; Dunn, J; Morris, K; Wang, E; Reinke, M; Podpaly, Y; Rice, J E; Barnsley, R; O' Mullane, M; Lee, S G

    2010-05-21

    Imaging XCS arrays are being developed as a US-ITER activity for Doppler measurement of Ti and v profiles of impurities (W, Kr, Fe) with ~7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a PPPL-MIT instrument on Alcator C-Mod, uses a spherically bent crystal and 2d x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure Ti and both poloidal and toroidal rotation velocity profiles. Measurement of many spatial chords permits tomographic inversion for inference of local parameters. The instrument design, predictions of performance, and results from C-Mod will be presented.

  7. Chest X-Ray

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    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. 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 ...

  9. 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 ...

  10. Consistency-based respiratory motion estimation in rotational angiography.

    Science.gov (United States)

    Unberath, Mathias; Aichert, André; Achenbach, Stephan; Maier, Andreas

    2017-09-01

    Rotational coronary angiography enables 3D reconstruction but suffers from intra-scan cardiac and respiratory motion. While gating handles cardiac motion, respiratory motion requires compensation. State-of-the-art algorithms rely on 3D-2D registration that depends on initial reconstructions of sufficient quality. We propose a compensation method that is applied directly in projection domain. It overcomes the need for reconstruction and thus complements the state-of-the-art. Virtual single-frame background subtraction based on vessel segmentation and spectral deconvolution yields non-truncated images of the contrasted lumen. This allows motion compensation based on data consistency conditions. We compensate craniocaudal shifts by optimizing epipolar consistency to (a) devise an image-based surrogate for cardiac motion and (b) compensate for respiratory motion. We validate our approach in two numerical phantom studies and three clinical cases. Correlation of the image-based surrogate for cardiac motion with the ECG-based ground truth was excellent yielding a Pearson correlation of 0.93 ± 0.04. Considering motion compensation, the target error measure decreased by 98% and 69%, respectively, for the phantom experiments while for the clinical cases the same figure of merit improved by 46 ± 21%. The proposed method is entirely image-based and accurately estimates craniocaudal shifts due to respiration and cardiac contraction. Future work will investigate experimental trajectories and possibilities for simplification of the single-frame subtraction pipeline. © 2016 American Association of Physicists in Medicine.

  11. Reconstruction of blood propagation in three-dimensional rotational X-ray angiography (3D-RA).

    Science.gov (United States)

    Schmitt, Holger; Grass, Michael; Suurmond, Rolf; Köhler, Thomas; Rasche, Volker; Hähnel, Stefan; Heiland, Sabine

    2005-10-01

    This paper presents a framework of non-interactive algorithms for the mapping of blood flow information to vessels in 3D-RA images. With the presented method, mapping of flow information to 3D-RA images is done automatically without user interaction. So far, radiologists had to perform this task by extensive image comparisons and did not obtain visualizations of the results. In our approach, flow information is reconstructed by forward projection of vessel pieces in a 3D-RA image to a two-dimensional projection series capturing the propagation of a short additional contrast agent bolus. For accurate 2D-3D image registration, an efficient patient motion compensation technique is introduced. As an exemplary flow-related quantity, bolus arrival times are reconstructed for the vessel pieces by matching of intensity-time curves. A plausibility check framework was developed which handles projection ambiguities and corrects for noisy flow reconstruction results. It is based on a linear programming approach to model the feeding structure of the vessel. The flow reconstruction method was applied to 12 cases of cerebral stenoses, AVMs and aneurysms, and it proved to be feasible in the clinical environment. The propagation of the injected contrast agent was reconstructed and visualized in three-dimensional images. The flow reconstruction method was able to visualize different types of useful information. In cases of stenosis of the middle cerebral artery (MCA), flow reconstruction can reveal impeded blood flow depending on the severeness of the stenosis. With cases of AVMs, flow reconstruction can clarify the feeding structure. The presented methods handle the problems imposed by clinical demands such as non-interactive algorithms, patient motion compensation, short reconstruction times, and technical requirements such as correction of noisy bolus arrival times and handling of overlapping vessel pieces. Problems occurred mainly in the reconstruction and segmentation of 3D-RA images in cases of complex AVMs. The concentration of injected contrast agent was often not sufficient to provide highly contrasted vessels in 3D-RA images. Another segmentation-related problem is known as 'kissing vessels' [19]. Kissing vessel artifacts introduce artificial vessel junctions and thereby distort the feeding structure of the vessel. This may finally cause implausible flow reconstruction results and inverse flow directions in vessel segments. We are currently planning to validate our reconstruction results using particle imaging velocimetry (PIV). PIV experiments with phantoms, for which the true flow parameters are known, will allow for the assessment of the accuracy of our contrast agent based method. In the context of computational fluid dynamics techniques, the potential of the presented flow reconstruction method is high. Flow reconstruction results based on the presented method could be used both as boundary conditions for simulations and as a reference for the validation of simulation results. Computational fluid dynamics provide useful information such as arterial wall shear stress and complex flow patterns in aneurysms.

  12. 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.

  13. Catheter Angiography

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    Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Contrast Materials CT Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  14. Catheter Angiography

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    Full Text Available ... examine blood vessels in key areas of the body for abnormalities such as aneurysms and disease such ... to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters ...

  15. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... and x-rays. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  16. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a regular x-ray ... material injection, you should immediately inform the technologist. Women should always inform their physician or x-ray ...

  17. Evaluation of Intracranial Microvessel Visualization in Mouse and Dog Models by Using a New Rotating Cerium Anode X-ray System.

    Science.gov (United States)

    Tanaka, Chiharu; Shizuma, Toru; Shinozaki, Yoshiro; Todoroki, Kikue; Ikeya, Yoshimori; Fukuyama, Naoto; Ueda, Toshihiko; Mori, Hidezo

    2017-04-20

    Lacunar stroke may be caused by infarction of small perforating branches of the middle cerebral artery. We developed a microangiographic X-ray system using a cerium anode to evaluate the perforating branches. Iodine has K-edges at 33.2 kilo electron volts. Cerium yields a characteristic X-ray of 34.6 kilo electron volts, therefore, the cerium anode X-ray system could detect tiny amounts of contrast material. First, an X-ray chart was used to evaluate the resolution. Second, the brains of mice were dissected and irradiated. Third, the brains of dogs were excluded and irradiated. Fourth, iodine was perfused into the carotid artery of living dogs during brain imaging. In the first experiment, the cerium anode X-ray system elicited 4.86 clear line pairs. In mice, the perforating branches of the middle cerebral artery could be visualized. The perforating branches were clearly observed in dog brains ex situ even through an acrylic plate, but not in conventional X-ray images. Iodine moving inside the perforating branches was visualized in dog brains in situ using the cerium anode X-ray system. The cerium anode X-ray system allowed us to visualize the perforating branches of the middle cerebral artery in living dogs.

  18. 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 ...

  19. Fast frame rate rodent cardiac x-ray imaging using scintillator lens coupled to CMOS camera

    Science.gov (United States)

    Swathi Lakshmi, B.; Sai Varsha, M. K. N.; Kumar, N. Ashwin; Dixit, Madhulika; Krishnamurthi, Ganapathy

    2017-03-01

    Micro-Computed Tomography (MCT) systems for small animal imaging plays a critical role for monitoring disease progression and therapy evaluation. In this work, an in-house built micro-CT system equipped with a X-ray scintillator lens coupled to a commercial CMOS camera was used to test the feasibility of its application to Digital Subtraction Angiography (DSA). Literature has reported such studies being done with clinical X-ray tubes that can be pulsed rapidly or with rotating gantry systems, thus increasing the cost and infrastructural requirements.The feasibility of DSA was evaluated by injected Iodinated contrast agent (ICA) through the tail vein of a mouse. Projection images of the heart were acquired pre and post contrast using the high frame rate X-ray detector and processing done to visualize transit of ICA through the heart.

  20. Determination of radial location of rotating magnetic islands by use of poloidal soft x-ray detector arrays in the STOR-M tokamak

    Science.gov (United States)

    Dreval, M.; Xiao, C.; Elgriw, S.; Trembach, D.; Wolfe, S.; Hirose, A.

    2011-05-01

    A technique is presented for determining the radial location of the rotating magnetic islands in the STOR-M tokamak by use of soft x-ray (SXR) detector arrays. The location is determined by examining the difference in the integrated SXR emission intensities through two adjacent lines of sight. A model for calculating dependence of the line integrated SXR emission intensity on the radius, the mode numbers and the magnetic island geometry, has been developed. The SXR difference signal shows phase inversion when the impact parameter of the line of sight sweeps across the magnetic islands. Experimentally, the difference SXR signals significantly reduce noise and suppress the influence of background plasma fluctuations through common mode rejection when a dominant mode exists in the STOR-M tokamak. The radial locations of the m = 2 magnetic islands have been determined under several experimental conditions in the STOR-M discharges. With the decrease in the tokamak discharge current and thus the increase of the safety factor at the edge, the radial location of the m = 2 magnetic islands has been found to move radially inward.

  1. Determining the masses and radii of rapidly rotating, oblate neutron stars using energy-resolved waveforms of their X-ray burst oscillations

    Science.gov (United States)

    Lamb, Frederick K.; Miller, M. Coleman

    2014-08-01

    We have developed new, more sophisticated, and much faster Bayesian analysis methods that enable us to estimate the masses and radii of rapidly rotating, oblate neutron stars using the energy-resolved waveforms of their X-ray burst oscillations and to determine the uncertainties in these mass and radius estimates. We first generate the energy-resolved burst oscillation waveforms that would be produced by a hot spot on various rapidly rotating, oblate stars, using the oblate-star Schwarzschild-spacetime (OS) approximation. In generating these synthetic data, we assume that 1 million counts have been collected from the hot spot and that the background is 9 million counts. This produces a realistic modulation amplitude and a total number of counts comparable to the number that could be obtained by a future space mission such as the proposed LOFT or AXTAR missions or the accepted NICER mission by combining data from many bursts from a given star. We then compute the joint posterior distribution of the mass M and radius R in standard models, for each synthetic waveform, and use these posterior distributions to determine the 1-, 2-, and 3-sigma confidence regions in the M-R plane for each synthetic waveform and model. We report here the confidence regions obtained when Schwarzschild+Doppler (S+D) and OS waveform models are used, including results obtained when the properties of the star used to generate the synthetic waveform data differ from the properties of the star used in modeling the waveform. These results are based on research supported by NSF grant AST0709015 at the University of Illinois and NSF grant AST0708424 at the University of Maryland.

  2. Chest X-Ray

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    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- ...

  3. Chest X-Ray

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    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 ...

  4. The detection of variable radio emission from the fast rotating magnetic hot B-star HR\\xA07355 and evidence for its X-ray aurorae

    Science.gov (United States)

    Leto, P.; Trigilio, C.; Oskinova, L.; Ignace, R.; Buemi, C. S.; Umana, G.; Ingallinera, A.; Todt, H.; Leone, F.

    2017-05-01

    In this paper, we investigate the multiwavelength properties of the magnetic early B-type star HR 7355. We present its radio light curves at several frequencies, taken with the Jansky Very Large Array, and X-ray spectra, taken with the XMM-Newton X-ray telescope. Modelling of the radio light curves for the Stokes I and V provides a quantitative analysis of the HR 7355 magnetosphere. A comparison between HR 7355 and a similar analysis for the Ap star CU Vir allows us to study how the different physical parameters of the two stars affect the structure of the respective magnetospheres where the non-thermal electrons originate. Our model includes a cold thermal plasma component that accumulates at high magnetic latitudes that influences the radio regime, but does not give rise to X-ray emission. Instead, the thermal X-ray emission arises from shocks generated by wind stream collisions close to the magnetic equatorial plane. The analysis of the X-ray spectrum of HR 7355 also suggests the presence of a non-thermal radiation. Comparison between the spectral index of the power-law X-ray energy distribution with the non-thermal electron energy distribution indicates that the non-thermal X-ray component could be the auroral signature of the non-thermal electrons that impact the stellar surface, the same non-thermal electrons that are responsible for the observed radio emission. On the basis of our analysis, we suggest a novel model that simultaneously explains the X-ray and the radio features of HR 7355 and is likely relevant for magnetospheres of other magnetic early-type stars.

  5. 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

  6. 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

  7. 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 ...

  8. 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 ...

  9. 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 ...

  10. Catheter Angiography

    Medline Plus

    Full Text Available ... treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection is needed to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging ( ...

  11. Catheter Angiography

    Medline Plus

    Full Text Available ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... View full size with caption Related Articles and Media Angioplasty and Vascular Stenting MR Angiography (MRA) Contrast Materials CT Angiography (CTA) X-ray, Interventional Radiology ...

  12. Rotational Angiography Based Three-Dimensional Left Atrial Reconstruction: A New Approach for Transseptal Puncture.

    Science.gov (United States)

    Koektuerk, Buelent; Yorgun, Hikmet; Koektuerk, Oezlem; Turan, Cem H; Gorr, Eduard; Horlitz, Marc; Turan, Ramazan G

    2016-02-01

    Rotational angiography is a well-known method for the three-dimensional (3-D) reconstruction of left atrium and pulmonary veins during left-sided atrial arrhythmia ablation procedures. In our study, we aimed to review our experience in transseptal puncture (TSP) using 3-D rotational angiography. We included a total of 271 patients who underwent atrial fibrillation ablation using cryoballoon. Rotational angiography was performed to get the three-dimensional left atrial and pulmonary vein reconstructions using cardiac C-arm computed tomography. The image reconstruction was made using the DynaCT Cardiac software (Siemens, Erlangen, Germany). The mean age of the study population was 61 ± 10 years. The indications for left atrial arrhythmia ablation were paroxysmal AF in 140 patients (52%) and persistent AF patients in 131 (48%) patients. The success rate of TSP using only rotational guidance was (264/271 patients, 97.4%). In the remaining seven patients, transesophageal guidance was used after the initial attempt due to thick interatrial septum in five patients and difficult TSP due to abnormal anatomy and mild pericardial effusion in the remaining two patients. Mean fluoroscopy dosage of the rotational angiography was 4896.4 ± 825.3 μGym(2). The mean time beginning from femoral vein puncture to TSP was 12.3 ± 5.5 min. TSP guided by rotational angiography is a safe and effective method. Our results indicate that integration of rotational angiographic images into the real-time fluoroscopy can guide the TSP during the procedure. © 2015 John Wiley & Sons Ltd.

  13. 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 ...

  14. 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. ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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 ( ...

  20. 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. ...

  1. 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 ...

  2. 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 ...

  3. X-ray

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    ... 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 ...

  4. 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 ...

  5. 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 ...

  6. 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. ...

  7. Chest X-Ray

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    Full Text Available ... posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Coronary CT Angiography Video: Myelography Video: CT ... posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Coronary CT Angiography Video: Myelography Video: CT ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. 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 ...

  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. ... Media Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to X-ray (Radiography) - ...

  13. 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 ...

  14. 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 ...

  15. [Clinical applications of synchrotron radiation X-ray].

    Science.gov (United States)

    Uyama, C

    1994-09-01

    Synchrotron Radiation X-ray (SR X-ray) is an extremely strong X-ray source with a photon number more than 10(4) compared with that of the current X-ray tube. X-rays obtained by monochromatizing SR X-ray have been applied to new techniques for medical diagnosis. Several studies are now being conducted at the beam site for medical use at the Accumulation Ring of the High Energy Physics Research Institute, Tsukuba. Applications being studied include (1) energy subtraction coronary angiography. (2) microdetection of metas in samples excised from subjects. (3) monochromatic X-ray computed tomography and so on. Energy subtraction coronary angiography might have a safety advantage over the current selective coronary angiography. Microdetection of mandatory metals and poisonous heavy metals in in vivo samples contributes to the development of pathologic knowledge and clinical treatment of cancer and heavy metal toxications. Monochromatic X-ray CT is expected to detect diseases in the early stage due to increased accuracy in CT values.

  16. Flow prediction in cerebral aneurysms based on geometry reconstruction from 3D rotational angiography

    NARCIS (Netherlands)

    Mikhal, Julia Olegivna; Kroon, Dirk-Jan; Slump, Cornelis H.; Geurts, Bernardus J.

    We present an immersed boundary (IB) method for the simulation of steady blood flow inside a realistic cerebral aneurysm. We reconstruct a segment of the cerebrovascular system that contains an aneurysm, by using medical images obtained with three dimensional rotational angiography (3DRA). The main

  17. Three-dimensional rotational angiography in children with an aortic coarctation

    NARCIS (Netherlands)

    Starmans, N L P; Krings, G J; Molenschot, M M C; van der Stelt, Femke; Breur, J M P J

    2016-01-01

    BACKGROUND: Children with aortic coarctations (CoA) are increasingly percutaneously treated. Good visualisation of the CoA is mandatory and can be obtained with three-dimensional rotational angiography (3DRA). This study aims to compare the diagnostic and therapeutic additional value of 3DRA with

  18. 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

  19. Locking of iridium magnetic moments to the correlated rotation of oxygen octahedra in Sr2IrO4 revealed by x-ray resonant scattering

    DEFF Research Database (Denmark)

    Boseggia, S.; Walker, H. C.; Vale, J.

    2013-01-01

    .8(1)° of the oxygen octahedra that characterizes its distorted layered perovskite structure. Using x-ray resonant scattering at the Ir L3 edge we have measured accurately the intensities of Bragg peaks arising from different components of the magnetic structure. From a careful comparison of integrated intensities...

  20. X-ray emission from normal stars

    Science.gov (United States)

    Rosner, Robert

    1990-01-01

    The paper addresses the potential for future X-ray missions to determine the fundamental cause of stellar X-ray emissions based on available results and existing analyses. The determinants of stellar X-ray emission are listed, and the relation of stellar X-ray emissions to the 'universal' activity-rotation connection is discussed. The specific rotation-activity connection for evolved stars is mentioned, and the 'decay' of stellar activity at the low-mass end of the main sequence is related to observational data. The data from Einstein and EXOSAT missions that correspond to these issues are found to be sparse, and more observational work is found to be necessary. Also, it is concluded that some issues need to be addressed, such as the X-ray dividing line in evolved stars and the absence of X-ray emission from dA stars. The related observational requirements and instrumental capabilities are given for each significant research focus.

  1. Nonvariceal Upper Gastrointestinal Bleeding: the Usefulness of Rotational Angiography after Endoscopic Marking with a Metallic Clip

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ji Soo; Kwak, Hyo Sung; Chung, Gyung Ho [Chonbuk National University Medical School, Chonju (Korea, Republic of)

    2011-08-15

    We wanted to assess the usefulness of rotational angiography after endoscopic marking with a metallic clip in upper gastrointestinal bleeding patients with no extravasation of contrast medium on conventional angiography. In 16 patients (mean age, 59.4 years) with acute bleeding ulcers (13 gastric ulcers, 2 duodenal ulcers, 1 malignant ulcer), a metallic clip was placed via gastroscopy and this had been preceded by routine endoscopic treatment. The metallic clip was placed in the fibrous edge of the ulcer adjacent to the bleeding point. All patients had negative results from their angiographic studies. To localize the bleeding focus, rotational angiography and high pressure angiography as close as possible to the clip were used. Of the 16 patients, seven (44%) had positive results after high pressure angiography as close as possible to the clip and they underwent transcatheter arterial embolization (TAE) with microcoils. Nine patients without extravasation of contrast medium underwent TAE with microcoils as close as possible to the clip. The bleeding was stopped initially in all patients after treatment of the feeding artery. Two patients experienced a repeat episode of bleeding two days later. Of the two patients, one had subtle oozing from the ulcer margin and that patient underwent endoscopic treatment. One patient with malignant ulcer died due to disseminated intravascular coagulation one month after embolization. Complete clinical success was achieved in 14 of 16 (88%) patients. Delayed bleeding or major/minor complications were not noted. Rotational angiography after marking with a metallic clip helps to localize accurately the bleeding focus and thus to embolize the vessel correctly.

  2. 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

  3. 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 ...

  4. 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 ...

  5. X-Rays from Saturn and its Rings

    Science.gov (United States)

    Bhardwaj, Anil; Elsner, Ron F.; Waite, J. Hunter; Gladstone, G. Randall; Cravens, Tom E.; Ford, Peter G.

    2005-01-01

    In January 2004 Saturn was observed by Chandra ACIS-S in two exposures, 00:06 to 11:00 UT on 20 January and 14:32 UT on 26 January to 01:13 UT on 27 January. Each continuous observation lasted for about one full Saturn rotation. These observations detected an X-ray flare from the Saturn's disk and indicate that the entire Saturnian X-ray emission is highly variable -- a factor of $\\sim$4 variability in brightness in a week time. The Saturn X-ray flare has a time and magnitude matching feature with the solar X-ray flare, which suggests that the disk X-ray emission of Saturn is governed by processes happening on the Sun. These observations also unambiguously detected X-rays from Saturn's rings. The X-ray emissions from rings are present mainly in the 0.45-0.6 keV band centered on the atomic OK$\\alpha$ fluorescence line at 525 eV: indicating the production of X-rays due to oxygen atoms in the water icy rings. The characteristics of X-rays from Saturn's polar region appear to be statistically consistent with those from its disk X-rays, suggesting that X-ray emission from the polar cap region might be an extension of the Saturn disk X-ray emission.

  6. 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 ...

  7. 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, ...

  8. 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) ...

  9. 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 ...

  10. 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.

  11. Three-dimensional rotational angiography of the foot in critical limb ischemia: a new dimension in revascularization strategy

    NARCIS (Netherlands)

    Jens, Sjoerd; Lucatelli, Pierleone; Koelemay, Mark J. W.; Marquering, Henk A.; Reekers, Jim A.

    2013-01-01

    To evaluate the additional value of three-dimensional rotational angiography (3DRA) of the foot compared with digital subtraction angiography (DSA) in patients with critical limb ischemia (CLI). For 3DRA, the C-arm was placed in the propeller position with the foot in an isocentric position. The

  12. 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.

  13. Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation

    NARCIS (Netherlands)

    R. Rodríguez-Olivares (Ramón); N. El Faquir (Nahid); Z. Rahhab (Zouhair); A.M. Maugenest; N.M. van Mieghem (Nicolas); C. Schultz (Carl); G. Lauritsch (Guenter); P.P.T. de Jaegere (Peter)

    2016-01-01

    textabstractTo study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including

  14. Kinematic X-Ray Analysis Apparatus

    NARCIS (Netherlands)

    Koningsberger, D.C.; Brinkgreve, P.

    1983-01-01

    In an X-ray analysis apparatus, a moving mechanism is provided by a main guide member along which a main slide device can be displaced. Rotatably connected with the main slide device is a detector guide member along which a detection slide device is displaced. The main slide device, as well as the

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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.

  20. 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 ...

  1. 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 ...

  2. 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 ( ...

  3. 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 ...

  4. 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? ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures ...

  5. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  12. 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 ...

  13. Comparison of a safety strategy using transradial access and dual-axis rotational coronary angiography with transfemoral access and standard coronary angiography.

    Science.gov (United States)

    Yasar, Ayse S; Perino, Alexander C; Dattilo, Philip B; Casserly, Ivan P; Carroll, John D; Messenger, John C

    2013-10-01

    We sought to investigate the radiation exposure and contrast utilization associated with using a strategy of transradial access and rotational angiography (radial-DARCA) compared to the traditional approach of transfemoral access and standard angiography (femoral-SA). There is an increased focus on optimizing patient safety during cardiac catheterization procedures. Professional guidelines have highlighted physician responsibility to minimize radiation doses and contrast volume. Dual axis rotational coronary angiography (DARCA) is the most recently investigated type of rotational angiography. This new technique permits complete visualization of the left or right coronary tree with a single injection, and is felt to reduce contrast and radiation exposure. A total of 56 consecutive patients who underwent radial-DARCA were identified. From the same time period, an age- and gender-matched group of 61 patients who had femoral-SA were selected for comparison. Total volume of contrast agent used, fluoroscopy time, and 2 measures of radiation dose (dose area product and air kerma) were recorded for each group. Mean contrast agent use and patient radiation exposure of the radial-DARCA group were significantly less than that of the femoral-SA group. There was no significant difference in fluoroscopy time between the 2 groups. Physicians can successfully employ an innovative safety strategy of transradial access combined with DARCA that is feasible and is associated with lower radiation doses and contrast volume than femoral artery access and traditional coronary angiography approach. © 2013, Wiley Periodicals, Inc.

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. Development of real-time x-ray microtomography system

    Science.gov (United States)

    Takano, H.; Morikawa, M.; Konishi, S.; Azuma, H.; Shimomura, S.; Tsusaka, Y.; Nakano, S.; Kosaka, N.; Yamamoto, K.; Kagoshima, Y.

    2013-10-01

    We have developed a four-dimensional (4D) x-ray microcomputed tomography (CT) system that can obtain time-lapse CT volumes in real time. The system consists of a high-speed sample rotation system and a high-frame-rate x-ray imager, which are installed at a synchrotron radiation x-ray beamline. As a result of system optimization and introduction of a "zoom resolution" procedure, a real-time 4D CT movie with a frame rate of 30 was obtained with a voxel size of 2.5 μm using 10 keV x-rays.

  18. 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.

  19. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a regular x-ray ... any possibility that they are pregnant. See the Safety page for more information about pregnancy and x- ...

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... your radiologist may advise that you take special medication for 24 hours before catheter angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast material injection. If a large amount of x-ray contrast ...

  1. A versatile three/four crystal X-ray diffractometer for X-ray optical elements: Performance and applications

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Jacobsen, E.

    1987-01-01

    A versatile X-ray diffractometer for the study of X-ray optical elements such as grazing incidence mirrors, crystals and X-ray gratings has been built and put into operation at the Danish Space Research Institute. The diffractrometer is built on a 1.5 m long granite bench with the X-ray source...... located at one end of the bench where it can be rotated around a fixed vertical axis. The beam defining elements are perfect crystals of Si, Ge or quartz. With these it is possible to define a highly collimated beam of a few arcsec fwhm in the scattering plane. Examples of measurements on various X...

  2. Chest X-Ray

    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 ... Awareness Month Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Coronary CT Angiography Video: ...

  3. Evaluation of angiograms obtained from a laser-based x-ray source in DESA regime

    Science.gov (United States)

    Scalzetti, Ernest M.; Krol, Andrzej; Gagne, George M.; Renvyle, Ted T.; Chamberlain, Charles C.; Kieffer, Jean-Claude; Jiang, Zhiming; Yu, Jianfan

    1999-05-01

    Contrast resolution of angiograms created using a laser-based x-ray source in Dual Energy Subtraction Angiography (DESA) regime has been investigated. It has been compared to contrast in angiograms obtained using an x-ray tube-based clinical angiography unit in DSA mode. Contrast detail phantoms and rats with opacified vascular structures were imaged. A table top terawatt laser was used (1019 Wcm-2, 150 fs or 450 fs per pulse). For Iodine contrast agent, an Iodine filter was used with the BaF2 target to obtain images with mean x-rays energy below the Iodine K-edge. La target and La filter was used to obtain images with mean x-rays energy above the Iodine K-edge. For Ba contrast agent, a Nd filter was used with the Nd target to obtain images with mean x-rays energy below the Ba K-edge. Gd target and Nd filter was used to obtain images with mean x-rays energy above the Barium K-edge. It has been determined that the laser-based DESA with properly selected targets demonstrates better contrast than a standard x-ray tube-based DSA angiography. We conclude that laser-based x-ray source has promise for angiography in DESA regime providing that sufficient x-ray flux can be delivered by the laser.

  4. 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.

  5. High Brightness Electron Gun for X-Ray Source

    CERN Document Server

    Ohsawa, Satoshi; Ikeda, Mitsuo; Kanno, K; Sugimura, Takashi; Tawada, Masafumi

    2005-01-01

    A new electron-gun system is under development in order to increase X-ray from a rotating target. In commercial X-ray sources electron beams usually hit targets at the outer part. Owing to deformation by centrifugal force, there has been a limit on electron beam intensities. In order to overcome this difficulty, we adopted a new injection system which strikes inside of a ring-shape projection on a rotating target. It has an advantage in that heated-up points have supports back side against centrifugal force. This merit allows us to raise electron beam to give stronger X-rays.

  6. Dose comparison of classical 2-plane DSA and 3D rotational angiography for the assessment of intracranial aneurysms.

    Science.gov (United States)

    Guberina, N; Lechel, U; Forsting, M; Mönninghoff, C; Dietrich, U; Ringelstein, A

    2016-07-01

    The purpose of this experimental phantom study was to compare radiation doses imparted to patients undergoing classical two-plane digital subtraction angiography (2-plane DSA) and 3D rotational angiography in interventional neuroradiology. Thermoluminescence dosimeter (TLD) measurements were performed at an anthropomorphic phantom using a digital interventional angiography system. Two-plane DSA included posterior/anterior (PA) and lateral (LAT) projections (frame-rate, 7.6 frames (PA) and 9.8 frames (LAT) for a scan time of approximately 8 s; image intensifier 27 cm (PA) and 25 cm (LAT)). For 3D rotational angiography, 122 images were acquired from one single image run with the imaging system rotating 240° around the phantom's head (image intensifier 37 cm). Effective dose was 0.4 mSv for 2-plane DSA compared to 0.1 mSv for 3D rotational angiography. Organ doses were approximately two to five times higher for classical 2-plane technique compared to the 3D rotational angiography, respectively: brain (11.4 vs. 2.4 mSv), eye lens (4.5 vs.1 mSv), salivary glands (7 vs. 1,7 mSv), oral mucosa (2.7 vs.0.9 mSv), thyroid (0.5 vs. 0.2 mSv), thymus (0.2 vs. 0.05 mSv), bone marrow within imaged region (1 vs. 0.2 mSv), oesophagus (0.07 vs. 0.03 mSv), endotracheal system (2.6 vs. 0.7 mSv) and skeletal components in the imaged region (0.7 vs. 0.2 mSv). Three-dimensional rotational angiography clearly reduces radiation doses compared to the classical 2-plane technique. Replacement of additional 2-plane DSA projections with 3D rotational angiography will lead to a remarkable decrease in patient radiation dose, without loss of image quality. Thus, we recommend routine application of 3D rotational angiography, in particular for diagnostic assessment of aneurysm morphology.

  7. 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.

  8. 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.

  9. 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.

  10. 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 ...

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. 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.

  15. 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, ...

  16. 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? ...

  17. A CCD area detector for X-ray diffraction under high pressure for ...

    Indian Academy of Sciences (India)

    Details of a two-dimensional X-ray area detector developed using a charge coupled device, a image intensifier and a fibre optic taper are given. The detector system is especially optimized for angle dispersive X-ray diffraction set up using rotating anode generator as X-ray source. The performance of this detector was ...

  18. A CCD area detector for X-ray diffraction under high pressure for ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Details of a two-dimensional X-ray area detector developed using a charge coupled device, a image intensifier and a fibre optic taper are given. The detector system is especially optimized for angle dispersive X-ray diffraction set up using rotating anode generator as X-ray source. The performance of this detector ...

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang; Goeler, Schweickhard von

    1999-05-01

    Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.

  1. 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...

  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. 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

  4. X-ray diffraction with novel geometry

    Energy Technology Data Exchange (ETDEWEB)

    Prokopiou, Danae [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Rogers, Keith, E-mail: k.d.rogers@cranfield.ac.uk [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Evans, Paul; Godber, Simon [Imaging Science Group, School of Science and Technology, Nottingham Trent University Clifton Campus, Nottingham (United Kingdom); Shackel, James [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Dicken, Anthony [Imaging Science Group, School of Science and Technology, Nottingham Trent University Clifton Campus, Nottingham (United Kingdom)

    2014-01-21

    An innovative geometry for high efficiency harvesting of diffracted X-rays is explored. Further to previous work where planar samples were fixed normal to the primary axis, this work extends focal construct geometry (FCG), to samples randomly oriented with respect to the incident beam. The effect of independent sample rotation around two axes upon the scattering distributions was investigated in analytical, simulation and empirical manners. It was found that, although the profile of Bragg maxima were modified when the sample was rotated, high intensity diffraction data was still acquired. Modelling produced a good match to the empirical data and it was shown that the distortions caused by sample rotation were not severe and predictable even when sample rotations were large. The implications for this are discussed.

  5. 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 ...

  6. 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...

  7. 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 ...

  8. 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 ...

  9. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  10. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  11. 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 ...

  12. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  13. 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? ... examination may also be necessary so that any change in a known abnormality can be monitored over ...

  14. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  15. 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 ... taken of the unaffected limb, or of a child's growth plate (where new bone is forming), for ...

  16. 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 ...

  17. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  18. 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, ... CT Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology ...

  19. Bone X-Ray (Radiography)

    Medline Plus

    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. ...

  20. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  1. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  2. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  3. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  4. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  5. 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? ... procedure varies. See the Safety page for more information about radiation dose. Women should always inform their ...

  6. 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 ... little information about muscles, tendons or joints. An MRI may be more useful in identifying bone and ...

  7. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  8. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  9. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  10. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  11. Bone X-Ray (Radiography)

    Medline Plus

    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. ...

  12. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  13. 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 ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  14. Bone X-Ray (Radiography)

    Medline Plus

    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, ...

  15. 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 ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  16. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  17. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  18. 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 ... to view and assess bone fractures, injuries and joint abnormalities. This exam requires little to no special ...

  19. 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? ... information you were looking for? Yes No Please type your comment or suggestion into the following text ...

  20. 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 parts of the body absorb the x-rays in varying degrees. Dense ...

  1. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  2. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  3. Bone X-Ray (Radiography)

    Medline Plus

    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. ...

  4. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  5. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  6. X-rays from Magnetic B-type Stars

    Science.gov (United States)

    Fletcher, Corinne; Petit, Véronique; Caballero-Nieves, Saida Maria; Nazé, Yaël; Owocki, Stan; Wade, Gregg; Cohen, David; Townsend, Richard; David-Uraz, Alexandre; Shultz, Matt

    2018-01-01

    Recent surveys have found that ~10% of OB-type stars host strong (~1kG), mostly dipolar magnetic fields. The prominent idea describing the interaction between the stellar winds and the magnetic field is the magnetically confined wind shock model. In this model, the ionized wind material is forced to move along the closed magnetic field loops and collides at the magnetic equator creating a shock. As the shocked material cools radiatively it will emit X-rays. Therefore, X-ray spectroscopy is a key tool in detecting and characterizing the wind material confined by the magnetic fields of these stars. Some of these magnetic B-type stars are found to have very short rotational periods. The effects of the rapid rotation on the X-ray production within the magnetosphere have yet to be explored in detail. The added centrifugal force is predicted to cause faster wind outflows along the field lines, which could lead to higher shock temperatures and harder X-rays. However, this is not observed in all rapidly rotating magnetic B-type stars. In order to address this question from a theoretical point of view, we use the X-ray Analytical Dynamical Magnetosphere model, developed for slow rotators and implement the physics of rapid rotation. Using X-ray spectroscopy from ESA’s XMM-Newton space telescope, we observed 5 rapidly rotating B-types stars to add to the previous list of observations. Comparing the observed X-ray luminosity and hardness ratio to that predicted by the XADM allows us to determine the role an added centrifugal acceleration plays in the magnetospheres of these stars.

  7. 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)

  8. 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.

  9. 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 ...

  10. 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.

  11. Three-dimensional rotational angiography in children with an aortic coarctation.

    Science.gov (United States)

    Starmans, N L P; Krings, G J; Molenschot, M M C; van der Stelt, F; Breur, J M P J

    2016-11-01

    Children with aortic coarctations (CoA) are increasingly percutaneously treated. Good visualisation of the CoA is mandatory and can be obtained with three-dimensional rotational angiography (3DRA). This study aims to compare the diagnostic and therapeutic additional value of 3DRA with conventional biplane angiography (CA) in children with a CoA. Patients undergoing percutaneous treatment of CoA with balloon angioplasty (BA) or stent between 2003 and 2015, were retrospectively reviewed on success rate, complications, radiation and technical settings. Diagnostic quality of CA and 3DRA and additional value of 3DRA were scored. In total, 134 patients underwent 183 catheterisations, 121 CA and 62 3DRA-guided. Median age was 0.52 years in the BA group and 11.19 years in the stent group. 3DRA was superior to CA in displaying the left ventricle (p = 0.008), ascending aorta (p success rate than CA (100.0 % versus 68.9 %, p = 0.016). All stent interventions were successful. Complication rates did not differ significantly. The median total dose area product did not significantly differ between CA and 3DRA in the BA (27.88 μGym(2)/kg versus 15.81 μGym(2)/kg, p = 0.275) or stent group (37.34 μGym(2)/kg versus 45.24 μGym(2)/kg, p = 0.090). 3DRA was of additional value in 96.8 % of the interventions. 3DRA is superior to CA in diagnostic quality and not associated with increased radiation exposure. It provides high additional value in guiding CoA related interventions.

  12. The exposure of radiologists and patients to radiation during coronary angiography and percutaneous transluminal coronary angioplasty (PTCA). The performance of cine x-ray equipment and film processing; Saeteilyaltistus sydaenangiografiatutkimuksissa ja kineangiografialaitteiden toimintakunto

    Energy Technology Data Exchange (ETDEWEB)

    Karppinen, J.; Parviainen, T.

    1993-03-01

    The exposure of radiologists and patients to radiation during coronary angiography and percutaneous transluminal coronary angioplasty (PTCA) in Finland was studied using phantom measurements. Additional tests were made concerning the performance of TV fluoroscopy systems, cine fluorographic units and film processing. These tests include sensitometric quality control of film processing, automatic exposure control in fluoroscopy and cinefluorography, and contrast and resolution in a cine frame and TV image.

  13. Description of a transmission X-ray computed tomography scanner

    Energy Technology Data Exchange (ETDEWEB)

    Hamideen, M.S., E-mail: mhamideen@fet.edu.jo [Department of Applied Science, Faculty of Engineering Technology, Al-Balqa' Applied University, Amman (Jordan); Sharaf, J.; Al-Saleh, K.A. [Department of Physics, University of Jordan, Amman (Jordan); Shaderma, M. [Department of Applied science, Faculty of Prince Abdullah bin Ghazi, Al-Balqa' Applied University, Amman (Jordan)

    2011-11-15

    A new prototype X-ray computed tomography scanner has been designed, constructed and tested locally. The major system employs an X-ray tube, a semiconductor detector, data logger and a three-dimensional sample position controller driven by three stepping motors, which allow two linear translations in addition to the rotational motion. The image resolution is determined by the step size and the diameter of the X-ray beam, which is controlled by the pinhole collimator. The scanner is designed to reconstruct two- and three-dimensional images mapping the internal structures of the object with the aid of the computer. This system, due to the semiconductor detector used, presents the novelty of being potentially able to acquire both in CT (transmission) mode and in SPECT (emission) mode. The imaging system performance is inspected for different phantoms, and some typical reconstructed images are presented. - Highlights: > A prototype X-ray transmission CT scanner system was designed and constructed successfully at the X-ray Laboratory in the University of Jordan. > X-ray CT scanner demonstrated its capability as a non-destructive tool for evaluating the internal atomic details of material objects. > Some general problems of X-ray CT scanning and image reconstruction are discussed and some suggested solutions are presented. > Scanner is designed to reconstruct two- and three-dimensional images mapping the internal structures of the object with the aid of the computer. > Internal geometrical structure can be determined from CT images.

  14. 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

    : Improvements in the readout speed and energy resolution of X-ray detectors are essential to enable chemically sensitive microscopies. Advances would make it possible to take images with simultaneous spatial and chemical information. Very high-energy-resolution X-ray detectors: The energy resolution of semiconductor detectors, while suitable for a wide range of applications, is far less than what can be achieved with X-ray optics. A direct detector that could rival the energy resolution of optics could dramatically improve the efficiency of a multitude of experiments, as experiments are often repeated at a number of different energies. Very high-energy-resolution detectors could make these experiments parallel, rather than serial. Low-background, high-spatial-resolution neutron detectors: Low-background detectors would significantly improve experiments that probe excitations (phonons, spin excitations, rotation, and diffusion in polymers and molecular substances, etc.) in condensed matter. Improved spatial resolution would greatly benefit radiography, tomography, phase-contrast imaging, and holography. Improved acquisition and visualization tools: In the past, with the limited variety of slow detectors, it was straightforward to visualize data as it was being acquired (and adjust experimental conditions accordingly) to create a compact data set that the user could easily transport. As detector complexity and data rates explode, this becomes much more challenging. Three goals were identified as important for coping with the growing data volume from high-speed detectors: Facilitate better algorithm development. In particular, algorithms that can minimize the quantity of data stored. Improve community-driven mechanisms to reduce data protocols and enhance quantitative, interactive visualization tools. Develop and distribute community-developed, detector-specific simulation tools. Aim for parallelization to take advantage of high-performance analysis platforms. Improved analysis

  15. Microfocus/Polycapillary-Optic Crystallographic X-Ray System

    Science.gov (United States)

    Joy, Marshall; Gubarev, Mikhail; Ciszak, Ewa

    2005-01-01

    A system that generates an intense, nearly collimated, nearly monochromatic, small-diameter x-ray beam has been developed for use in macromolecular crystallography. A conventional x-ray system for macromolecular crystallography includes a rotating-anode x-ray source, which is massive (.500 kg), large (approximately 2 by 2 by 1 m), and power-hungry (between 2 and 18 kW). In contrast, the present system generates a beam of the required brightness from a microfocus source, which is small and light enough to be mounted on a laboratory bench, and operates at a power level of only tens of watts. The figure schematically depicts the system as configured for observing x-ray diffraction from a macromolecular crystal. In addition to the microfocus x-ray source, the system includes a polycapillary optic . a monolithic block (typically a bundle of fused glass tubes) that contains thousands of straight or gently curved capillary channels, along which x-rays propagate with multiple reflections. This particular polycapillary optic is configured to act as a collimator; the x-ray beam that emerges from its output face consists of quasi-parallel subbeams with a small angular divergence and a diameter comparable to the size of a crystal to be studied. The gap between the microfocus x-ray source and the input face of the polycapillary optic is chosen consistently with the focal length of the polycapillary optic and the need to maximize the solid angle subtended by the optic in order to maximize the collimated x-ray flux. The spectrum from the source contains a significant component of Cu K (photon energy is 8.08 keV) radiation. The beam is monochromatized (for Cu K ) by a nickel filter 10 m thick. In a test, this system was operated at a power of 40 W (current of 897 A at an accelerating potential of 45 kV), with an anode x-ray spot size of 41+/-2 microns. Also tested, in order to provide a standard for comparison, was a commercial rotating-anode x-ray crystallographic system with a

  16. Parabolic refractive X-ray lenses: a breakthrough in X-ray optics

    CERN Document Server

    Lengeler, B; Benner, B; Guenzler, T F; Kuhlmann, M; Tümmler, J; Simionovici, A S; Drakopoulos, M; Snigirev, A; Snigireva, I

    2001-01-01

    Refractive X-ray lenses, considered for a long time as unfeasible, have been realized with a rotational parabolic profile at our institute: The main features of the new lenses are: they focus in two directions and are free of spherical aberration. By varying the number of individual lenses in the stack the focal length can be chosen in a typical range from 0.5 to 2 m for photon energies between about 6 and 60 keV. The aperture of the lens is about 1 mm matching the angular divergence of undulator beams at 3d generation synchrotron radiation sources. They cope without problems with the heat load from the white beam of an undulator. Finally, they are easy to align and to operate. Refractive X-ray lenses can be used with hard X-rays in the same way as glass lenses can be used for visible light, if it is take into account that the numerical aperture is small (of the order 10 sup - sup 4). Being high-quality optical elements, the refractive X-ray lenses can be used for generating a focal spot in the mu m range wit...

  17. 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.

  18. 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.

  19. Do we see accreting magnetars in X-ray pulsars?

    Directory of Open Access Journals (Sweden)

    Postnov K.A.

    2014-01-01

    Full Text Available Strong magnetic field of accreting neutron stars (1014 G is hard to probe by Xray spectroscopy but can be indirectly inferred from spin-up/spin-down measurement in X-ray pulsars. The existing observations of slowly rotating X-ray pulsars are discussed. It is shown that magnetic fields of neutron stars derived from these observations (or lower limits in some cases fall within the standard 1012-1013 G range. Claims about the evidence for accreting magnetars are critically discussed in the light of recent progress in understanding of accretion onto slowly rotating neutron stars in the subsonic regime.

  20. X-ray monochromator for divergent beam radiography using conventional and laser-produced x-ray sources

    Science.gov (United States)

    Schnopper, Herbert W.; Romaine, Suzanne E.; Krol, Andrzej

    2001-12-01

    We discuss technology that will produce a wide angle monochromatic beam of X-rays that appears to diverge from a virtual point source. Although our ideas are discussed in the context of dual energy subtraction angiography (DESA) that we are developing to operate in a clinical setting, they are widely adaptable to all applications of x-ray radiography. The best DESA analysis is obtained from X-ray images made in narrow energy bands just below and just above the I K-absorption edge. Our monochromator will be used to isolate these narrow bands to produce high contrast, high spatial resolution, ECG gated angiographic images. Emission lines, that have X-ray energies below (E-) and above (E+) the I K-absorption edge at 33.2 keV, are readily available. We have deposited variable d-spacing artificial crystals, called multilayers, on optically flat, very smooth substrates, to create narrow pass band X-ray monochromators centered on La and Ba K-emission lines. We will record (E-) and (E+) exposures on either photographic plates or, in the future, with energy sensitive pixelated arrays of solid state detectors. After a suitable normalization, the exposures will be subtracted to yield a high resolution, high contrast image of the I filled arteries. Although initial results will be obtained with conventional X-ray tubes, our goal is to couple the monochromators to a high intensity, laser produced, X-ray plasma. We will present early test data that shows the multilayer performance.

  1. 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. ...

  2. 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 ...

  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 ... to current x-ray images for diagnosis and disease management. top of page How is the procedure ...

  4. 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 ...

  5. 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 ...

  6. 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.

  7. 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 ...

  8. 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.

  9. 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 ...

  10. 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 ...

  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. 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- ...

  13. 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 ...

  14. 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 ...

  15. 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 ...

  16. 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

  17. 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.

  18. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Nazé, Yaël [GAPHE, Département AGO, Université de Liège, Allée du 6 Août 17, Bat. B5C, B-4000 Liège (Belgium); Petit, Véronique [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States); Rinbrand, Melanie; Owocki, Stan [Department of Physics and Astronomy, University of Delaware, Bartol Research Institute, Newark, DE 19716 (United States); Cohen, David [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Ud-Doula, Asif [Penn State Worthington Scranton, Dunmore, PA 18512 (United States); Wade, Gregg A., E-mail: naze@astro.ulg.ac.be [Department of Physics, Royal Military College of Canada, PO Box 17000, Station Forces, Kingston, ON K7K 4B4 (Canada)

    2014-11-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.

  19. Effective X-ray beam size measurements of an X-ray tube and polycapillary X-ray lens system using a scanning X-ray fluorescence method

    Energy Technology Data Exchange (ETDEWEB)

    Gherase, Mihai R., E-mail: mgherase@csufresno.edu; Vargas, Andres Felipe

    2017-03-15

    Size measurements of an X-ray beam produced by an integrated polycapillary X-ray lens (PXL) and X-ray tube system were performed by means of a scanning X-ray fluorescence (SXRF) method using three different metallic wires. The beam size was obtained by fitting the SXRF data with the analytical convolution between a Gaussian and a constant functions. For each chemical element in the wire an effective energy was calculated based on the incident X-ray spectrum and its photoelectric cross section. The proposed method can be used to measure the effective X-ray beam size in XRF microscopy studies.

  20. The Bragg solar x-ray spectrometer SolpeX

    Science.gov (United States)

    Ścisłowski, D.; Sylwester, J.; Steślicki, M.; Płocieniak, S.; Bąkała, J.; Szaforz, Ż.; Kowaliński, M.; Podgórski, P.; Trzebiński, W.; Hernandez, J.; Barylak, J.; Barylak, A.; Kuzin, Sergey

    2015-09-01

    Detection of polarization and spectra measurement of X-ray solar flare emission are indispensable in improving our understanding of the processes releasing energy of these most energetic phenomena in the solar system. We shall present some details of the construction of SolpeX - an innovative Bragg soft X-ray flare polarimeter and spectrometer. The instrument is a part of KORTES - Russian instrument complex to be mounted aboard the science module to be attached to the International Space Station (2017/2018). The SolpeX will be composed of three individual measuring units: the soft X-ray polarimeter with 1-2% linear polarization detection threshold, a fast-rotating flat crystal X-ray spectrometer with a very high time resolution (0.1 s) and a simple pinhole soft X-ray imager-spectrometer with a moderate spatial (~20 arcsec), spectral (0.5 keV) and high time resolution (0.1 s). Having a fast rotating unit to be served with power, telemetry and "intelligence" poses a challenge for the designer. Some of the solutions to this will be provided and described.

  1. X-Ray structural investigation of VAS-393 crystals

    CERN Document Server

    Martirosian, A H; Harurtjunian, V S

    2001-01-01

    X-ray structural study of VAS-393 crystals was performed. Investigations were carried out with the use of the Weissenberg rotating and powder (employing the Bjornstrem diagrams) methods. The lattice constants ''c'' and ''a''are calculated. The crystal is shown to belong to the trigonal syngony (medium category)

  2. Diffractive X-ray Telescopes

    OpenAIRE

    Skinner, Gerald K

    2010-01-01

    Diffractive X-ray telescopes using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution several orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted space- time in the immediate vicinity of the super...

  3. Einstein X-ray survey of the Pleiades - The dependence of X-ray emission on stellar age

    Science.gov (United States)

    Micela, G.; Sciortino, S.; Serio, S.; Vaiana, G. S.; Bookbinder, J.; Golub, L.; Harnden, F. R., Jr.; Rosner, R.

    1985-01-01

    The data obtained with two pointed observations of 1 deg by 1 deg fields of the Pleiades region have been analyzed, and the results are presented. The maximum-likelihood X-ray luminosity functions for the Pleiades G and K stars in the cluster are derived, and it is shown that, for the G stars, the Pleiades X-ray luminosity function is significantly brighter than the corresponding function for Hyades G dwarf stars. This finding indicates a dependence of X-ray luminosity on stellar age, which is confirmed by comparison of the same data with median X-ray luminosities of pre-main sequence and local disk population dwarf G stars. It is suggested that the significantly larger number of bright X-ray sources associated with G stars than with K stars, the lack of detection of M stars, and the relatively rapid rotation of the Pleiades K stars can be explained in terms of the onset of internal differential rotation near the convective envelope-radidative core interface after the spin-up phase during evolution to the main sequence.

  4. Localization of cardiac volume and patient features in inverse geometry x-ray fluoroscopy

    Science.gov (United States)

    Speidel, Michael A.; Slagowski, Jordan M.; Dunkerley, David A. P.; Wagner, Martin; Funk, Tobias; Raval, Amish N.

    2017-03-01

    The scanning-beam digital x-ray (SBDX) system is an inverse geometry x-ray fluoroscopy technology that performs real-time tomosynthesis at planes perpendicular to the source-detector axis. The live display is a composite image which portrays sharp features (e.g. coronary arteries) extracted from a 16 cm thick reconstruction volume. We present a method for automatically determining the position of the cardiac volume prior to acquisition of a coronary angiogram. In the algorithm, a single non-contrast frame is reconstructed over a 44 cm thickness using shift-and-add digital tomosynthesis. Gradient filtering is applied to each plane to emphasize features such as the cardiomediastinal contour, diaphragm, and lung texture, and then sharpness vs. plane position curves are generated. Three sharpness metrics were investigated: average gradient in the bright field, maximum gradient, and the number of normalized gradients exceeding 0.5. A model correlating the peak sharpness in a non-contrast frame and the midplane of the coronary arteries in a contrast-enhanced frame was established using 37 SBDX angiographic loops (64-136 kg human subjects, 0-30° cranial- caudal). The average gradient in the bright field (primarily lung) and the number of normalized gradients >0.5 each yielded peaks correlated to the coronary midplane. The rms deviation between the predicted and true midplane was 1.57 cm. For a 16 cm reconstruction volume and the 5.5-11.5 cm thick cardiac volumes in this study, midplane estimation errors of 2.25-5.25 cm were tolerable. Tomosynthesis-based localization of cardiac volume is feasible. This technique could be applied prior to coronary angiography, or to assist in isocentering the patient for rotational angiography.

  5. A MEMS-based high frequency x-ray chopper

    Energy Technology Data Exchange (ETDEWEB)

    Siria, A; Schwartz, W; Chevrier, J [Institut Neel, CNRS-Universite Joseph Fourier Grenoble, BP 166, F-38042 Grenoble Cedex 9 (France); Dhez, O; Comin, F [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble Cedex 9 (France); Torricelli, G [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  6. Science with a Thomson X-ray Polarimeter

    Science.gov (United States)

    Paul, Biswajit; R, Gopala Krishna M.; Puthiya Veetil, Rishin; Duraichelvan, R.; Maitra, Chandreyee

    We will describe the design, specifications, sensitivity, and development status of a Thomson X-ray polarimeter for a small satellite mission. The prime objectives of this instrument include both pulse phase averaged and pulse phase resolved polarisation measurement in accretion powered pulsars, accreting black holes in their hard and soft states, rotation powered pulsars and magnetars etc. This instrument will provide unprecedented opportunity for exploring X-ray polarisation in enregy range of 5-30 keV, in more than 50 sources with a minimum detectable linear polarisation degree of 2-3%.

  7. Optimized Volumetric Scanning for X-Ray Array Sources

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-29

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

  8. A MEMS-based high frequency x-ray chopper.

    Science.gov (United States)

    Siria, A; Dhez, O; Schwartz, W; Torricelli, G; Comin, F; Chevrier, J

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  9. Center for X-ray Optics, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source.

  10. X-Ray Exam: Scoliosis (For Parents)

    Science.gov (United States)

    ... for Educators Search English Español X-Ray Exam: Scoliosis KidsHealth / For Parents / X-Ray Exam: Scoliosis What's in this article? What It Is Why ... You Have Questions Print What It Is A scoliosis X-ray is a relatively safe and painless ...

  11. Techniques in X-ray Astronomy

    Indian Academy of Sciences (India)

    ray telescopes in space, leading to a veritable revolution. Stich telescopes require distortion free focusing of X-rays and the use of position sensitive X- ray detectors. In this article I shall describe the importance of X-ray imaging, the optical ...

  12. Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation.

    Science.gov (United States)

    Rodríguez-Olivares, Ramón; El Faquir, Nahid; Rahhab, Zouhair; Maugenest, Anne-Marie; Van Mieghem, Nicolas M; Schultz, Carl; Lauritsch, Guenter; de Jaegere, Peter P T

    2016-07-01

    To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3-5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3-9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2-5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0-1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality.

  13. Mutual control of X-rays and nuclear transitions

    Energy Technology Data Exchange (ETDEWEB)

    Gunst, Jonas Friedrich

    2015-12-14

    In the course of this Thesis the mutual control between X-rays and nuclear transitions is investigated theoretically. In the first Part, we study the nuclear photoexcitation with the highly brilliant and coherent X-ray free-electron lasers (XFELs). Apart from amplifying the direct resonant interaction with nuclear transitions, the super-intense XFEL can produce new states of matter like cold, high-density plasmas where secondary nuclear excitation channels may come into play, e.g., nuclear excitation by electron capture (NEEC). Our results predict that in the case of {sup 57}Fe targets secondary NEEC can be safely neglected, whereas it is surprisingly the dominating contribution (in comparison to the direct photoexcitation) for the XFEL-induced {sup 93m}Mo isomer triggering. Based on these case studies, we elaborate a general set of criteria to identify the prevailing excitation channel for a certain nuclear isotope. These criteria may be most relevant for future nuclear resonance experiments at XFEL facilities. On the opposite frontier, the interplay between single X-ray photons and nuclear transitions offer potential storage and processing applications for information science in their most compact form. In the second Part of this Thesis, we show that nuclear forward scattering off {sup 57}Fe targets can be employed to process polarization-encoded single X-rays via timed magnetic field rotations. Apart from the realization of logical gates with X-rays, the polarization encoding is used to design an X-ray quantum eraser scheme where the interference between scattering paths can be switched off and on in a controlled manner. Such setups may advance time-energy complementarity tests to so far unexplored parameter regimes, e.g., to the domain of X-ray quanta.

  14. Discovery of extended X-ray emission around the highly magnetic RRAT J1819-1458

    NARCIS (Netherlands)

    Rea, N.; McLaughlin, M.A.; Gaensler, B.M.; Slane, P.O.; Stella, L.; Reynolds, S.P.; Burgay, M.; Israel, G.L.; Possenti, A.; Chatterjee, S.

    2009-01-01

    We report on the discovery of extended X-ray emission around the high magnetic field rotating radio transient J1819-1458. Using a 30 ks Chandra ACIS-S observation, we found significant evidence for extended X-ray emission with a peculiar shape: a compact region out to similar to 5.'' 5, and more

  15. 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....

  16. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  17. NIKOLA TESLA AND THE X-RAY

    OpenAIRE

    Rade R. Babic

    2005-01-01

    After professor Wilhelm Konrad Röntgen published his study of an x-ray discovery (Academy Bulletin, Berlin, 08. 11. 1895.), Nikola Tesla published his first study of an x-ray on the 11th of March in 1896. (X-ray, Electrical Review). Until the 11th of August in 1897 he had published ten studies on this subject. All Tesla,s x-ray studies were experimental, which is specific to his work. Studying the nature of the x-ray, he established a new medical branch-radiology. He wrote:” There’s no doubt...

  18. X-ray Spectroscopy of Cooling Cluster

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-17

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

  19. Radiation exposure to operating staff during rotational flat-panel angiography and C-arm cone beam computed tomography (CT) applications.

    Science.gov (United States)

    Schulz, Boris; Heidenreich, Ralf; Heidenreich, Monika; Eichler, Katrin; Thalhammer, Axel; Naeem, Naguib Nagy Naguib; Vogl, Thomas Josef; Zangos, Stefan

    2012-12-01

    To evaluate the radiation exposure for operating personnel associated with rotational flat-panel angiography and C-arm cone beam CT. Using a dedicated angiography-suite, 2D and 3D examinations of the liver were performed on a phantom to generate scattered radiation. Exposure was measured with a dosimeter at predefined heights (eye, thyroid, breast, gonads and knee) at the physician's location. Analysis included 3D procedures with a field of view (FOV) of 24 cm × 18 cm (8s/rotation, 20s/rotation and 5s/2 rotations), and 47 cm×18 cm (16s/2 rotations) and standard 2D angiography (10s, FOV 24 cm×18 cm). Measurements showed the highest radiation dose at the eye and thyroid level. In comparison to 2D-DSA (3.9 μSv eye-exposure), the 3D procedures caused an increased radiation exposure both in standard FOV (8s/rotation: 28.0 μSv, 20s/rotation: 79.3 μSv, 5s/2 rotations: 32.5 μSv) and large FOV (37.6 μSv). Proportional distributions were measured for the residual heights. With the use of lead glass, irradiation of the eye lens was reduced to 0.2 μSv (2D DSA) and 10.6 μSv (3D technique with 20s/rotation). Rotational flat-panel angiography and C-arm cone beam applications significantly increase radiation exposure to the attending operator in comparison to 2D angiography. Our study indicates that the physician should wear protective devices and leave the examination room when performing 3D examinations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  20. Einstein X-ray observations of Herbig Ae/Be stars

    Science.gov (United States)

    Damiani, F.; Micela, G.; Sciortino, S.; Harnden, F. R., Jr.

    1994-01-01

    We have investigated the X-ray emission from Herbig Ae/Be stars, using the full set of Einstein Imaging Proportional Counter (IPC) observations. Of a total of 31 observed Herbig stars, 11 are confidently identified with X-ray sources, with four additonal dubious identifications. We have used maximum likelihood luminosity functions to study the distribution of X-ray luminosity, and we find that Be stars are significantly brighter in X-rays than Ae stars and that their X-ray luminosity is independent of projected rotational velocity v sin i. The X-ray emission is instead correlated with stellar bolometric luminosity and with effective temperature, and also with the kinetic luminosity of the stellar wind. These results seem to exclude a solar-like origin for the X-ray emission, a possibility suggested by the most recent models of Herbig stars' structure, and suggest an analogy with the X-ray emission of O (and early B) stars. We also observe correlations between X-ray luminosity and the emission at 2.2 microns (K band) and 25 microns, which strengthen the case for X-ray emission of Herbig stars originating in their circumstellar envelopes.

  1. Toward active x-ray telescopes II

    Science.gov (United States)

    O'Dell, Stephen L.; Aldcroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Rodriguez Sanmartin, Daniel; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2012-10-01

    In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the observation time required to achieve a given sensitivity has decreased by eight orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope, culminating with the exquisite subarcsecond imaging performance of the Chandra X-ray Observatory. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (technologically challenging—requiring precision fabrication, alignment, and assembly of large areas (x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes current progress toward active x-ray telescopes.

  2. On stellar X-ray emission

    Science.gov (United States)

    Rosner, R.; Golub, L.; Vaiana, G. S.

    1985-01-01

    Stellar X-ray astronomy represents an entirely new astronomical discipline which has emerged during the past five years. It lies at the crossroads of solar physics, stellar physics, and general astrophysics. The present review is concerned with the main physical problems which arise in connection with a study of the stellar X-ray data. A central issue is the extent to which the extrapolation from solar physics is justified and the definition (if possible) of the limits to such extrapolation. The observational properties of X-ray emission from stars are considered along with the solar analogy and the modeling of X-ray emission from late-type stars, the modeling of X-ray emission from early-type stars, the physics of stellar X-ray emission, stellar X-ray emission in the more general astrophysical context, and future prospects.

  3. 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.

  4. 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.

  5. 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.

  6. Diffractive X-Ray Telescopes

    Science.gov (United States)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  7. The X-ray corona of Procyon

    Science.gov (United States)

    Schmitt, J. H. M. M.; Harnden, F. R., Jr.; Rosner, R.; Peres, G.; Serio, S.

    1985-01-01

    X-ray emission from the nearby system Procyon A/B (F5 IV + DF) was detected, using the IPC (Imaging Proportional Counter) on board the Einstein Observatory. Analysis of the X-ray pulse height spectrum suggests that the observed X-ray emission originates in Procyon A rather than in the white dwarf companion Procyon B, since the derived X-ray temperature, log T = 6.2, agrees well with temperatures found for quiescent solar X-ray emission. Modeling Procyon's corona with loops characterized by some apex temperature Tmax and emission length scale L, it is found that Tmax is well constrained, but L, and consequently the filling factor of the X-ray emitting gas, are essentially unconstrained even when EUV emission from the transition region is included in the analysis.

  8. 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.

  9. 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.

  10. Radiation safety in X-ray facilities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-09-01

    The guide specifies the radiation safety requirements for structural shielding and other safety arrangements used in X-ray facilities in medical and veterinary X-ray activities and in industry, research and education. The guide is also applicable to premises in which X-ray equipment intended for radiation therapy and operating at a voltage of less than 25 kV is used. The guide applies to new X-ray facilities in which X-ray equipment that has been used elsewhere is transferred. The radiation safety requirements for radiation therapy X-ray devices operating at a voltage exceeding 25 kV, and for the premices in which such devices are used, are set out in Guide ST 2.2.

  11. Model experiment of in vivo synchrotron X-ray diffraction of human kidney stones

    Energy Technology Data Exchange (ETDEWEB)

    Ancharov, A.I. [Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk (Russian Federation)]. E-mail: ancharov@mail.ru; Potapov, S.S. [Institute of Mineralogy UB RAS, Miass (Russian Federation); Moiseenko, T.N. [The State Regional Clinical Hospital, Novosibirsk (Russian Federation); Feofilov, I.V. [The State Regional Clinical Hospital, Novosibirsk (Russian Federation); Nizovskii, A.I. [Boreskov Institute of Catalysis SB RAS, Novosibirsk (Russian Federation)

    2007-05-21

    The diffraction of synchrotron radiation (SR) was used to explore the phase composition of kidney stones placed into a specific object phantom, which imitated the human body. As an imitation of the patient breath, the kidney stone was moved vertically and rotated to an angle of 15{sup o} during the recording of the X-ray pattern. It was shown that rotation and displacement did not distort the X-ray pattern.

  12. Handbook of X-ray Astronomy

    Science.gov (United States)

    Arnaud, Keith; Smith, Randall; Siemiginowska, Aneta; Ellis, Richard; Huchra, John; Kahn, Steve; Rieke, George; Stetson, Peter B.

    2011-11-01

    Practical guide to X-ray astronomy for graduate students, professional astronomers and researchers. Presenting X-ray optics, basic detector physics and data analysis. It introduces the reduction and calibration of X-ray data, scientific analysis, archives, statistical issues and the particular problems of highly extended sources. The appendices provide reference material often required during data analysis. The handbook web page contains figures and tables: http://xrayastronomyhandbook.com/

  13. Sandia Mark II X-Ray System

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, L.W.

    1979-11-01

    The Sandia Mark II X-Ray System was designed and developed to provide an intense source of mononergetic, ultra-soft x rays with energies between 0.282 and 1.486 keV. The x-ray tube design is similar to one developed by B.L. Henke and incorporates modifications made by Tom Ellsberry. An operations manual section is incorporated to help the experimenter/operator.

  14. X-ray data booklet. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, D. (ed.)

    1986-04-01

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

  15. Symbiotic Stars in X-rays

    Science.gov (United States)

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

    2014-01-01

    Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of 9 white dwarf symbiotics that were not previously known to be X-ray sources and one that was previously detected as a supersoft X-ray source. The 9 new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. Swift/XRT detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component, which we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component, which likely arises in a region where low-velocity shocks produce X-ray emission, i.e. a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the alpha/beta/gamma classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new sigma classification for sources with

  16. Ultrashort X-ray pulse science

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Alan Hap [Univ. of California, Berkeley, CA (US). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    1998-05-01

    A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90° Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ~ 300 fs, 30 keV (0.4 Å) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been demonstrated as a

  17. X-ray Observations at Gaisberg Tower

    Directory of Open Access Journals (Sweden)

    Pasan Hettiarachchi

    2018-01-01

    Full Text Available We report the occurrence of X-rays at ground level due to cloud-to-ground flashes of upward-initiated lightning from Gaisberg Tower, in Austria, which is located at an altitude of 1300 m. This is the first observation of X-ray emissions from upward lightning from a tower top located at high altitude. Measurements were carried out using scintillation detectors installed close to the tower top in two phases from 2011 to 2015. X-rays were recorded in three subsequent strokes of three flashes out of the total of 108 flashes recorded in the system during both phases. In contrast to the observations from downward natural or triggered lightning, X-rays were observed only within 10 µs before the subsequent return stroke. This shows that X-rays were emitted when the dart leader was in the vicinity of the tower top, hence during the most intense phase of the dart leader. Both the detected energy and the fluence of X-rays are far lower compared to X-rays from downward natural or rocket-triggered lightning. In addition to the above 108 flashes, an interesting observation of X-rays produced by a nearby downward flash is also presented. The shorter length of dart-leader channels in Gaisberg is suggested as a possible cause of this apparently weaker X-ray production.

  18. X-ray laser microscope apparatus

    Science.gov (United States)

    Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

    1990-01-01

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

  19. Detector development for x-ray imaging

    Science.gov (United States)

    Mentzer, M. A.; Herr, D. A.; Brewer, K. J.; Ojason, N.; Tarpine, H. A.

    2010-02-01

    X-ray imaging requires unique optical detector system configuration for optimization of image quality, resolution, and contrast ratio. A system is described whereby x-ray photons from multiple anode sources create a series of repetitive images on fast-decay scintillator screens, from which an intensified image is transferred to a fast phosphor on a GEN II image intensifier and collected as a cineradiographic video with high speed digital imagery. The work addresses scintillator material formulation, flash x-ray implementation, image intensification, and high speed video processing and display. Novel determination of optimal scintillator absorption, x-ray energy and dose relationships, contrast ratio determination, and test results are presented.

  20. X-ray flares from postmerger millisecond pulsars.

    Science.gov (United States)

    Dai, Z G; Wang, X Y; Wu, X F; Zhang, B

    2006-02-24

    Recent observations support the suggestion that short-duration gamma-ray bursts are produced by compact star mergers. The x-ray flares discovered in two short gamma-ray bursts last much longer than the previously proposed postmerger energy-release time scales. Here, we show that they can be produced by differentially rotating, millisecond pulsars after the mergers of binary neutron stars. The differential rotation leads to windup of interior poloidal magnetic fields and the resulting toroidal fields are strong enough to float up and break through the stellar surface. Magnetic reconnection-driven explosive events then occur, leading to multiple x-ray flares minutes after the original gamma-ray burst.

  1. Two-axis Neutron and X-ray Reflectivity

    DEFF Research Database (Denmark)

    Bouwman, W.G.; Vigild, M.E.; Findeisen, E.

    1997-01-01

    Sample alignment for neutron (and in some cases x-ray) reflectometry can be complicated due to a coupling between angle and position which occurs when slits are used to define the path of the beam. Misalignments in sample position or sample rotation angle give rise to systematic errors in the exp......Sample alignment for neutron (and in some cases x-ray) reflectometry can be complicated due to a coupling between angle and position which occurs when slits are used to define the path of the beam. Misalignments in sample position or sample rotation angle give rise to systematic errors...... in the experiments. By measuring the reflectivity both from the back and from the front faces of the sample (twin reflectometry) these alignment errors can be detected and corrected for....

  2. Method of and device for measuring image lag in x-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, J.N.; Schmal, F.

    1990-01-16

    This patent describes a method of measuring image lag in an x-ray system. The system comprises an x-ray source, an image intensifier and a video camera, in which a disc having a pattern of comparatively strongly and comparatively weakly x-ray-absorbing areas is placed between the x-ray source and the image intensifier with its axis substantially parallel to the axis of an x-ray beam emitted by the x-ray source, which disc is made to rotate bout its axis, and in which the image lag of the x-ray system is determined from the output signal of the video camera. The pattern of the disc comprises at least a coiled comparatively strongly x-ray-absorbing area which is coaxial with the disc, that at least one video line, that is situated in a part of the image on which the center of the disc is displayed, is selected from the video signal produced by the video camera that the signal amplitude of the selected video line is determined. The image lag is measured from the ratio of the signal amplitude measured while the disc is stationary and the signal amplitude measured while the disc is rotating at a given speed.

  3. X-ray spectrometry using polycapillary X-ray optics and position sensitive detector.

    Science.gov (United States)

    Ding, X; Xie, J; He, Y; Pan, Q; Yan, Y

    2000-10-02

    Polycapillary X-ray optics (capillary X-ray lens) are now popular in X-ray fluorescence (XRF) analysis. Such an X-ray lens can collect X-rays emitted from an X-ray source in a large solid angle and form a very intense X-ray microbeam which is very convenient for microbeam X-ray fluorescence (MXRF) analysis giving low minimum detection limits (MDLs) in energy dispersive X-ray fluorescence (EDXRF). A new method called position sensitive X-ray spectrometry (PSXS) which combines an X-ray lens used to form an intense XRF source and a position sensitive detector (PSD) used for wavelength dispersive spectrometry (WDS) measurement was developed recently in the X-ray Optics Laboratory of Institute of Low Energy Nuclear Physics (ILENP) at Beijing Normal University. Such a method can give high energy and spacial resolution and high detection efficiency simultaneously. A short view of development of both the EDXRF using a capillary X-ray lens and the new PSXS is given in this paper.

  4. Image enhancement in digital X-ray angiography

    NARCIS (Netherlands)

    Meijering, H.W.

    2000-01-01

    Anyone who does not look back to the beginning throughout a course of action, does not look forward to the end. Hence it necessarily follows that an intention which looks ahead, depends on a recollection which looks back. | Aurelius Augustinus, De civitate Dei, VII.7 (417 A.D.) Chapter

  5. The X-ray properties of Be/X-ray pulsars in quiescence

    Science.gov (United States)

    Tsygankov, Sergey S.; Wijnands, Rudy; Lutovinov, Alexander A.; Degenaar, Nathalie; Poutanen, Juri

    2017-09-01

    Observations of accreting neutron stars (NSs) with strong magnetic fields can be used not only for studying the accretion flow interaction with the NS magnetospheres, but also for understanding the physical processes inside NSs and for estimating their fundamental parameters. Of particular interest are (I) the interaction of a rotating NS (magnetosphere) with the infalling matter at different accretion rates, and (II) the theory of deep crustal heating and the influence of a strong magnetic field on this process. Here, we present results of the first systematic investigation of 16 X-ray pulsars with Be optical companions during their quiescent states, based on data from the Chandra, XMM-Newton and Swift observatories. The whole sample of sources can be roughly divided into two distinct groups: (I) relatively bright objects with a luminosity around ˜1034 erg s-1 and (hard) power-law spectra, and (II) fainter ones showing thermal spectra. X-ray pulsations were detected from five objects in group (I) with quite a large pulse fraction of 50-70 per cent. The obtained results are discussed within the framework of the models describing the interaction of the infalling matter with the NS magnetic field and those describing heating and cooling in accreting NSs.

  6. Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries.

    Science.gov (United States)

    Seymour, H R; Matson, M B; Belli, A M; Morgan, R; Kyriou, J; Patel, U

    2001-02-01

    Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

  7. Accurate determination of segmented X-ray detector geometry

    Science.gov (United States)

    Yefanov, Oleksandr; Mariani, Valerio; Gati, Cornelius; White, Thomas A.; Chapman, Henry N.; Barty, Anton

    2015-01-01

    Recent advances in X-ray detector technology have resulted in the introduction of segmented detectors composed of many small detector modules tiled together to cover a large detection area. Due to mechanical tolerances and the desire to be able to change the module layout to suit the needs of different experiments, the pixels on each module might not align perfectly on a regular grid. Several detectors are designed to permit detector sub-regions (or modules) to be moved relative to each other for different experiments. Accurate determination of the location of detector elements relative to the beam-sample interaction point is critical for many types of experiment, including X-ray crystallography, coherent diffractive imaging (CDI), small angle X-ray scattering (SAXS) and spectroscopy. For detectors with moveable modules, the relative positions of pixels are no longer fixed, necessitating the development of a simple procedure to calibrate detector geometry after reconfiguration. We describe a simple and robust method for determining the geometry of segmented X-ray detectors using measurements obtained by serial crystallography. By comparing the location of observed Bragg peaks to the spot locations predicted from the crystal indexing procedure, the position, rotation and distance of each module relative to the interaction region can be refined. We show that the refined detector geometry greatly improves the results of experiments. PMID:26561117

  8. Magnetar-like X-Ray Bursts Suppress Pulsar Radio Emission

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, R. F.; Lyutikov, M.; Kaspi, V. M.; Tendulkar, S. P. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Burgay, M.; Possenti, A. [INAF–Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Esposito, P.; Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Israel, G. [INAF–Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Kerr, M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Sarkissian, J. [CSIRO Astronomy and Space Science, Parkes Observatory, P.O. Box 276, Parkes, NSW 2870 (Australia); Scholz, P., E-mail: archibald@astro.utoronto.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada)

    2017-11-10

    Rotation-powered pulsars and magnetars are two different observational manifestations of neutron stars: rotation-powered pulsars are rapidly spinning objects that are mostly observed as pulsating radio sources, while magnetars, neutron stars with the highest known magnetic fields, often emit short-duration X-ray bursts. Here, we report simultaneous observations of the high-magnetic-field radio pulsar PSR J1119−6127 at X-ray, with XMM-Newton and NuSTAR , and at radio energies with the Parkes radio telescope, during a period of magnetar-like bursts. The rotationally powered radio emission shuts off coincident with the occurrence of multiple X-ray bursts and recovers on a timescale of ∼70 s. These observations of related radio and X-ray phenomena further solidify the connection between radio pulsars and magnetars and suggest that the pair plasma produced in bursts can disrupt the acceleration mechanism of radio-emitting particles.

  9. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  10. X-ray Emission from Solar Flares

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Solar X-ray Spectrometer (SOXS), the first space-borne solar astronomy experiment of India was designed to improve our current understanding of X-ray emission from the Sun in general and solar flares in particular. SOXS mission is composed of two solid state detectors, viz., Si and CZT semiconductors ...

  11. Low Energy X-Ray Diagnostics - 1981.

    Science.gov (United States)

    1981-01-01

    ray Analysis, 18, 26 (1975). practicA !ity of thermal recording of intense x-rays. 2. R.P. Godwin, Adv. in X-rays Analysis, 19, 533 Many optical...the 15. T. W. Barbee Jr., in "National Science Foundation behavior of LSM dispersion elements. - Twenty Sixth Annual Report for Fiscal Year Extension

  12. Instrumental technique in X-ray astronomy

    Science.gov (United States)

    Peterson, L. E.

    1975-01-01

    A detailed review of the development of instruments for X-ray astronomy is given with major emphasis on nonfocusing high-sensitivity counter techniques used to detect cosmic photons in the energy range between 0.20 and 300 keV. The present status of X-ray astronomy is summarized together with significant results of the Uhuru observations, and photon interactions of importance for the detection of X-rays in space are noted. The three principal devices used in X-ray astronomy (proportional, scintillation, and solid-state counters) are described in detail, data-processing systems for these devices are briefly discussed, and the statistics of nuclear counting as applied to X-ray astronomy is outlined analytically. Effects of the near-earth X-ray environment and atmospheric gamma-ray production on X-ray detection by low-orbit satellites are considered. Several contemporary instruments are described (proportional-counter systems, scintillation-counter telescopes, modulation collimators), and X-ray astronomical satellite missions are tabulated.

  13. X-ray Galaxy Clusters & Cosmology

    Science.gov (United States)

    Ettori, Stefano

    2011-09-01

    I present a summary of the four lectures given on these topics: (i) Galaxy Clusters in a cosmological context: an introduction; (ii) Galaxy Clusters in X-ray: how and what we observe, limits and prospects; (iii) X-ray Galaxy Clusters and Cosmology: total mass, gas mass & systematics; (iv) Properties of the ICM: scaling laws and metallicity.

  14. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  15. The Beginnings of X-ray Crystallography

    Indian Academy of Sciences (India)

    IAS Admin

    Those were the days when Science was hovering around the wave–particle duality. William. Henry Bragg was toying with the idea that X-rays are particles and the observation made by Max von Laue that X-rays are diffracted by crystals could indeed lead to the understanding of crystal structures. On the other hand, his son, ...

  16. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+ ...

    Indian Academy of Sciences (India)

    tribpo

    X-ray Measurements of Black Hole X-ray Binary Source GRS. 1915+105 and the Evolution of Hard X-ray Spectrum. R. K. Manchanda, Tata Institute of Fundamental Research, Mumbai 400 005, India,. Received 1999 December 28; accepted 2000 February 9. Abstract. We report the spectral measurement of GRS 1915+105 ...

  17. Rotational angiography with motion compensation: first-in-man use for the 3D evaluation of transcatheter valve prostheses.

    Science.gov (United States)

    Schultz, Carl J; Lauritsch, Guenter; Van Mieghem, Nicholas; Rohkohl, Christopher; Serruys, Patrick W; van Geuns, Robert Jan; de Jaegere, Peter P T

    2015-08-01

    We evaluated a novel motion-compensating 3D reconstruction technique applied to rotational angiography (R-angio) which produces MSCT-like images for evaluation of implanted TAVI prostheses without requiring rapid pacing. Fifty-one consecutive patients were retrospectively identified who were evaluated with rotational angiography (R-angio) using the Siemens Artis zee angiographic C-arm system after TAVI with a Medtronic CoreValve prosthesis. A novel 3D image reconstruction technique was applied which corrects for cardiac motion. CoreValve frame geometry was evaluated according to the same protocol for MSCT and R-angio at the level of: 1) the inflow, 2) the nadirs, 3) central coaptation, and 4) the commissures. The native aortic annulus dimensions were measured at the nadirs of the three leaflets. Sizing ratio, prosthesis expansion and frame ellipticity were assessed. Good quality 3D reconstructions were obtained in 43 patients (84%) and failure was predictable prior to reconstruction in six of the other seven patients (superposition of radiographically dense object n=4, obesity n=2). Prosthesis inflow ellipticity and expansion were correlated with implantation depth (respectively r=-0.46, pprosthesis ellipticity at the level of central coaptation (median [25th-75th percentile]: 1.15 [1.10-1.20] vs. 1.08 [1.06-1.12], p=0.009). The inter-observer, inter-modality (MSCT, R-angio) variability in measurement at the level of coaptation for minimum diameter, maximum diameter and area were all low (respectively, mean ±SD:1.2% ±1.2; 1.7% ±1.8 and 2.0% ±1.3). R-angio with motion-compensated reconstruction offers new possibilities for evaluation of the post-implantation geometry of percutaneous structural heart prostheses and the potential clinical effects.

  18. The X-ray imager on AXO

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Carl; Kuvvetli, Irfan; Westergaard, Niels Jørgen Stenfeldt

    2001-01-01

    DSRI has initiated a development program of CZT X-ray and gamma-ray detectors employing strip readout techniques. A dramatic improvement of the energy response was found operating the detectors as the so-called drift detectors. For the electronic readout, modern ASIC chips were investigated....... Modular design and the low-power electronics will make large area detectors using the drift strip method feasible. The performance of a prototype CZT system will be presented and discussed. One such detector system has been proposed for future space missions: the X-Ray Imager (XRI) on the Atmospheric X-ray...... Observatory (AXO), which is a mission proposed to the Danish Small Satellite Program and is dedicated to observations of X-ray generating processes in the Earth's atmosphere. Of special interest will be simultaneous optical and X-ray observations of sprites that are flashes appearing directly above an active...

  19. 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.

  20. X-ray modeling for SMILE

    Science.gov (United States)

    Sun, T.; Wang, C.; Wei, F.; Liu, Z. Q.; Zheng, J.; Yu, X. Z.; Sembay, S.; Branduardi-Raymont, G.

    2016-12-01

    SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) is a novel mission to explore the coupling of the solar wind-magnetosphere-ionosphere system via providing global images of the magnetosphere and aurora. As the X-ray imaging is a brand new technique applied to study the large scale magnetopause, modeling of the solar wind charge exchange (SWCX) X-ray emissions in the magnetosheath and cusps is vital in various aspects: it helps the design of the Soft X-ray Imager (SXI) on SMILE, selection of satellite orbits, as well as the analysis of expected scientific outcomes. Based on the PPMLR-MHD code, we present the simulation results of the X-ray emissions in geospace during storm time. Both the polar orbit and the Molniya orbit are used. From the X-ray images of the magnetosheath and cusps, the magnetospheric responses to an interplanetary shock and IMF southward turning are analyzed.

  1. 3D X-ray imaging methods in support catheter ablations of cardiac arrhythmias.

    Science.gov (United States)

    Stárek, Zdeněk; Lehar, František; Jež, Jiří; Wolf, Jiří; Novák, Miroslav

    2014-10-01

    Cardiac arrhythmias are a very frequent illness. Pharmacotherapy is not very effective in persistent arrhythmias and brings along a number of risks. Catheter ablation has became an effective and curative treatment method over the past 20 years. To support complex arrhythmia ablations, the 3D X-ray cardiac cavities imaging is used, most frequently the 3D reconstruction of CT images. The 3D cardiac rotational angiography (3DRA) represents a modern method enabling to create CT like 3D images on a standard X-ray machine equipped with special software. Its advantage lies in the possibility to obtain images during the procedure, decreased radiation dose and reduction of amount of the contrast agent. The left atrium model is the one most frequently used for complex atrial arrhythmia ablations, particularly for atrial fibrillation. CT data allow for creation and segmentation of 3D models of all cardiac cavities. Recently, a research has been made proving the use of 3DRA to create 3D models of other cardiac (right ventricle, left ventricle, aorta) and non-cardiac structures (oesophagus). They can be used during catheter ablation of complex arrhythmias to improve orientation during the construction of 3D electroanatomic maps, directly fused with 3D electroanatomic systems and/or fused with fluoroscopy. An intensive development in the 3D model creation and use has taken place over the past years and they became routinely used during catheter ablations of arrhythmias, mainly atrial fibrillation ablation procedures. Further development may be anticipated in the future in both the creation and use of these models.

  2. Template-based CTA X-ray angio rigid registration of coronary arteries in frequency domain

    Science.gov (United States)

    Aksoy, Timur; Demirci, Stefanie; Degertekin, Muzaffer; Navab, Nassir; Unal, Gozde

    2013-03-01

    This study performs 3D to 2D rigid registration of segmented pre-operative CTA coronary arteries with a single segmented intra-operative X-ray Angio frame in both frequency and spatial domains for real-time Angiography interventions by C-arm fluoroscopy. Most of the work on rigid registration in literature required a close initial- ization of poses and/or positions because of the abundance of local minima and high complexity that searching algorithms face. This study avoids such setbacks by transforming the projections into translation-invariant Fourier domain for estimating the 3D pose. First, template DRRs as candidate poses of 3D vessels of segmented CTA are produced by rotating the camera (image intensifier) around the DICOM angle values with a wide range as in C-arm setup. We have compared the 3D poses of template DRRs with the real X-ray after equalizing the scales (due to disparities in focal length distances) in 3 domains, namely Fourier magnitude, Fourier phase and Fourier polar. The best pose candidate was chosen by one of the highest similarity measures returned by the methods in these domains. It has been noted in literature that these methods are robust against noise and occlusion which was also validated by our results. Translation of the volume was then recovered by distance-map based BFGS optimization well suited to convex structure of our objective function without local minima due to distance maps. Final results were evaluated in 2D projection space rather than with actual values in 3D due to lack of ground truth, ill-posedness of the problem which we intend to address in future.

  3. Line focus x-ray tubes—a new concept to produce high brilliance x-rays

    Science.gov (United States)

    Bartzsch, Stefan; Oelfke, Uwe

    2017-11-01

    Currently hard coherent x-ray radiation at high photon fluxes can only be produced with large and expensive radiation sources, such as 3rd generation synchrotrons. Especially in medicine, this limitation prevents various promising developments in imaging and therapy from being translated into clinical practice. Here we present a new concept of highly brilliant x-ray sources, line focus x-ray tubes (LFXTs), which may serve as a powerful and cheap alternative to synchrotrons and a range of other existing technologies. LFXTs employ an extremely thin focal spot and a rapidly rotating target for the electron beam which causes a change in the physical mechanism of target heating, allowing higher electron beam intensities at the focal spot. Monte Carlo simulations and numeric solutions of the heat equation are used to predict the characteristics of the LFXT. In terms of photon flux and coherence length, the performance of the line focus x-ray tube compares with inverse Compton scattering sources. Dose rates of up to 180 Gy s-1 can be reached in 50 cm distance from the focal spot. The results demonstrate that the line focus tube can serve as a powerful compact source for phase contrast imaging and microbeam radiation therapy. The production of a prototype seems technically feasible.

  4. Constraining pulsar birth properties with supernova X-ray observations

    Science.gov (United States)

    Gallant, Y. A.; Bandiera, R.; Bucciantini, N.; Amato, E.

    2017-02-01

    A large fraction of core-collapse supernovae are thought to result in the birth of a rotation-powered pulsar, which is later observable as a radio pulsar up to great ages. The birth properties of these pulsars, and in particular the distribution of their initial rotation periods, are however difficult to infer from studies of the radio pulsar population in our Galaxy. Yet the distributions of their birth properties is an important assumption for scenarios in which ultra-high-energy cosmic rays (UHECRs) originate in very young, extragalactic pulsars with short birth periods and/or high magnetic fields. Using a model of the very young pulsar wind nebula's dynamical and spectral evolution, with pulsar wind and accelerated particle parameters assumed similar to those inferred from modeling young pulsar wind nebulae (PWNe) in our Galaxy, we show that X-ray observations of supernovae, a few years to decades after the explosion, constitute a favored window to obtain meaningful constraints on the initial spin-down luminosity of the newly-formed pulsar. We examine the expected emerging PWN spectral component, taking into account the X-ray opacity of the expanding supernova ejecta, and find that it is typically best detectable in building on the work of Perna et al. (2008). We note that a resulting limit on spin-down luminosity corresponds univocally to a limit on the maximum magnetospheric acceleration potential, irrespective of the specific combination of magnetic field and rotation period that achieves it. We use available X-ray observations of supernovae to place constraints on the birth spin-down luminosity and period distribution of classical pulsars. We also examine the case of magnetars, born with much higher magnetic fields, and show that their much shorter initial spin-down time implies that any plausible signature of young magnetar wind nebulae can only be observed in harder X-ray or gamma-rays.

  5. Catheter Angiography

    Medline Plus

    Full Text Available ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ... material injection, you should immediately inform the technologist. Women should always inform their physician or x-ray ...

  6. Quantitative X-ray microtomography with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Donath, T. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2007-07-01

    Synchrotron-radiation-based computed microtomography (SR{sub {mu}}CT) is an established method for the examination of volume structures. It allows to measure the x-ray attenuation coefficient of a specimen three-dimensionally with a spatial resolution of about one micrometer. In contrast to conventional x-ray sources (x-ray tubes), the unique properties of synchrotron radiation enable quantitative measurements that do not suffer from beam-hardening artifacts. During this work the capabilities for quantitative SR{sub {mu}}CT measurements have been further improved by enhancements that were made to the SR{sub {mu}}CT apparatus and to the reconstruction chain. For high-resolution SR{sub {mu}}CT an x-ray camera consisting of luminescent screen (x-ray phosphor), lens system, and CCD camera was used. A significant suppression of blur that is caused by reflections inside the luminescent screen could be achieved by application of an absorbing optical coating to the screen surface. It is shown that blur and ring artifacts in the tomographic reconstructions are thereby drastically reduced. Furthermore, a robust and objective method for the determination of the center of rotation in projection data (sinograms) is presented that achieves sub-pixel precision. By implementation of this method into the reconstruction chain, complete automation of the reconstruction process has been achieved. Examples of quantitative SR{sub {mu}}CT studies conducted at the Hamburger Synchrotronstrahlungslabor HASYLAB at the Deutsches Elektronen-Synchrotron DESY are presented and used for the demonstration of the achieved enhancements. (orig.)

  7. Unwrapping the X-ray spectra of active galactic nuclei

    Science.gov (United States)

    Reynolds, C. S.

    2016-05-01

    Active galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity. And on all scales from the black hole outwards, powerful winds are seen that probably affect the evolution of the host galaxy as well as regulate the feeding of the AGN itself. In this review article, we discuss how X-ray spectroscopy can be used to study each of these components. We highlight how recent measurements of the high-energy cutoff in the X-ray continuum by NuSTAR are pushing us to conclude that X-ray coronae are radiatively-compact and have electron temperatures regulated by electron-positron pair production. We show that the predominance of rapidly-rotating objects in current surveys of SMBH spin is entirely unsurprising once one accounts for the observational selection bias resulting from the spin-dependence of the radiative efficiency. We review recent progress in our understanding of fast (v˜ (0.1-0.3)c, highly-ionized (mainly visible in Fe XXV and Fe XXVI lines), high-column density winds that may dominate quasar-mode galactic feedback. Finally, we end with a brief look forward to the promise of Astro-H and future X-ray spectropolarimeters.

  8. Einstein Observations of X-ray emission from A stars

    Science.gov (United States)

    Golub, L.; Harnden, F. R., Jr.; Maxson, C. W.; Vaiana, G. S.; Snow, T. P., Jr.; Rosner, R.; Cash, W. C., Jr.

    1983-01-01

    Results are reported from the combined CfA Stellar Survey of selected bright A stars and an Einstein Guest Observer program for Ap and Am stars. In an initial report of results from the CfA Stellar Surveys by Vaiana et al. (1981) it was noted that the spread in observed X-ray luminosities among the few A stars observed was quite large. The reasons for this large spread was studied by Pallavicini et al. (1981). It was found that the X-ray emission from normal stars is related very strongly to bolometric luminosity for early-type stars and to rotation rate for late-type stars. However, an exception to this rule has been the apparently anomalous behavior of A star X-ray emission, for which the large spread in luminosity showed no apparent correlation with either bolometric luminosity or stellar rotation rate. In the present study, it is shown that the level of emission from normal A stars agrees with the correlation observed for O and B stars.

  9. X-Ray Background from Early Binaries

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

  10. Toward Adaptive X-Ray Telescopes

    Science.gov (United States)

    O'Dell, Stephen L.; Atkins, Carolyn; Button, Tim W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peer; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffrey J.; hide

    2011-01-01

    Future x-ray observatories will require high-resolution (less than 1 inch) optics with very-large-aperture (greater than 25 square meter) areas. Even with the next generation of heavy-lift launch vehicles, launch-mass constraints and aperture-area requirements will limit the surface areal density of the grazing-incidence mirrors to about 1 kilogram per square meter or less. Achieving sub-arcsecond x-ray imaging with such lightweight mirrors will require excellent mirror surfaces, precise and stable alignment, and exceptional stiffness or deformation compensation. Attaining and maintaining alignment and figure control will likely involve adaptive (in-space adjustable) x-ray optics. In contrast with infrared and visible astronomy, adaptive optics for x-ray astronomy is in its infancy. In the middle of the past decade, two efforts began to advance technologies for adaptive x-ray telescopes: The Generation-X (Gen-X) concept studies in the United States, and the Smart X-ray Optics (SXO) Basic Technology project in the United Kingdom. This paper discusses relevant technological issues and summarizes progress toward adaptive x-ray telescopes.

  11. Multiple beam x-ray diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kewish, C.M.; Davis, J.R.; Coyle, R.A. [Monash University, Clayton, VIC (Australia). Department of Physics

    1999-12-01

    Full text: X-ray diffraction computed tomography (XDT) is an imaging modality that utilises scattered x-rays to reconstruct an image. Since its inception in 1985, various detection scenarios and imaging techniques have been developed to demonstrate the accuracy and applicability of XDT. Many of the previous methods for measuring the scattered x-rays from an object utilise detectors that accept x-rays scattered from the entire length of the raypath through the object. The detector apertures must therefore have dimensions similar to the largest width of the scanned object. This creates a situation where the detected x-rays are not derived from a single scattering angle. A new method of scanning the x-rays scattered from an object is presented which allows quantitative determination of the spatial distribution of differential scattering cross section within a cross-sectional plane of the object. The new method incorporates a position sensitive detector and an arrangement of Soller slits. The acquired data represents both spatial and angular information. For each raypath through the object, a partial diffraction projection is measured at the off-axis detector and a set of diffraction projections is assembled by combining the diffracted signal from all rays through the object. A reconstruction strategy that accounts for attenuation of the primary beam and the scattered beam allows us to reconstruct a map of the differential scattering cross section in the sample for a given angle. Copyright (1999) Australian X-ray Analytical Association Inc. 3 refs.

  12. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum tears in the shoulder) and in imaging of the spine (because both the bones and the spinal cord can be evaluated). MRI can also detect ...

  13. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum tears in the shoulder) and in imaging of the spine (because both the bones and the spinal cord can be evaluated). MRI can also detect subtle ...

  14. Synchrotron X-Ray Radiation and Deformation Studies

    DEFF Research Database (Denmark)

    Fæster Nielsen, Søren

    machining. The conical slit has six 25µm thick conically shaped openings matching six of the Debye-Scherrer cones from a fcc powder. By combining the conical slit with a micro-focused incoming beam of hard X-rays an embedded gauge volume is defined. Using a 2D detector, fast and complete information can...... the embedded grains within thick samples in three dimensions. All essential features like the position, volume, orien-tation, stress-state of individual grains can be determined, including the morphology of the grain boundaries. The first results obtained by using the novel tracking technique are presented...... in combination with synchrotron X-ray tomography in order to gain new in-formation on the wetting kinetics of liquid gallium in aluminium grain boundaries. Finally, an electron microscopy investigation was carried out in order to describe the lattice rotations and texture evolution in uniaxially compressed...

  15. X- rays and matter- the basic interactions

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens

    2008-01-01

    In this introductory article we attempt to provide the theoretical basis for developing the interaction between X-rays and matter, so that one can unravel properties of matter by interpretation of X-ray experiments on samples. We emphasize that we are dealing with the basics, which means that we...... shall limit ourselves to a discussion of the interaction of an X-ray photon with an isolated atom, or rather with a single electron in a Hartree-Fock atom. Subsequent articles in this issue deal with more complicated - and interesting - forms of matter encompassing many atoms or molecules. To cite...

  16. X-ray Emission from Millisecond Pulsars

    Science.gov (United States)

    Zavlin, Vyacheslav

    2006-01-01

    Isolated (solitary or non-accreting) millisecond pulsars with observed X-ray emission can be divided in two distinct groups: those emitting nonthermal (magnetospheric) radiation and pulsars with the bulk of X-rays of a thermal origin, presumably emitted from small hot spots around the magnetic poles on the neutron star surface (polar caps). I will discuss properties of X-ray emission detected with Chandra and XMM-Newton from a number of millisecond pulsars, with emphasis on those of the thermal component, and compare them with predictions of radio pulsar models.

  17. Two-dimensional x-ray diffraction

    CERN Document Server

    He, Bob B

    2009-01-01

    Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

  18. Materials for refractive x-ray optics.

    Science.gov (United States)

    Lund, M W

    1997-01-01

    An X-ray lens using refraction has been proposed by Tomie, and demonstrated for 14 keV X-rays by Snigirev et al. This type of lens is made from a series of very weak lens elements. I calculate the properties of such lenses constructed of various chemical elements and compounds over the range of 1 to 30 keV. In general, I find that X-ray optics made from low density, low Z materials have the widest useful apertures, but require more lens elements than denser and higher Z materials.

  19. The Future of X-Ray Optics

    Science.gov (United States)

    Weisskopf, Martin C.

    2013-01-01

    The most important next step is the development of X-ray optics comparable to (or better than) Chandra in angular resolution that far exceed Chandra s effective area. Use the long delay to establish an adequately funded, competitive technology program along the lines I have recommended. Don't be diverted from this objective, except for Explorer-class missions. Progress in X-ray optics, with emphasis on the angular resolution, is central to the paradigm-shifting discoveries and the contributions of X-ray astronomy to multiwavelength astrophysics over the past 51 years.

  20. The ROSAT X-ray Background Dipole

    OpenAIRE

    Plionis, M.; Georgantopoulos, I.

    1998-01-01

    We estimate the dipole of the diffuse 1.5 keV X-ray background from the ROSAT all-sky survey map of Snowden et al (1995). We first subtract the diffuse Galactic emission by fitting to the data an exponential scale height, finite radius, disk model. We further exclude regions of low galactic latitudes, of local X-ray emission (eg the North Polar Spur) and model them using two different methods. We find that the ROSAT X-ray background (XRB) dipole points towards $(l,b) ~ (288, 25) \\pm 19 degree...

  1. Two methods for studying the X-ray variability

    NARCIS (Netherlands)

    Yan, Shu-Ping; Ji, Li; Méndez, Mariano; Wang, Na; Liu, Siming; Li, Xiang-Dong

    2016-01-01

    The X-ray aperiodic variability and quasi-periodic oscillation (QPO) are the important tools to study the structure of the accretion flow of X-ray binaries. However, the origin of the complex X-ray variability from X-ray binaries remains yet unsolved. We proposed two methods for studying the X-ray

  2. Hafnium-Based Contrast Agents for X-ray Computed Tomography.

    Science.gov (United States)

    Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

    2017-05-15

    Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

  3. X-ray emission from open star clusters with Spectrum-Rontgen-Gamma

    DEFF Research Database (Denmark)

    Singh, K.P.; Ojha, D.K.; Schnopper, H.W.

    1998-01-01

    The study of X-ray emission from co-evolving populations of stars in open dusters is extremely important for understanding the dynamo activity among the stars. With this objective, we propose to observe a number of open clusters in the X-ray and UV bands using SPECTRUM-Rontgen-Gamma. The high...... throughput of SPECTRUM-Rontgen-Gamma will help detect main sequence stars like Sun in middle-aged and old clusters. We will study the relationships between various parameters - age, rotation, abundance, UBV colors, X-ray luminosity, coronal temperature etc. X-ray spectra of younger and brighter populations...... of stars which include synchronous binaries, rapid rotators and peculiar stars, would also be carried out....

  4. The photoelectric effect from CsI by polarized soft X-rays

    Science.gov (United States)

    Shaw, Ping S.; Church, Eric D.; Hanany, Shaul; Liu, Yee; Fleischman, Judith; Kaaret, Philip; Novick, Robert; Manzo, Giuseppe

    1991-01-01

    Studies of the polarization dependence of the photoelectric effect produced by soft X-rays from CsI indicate that the geometrical effects in these experiments can often mimic the polarization signature. This paper presents a detailed calculation of these geometrical effects that are produced when the X-ray beam is not precisely aligned on a rotatable plane photocathode. The experimentally observed geometrical effects were used to precisely determine the realignment of the incident beam of polarized X-rays on a rotatable photocathode. The results allow determinations of the true polarization dependence of the photoemission from CsI. It is shown that the photoelectric effect in CsI depends on the polarization state of the X-rays.

  5. The complete Einstein Observatory X-ray survey of the Orion Nebula region.

    Science.gov (United States)

    Gagne, Marc; Caillault, Jean-Pierre

    1994-01-01

    We have analyzed archival Einstein Observatory images of a roughly 4.5 square degree region centered on the Orion Nebula. In all, 245 distinct X-ray sources have been detected in six High Resolution Imager (HRI) and 17 Imaging Proportional Counter (IPC) observations. An optical database of over 2700 stars has been assembled to search for candidate counterparts to the X-ray sources. Roughly half the X-ray sources are identified with a single Orion Nebula cluster member. The 10 main-sequence O6-B5 cluster stars detected in Orion have X-ray activity levels comparable to field O and B stars. X-ray emission has also been detected in the direction of four main-sequence late-B and early-A type stars. Since the mechanisms producing X-rays in late-type coronae and early-type winds cannot operate in the late-B and early-A type atmospheres, we argue that the observed X-rays, with L(sub X) approximately = 3 x 10(exp 30) ergs/s, are probably produced in the coronae of unseen late-type binary companions. Over 100 X-ray sources have been associated with late-type pre-main sequence stars. The upper envelope of X-ray activity rises sharply from mid-F to late-G, with L(sub x)/L(sub bol) in the range 10(exp -4) to 2 x 10(exp -3) for stars later than approximately G7. We have looked for variability of the late-type cluster members on timescales of a day to a year and find that 1/4 of the stars show significantly variable X-ray emission. A handful of the late-type stars have published rotational periods and spectroscopic rotational velocities; however, we see no correlation between X-ray activity and rotation. Thus, for this sample of pre-main-sequence stars, the large dispersion in X-ray activity does not appear to be caused by the dispersion in rotation, in contrast with results obtained for low-mass main-sequence stars in the Pleiades and pre-main-sequence stars in Taurus-Auriga.

  6. Two-dimensional x-ray correlation spectroscopy of remote core states

    Directory of Open Access Journals (Sweden)

    Daniel Healion

    2014-01-01

    Full Text Available Nonlinear all-X-ray signals that involve large core-atom separation compared to the X-ray wavelengths may not be described by the dipole approximation since they contain additional phase factors. Expressions for the rotationally averaged 2D X-ray photon echo signals from randomly oriented systems that take this position-dependent phase into account for arbitrary ratio between the core separation and the resonant wavelength are presented. Application is made to the Se K-edge of a selenium dipeptide system.

  7. X-ray diffraction-based electronic structure calculations and experimental x-ray analysis for medical and materials applications

    Science.gov (United States)

    Mahato, Dip Narayan

    This thesis includes x-ray experiments for medical and materials applications and the use of x-ray diffraction data in a first-principles study of electronic structures and hyperfine properties of chemical and biological systems. Polycapillary focusing lenses were used to collect divergent x rays emitted from conventional x-ray tubes and redirect them to form an intense focused beam. These lenses are routinely used in microbeam x-ray fluorescence analysis. In this thesis, their potential application to powder diffraction and focused beam orthovoltage cancer therapy has been investigated. In conventional x-ray therapy, very high energy (˜ MeV) beams are used, partly to reduce the skin dose. For any divergent beam, the dose is necessarily highest at the entry point, and decays exponentially into the tissue. To reduce the skin dose, high energy beams, which have long absorption lengths, are employed, and rotated about the patient to enter from different angles. This necessitates large expensive specialized equipment. A focused beam could concentrate the dose within the patient. Since this is inherently skin dose sparing, lower energy photons could be employed. A primary concern in applying focused beams to therapy is whether the focus would be maintained despite Compton scattering within the tissue. To investigate this, transmission and focal spot sizes as a function of photon energy of two polycapillary focusing lenses were measured. The effects of tissue-equivalent phantoms of different thicknesses on the focal spot size were studied. Scatter fraction and depth dose were calculated. For powder diffraction, the polycapillary optics provide clean Gaussian peaks, which result in angular resolution that is much smaller than the peak width due to the beam convergence. Powder diffraction (also called coherent scatter) without optics can also be used to distinguish between tissue types that, because they have different nanoscale structures, scatter at different angles

  8. Insights from soft X-rays

    DEFF Research Database (Denmark)

    Raaf, Jennifer; Issinger, Olaf-Georg; Niefind, Karsten

    2008-01-01

    The diffraction pattern of a protein crystal is normally a product of the interference of electromagnetic waves scattered by electrons of the crystalline sample. The diffraction pattern undergoes systematic changes in case additionally X-ray absorption occurs, meaning if the wavelength of the pri......The diffraction pattern of a protein crystal is normally a product of the interference of electromagnetic waves scattered by electrons of the crystalline sample. The diffraction pattern undergoes systematic changes in case additionally X-ray absorption occurs, meaning if the wavelength...... of the primary X-ray beam is relatively close to the absorption edge of selected elements of the sample. The resulting effects are summarized as "anomalous dispersion" and can be always observed with "soft" X-rays (wavelength around 2 A) since they match the absorption edges of sulfur and chlorine...

  9. Demonstration of X-ray talbot interferometry

    CERN Document Server

    Momose, A; Kawamoto, S; Hamaishi, Y; Takai, K; Suzuki, Y

    2003-01-01

    First Talbot interferometry in the hard X-ray region was demonstrated using a pair of transmission gratings made by forming gold stripes on glass plates. By aligning the gratings on the optical axis of X-rays with a separation that caused the Talbot effect by the first grating, moire fringes were produced inclining one grating slightly against the other around the optical axis. A phase object placed in front of the first grating was detected by moire-fringe bending. Using the technique of phase-shifting interferometry, the differential phase corresponding to the phase object could also be measured. This result suggests that X-ray Talbot interferometry is a novel and simple method for phase-sensitive X-ray radiography. (author)

  10. Center for X-ray Optics (CXRO)

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for X-Ray Optics at Lawrence Berkeley National Laboratory works to further science and technology using short wavelength optical systems and techniques....

  11. Chest X-Ray (Chest Radiography)

    Science.gov (United States)

    ... Lung tissue absorbs little radiation and will appear dark on the image. Until recently, x-ray images ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  12. 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...

  13. X-ray Optics Development at MSFC

    Science.gov (United States)

    Sharma, Dharma P.

    2017-01-01

    Development of high resolution focusing telescopes has led to a tremendous leap in sensitivity, revolutionizing observational X-ray astronomy. High sensitivity and high spatial resolution X-ray observations have been possible due to use of grazing incidence optics (paraboloid/hyperboloid) coupled with high spatial resolution and high efficiency detectors/imagers. The best X-ray telescope flown so far is mounted onboard Chandra observatory launched on July 23,1999. The telescope has a spatial resolution of 0.5 arc seconds with compatible imaging instruments in the energy range of 0.1 to 10 keV. The Chandra observatory has been responsible for a large number of discoveries and has provided X-ray insights on a large number of celestial objects including stars, supernova remnants, pulsars, magnetars, black holes, active galactic nuclei, galaxies, clusters and our own solar system.

  14. Silicon Wafer X-ray Mirror Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this one year research project, we propose to do the following four tasks; (1) Design the silicon wafer X-ray mirror demo unit and develop a ray-tracing code to...

  15. Tuberculosis, advanced - chest x-rays (image)

    Science.gov (United States)

    Tuberculosis is an infectious disease that causes inflammation, the formation of tubercules and other growths within tissue, ... death. These chest x-rays show advanced pulmonary tuberculosis. There are multiple light areas (opacities) of varying ...

  16. 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...

  17. Experimental X-Ray Ghost Imaging.

    Science.gov (United States)

    Pelliccia, Daniele; Rack, Alexander; Scheel, Mario; Cantelli, Valentina; Paganin, David M

    2016-09-09

    We report an experimental proof of principle for ghost imaging in the hard-x-ray energy range. We use a synchrotron x-ray beam that is split using a thin crystal in Laue diffraction geometry. With an ultrafast imaging camera, we are able to image x rays generated by isolated electron bunches. At this time scale, the shot noise of the synchrotron emission process is measurable as speckles, leading to speckle correlation between the two beams. The integrated transmitted intensity from a sample located in the first beam is correlated with the spatially resolved intensity measured in the second, empty, beam to retrieve the shadow of the sample. The demonstration of ghost imaging with hard x rays may open the way to protocols to reduce radiation damage in medical imaging and in nondestructive structural characterization using free electron lasers.

  18. X-ray induced optical reflectivity

    Directory of Open Access Journals (Sweden)

    Stephen M. Durbin

    2012-12-01

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

  19. Milli X-Ray Fluorescence Spectrometer

    Data.gov (United States)

    Federal Laboratory Consortium — The Eagle III Micro XRF unit is similar to a traditional XRF unit, with the primary difference being that the X-rays are focused by a polycapillary optic into a spot...

  20. Silicon Wafer X-ray Mirror Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this one year research project, we propose to do the following four tasks;(1) Design the silicon wafer X-ray mirror demo unit and develop a ray-tracing code to...

  1. Quantum optics with X-rays

    Science.gov (United States)

    Kuznetsova, Elena; Kocharovskaya, Olga

    2017-11-01

    The demonstration of strong coupling between two nuclear polariton modes in the X-ray spectral region using two coupled cavities each containing a thin layer of iron brings new opportunities for exploring quantum science.

  2. Linking Jet Emission, X-Ray States, and Hard X-Ray Tails in the Neutron Star X-Ray Binary GX 17+2

    NARCIS (Netherlands)

    Migliari, S.; Miller-Jones, J.C.A.; Fender, R.P.; Homan, J.; di Salvo, T.; Rothschild, R.E.; Rupen, M.P.; Tomsick, J.A.; Wijnands, R.; van der Klis, M.

    2007-01-01

    We present the results of simultaneous radio (VLA) and X-ray (RXTE) observations of the Z-type neutron star X-ray binary GX 17+2. The aim is to assess the coupling between X-ray and radio properties throughout its three rapidly variable X-ray states and during the time-resolved transitions. These

  3. Capacitor discharges, magnetohydrodynamics, X-rays, ultrasonics

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology, Volume 1: Capacitor Discharges - Magnetohydrodynamics - X-Rays - Ultrasonics deals with the theoretical and engineering problems that arise in the capacitor discharge technique.This book discusses the characteristics of dielectric material, symmetrical switch tubes with mercury filling, and compensation conductor forms. The transformed discharge for highest current peaks, ignition transformer for internal combustion engines, and X-ray irradiation of subjects in mechanical motion are also elaborated. This text likewise covers the transformed capacitor discharge in w

  4. Parametric X-rays at FAST

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Tanaji [Fermilab

    2016-06-01

    We discuss the generation of parametric X-rays (PXR) in the photoinjector at the new FAST facility at Fermilab. Detailed calculations of the intensity spectrum, energy and angular widths and spectral brilliance with a diamond crystal are presented. We also report on expected results with PXR generated while the beam is channeling. The low emittance electron beam makes this facility a promising source for creating brilliant X-rays.

  5. Nanofocusing Refractive X-Ray Lenses

    OpenAIRE

    Boye, Pit

    2010-01-01

    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. ...

  6. Lacquer polishing of x-ray optics.

    Science.gov (United States)

    Catura, R C; Joki, E G; Roethig, D T; Brookover, W J

    1987-04-15

    Techniques for polishing figured x-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth wave in red light and very effectively covers surface roughness with spatial wavelengths less than ~0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient x-ray reflectivity.

  7. X-Ray Emission from Compact Sources

    Energy Technology Data Exchange (ETDEWEB)

    Cominsky, L

    2004-03-23

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

  8. Monochromatic Mammographic Imaging Using X-ray Polycapillary Optics

    National Research Council Canada - National Science Library

    Sugiro, Francisca

    2000-01-01

    .... Monochromatic x rays can be used to produce higher contrast images. Polycapillary x-ray optics technology can produce a highly parallel, monochromatic, x-ray beam from a conventional radiographic source...

  9. Optics Developments for X-Ray Astronomy

    Science.gov (United States)

    Ramsey, Brian

    2014-01-01

    X-ray optics has revolutionized x-ray astronomy. The degree of background suppression that these afford, have led to a tremendous increase in sensitivity. The current Chandra observatory has the same collecting area (approx. 10(exp 3)sq cm) as the non-imaging UHURU observatory, the first x-ray observatory which launched in 1970, but has 5 orders of magnitude more sensitivity due to its focusing optics. In addition, its 0.5 arcsec angular resolution has revealed a wealth of structure in many cosmic x-ray sources. The Chandra observatory achieved its resolution by using relatively thick pieces of Zerodur glass, which were meticulously figured and polished to form the four-shell nested array. The resulting optical assembly weighed around 1600 kg, and cost approximately $0.5B. The challenge for future x-ray astronomy missions is to greatly increase the collecting area (by one or more orders of magnitude) while maintaining high angular resolution, and all within realistic mass and budget constraints. A review of the current status of US optics for x-ray astronomy will be provided along with the challenges for future developments.

  10. X-ray Studies of Planetary Nebulae

    Science.gov (United States)

    Montez, Rodolfo

    2017-10-01

    X-ray emission from planetary nebulae (PNe) provides unique insight on the formation and evolution of PNe. Past observations and the ongoing Chandra Planetary Nebulae Survey (ChanPlaNS) provide a consensus on the two types of X-ray emission detected from PNe: extended and compact point-like sources. Extended X-ray emission arises from a shocked ``hot bubble'' plasma that resides within the nebular shell. Cooler than expected hot bubble plasma temperatures spurred a number of potential solutions with one emerging as the likely dominate process. The origin of X-ray emission from compact sources at the location of the central star is less clear. These sources might arise from one or combinations of the following processes: self-shocking stellar winds, spun-up binary companions, and/or accretion, perhaps from mass transfer, PN fallback, or debris disks. In the discovery phase, X-ray studies of PNe have mainly focused on the origin of the various emission processes. New directions incorporate multi-wavelength observations to study the influence of X-ray emission on the rest of the electromagnetic spectrum.

  11. 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...

  12. X-rays as a probe of the Universe

    Indian Academy of Sciences (India)

    Table of contents. X-rays as a probe of the Universe · Probing the Universe ….. Flux = sT4 umax = 1011 T (in Kelvin) · History of x-ray astronomy · X-ray Production · X-ray spectra · Celestial sphere as seen by UHURU (1970) · Slide 8 · X-rays from accreting binary systems · Slide 10 · Neutron stars: Black Hole: · Primary X-ray ...

  13. [X-ray hardening correction for ICT in testing workpiece].

    Science.gov (United States)

    Peng, Guang-han; Cai, Xin-hua; Han, Zhong; Yang, Xue-heng

    2008-06-01

    Since energy spectrum of X-ray is polychromatic source in X-ray industrial computerized tomography, the variation of attenuation coefficient with energy leads to the lower energy of X-ray radiation being absorbed preferentially when X-ray is transmitting the materials. And the higher the energy of X-ray, the lower the attenuation coefficient of X-ray. With the increase in the X-ray transmission thickness, it becomes easier for the X-ray to transmit the matter. Thus, the phenomenon of energy spectrum hardening of X-ray takes place, resulting from the interaction between X-ray and the materials. This results in false images in the reconstruction of X-ray industrial computerized tomography. Therefore, hardening correction of energy spectrum of X-ray has to be done. In the present paper, not only is the hardening phenomenon of X-ray transmitting the materials analyzed, but also the relation between the X-ray beam sum and the transmission thickness of X-ray is discussed. And according to the Beer law and the characteristics of interaction when X-ray is transmitting material, and by getting the data of X-ray beam sum, the relation equation is fitted between the X-ray beam sum and X-ray transmission thickness. Then, the relation and the method of equivalence are carried out for X-ray beam sum being corrected. Finally, the equivalent and monochromatic attenuation coefficient fitted value for X-ray transmitting the material is reasoned out. The attenuation coefficient fitted value is used for product back-projection image reconstruction in X-ray industrial computerized tomography. Thus, the effect caused by X-ray beam hardening is wiped off effectively in X-ray industrial computerized tomography.

  14. X-ray diffraction from single GaAs nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Biermanns, Andreas

    2012-11-12

    In recent years, developments in X-ray focussing optics have allowed to produce highly intense, coherent X-ray beams with spot sizes in the range of 100 nm and below. Together with the development of new experimental stations, X-ray diffraction techniques can now be applied to study single nanometer-sized objects. In the present work, X-ray diffraction is applied to study different aspects of the epitaxial growth of GaAs nanowires. Besides conventional diffraction methods, which employ X-ray beams with dimensions of several tens of {mu}m, special emphasis lies on the use of nanodiffraction methods which allow to study single nanowires in their as-grown state without further preparation. In particular, coherent X-ray diffraction is applied to measure simultaneously the 3-dimensional shape and lattice parameters of GaAs nanowires grown by metal-organic vapor phase epitaxy. It is observed that due to a high density of zinc-blende rotational twins within the nanowires, their lattice parameter deviates systematically from the bulk zinc-blende phase. In a second step, the initial stage in the growth of GaAs nanowires on Si (1 1 1) surfaces is studied. This nanowires, obtained by Ga-assisted growth in molecular beam epitaxy, grow predominantly in the cubic zinc-blende structure, but contain inclusions of the hexagonal wurtzite phase close to their bottom interface. Using nanodiffraction methods, the position of the different structural units along the growth axis is determined. Because the GaAs lattice is 4% larger than silicon, these nanowires release their lattice mismatch by the inclusion of dislocations at the interface. Whereas NWs with diameters below 50 nm are free of strain, a rough interface structure in nanowires with diameters above 100 nm prevents a complete plastic relaxation, leading to a residual strain at the interface that decays elastically along the growth direction. Finally, measurements on GaAs-core/InAs-shell nanowire heterostructures are presented

  15. Proton-induced x-ray fluorescence CT imaging.

    Science.gov (United States)

    Bazalova-Carter, Magdalena; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Matsuo, Yuto; Fahrig, Rebecca; Shirato, Hiroki; Umegaki, Kikuo; Xing, Lei

    2015-02-01

    To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%-5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm(2) CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%-5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R(2) > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Proton-induced x-ray fluorescence CT imaging of 3%-5% gold solutions in a small animal sized water phantom has been demonstrated

  16. Fabrication of large area X-ray diffraction grating for X-ray phase imaging

    Science.gov (United States)

    Noda, Daiji; Tokuoka, Atsushi; Katori, Megumi; Minamiyama, Yasuto; Yamashita, Kenji; Nishida, Satoshi; Hattori, Tadashi

    2012-07-01

    X-ray lithography, which uses highly directional synchrotron radiation, is one of the technologies that can be used for fabricating micrometer-sized structures. In X-ray lithography, the accuracy of the fabricated structure depends largely on the accuracy of the X-ray mask. Since X-ray radiation is highly directional, a micro-fabrication technology that produces un-tapered and high aspect ratio highly absorbent structures on a low absorbent membrane is required. Conventionally, a resin material is used as the support membrane for large area X-ray masks. However, resin membranes have the disadvantage that they can sag after several cycles of X-ray exposure due to the heat generated by the X-rays. Therefore, we proposed and used thin carbon wafers for the membrane material because carbon has an extremely small thermal expansion coefficient. We fabricated new carbon membrane X-ray masks, and these results of X-ray lithography demonstrate the superior performance.

  17. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron Laser

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Bressler, Christian; Chen, Lin X.

    2013-01-01

    X-ray free electron lasers (XFELs) deliver short (hard X-rays, making them excellent sources for time-resolved studies. Here we show that, despite the inherent instabilities of current (SASE based) XFELs, they can be used for measuring high......-quality X-ray absorption data and we report femtosecond time-resolved X-ray absorption near-edge spectroscopy (XANES) measurements of a spin-crossover system, iron(II) tris(2,2'-bipyridine) in water. The data indicate that the low-spin to high-spin transition can be modeled by single-exponential kinetics...

  18. 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...

  19. Ultrafast x-ray-induced nuclear dynamics in diatomic molecules using femtosecond x-ray-pump–x-ray-probe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, C. S.; Picón, A.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Moonshiram, D.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

    2016-07-01

    The availability at x-ray free electron lasers of generating two intense, femtosecond x-ray pulses with controlled time delay opens the possibility of performing time-resolved experiments for x-ray induced phenomena. We have applied this capability to molecular dynamics. In diatomic molecules composed of low-Z elements, K-shell ionization creates a core-hole state in which the main decay is an Auger process involving two electrons in the valence shell. After Auger decay, the nuclear wavepackets of the transient two-valence-hole states continue evolving on the femtosecond timescale, leading either to separated atomic ions or long-lived quasi-bound states. By using an x-ray pump and an x-ray probe pulse tuned above the K-shell ionization threshold of the nitrogen molecule, we are able to observe ion dissociation in progress by measuring the time-dependent kinetic energy releases of different breakup channels. We simulated the measurements on N2 with a molecular dynamics model that accounts for K-shell ionization, Auger decay, and time evolution of the nuclear wavepackets. In addition to explaining the time-dependent feature in the measured kinetic energy release distributions from the dissociative states, the simulation also reveals the contributions of quasi-bound states.

  20. The Polarimeter for Relativistic Astrophysical X-ray Sources

    Science.gov (United States)

    Jahoda, Keith; Kallman, Timothy R.; Kouveliotou, Chryssa; Angelini, Lorella; Black, J. Kevin; Hill, Joanne E.; Jaeger, Theodore; Kaaret, Phillip E.; Markwardt, Craig B.; Okajima, Takashi; hide

    2016-01-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study, with a launch date in 2020. The PRAXyS Observatory exploits grazing incidence X-ray mirrors and Time Projection Chamber Polarimeters capable of measuring the linear polarization of cosmic X-ray sources in the 2-10 keV band. PRAXyS combines well-characterized instruments with spacecraft rotation to ensure low systematic errors. The PRAXyS payload is developed at the Goddard Space Flight Center with the Johns Hopkins University Applied Physics Laboratory, University of Iowa, and RIKEN (JAXA) collaborating on the Polarimeter Assembly. The LEOStar-2 spacecraft bus is developed by Orbital ATK, which also supplies the extendable optical bench that enables the Observatory to be compatible with a Pegasus class launch vehicle. A nine month primary mission will provide sensitive observations of multiple black hole and neutron star sources, where theory predicts polarization is a strong diagnostic, as well as exploratory observations of other high energy sources. The primary mission data will be released to the community rapidly and a Guest Observer extended mission will be vigorously proposed.

  1. Optical, UV, and X-ray evidence for a 7-yr stellar cycle in Proxima Centauri

    Science.gov (United States)

    Wargelin, B. J.; Saar, S. H.; Pojmański, G.; Drake, J. J.; Kashyap, V. L.

    2017-01-01

    Stars of stellar type later than about M3.5 are believed to be fully convective and therefore unable to support magnetic dynamos like the one that produces the 11-yr solar cycle. Because of their intrinsic faintness, very few late M stars have undergone long-term monitoring to test this prediction, which is critical to our understanding of magnetic field generation in such stars. Magnetic activity is also of interest as the driver of UV and X-ray radiation, as well as energetic particles and stellar winds, that affects the atmospheres of close-in planets that lie within habitable zones, such as the recently discovered Proxima b. We report here on several years of optical, UV, and X-ray observations of Proxima Centauri (GJ 551; dM5.5e): 15 yr of All Sky Automated Survey photometry in the V band (1085 nights) and 3 yr in the I band (196 nights), 4 yr of Swift X-Ray Telescope and UV/Optical Telescope observations (more than 120 exposures), and nine sets of X-ray observations from other X-ray missions (ASCA, XMM-Newton, and three Chandra instruments) spanning 22 yr. We confirm previous reports of an 83-d rotational period and find strong evidence for a 7-yr stellar cycle, along with indications of differential rotation at about the solar level. X-ray/UV intensity is anticorrelated with optical V-band brightness for both rotational and cyclical variations. From comparison with other stars observed to have X-ray cycles, we deduce a simple empirical relationship between X-ray cyclic modulation and Rossby number, and we also present Swift UV grism spectra covering 2300-6000 Å.

  2. 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.

  3. 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.

  4. 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.

  5. X-ray detectors for digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Yaffe, M.J.; Rowlands, J.A. [Imaging Research Program, Sunnybrook Health Science Centre, University of Toronto, Toronto, ON (Canada)

    1997-01-01

    Digital radiography offers the potential of improved image quality as well as providing opportunities for advances in medical image management, computer-aided diagnosis and teleradiology. Image quality is intimately inked to the precise and accurate acquisition of information from the x-ray beam transmitted by the patient, i.e. to the performance of the x-ray detector. Detectors for digital radiography must meet the needs of the specific radiological procedure where they will be used. Key parameters are partial resolution, uniformity of response, contrast sensitivity, dynamic range, acquisition speed and frame rate. The underlying physical considerations defining the performance of x-ray detectors for radiography will be reviewed. Some of the more promising existing and experimental detector technologies which may be suitable for digital radiography will be considered. Devices that can be employed in full-area detectors and also those more appropriate for scanning x-ray systems will be discussed. These include various approaches based on phosphor x-ray converters, where light quanta are produced as an intermediate stage, as well as direct -ray-to-charge conversion materials such as zinc cadmium telluride, amorphous selenium and crystalline silicon. (author)

  6. 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.

  7. 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...

  8. Globular cluster X-ray sources

    Science.gov (United States)

    Pooley, D.

    We know from observations that globular clusters are very efficient catalysts in forming unusual binary systems, such as low-mass X-ray binaries (LMXBs), cataclysmic variables (CVs), and millisecond pulsars (MSPs), with formation rates per unit mass exceeding those in the Galactic disk by orders of magnitude. The high stellar densities in globular clusters trigger various dynamical interactions: exchange encounters, direct collisions, destruction of binaries, and tidal capture. This binary population is, in turn, critical to the stabilization of globular clusters against gravitational collapse; the long-term stability of a cluster is thought to depend on tapping into the gravitational binding energy of such close binaries. I will present an overview of the current state of globular cluster X-ray observations, as well as our work on deep Chandra observations of M4, where we reach some of the lowest X-ray luminosities in any globular cluster (comparable to the deep observations of 47 Tuc and NGC 6397). One of M4 X-ray sources previously classified as a white dwarf binary is likely a neutron star binary, and another X-ray source is a sub-subgiant, the nature of which is still unclear. skip=3pt

  9. X-ray irradiation of yeast cells

    Science.gov (United States)

    Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

    1997-10-01

    Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

  10. X-ray tomographic image magnification process, system and apparatus therefor

    Science.gov (United States)

    Kinney, John H.; Bonse, Ulrich K.; Johnson, Quintin C.; Nichols, Monte C.; Saroyan, Ralph A.; Massey, Warren N.; Nusshardt, Rudolph

    1993-01-01

    A computerized three-dimensional x-ray tomographic microscopy system is disclosed, comprising: a) source means for providing a source of parallel x-ray beams, b) staging means for staging and sequentially rotating a sample to be positioned in the path of the c) x-ray image magnifier means positioned in the path of the beams downstream from the sample, d) detecting means for detecting the beams after being passed through and magnified by the image magnifier means, and e) computing means for analyzing values received from the detecting means, and converting the values into three-dimensional representations. Also disclosed is a process for magnifying an x-ray image, and apparatus therefor.

  11. Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shear, Trevor A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-16

    This literature review will focus on both laboratory and synchrotron based X-ray tomography of materials and highlight the inner workings of these instruments. X-ray fluorescence spectroscopy will also be reviewed and applications of the tandem use of these techniques will be explored. The real world application of these techniques during the internship will also be discussed.

  12. X-ray photoelectron spectroscopy, high-resolution X-ray diffraction ...

    Indian Academy of Sciences (India)

    Powder X-ray diffraction studies were carried out on doped lithium niobate for phase identification. High-resolution X-ray diffraction technique was used to study the crystalline quality through full-width at half-maximum values. The refractive index values are more for doped samples than for pure sample as determined by ...

  13. X-ray optics developments at ESA

    DEFF Research Database (Denmark)

    Bavdaz, M.; Wille, E.; Wallace, K.

    2013-01-01

    Future high energy astrophysics missions will require high performance novel X-ray optics to explore the Universe beyond the limits of the currently operating Chandra and Newton observatories. Innovative optics technologies are therefore being developed and matured by the European Space Agency (ESA......) in collaboration with research institutions and industry, enabling leading-edge future science missions. Silicon Pore Optics (SPO) [1 to 21] and Slumped Glass Optics (SGO) [22 to 29] are lightweight high performance X-ray optics technologies being developed in Europe, driven by applications in observatory class...... reflective coatings [30 to 35]. In addition, the progress with the X-ray test facilities and associated beam-lines is discussed [36]. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only....

  14. The quantum X-ray radiology apparatus

    CERN Document Server

    Hilt, B; Prevot, G

    2000-01-01

    The paper entitled 'New Quantum Detection System for Very Low Dose X-ray Radiology', presented at the talk session, discusses the preliminary data obtained using a new quantum X-ray radiology system with a high-efficiency solid-state detector and highly sensitive electronics, making it possible to reduce significantly the dose administered to a patient in X-ray radiology examinations. The present paper focuses more on the technological aspects of the apparatus, such as the integration of the detector with the two Asics, and the computer system. Namely, it is shown how the computer system calibrates the detection system, acquires the data in real time, and controls the scan parameters and image filtering process.

  15. X-ray optics of tapered capillaries.

    Science.gov (United States)

    Balaic, D X; Nugent, K A

    1995-11-01

    The optics of x-ray concentration by tapered glass capillaries is analyzed in terms of a phase-space construction describing their transmission efficiency. The parameters defining the intensity gain are given in terms of parameters describing the x-ray source used, the capillary taper profile, and glass characteristics. We introduce some key concepts in understanding these devices: the extreme ray and a phase-space description of sources and optics. They are used to develop an analytical formulation for the optimum gain characteristics of generalized tapers for use with synchrotrons and other low-divergence sources. This general solution is solved further for the case of conical taper profile. The predictions of this theory are compared with the results of three-dimensional, ray-tracing simulations of x-ray concentration efficiency for conical and paraboloidal tapers.

  16. Bone diagnosis by X-ray techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lima, I. [Nuclear Engineering Program/COPPE/UFRJ, P.O. Box 68509, Av. Horacio Macedo, 2030, Sala I-133, Cidade Universitaria, Zip Code: 21941-972 Rio de Janeiro, RJ (Brazil)], E-mail: inaya@lin.ufrj.br; Anjos, M.J. [Nuclear Engineering Program/COPPE/UFRJ, P.O. Box 68509, Av. Horacio Macedo, 2030, Sala I-133, Cidade Universitaria, Zip Code: 21941-972 Rio de Janeiro, RJ (Brazil); Physics Institute, UERJ (Brazil); Farias, M.L.F. [University Hospital, UFRJ (Brazil); Parcegoni, N.; Rosenthal, D. [Biophysics Institute, UFRJ (Brazil); Duarte, M.E.L. [Histologic and Embriology Department, UFRJ (Brazil); Lopes, R.T. [Nuclear Engineering Program/COPPE/UFRJ, P.O. Box 68509, Av. Horacio Macedo, 2030, Sala I-133, Cidade Universitaria, Zip Code: 21941-972 Rio de Janeiro, RJ (Brazil)

    2008-12-15

    In this work, two X-ray techniques used were 3D microcomputed tomography (micro-CT) and X-ray microfluorescence (micro-XRF) in order to investigate the internal structure of the bone samples. Those two techniques work together, e.g. as a complement to each other, to characterize bones structure and composition. Initially, the specimens were used to do the scan procedure in the microcomputer tomography system and the second step consists of doing the X-ray microfluorescence analysis. The results show that both techniques are powerful methods for analyzing, inspecting and characterizing bone samples: they are alternative procedures for examining bone structures and compositions and they are complementary.

  17. Observations of the Jovian System with the Chandra X-Ray Observatory

    Science.gov (United States)

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

    2002-01-01

    The {\\sl Chandra X-ray Observatory) observed the Jovian system on 25-26 Nov 1999 with the Advanced CCD Imaging Spectrometer (ACIS), in support of the Galileo flyby of Io, and on 18 Dec 2000 with the imaging array of the High Resolution Camera (HRC-I), in support of the Cassini flyby of Jupiter. These sensitive, very high spatial-resolution X-ray observations have revealed that Jupiter's northern x-ray aurora originates at a spot fixed in a coordinate system rotating with the planet at latitude (60--70 deg north) and longitude (160--180 deg System III). Contrary to previous expectations, this location is poleward of the main FUV auroral oval and the foot of the Io Flux Tube, and is apparently connected magnetically to a region of the outer magnetosphere beyond $\\sim$30 Jupiter radii. The northern auroral x-ray emission varies with a period $\\sim$45 minute and has a an average power of $\\sim$1 GW. The earlier view that Jupiter's x-ray aurora resulted from the precipitation of heavy ions from the outer edge of the lo Plasma Torus is now in doubt. Jupiter's disk also emits x-rays with a power of $\\sim$2 GW, perhaps resulting from reprocessing of solar x-rays in its atmosphere. These observations reveal for the first time x-ray emission from the Io Plasma Torus, with a power of $\\sim$0.1 Gw. The origin of this emission is not currently understood, although bremmstrahlung from non-thermal electrons may play a significant role. Finally, we report the discovery of very faint ($\\sim$1--2 MW) soft x-ray emission from the Galilean satellites Io, Europa, and probably Ganymede, most likely as a result of bombardment of their surfaces by energetic ($ greater than $10 keV) H, O, and S ions from the region of the Io Plasma Torus.

  18. X-ray reflectivity imager with 15 W power X-ray source.

    Science.gov (United States)

    Jiang, Jinxing; Sakurai, Kenji

    2016-09-01

    X-ray reflectivity is usually used for the routine analysis of layered structures of uniform thin films. So far, the technique has some limitations in the application to more practical inhomogeneous/patterned samples. X-ray reflectivity imaging is recently developed technique and can give the reconstructed image from many X-ray reflection projections. The present article gives the instrumental details of the compact X-ray reflectivity imager. Though the power of X-ray source is only 15 W, it works well. The calibration of the system has been discussed, because it is particularly important for the present grazing incidence geometry. We also give a visualization example of the buried interface, physical meaning of the reconstructed image, and discussions about possibilities for improvement.

  19. Differential phase contrast X-ray imaging system and components

    Energy Technology Data Exchange (ETDEWEB)

    Stutman, Daniel; Finkenthal, Michael

    2017-11-21

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

  20. Differential phase contrast X-ray imaging system and components

    Science.gov (United States)

    Stutman, Daniel; Finkenthal, Michael

    2017-01-31

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

  1. Soft X-ray focusing Telescope aboard AstroSat

    DEFF Research Database (Denmark)

    Singh, K. P.; Dewangan, G. C.; Chandra, S.

    2017-01-01

    The Soft X-ray focusing Telescope (SXT) is a moderateresolution X-ray imaging spectrometer supplementing the ultraviolet and hard X-ray payloads for broadband studies of cosmic sources with AstroSat. Well suited for observing bright X-ray sources, SXT observations of nearby active galactic nuclei...

  2. Grazing Incidence X-ray Scattering and Diffraction

    Indian Academy of Sciences (India)

    ... Journals; Resonance – Journal of Science Education; Volume 19; Issue 12. Grazing Incidence X-ray Scattering and Diffraction. Jaydeep K Basu. General Article Volume 19 Issue 12 December ... Keywords. X-ray reflectivity; X-ray diffuse scattering; grazing incident diffraction; grazing incident; small angle X-ray scattering.

  3. 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....

  4. Tantalum/Copper X-Ray Targets

    Science.gov (United States)

    Waters, William J.; Edmonds, Brian

    1993-01-01

    Lewis Research Center developed unique solution to subsidiary problem of fabrication of x-ray target. Plasma spraying enabled fabrication of lightweight, high-performance targets. Power settings, atmosphere-control settings, rate of deposition, and other spraying parameters developed. Thin coats of tantalum successfully deposited on copper targets. Targets performed successfully in tests and satisfied all criteria expressed in terms of critical parameters. Significantly reduces projected costs of fabrication of targets and contributes to development of improved, long-lived, lightweight x-ray system.

  5. Studying Microquasars with X-Ray Polarimetry

    Directory of Open Access Journals (Sweden)

    Giorgio Matt

    2018-03-01

    Full Text Available Microquasars are Galactic black hole systems in which matter is transferred from a donor star and accretes onto a black hole of, typically, 10–20 solar masses. The presence of an accretion disk and a relativistic jet made them a scaled down analogue of quasars—thence their name. Microquasars feature prominently in the scientific goals of X-ray polarimeters, because a number of open questions, which are discussed in this paper, can potentially be answered: the geometry of the hot corona believed to be responsible for the hard X-ray emission; the role of the jet; the spin of the black hole.

  6. Hard X-ray Laue monochromator

    Science.gov (United States)

    Kocharyan, V. R.; Gogolev, A. S.; Kiziridi, A. A.; Batranin, A. V.; Muradyan, T. R.

    2016-06-01

    Experimental studies of X-ray diffraction from reflecting atomic planes (10¯11) of X-cut quartz single crystal in Laue geometry influenced by the temperature gradient were carried out. It is shown that by using the temperature gradient it is possible to reflect a hard X- ray beam with photon energy near the 100 keV with high efficiency. It has been experimentally proved that the intensity of the reflected beam can be increased by more than order depending on the value of the temperature gradient.

  7. Radiobiological studies using gamma and x rays.

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R.; Lin, Yong; Wilder, Julie; Hutt, Julie A.; Padilla, Mabel T.; Gott, Katherine M.

    2013-02-01

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

  8. Single Particle X-ray Diffractive Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bogan, M J; Benner, W H; Boutet, S; Rohner, U; Frank, M; Seibert, M; Maia, F; Barty, A; Bajt, S; Riot, V; Woods, B; Marchesini, S; Hau-Riege, S P; Svenda, M; Marklund, E; Spiller, E; Hajdu, J; Chapman, H N

    2007-10-01

    In nanotechnology, strategies for the creation and manipulation of nanoparticles in the gas phase are critically important for surface modification and substrate-free characterization. Recent coherent diffractive imaging with intense femtosecond X-ray pulses has verified the capability of single-shot imaging of nanoscale objects at sub-optical resolutions beyond the radiation-induced damage threshold. By intercepting electrospray-generated particles with a single 15 femtosecond soft-X-ray pulse, we demonstrate diffractive imaging of a nanoscale specimen in free flight for the first time, an important step toward imaging uncrystallized biomolecules.

  9. X-ray shout echoing through space

    Science.gov (United States)

    2004-01-01

    a flash of X-rays hi-res Size hi-res: 3991 Kb Credits: ESA, S. Vaughan (University of Leicester) EPIC camera shows the expanding rings caused by a flash of X-rays 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. a flash of X-rays hi-res Size hi-res: 2153 Kb Credits: ESA, S. Vaughan (University of Leicester) EPIC camera shows the expanding rings caused by a flash of X-rays (Please choose "hi-res" version for animation) 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 seconds. At their largest size, the rings would appear in the sky about five times smaller than the full moon. This echo forms when the powerful radiation of a gamma-ray burst, coming from far away, crosses a slab of dust in our Galaxy and is scattered by it, like the beam of a lighthouse in clouds. Using the expanding rings to precisely pin-point the location of this dust, astronomers can identify places where new stars and planets are likely to form. On 3 December 2003 ESA's observatory, Integral, detected a burst of gamma rays, lasting about 30 seconds, from the direction of a distant galaxy. Within minutes of the detection, thanks to a sophisticated alert network, many

  10. X-ray insights into star and planet formation

    OpenAIRE

    Feigelson, Eric D.

    2010-01-01

    Although stars and planets form in cold environments, X-rays are produced in abundance by young stars. This review examines the implications of stellar X-rays for star and planet formation studies, highlighting the contributions of NASA’s (National Aeronautics and Space Administration) Chandra X-ray Observatory. Seven topics are covered: X-rays from protostellar outflow shocks, X-rays from the youngest protostars, the stellar initial mass function, the structure of young stellar clusters, the...

  11. Breast lesion co-localisation between X-ray and MR images using finite element modelling.

    Science.gov (United States)

    Lee, Angela W C; Rajagopal, Vijayaraghavan; Babarenda Gamage, Thiranja P; Doyle, Anthony J; Nielsen, Poul M F; Nash, Martyn P

    2013-12-01

    This paper presents a novel X-ray and MR image registration technique based on individual-specific biomechanical finite element (FE) models of the breasts. Information from 3D magnetic resonance (MR) images was registered to X-ray mammographic images using non-linear FE models subject to contact mechanics constraints to simulate the large compressive deformations between the two imaging modalities. A physics-based perspective ray-casting algorithm was used to generate 2D pseudo-X-ray projections of the FE-warped 3D MR images. Unknown input parameters to the FE models, such as the location and orientation of the compression plates, were optimised to provide the best match between the pseudo and clinical X-ray images. The methods were validated using images taken before and during compression of a breast-shaped phantom, for which 12 inclusions were tracked between imaging modalities. These methods were then applied to X-ray and MR images from six breast cancer patients. Error measures (such as centroid and surface distances) of segmented tumours in simulated and actual X-ray mammograms were used to assess the accuracy of the methods. Sensitivity analysis of the lesion co-localisation accuracy to rotation about the anterior-posterior axis was then performed. For 10 of the 12 X-ray mammograms, lesion localisation accuracies of 14 mm and less were achieved. This analysis on the rotation about the anterior-posterior axis indicated that, in cases where the lesion lies in the plane parallel to the mammographic compression plates, that cuts through the nipple, such rotations have relatively minor effects.This has important implications for clinical applicability of this multi-modality lesion registration technique, which will aid in the diagnosis and treatment of breast cancer. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. X-ray Chirped Pulse Amplification: towards GW Soft X-ray Lasers

    Directory of Open Access Journals (Sweden)

    Marta Fajardo

    2013-07-01

    Full Text Available Extensive modeling of the seeding of plasma-based soft X-ray lasers is reported in this article. Seminal experiments on amplification in plasmas created from solids have been studied in detail and explained. Using a transient collisional excitation scheme, we show that a 18 µJ, 80 fs fully coherent pulse is achievable by using plasmas pumped by a compact 10 Hz laser. We demonstrate that direct seeding of plasmas created by nanosecond lasers is not efficient. Therefore, we propose and fully study the transposition to soft X-rays of the Chirped Pulse Amplification (CPA technique. Soft X-ray pulses with energy of 6 mJ and 200 fs duration are reachable by seeding plasmas pumped by compact 100 J, sub-ns, 1 shot/min lasers. These soft X-ray lasers would reach GW power, corresponding to an increase of 100 times as compared to the highest peak power achievable nowadays in the soft X-ray region (30 eV–1 keV. X-ray CPA is opening new horizon for soft x-ray ultra-intense sources.

  13. Global Properties of X-Ray Flashes and X-Ray-Rich GRBs Observed by Swift

    Science.gov (United States)

    Sakamoto, T.; Yamazaki, R.; Cummings, J.; Krimm, H.; Parsons, A.; Hullinger, D.; Barbier, L.; Fenimore, E.; Markwardt, C.; Tueller, J.; hide

    2007-01-01

    We describe and discuss the spectral and temporal characteristics of the prompt emission and X-ray afterglow emission of X-ray flashes (XRFs) detected and observed by Swift between December 2005 and September 2006. We compare these characteristics to a sample of X-ray rich gamma-ray bursts (XRRs) and conventional classical gamma-ray bursts (C-GRBs)observed during the same period. We confirm the correlation between Epeak and fluence noted by others and find further evidence that XRFs and C-GRBs form a continuum. We also confirmed that our known redshift samples are consistent with the correlation between the peak energy (Epeak) and the isotropic radiated energy (Eiso), so called the Epeak-Eiso relation. The spectral properties of X-ray afterglows are similar to those of gamma-ray burst afterglows, but the temporal properties of the two classes are quite different. We found that the light curves of C-GRBs afterglow show a break to steeper indices (shallow-to-steep break) at much earlier times than do XRF afterglows. Moreover, the overall luminosity of X-ray afterglows of XRFs are systematically smaller by a factor of two or more compared with that of C-GRBs. These distinct differences in the X-ray afterglow between XRFs and C-GRBs are key to understanding not only a mysterious shallow-to-steep phase in the X-ray afterglow but also the unique nature of XRFs.

  14. 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

  15. ROSAT: X ray survey of compact groups

    NARCIS (Netherlands)

    van Gorkom, Jacqueline

    1993-01-01

    This is the final technical report on grant NAG5-1954, which was awarded under the NASA ROSAT Guest Investigator Program to Columbia University. This grant was awarded for a number of projects on two rather different topics: (1) an x-ray survey of compact groups of galaxies; and (2) the fate of gas

  16. Fourier techniques in X-ray timing

    NARCIS (Netherlands)

    van der Klis, M.

    1988-01-01

    Basic principles of Fourier techniques often used in X-ray time series analysis are reviewed. The relation between the discrete Fourier transform and the continuous Fourier transform is discussed to introduce the concepts of windowing and aliasing. The relation is derived between the power spectrum

  17. A microcapillary lens for X-rays

    CERN Document Server

    Dudchik, Y I

    1999-01-01

    A new design of a compound refractive lens for X-rays is proposed. The lens is made as a set of glue microlenses placed in a glass capillary. The technique of lens fabrication is described. Results of ray tracing calculations for 8 and 15 keV photons are represented.

  18. X-ray optics for axion helioscopes

    DEFF Research Database (Denmark)

    Jakobsen, Anders Clemen; Pivovaroff, Michael J.; Christensen, Finn Erland

    2013-01-01

    A method of optimizing grazing incidence x-ray coatings in ground based axion helioscopes is presented. Software has been been developed to find the optimum coating when taking both axion spectrum and Micromegas detector quantum efficiency into account. A comparison of the relative effective area...... of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only....

  19. Exploring subluminous X-ray binaries

    NARCIS (Netherlands)

    Degenaar, N.D.

    2010-01-01

    Halfway the twentieth century, technological developments made it possible to carry detection instruments outside the absorbing layers of the Earth’s atmosphere onboard rockets and satellites. This opened up the opportunity to detect the emission from celestial objects at X-ray wavelengths, thereby

  20. 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 ...

  1. Supernova remnants: the X-ray perspective

    NARCIS (Netherlands)

    Vink, J.

    2012-01-01

    Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And

  2. Reconstructing misaligned x-ray CT data

    Energy Technology Data Exchange (ETDEWEB)

    Divin, C. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-24

    Misalignment errors for x-ray computed tomography (CT) systems can manifest as artifacts and a loss of spatial and contrast resolution. To mitigate artifacts, significant effort is taken to determine the system geometry and minimizing any residual error in the system alignment. This project improved our ability to post-correct data which was acquired on a misaligned CT system.

  3. X-ray signals in renal osteopathy

    Energy Technology Data Exchange (ETDEWEB)

    Rieden, K.

    1984-10-01

    Chronic renal insufficiency is associated with metabolic disturbances which ultimately lead to typical, partly extremely painful changes in the skeletal system the longer the disease persists. Regular X-ray control of certain skeletal segments allows early detection of renal oesteopathy if the radiological findings described in this article are carefully scrutinised and interpreted.

  4. X-ray Studies of Flaring Plasma

    Indian Academy of Sciences (India)

    We present some methods of X-ray data analysis employed in our laboratory for deducing the physical parameters of flaring plasma. For example, we have used a flare well observed with Polish instrument RESIK aboard Russian CORONAS-F satellite. Based on a careful instrument calibration, the absolute fluxes in a ...

  5. X-ray microscopy of human malaria

    Energy Technology Data Exchange (ETDEWEB)

    Magowan, C.; Brown, J.T.; Mohandas, N.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Associations between intracellular organisms and host cells are complex and particularly difficult to examine. X-ray microscopy provides transmission images of subcellular structures in intact cells at resolutions superior to available methodologies. The spatial resolution is 50-60nm with a 1 micron depth of focus, superior to anything achievable with light microscopy. Image contrast is generated by differences in photoelectric absorption by the atoms in different areas (i.e. subcellular structures) throughout the full thickness of the sample. Absorption due to carbon dominates among all the elements in the sample at 2.4 nm x-ray wavelength. Thus images show features or structures, in a way not usually seen by other types of microscopy. The authors used soft x-ray microscopy to investigate structural development of Plasmodium falciparum malaria parasites in normal and genetically abnormal erythrocytes, and in infected erythrocytes treated with compounds that have anti-malarial effects. X-ray microscopy showed newly elaborated structures in the cytosol of unstained, intact erythrocytes, redistribution of mass (carbon) in infected erythrocytes, and aberrant parasite morphology. Better understanding of the process of intracellular parasite maturation and the interactions between the parasite and its host erythrocyte can help define new approaches to the control of this deadly disease.

  6. X-Ray Exam: Cervical Spine

    Science.gov (United States)

    ... open mouth (odontoid view). Occasionally, additional pictures like flexion and extension views of the cervical spine might be needed. continue Why It's Done A cervical spine X-ray can help find the cause of symptoms such as neck, shoulder, upper back, or arm pain, as well ...

  7. X-Ray Exam: Femur (Upper Leg)

    Science.gov (United States)

    ... leg, and an image is recorded on special film or a computer. This image shows the soft tissues and the bone in the upper leg, which is called the femur. The X-ray image is black and white. Dense body parts that block the passage of the X- ...

  8. PREPARATION, SPECTROSCOPIC STUDIES AND X-RAY ...

    African Journals Online (AJOL)

    These complexes have been characterized by analysis, molar conductance, magnetic measurements, infrared spectral studies and X-ray diffraction. The analytical data showed 1:3 (metal:ligand) stoichiometry. Molar conductance measurements in dmf indicate 1:3 electrolytes in all cases. Magnetic moment values are close ...

  9. X-ray spectroscopy of manganese clusters

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-06-01

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

  10. 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

  11. Mystery of Cometary X-Rays Solved

    Science.gov (United States)

    2000-07-01

    On July 14, 2000 NASA's Chandra X-ray Observatory imaged Comet C/1999 S4 (LINEAR) and detected X-rays from oxygen and nitrogen ions. The details of the X-ray emission, as recorded on Chandra's Advanced CCD Imaging Spectrometer, show that they are produced by collisions of ions racing away from the Sun with gas in the comet. "This observation solves one mystery. It proves how comets produce X-rays," said Dr. Carey Lisse of the Space Telescope Science Institute (STScI) leader of a team of scientists from STScI, NASA's Goddard Space Flight Center, Max Planck Institute in Germany, Johns Hopkins University, the University of California, Berkeley, and the Harvard-Smithsonian Center for Astrophysics. "With an instrument like Chandra, we can now study the chemistry of the solar wind, and observe the X-ray glow from the atmospheres of comets as well as planets such as Venus. It may even be possible to observe other, nearby solar systems." Comets, which resemble "dirty snow balls" a few miles in diameter, were thought to be too cold for such energetic emission, so the detection of X-rays by the ROSAT observatory from comet Hyakutake in 1996 was a surprise. Several explanations were suggested, but the source of cometary X-ray emission remained a puzzle until the Chandra observation of Comet C/1999 S4 (LINEAR). Chandra's imaging spectrometer revealed a strong X-ray signal from oxygen and nitrogen ions, clinching the case for the production of X-rays due to the exchange of electrons in collisions between nitrogen and oxygen ions in the solar wind and electrically neutral elements (predominantly hydrogen) in the comets atmosphere. The Chandra observation was taken with the Advanced CCD Imaging Spectrometer (ACIS) on July 14, 2000 for a total of 2 ½ hours. The comet will be re-observed with Chandra during the weeks of July 29 - Aug 13. Comet C/1999 S4 (LINEAR) was discovered in September 1999 by the Lincoln Near Earth Asteroid Research (LINEAR) project, which is operated by the

  12. Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, S., E-mail: sebastian.eckert@helmholtz-berlin.de, E-mail: martin.beye@helmholtz-berlin.de; Beye, M., E-mail: sebastian.eckert@helmholtz-berlin.de, E-mail: martin.beye@helmholtz-berlin.de; Pietzsch, A.; Quevedo, W.; Hantschmann, M. [Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Ochmann, M.; Huse, N. [Institute for Nanostructure and Solid State Physics, University of Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg (Germany); Ross, M.; Khalil, M. [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States); Minitti, M. P.; Turner, J. J.; Moeller, S. P.; Schlotter, W. F.; Dakovski, G. L. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Föhlisch, A. [Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam (Germany)

    2015-02-09

    The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response.

  13. Catheter Angiography

    Medline Plus

    Full Text Available ... images are captured using a small dose of ionizing radiation ( x-rays ). top of page What are ... a form of radiation like light or radio waves. X-rays pass through most objects, including the ...

  14. Catheter Angiography

    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 ...

  15. Catheter Angiography

    Medline Plus

    Full Text Available ... The video is produced by the x-ray machine and a detector that is suspended over a ... of the body being examined, an x-ray machine produces a small burst of radiation that passes ...

  16. Station Explorer for X-Ray Timing and Navigation Technology Architecture Overview

    Science.gov (United States)

    Hasouneh, Monther Abdel Hamid

    2014-01-01

    The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron-star Interior Composition Explorer (NICER) mission. NICER is a NASA astrophysics Explorer Mission of Opportunity, scheduled for launch in mid-2016, that will be hosted on the International Space Station (ISS) via the ExPRESS Logistics Carrier (ELC). By exploiting the regular pulsations emit-ted by the ultra dense remnants of dead stars, which rotate many hundreds of times per second, SEXTANT will, for the first-time, demonstrate real-time, on-board X-ray pulsar-based navigation is a significant milestone in the quest to establish a GPS-like navigation capability available throughout our Solar System and beyond and include the worlds first completely functional system architecture for navigation using X-ray pulsars. In addition, NICER SEXTANT will investigate the suit-ability of these millisecond X-ray pulsars (MSPs) as a Solar System-wide timing infrastructure to rival terrestrial atomic clocks on long timescales. This paper provides a brief overview of the SEXTANT demonstration and the design of the system architecture that consists of the NICER X-ray timing instrument, the SEXTANT flight software and algorithms, supporting ground system, and the GSFC X-ray Navigation Laboratory Testbed (GXLT).

  17. An Einstein Observatory X-ray survey of main-sequence stars with shallow convection zones

    Science.gov (United States)

    Schmitt, J. H. M. M.; Golub, L.; Harnden, F. R., Jr.; Maxson, C. W.; Rosner, R.; Vaiana, G. S.

    1985-01-01

    The results of an X-ray survey of bright late A and early F stars on the main B-V sequence between 0.1 and 0.5 are presented. All the stars were observed with the Einstein Observatory for a period of at least 500 seconds. The survey results show significantly larger X-ray luminosities for the sample binaries than for the single stars. It is suggested that the difference is due to the presence of multiple X-ray sources in binaries. It is shown that the X-ray luminosities for single stars increase rapidly with increasing color, and that the relation Lx/Lbol is equal to about 10 to the -7th does not hold for A stars. No correlation was found between X-ray luminosity and projected equatorial rotation velocity. It is argued on the basis of the observations that X-ray emission in the sample stars originated from coronae. The available observational evidence supporting this view is discussed.

  18. Advanced Nanoscale Characterization of Cement Based Materials Using X-Ray Synchrotron Radiation: A Review

    KAUST Repository

    Chae, Sejung R.

    2013-05-22

    We report various synchrotron radiation laboratory based techniques used to characterize cement based materials in nanometer scale. High resolution X-ray transmission imaging combined with a rotational axis allows for rendering of samples in three dimensions revealing volumetric details. Scanning transmission X-ray microscope combines high spatial resolution imaging with high spectral resolution of the incident beam to reveal X-ray absorption near edge structure variations in the material nanostructure. Microdiffraction scans the surface of a sample to map its high order reflection or crystallographic variations with a micron-sized incident beam. High pressure X-ray diffraction measures compressibility of pure phase materials. Unique results of studies using the above tools are discussed-a study of pores, connectivity, and morphology of a 2,000 year old concrete using nanotomography; detection of localized and varying silicate chain depolymerization in Al-substituted tobermorite, and quantification of monosulfate distribution in tricalcium aluminate hydration using scanning transmission X-ray microscopy; detection and mapping of hydration products in high volume fly ash paste using microdiffraction; and determination of mechanical properties of various AFm phases using high pressure X-ray diffraction. © 2013 The Author(s).

  19. An ultraluminous X-ray source powered by an accreting neutron star

    DEFF Research Database (Denmark)

    Bachetti, M.; Harrison, F. A.; Walton, D. J.

    2014-01-01

    The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes(1,2). Their X-ray luminosities in the 0...... at the luminous end of the range (more than 10(40) ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear...... region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity...

  20. AX J1910.7+0917: the slowest X-ray pulsar

    Science.gov (United States)

    Sidoli, L.; Israel, G. L.; Esposito, P.; Rodríguez Castillo, G. A.; Postnov, K.

    2017-08-01

    Pulsations from the high-mass X-ray binary AX J1910.7+0917 were discovered during Chandra observations performed in 2011. We report here more details on this discovery and discuss the source nature. The period of the X-ray signal is P = 36200 ± 110 s, with a pulsed fraction, PF, of 63 ± 4 per cent. Given the association with a massive B-type companion star, we ascribe this long periodicity to the rotation of the neutron star (NS), making AX J1910.7+0917 the slowest known X-ray pulsar. We also report on the spectroscopy of XMM-Newton observations that serendipitously covered the source field, resulting in a highly absorbed (column density almost reaching 1023 cm-2), power-law X-ray spectrum. The X-ray flux is variable on a time-scale of years, spanning a dynamic range ≳ 60. The very long NS spin period can be explained within a quasi-spherical settling accretion model that applies to low luminosity, wind-fed, X-ray pulsars.

  1. Catheter Angiography

    Medline Plus

    Full Text Available ... What are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive medical ... top of page What are some common uses of the procedure? Catheter angiography is used to examine ...

  2. Influence by x-ray facula on dimension measurement

    Science.gov (United States)

    Qin, Xulei; Li, Ye; Duanmu, Qingduo; Zhao, Peng

    2015-03-01

    Based on the imaging features of the original image intensifier of X-ray, the light halo caused by X-ray projective halation is analyzed, the result shows the stray X-ray energy is lower than the direct X-ray energy. The screen brightness generated by the image intensifier of X-ray stimulated by the stray X-ray energy is weaker than that generated by the direct X-ray energy. In addition the projector facula reflected from the direct X-ray is focused on the central region of X-ray image intensifier, therefore a toroidal ring similar to the solar halation is formed around the projector halation. The results of the theoretical analysis and experimental discovery show this phenomenon caused by X-ray tube on X-ray image intensifier can not be eliminated and in the system of X-ray size detection composed of them the X-ray halation will reduce the detection accuracy resulting in measurement results' deviation dispersion under given conditions. This kind of nonlinear system error can not be canceled out by the segmented modification of coefficient compensation but it can be restrained through the adjustment of correction coefficients. After the physical testing and comparison of the physical normal size the accuracy of 0.1mm of the compensated X-ray measurement results after the adjustment of correction coefficient has been reached. The results are highly reproducible and the method of the segmented coefficient compensation has been improved.

  3. X-ray scattering measurements from thin-foil x-ray mirrors

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; BYRNAK, BP; Hornstrup, Allan

    1992-01-01

    Thin foil X-ray mirrors are to be used as the reflecting elements in the telescopes of the X-ray satellites Spectrum-X-Gamma (SRG) and ASTRO-D. High resolution X-ray scattering measurements from the Au coated and dip-lacquered Al foils are presented. These were obtained from SRG mirrors positioned...... in a test quadrant of the telescope structure and from ASTRO-D foils held in a simple fixture. The X-ray data is compared with laser data and other surface structure data such as STM, atomic force microscopy (AFM), TEM, and electron micrography. The data obtained at Cu K-alpha(1), (8.05 keV) from all...

  4. X-ray optics the diffraction of X-rays by finite and imperfect crystals

    CERN Document Server

    Wilson, Arthur J C

    1949-01-01

    This fascinating text contains a detailed treatise on the use of X-Ray optics in the taxonomy of minerals and gem stones. An interesting and informative book on the subject, X-Ray Optics - The Diffraction of X-Rays by Finite and Imperfect Crystals is a must-have for anyone with an interest the study of crystals and constitutes a great addition to any gemmological collection. Arthur James Cochran Wilson (28 November 1914 - 1 July 1995) was a Canadian crystallographer, most famous for his contributions to X-ray crystallography and elected as a Fellow of the Royal Society in 1963. This book has been elected for republication now due to its immense educational value, and is proudly republished here complete with a new introduction to the subject.

  5. X-Ray Optics on a Chip: Guiding X Rays in Curved Channels.

    Science.gov (United States)

    Salditt, T; Hoffmann, S; Vassholz, M; Haber, J; Osterhoff, M; Hilhorst, J

    2015-11-13

    We study the propagation of hard x rays in single curved x-ray waveguide channels and observe waveguide effects down to surprisingly small radii of curvature R≃10  mm and a large contour length s≃5  mm, deflecting beams up to 30°. At these high angles, about 2 orders of magnitude above the critical angle of total reflection θ(c), most radiation modes are lost by "leaking" into the cladding, while certain "survivor" modes persist. This may open up a new form of integrated x-ray optics "on a chip," requiring curvatures mostly well below the extreme values studied here, e.g., to split and to delay x-ray pulses.

  6. Soft X-ray Absorbers Enabling Study of the Diffuse X-ray Background Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Absorbers for soft x-rays need to be made thinner and with larger area, to collect more photons, and with minimal number of support stems. However, the structure is...

  7. Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

    Directory of Open Access Journals (Sweden)

    Malik Muhammad Abdullah

    2016-09-01

    Full Text Available We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop.

  8. X-Ray Scattering Applications Using Pulsed X-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Larson, B.C.

    1999-05-23

    Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.

  9. Behavior of characteristic X-rays from a partial-transmission-type X-ray target.

    Science.gov (United States)

    Raza, Hamid Saeed; Kim, Hyun Jin; Ha, Jun Mok; Cho, Sung Oh

    2013-10-01

    The angular distribution of characteristic X-rays using a partial-transmission tungsten target was analyzed. Twenty four tallies were modeled to cover a 360° envelope around the target. The Monte Carlo N-Particle (MCNP5) simulation results revealed that the characteristic X-ray flux is not always isotropic around the target. Rather, the flux mainly depends on the target thickness and the energy of the incident electron beam. A multi-energy photon generator is proposed to emit high-energy characteristic X-rays, where the target acts as a filter for the low-energy characteristic X-rays. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Monolithic CMOS imaging x-ray spectrometers

    Science.gov (United States)

    Kenter, Almus; Kraft, Ralph; Gauron, Thomas; Murray, Stephen S.

    2014-07-01

    The Smithsonian Astrophysical Observatory (SAO) in collaboration with SRI/Sarnoff is developing monolithic CMOS detectors optimized for x-ray astronomy. The goal of this multi-year program is to produce CMOS x-ray imaging spectrometers that are Fano noise limited over the 0.1-10keV energy band while incorporating the many benefits of CMOS technology. These benefits include: low power consumption, radiation "hardness", high levels of integration, and very high read rates. Small format test devices from a previous wafer fabrication run (2011-2012) have recently been back-thinned and tested for response below 1keV. These devices perform as expected in regards to dark current, read noise, spectral response and Quantum Efficiency (QE). We demonstrate that running these devices at rates ~> 1Mpix/second eliminates the need for cooling as shot noise from any dark current is greatly mitigated. The test devices were fabricated on 15μm, high resistivity custom (~30kΩ-cm) epitaxial silicon and have a 16 by 192 pixel format. They incorporate 16μm pitch, 6 Transistor Pinned Photo Diode (6TPPD) pixels which have ~40μV/electron sensitivity and a highly parallel analog CDS signal chain. Newer, improved, lower noise detectors have just been fabricated (October 2013). These new detectors are fabricated on 9μm epitaxial silicon and have a 1k by 1k format. They incorporate similar 16μm pitch, 6TPPD pixels but have ~ 50% higher sensitivity and much (3×) lower read noise. These new detectors have undergone preliminary testing for functionality in Front Illuminated (FI) form and are presently being prepared for back thinning and packaging. Monolithic CMOS devices such as these, would be ideal candidate detectors for the focal planes of Solar, planetary and other space-borne x-ray astronomy missions. The high through-put, low noise and excellent low energy response, provide high dynamic range and good time resolution; bright, time varying x-ray features could be temporally and

  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-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. Chandra ACIS Observations of Jovian X-Ray Emission

    Science.gov (United States)

    Garmire, Gordon; Elsner, Ronald; Feigelson, Eric; Ford, Peter; Gladstone, G. Randall; Hurley, Kevin; Metzger, Albert; Waite, J. Hunter, Jr.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    On November 25 and 26, 1999, the Chandra X-ray spacecraft conducted a set of four 19,000 sec observations of Jupiter. The ACIS-S instrument configuration was used for its good low energy efficiency and spatial resolution. An anomalous response was obtained which was subsequently attributed to strong jovian infrared radiation penetrating the detector and piling up spurious events across the entire X-ray range. However, the pre-observation establishment of an offsetting bias field has allowed the recovery of data from that portion of Jupiter's disc which remained within the elevated portion of the bias field during the observation. This ranges from fewer than 3000 sec to the entire observing time for about 10% of the planet. Auroral emission is seen near both poles in each observation. The northern aurora ia overall more intense than the southern, consistent with prior Einstein and ROSAT Observatory results. The southern aurora shows more modulation with Jupiter's rotation than the northern. Spatial resolution has been improved by at least a factor of two over prior measurements but convincing evidence of structure has not been seen. Lower latitude emission, first observed by ROSAT, is confirmed with flux levels averaging more than a factor of five below peak auroral values. Pronounced variation in the observed emission has occurred over the observing period. The spectral response extends from 0.24 keV, below which noise dominates, to about 1.2 keV. For all four observations the spectrum is clearly enhanced between 0.45 and 0.85 keV. This is apparently unequivocal evidence that Jupiter's X-ray emission is the result of oxygen and perhaps sulfur ions precipitating into the planet's atmosphere, where they undergo charge exchange interactions. The identification of specific transitions lines in the spectrum is among the ongoing efforts. A bremsstrahlung component has not yet been identified.

  14. Femtosecond X-ray scattering in condensed matter

    Energy Technology Data Exchange (ETDEWEB)

    Korff Schmising, Clemens von

    2008-11-24

    This thesis investigates the manifold couplings between electronic and structural properties in crystalline Perovskite oxides and a polar molecular crystal. Ultrashort optical excitation changes the electronic structure and the dynamics of the connected reversible lattice rearrangement is imaged in real time by femtosecond X-ray scattering experiments. An epitaxially grown superlattice consisting of alternating nanolayers of metallic and ferromagnetic strontium ruthenate (SRO) and dielectric strontium titanate serves as a model system to study optically generated stress. In the ferromagnetic phase, phonon-mediated and magnetostrictive stress in SRO display similar sub-picosecond dynamics, similar strengths but opposite sign and different excitation spectra. The amplitude of the magnetic component follows the temperature dependent magnetization square, whereas the strength of phononic stress is determined by the amount of deposited energy only. The ultrafast, phonon-mediated stress in SRO compresses ferroelectric nanolayers of lead zirconate titanate in a further superlattice system. This change of tetragonal distortion of the ferroelectric layer reaches up to 2 percent within 1.5 picoseconds and couples to the ferroelectric soft mode, or ion displacement within the unit cell. As a result, the macroscopic polarization is reduced by up to 100 percent with a 500 femtosecond delay that is due to final elongation time of the two anharmonically coupled modes. Femtosecond photoexcitation of organic chromophores in a molecular, polar crystal induces strong changes of the electronic dipole moment via intramolecular charge transfer. Ultrafast changes of transmitted X-ray intensity evidence an angular rotation of molecules around excited dipoles following the 10 picosecond kinetics of the charge transfer reaction. Transient X-ray scattering is governed by solvation, masking changes of the chromophore's molecular structure. (orig.)

  15. ZBLAN-based x-ray storage phosphors and scintillators for digital x-ray imaging

    Science.gov (United States)

    Chen, Gang; Johnson, Jacqueline A.; Weber, Richard; Schweizer, Stefan; MacFarlane, Douglas; Woodford, John; De Carlo, Francesco

    2005-04-01

    X-ray storage phosphors have several advantages over traditional films as well as digital X-ray detectors based on thin-film transistors (TFT). Commercially used storage phosphors do not have high resolution due to light scattering from powder grains. To solve this problem, we have developed storage phosphor plates based on modified fluorozirconate (ZBLAN) glasses. The newly developed imaging plates are "grainless" and, therefore, can significantly reduce light scattering and improve image resolution. To study the structure and image performance of the novel storage phosphor plates, we conducted X-ray diffraction (XRD) and X-ray imaging analyses at the Advanced Photon Source, Argonne National Laboratory. The XRD results show that BaCl2 crystallites are embedded in the glass matrix. These crystallites enlarge and are under residual stress after heat treatment. The X-ray imaging study shows that these storage phosphor plates have a much better resolution than a commercially used storage phosphor screen. The results also show that some of the glass ceramics are high-resolution scintillators. Our study demonstrates that these fluorozirconate-based glass ceramics are a promising candidate for high-resolution digital X-ray detectors for both medical and scientific research purposes.

  16. HERMES: a soft X-ray beamline dedicated to X-ray microscopy.

    Science.gov (United States)

    Belkhou, Rachid; Stanescu, Stefan; Swaraj, Sufal; Besson, Adrien; Ledoux, Milena; Hajlaoui, Mahdi; Dalle, Didier

    2015-07-01

    The HERMES beamline (High Efficiency and Resolution beamline dedicated to X-ray Microscopy and Electron Spectroscopy), built at Synchrotron SOLEIL (Saint-Auban, France), is dedicated to soft X-ray microscopy. The beamline combines two complementary microscopy methods: XPEEM (X-ray Photo Emitted Electron Microscopy) and STXM (Scanning Transmission X-ray Microscopy) with an aim to reach spatial resolution below 20 nm and to fully exploit the local spectroscopic capabilities of the two microscopes. The availability of the two methods within the same beamline enables the users to select the appropriate approach to study their specific case in terms of sample environment, spectroscopy methods, probing depth etc. In this paper a general description of the beamline and its design are presented. The performance and specifications of the beamline will be reviewed in detail. Moreover, the article is aiming to demonstrate how the beamline performances have been specifically optimized to fulfill the specific requirements of a soft X-ray microscopy beamline in terms of flux, resolution, beam size etc. Special attention has been dedicated to overcome some limiting and hindering problems that are usually encountered on soft X-ray beamlines such as carbon contamination, thermal stability and spectral purity.

  17. 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.

  18. X-ray bursts observed with JEM-X

    DEFF Research Database (Denmark)

    Brandt, Søren Kristian; Chenevez, Jérôme; Lund, Niels

    2006-01-01

    We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found.......We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found....

  19. A soft X-ray image of the moon

    Science.gov (United States)

    Schmitt, J. H. M. M.; Aschenbach, B.; Hasinger, G.; Pfeffermann, E.; Snowden, S. L.

    1991-01-01

    A soft X-ray image of the moon obtained by the Roentgen Observatory Satellite ROSAT clearly shows a sunlit crescent, demonstrating that the moon's X-ray luminosity arises from backscattering of solar X-rays. The moon's optically dark side is also X-ray dark, and casts a distinct shadow on the diffuse cosmic X-ray background. Unexpectedly, the dark side seems to emit X-rays at a level about one percent of that of the bright side; this emission very probably results from energetic solar-wind electrons striking the moon's surface.

  20. A search for X-ray reprocessing echoes in the power spectral density functions of AGN

    Science.gov (United States)

    Emmanoulopoulos, D.; Papadakis, I. E.; Epitropakis, A.; Pecháček, T.; Dovčiak, M.; McHardy, I. M.

    2016-09-01

    We present the results of a detailed study of the X-ray power spectral density (PSD) functions of 12 X-ray bright AGN, using almost all the archival XMM-Newton data. The total net exposure of the EPIC-pn light curves is larger than 350 ks in all cases (and exceeds 1 Ms in the case of 1H 0707-497). In a physical scenario in which X-ray reflection occurs in the inner part of the accretion disc of AGN, the X-ray reflection component should be a filtered echo of the X-ray continuum signal and should be equal to the convolution of the primary emission with the response function of the disc. Our primary objective is to search for these reflection features in the 5-7 keV (iron line) and 0.5-1 keV (soft) bands, where the X-ray reflection fraction is expected to be dominant. We fit to the observed periodograms two models: a simple bending power-law model (BPL) and a BPL model convolved with the transfer function of the accretion disc assuming the lamp-post geometry and X-ray reflection from a homogeneous disc. We do not find any significant features in the best-fitting BPL model residuals either in individual PSDs in the iron band, soft and full band (0.3-10 keV) or in the average PSD residuals of the brightest and more variable sources (with similar black hole mass estimates). The typical amplitude of the soft and full-band residuals is around 3-5 per cent. It is possible that the expected general relativistic effects are not detected because they are intrinsically lower than the uncertainty of the current PSDs, even in the strong relativistic case in which X-ray reflection occurs on a disc around a fast rotating black hole having an X-ray source very close above it. However, we could place strong constrains to the X-ray reflection geometry with the current data sets if we knew in advance the intrinsic shape of the X-ray PSDs, particularly its high-frequency slope.

  1. X-ray radiography for container inspection

    Science.gov (United States)

    Katz, Jonathan I [Clayton, MO; Morris, Christopher L [Los Alamos, NM

    2011-06-07

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

  2. Soft X-ray multilayers and filters

    CERN Document Server

    Wang Zhan Shan; Tang Wei Xing; Qin Shuji; Zhou Bing; Chen Ling Ya

    2002-01-01

    The periodic and non-periodic multilayers were designed by using a random number to change each layer and a suitable merit function. Ion beam sputtering and magnetron sputtering were used to fabricate various multilayers and beam splitters in soft X-ray range. The characterization of multilayers by small angle X-ray diffraction, Auger electron spectroscopy, Rutherford back scattering spectroscopy and reflectivity illustrated the multilayers had good structures and smooth interlayers. The reflectivity and transmission of a beam splitter is about 5%. The fabrication and transmission properties of Ag, Zr were studied. The Rutherford back scattering spectroscopy and auger electron spectroscopy were used to investigate the contents and distributions of impurities and influence on qualities of filters. The attenuation coefficients were corrected by the data obtained by measurements

  3. 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...

  4. High precision x ray lithographic masks

    Science.gov (United States)

    Pease, R. F.; Browning, R.

    1992-09-01

    This contract period was first concerned with winding up the projects on the embedded X-ray Mask structure and on the 'quantum lithography' idea. As a result of developments elsewhere it became clear that among the most critical issues in achieving high precision X-ray masks were those associated with achieving high precision in both feature size and feature placement in electron beam lithography. Most of the effort in this reporting period was aimed at achieving precision in feature size; notably an attack on the problem of proximity effects. There were two approaches: (1) A short term approach aimed at correcting effects in existing electron beam pattern generators (notably the ETEC MEBES 3 and 4) for feature sizes down 500 nm; and (2) A long term approach aimed at avoiding proximity effects by employing low energy electron exposure for feature size below 500 nm.

  5. X-ray Winds from Black Holes

    Science.gov (United States)

    Miller, Jon M.

    2017-08-01

    Across the mass scale, high-resolution X-ray spectroscopy has transformed our view of accretion onto black holes. The ionized disk winds observed from stellar-mass black holes may sometimes eject more mass than is able to accrete onto the black hole. It is possible that these winds can probe the fundamental physics that drive disk accretion. The most powerful winds from accretion onto massive black holes may play a role in feedback, seeding host bulges with hot gas and halting star formation. The lessons and techniques emerging from these efforts can also reveal the accretion flow geometry in tidal disruption events (TDEs), an especially rich discovery space. This talk will review some recent progress enabled by high-resolution X-ray spectroscopy, and look at the potential of gratings spectrometers and microcalorimeters in the years ahead.

  6. The microchannel x-ray telescope status

    Science.gov (United States)

    Götz, D.; Meuris, A.; Pinsard, F.; Doumayrou, E.; Tourrette, T.; Osborne, J. P.; Willingale, R.; Sykes, J. M.; Pearson, J. F.; Le Duigou, J. M.; Mercier, K.

    2016-07-01

    We present design status of the Microchannel X-ray Telescope, the focussing X-ray telescope on board the Sino- French SVOM mission dedicated to Gamma-Ray Bursts. Its optical design is based on square micro-pore optics (MPOs) in a Lobster-Eye configuration. The optics will be coupled to a low-noise pnCCD sensitive in the 0.2{10 keV energy range. With an expected point spread function of 4.5 arcmin (FWHM) and an estimated sensitivity adequate to detect all the afterglows of the SVOM GRBs, MXT will be able to provide error boxes smaller than 60 (90% c.l.) arc sec after five minutes of observation.

  7. Connecting the coherent and stochastic X-ray variability of accreting millisecond pulsars

    NARCIS (Netherlands)

    Bult, P.M.

    2015-01-01

    Accreting millisecond pulsars are rapidly rotating neutron stars with a dynamically important magnetic field. These objects are found in low-mass X-ray binary systems, where a small companion star acts as a mass donor, transferring material to the neutron star. As this plasma spirals toward the

  8. Two-channel X-ray reflectometer

    CERN Document Server

    Touryanski, A G; Pirshin, I V

    2000-01-01

    The two-channel X-ray reflectometer is proposed providing an increase in accuracy and sensitivity especially to nanoscale oxide layers. The reflectometer has two independent measuring channels controlled by a processor and the beam-splitting and spectral selection device based on a row of semitransparent plates of pyrolitic graphite. Results of reflection curve measurements in a relative mode are presented for an Ni film and GaAs monocrystal.

  9. X-ray microimaging by diffractive techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kirz, Janos; Jacobsen, Chris

    2001-07-31

    The report summarizes the development of soft x-ray microscopes at the National Synchrotron Light Source X-1A beamline. We have developed a soft x-ray microscopy beamline (X-1A) at the National Synchrotron Light Source at Brookhaven National Laboratory. This beamline has been upgraded recently to provide two endstations dedicated to microscopy experiments. One endstation hosts a brand new copy of the redesigned room temperature scanning x-ray microscope (STXM), and the other end station hosts a cryo STXM and the original redesigned room temperature microscope, which has been commissioned and has started operation. Cryo STXM and the new microscope use the same new software package, running under the LINUX operating system. The new microscope is showing improved image resolution and extends spectromicroscopy to the nitrogen, oxygen and iron edges. These microscopes are used by us, and by users of the facility, to image hydrated specimens at 50 nm or better spatial resolution and with 0.1-0.5 eV energy resolution. This allows us to carry out chemical state mapping in biological, materials science, and environmental and colloidal science specimens. In the cryo microscope, we are able to do chemical state mapping and tomography of frozen hydrated specimens, and this is of special importance for radiation-sensitive biological specimens. for spectromicroscopic analysis, and methods for obtaining real-space images from the soft x-ray diffraction patterns of non-crystalline specimens. The user program provides opportunities for collaborators and other groups to exploit the techniques available and to develop them further. We have also developed new techniques such as an automated method for acquiring ''stacks'' of images.

  10. 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.

  11. Early x-ray diagnosis of coxarthrosis

    Energy Technology Data Exchange (ETDEWEB)

    Lingg, G.; Nebel, G.

    Radiological and pathological comparisons on specimen of femur head and neck at autopsy have shown a statistical relationship between osteophytosis of the femoral head and ulcerations of the joint cartilage. Especially, there are highly significant relationships between the length of osteophytes and the diameter of the ulcera. The 'plaque'-sign is shown to be a very sensitive indicator of early arthrosis. So there exist semiquantitative parameters for the X-ray diagnosis of early coxarthrosis.

  12. 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.

  13. Monitoring Instrument for X-Ray Box

    CERN Document Server

    Cifuentes Ospina, Alberto; Kuehn, Susanne; Schaepe, Steffen; CERN. Geneva. EP Department

    2017-01-01

    A humidity and temperature readout instrument has been designed and implemented in order to monitor the X-Ray Box used for testing the silicon detectors prototypes of the ITk. The sensors are connected to an Arduino Mega board equipped with 16 analog inputs and a serial port to a computer. A user-friendly software has been also designed in order to give an easy access to all measurements.

  14. Basic of X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Giacovazzo, C. [Bari Univ. (Italy). Dip. Geomineralogico

    1996-09-01

    The basic concepts of X-ray diffraction may be more easily understood if it is made preliminary use of a mathematical background. In these pages the authors will first define the delta function and its use for the representation of a lattice. Then the concepts of Fourier transform and convolution are given. At the end of this talk one should realize that a crystal is the convolution of the lattice with a function representing the content of the unit cell.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. X-ray Reverberation Mapping in Active Galactic Nuclei

    Science.gov (United States)

    Kara, Erin

    2018-01-01

    Active Galactic Nuclei can produce as much or more electromagnetic and kinetic luminosities than the combined stellar luminosity of an entire galaxy. The energy output from AGN comes from the gravitational potential energy of the infalling material and the rotational energy of the black hole, both of which are released very close to the black hole. Therefore, probing the relativistic region of the inner accretion flow is essential to understanding how AGN work and effect their environments. In this talk, I will present a new technique for probing these relativistic environments: X-ray reverberation mapping. Similar to Optical reverberation mapping, where time delays of days or weeks between the continuum and Broad Line Region lines map out centiparsec scales, X-ray reverberation reveals time delays of tens of seconds, which map out microparsec scales in the accretion flow—well beyond the spatial resolution power of any instrument. This technique has been discovered in the past decade, so I will give a brief overview of how the measurements are made, and highlight some recent discoveries, which allow us to map the gas falling on to the black hole and measure the effects of strongly curved spacetime close to the event horizon.

  20. 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.