Science.gov

Sample records for high-energy x-ray reflectometry

  1. Direct structural observation of a molecular junction by high-energy x-ray reflectometry

    PubMed Central

    Lefenfeld, Michael; Baumert, Julian; Sloutskin, Eli; Kuzmenko, Ivan; Pershan, Peter; Deutsch, Moshe; Nuckolls, Colin; Ocko, Benjamin M.

    2006-01-01

    We report a direct angstrom resolution measurement of the structure of a molecular-size electronic junction comprising a single (or a double) layer of alkyl-thiol and alkyl-silane molecules at the buried interface between solid silicon and liquid mercury. The high-energy synchrotron x-ray measurements reveal densely packed layers comprising roughly interface-normal molecules. The monolayer’s thickness is found to be 3–4 Å larger than that of similar layers at the free surfaces of both mercury and silicon. The origins of this and the other unusual features detected are discussed in this article. Measurements of the bilayer junction with an applied potential did not show visible changes in the surface normal structure. PMID:16467139

  2. Direct Structural Observation of a Molecular Junction by High-Energy X-ray Reflectometry

    SciTech Connect

    Lefenfeld,M.; Baumert, J.; Sloutskin, E.; Kuzmenko, I.; Pershan, P.; Deutsch, M.; Nuckolls, C.; Ocko, B.

    2006-01-01

    We report a direct angstrom resolution measurement of the structure of a molecular-size electronic junction comprising a single (or a double) layer of alkyl-thiol and alkyl-silane molecules at the buried interface between solid silicon and liquid mercury. The high-energy synchrotron x-ray measurements reveal densely packed layers comprising roughly interface-normal molecule . The monolayer's thickness is found to be 3-4 Angstroms larger than that of similar layers at the free surfaces of both mercury and silicon. The origins of this and the other unusual features detected are discussed in this article. Measurements of the bilayer junction with an applied potential did not show visible changes in the surface normal structure.

  3. Theoretical foundation of X-ray and neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao-Lin; Chen, Sow-Hsin

    1995-06-01

    This review attempts to give a systematic exposition of the theoretical foundation underlying surface depth profiling at the molecular level using X-ray and neutron specular reflectometry. It covers the fundamentals of X-ray and neutron interactions with matter, the direct theory of specular reflection from stratified media, the inverse theory of specular reflection for obtaining the surface depth profile from measured specular reflection data, and demonstration of how the theories can be used in practice. The part on X-ray and neutron interactions with matter begins with the basic quantum mechanical and classical electromagnetic descriptions of scattering, discusses the important concepts of scattering and absorption cross sections, the scattering length density and the refractive index of matter, and derives the one-dimensional Helmholtz wave equation which fully describes the specular reflection of slow neutrons and X-rays from a macroscopic stratified medium. The direct theory begins with the development of the solution of the Helmholtz wave equation in the form of a discrete formulation, namely, Parratt's recurrence relation, and proceeds to several continuous formulations, such as the Born and distorted wave Born (DWBA) approximations, the small-curvature approximation (SCA), the modified WKB approximation (MWKB) and the weighted-superposition approximation (WSA), and ends with a discussion about the effect of surface roughness. The inverse theory presents methods for the reconstruction of the depth profile of the surface scattering length density from a set of specular reflection data. This includes the feasibility of data inversion, some simple examples of analytic data inversion, a matrix-iteration method (MIM), and a groove-tracking method (GTM). For demonstration of the use of the theories, we give an example of neutron reflectivity data analyses, from which the surface-layering phenomenon in bicontinuous microemulsions is revealed.

  4. The high energy X-ray universe

    PubMed Central

    Giacconi, Riccardo

    2010-01-01

    Since its beginning in the early 1960s, the field of X-ray astronomy has exploded, experiencing a ten-billion-fold increase in sensitivity, which brought it on par with the most advanced facilities at all wavelengths. I will briefly describe the revolutionary first discoveries prior to the launch of the Chandra and XMM-Newton X-ray observatories, present some of the current achievements, and offer some thoughts about the future of this field. PMID:20404148

  5. High energy-resolution inelastic x-ray scattering

    SciTech Connect

    Hastings, J.B.; Moncton, D.E.; Fujii

    1984-01-01

    A brief review is presented of various aspects of high energy-resolution inelastic x-ray scattering based on synchrotron sources. We show what kinematical advantages are provided by the photon probe and propose mirror and monochromator designs to achieve an optically efficient beam line for inelastic x-ray scattering.

  6. The High Energy Astronomy Observatory X-ray Telescope

    NASA Technical Reports Server (NTRS)

    Miller, R.; Austin, G.; Koch, D.; Jagoda, N.; Kirchner, T.; Dias, R.

    1978-01-01

    The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

  7. Treatment of foods with high-energy X rays

    NASA Astrophysics Data System (ADS)

    Cleland, M. R.; Meissner, J.; Herer, A. S.; Beers, E. W.

    2001-07-01

    The treatment of foods with ionizing energy in the form of gamma rays, accelerated electrons, and X rays can produce beneficial effects, such as inhibiting the sprouting in potatoes, onions, and garlic, controlling insects in fruits, vegetables, and grains, inhibiting the growth of fungi, pasteurizing fresh meat, poultry, and seafood, and sterilizing spices and food additives. After many years of research, these processes have been approved by regulatory authorities in many countries and commercial applications have been increasing. High-energy X rays are especially useful for treating large packages of food. The most attractive features are product penetration, absorbed dose uniformity, high utilization efficiency and short processing time. The ability to energize the X-ray source only when needed enhances the safety and convenience of this technique. The availability of high-energy, high-power electron accelerators, which can be used as X-ray generators, makes it feasible to process large quantities of food economically. Several industrial accelerator facilities already have X-ray conversion equipment and several more will soon be built with product conveying systems designed to take advantage of the unique characteristics of high-energy X rays. These concepts will be reviewed briefly in this paper.

  8. Radiation processing with high-energy X-rays

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.; Stichelbaut, Frédéric

    2013-03-01

    The radiation processing of materials and commercial products with high-energy X-rays, which are also identified by the German term bremsstrahlung, can produce beneficial changes that are similar to those obtained by irradiation with nuclear gamma rays emitted by cobalt-60 sources. Both X-rays and gamma rays are electromagnetic radiations with short wavelengths and high photon energies that can stimulate chemical reactions by creating ions and free radicals in irradiated materials. Nevertheless, there are some physical differences in these energy sources that can influence the choice for practical applications. The English translation of bremsstrahlung is braking radiatiorn or deceleration radiation. It is produced when energetic electrons are deflected by the strong electric field near an atomic nucleus. The efficiency for producing this kind of electromagnetic energy increases with the kinetic energy of the electrons and the atomic number of the target material. The energy spectrum of the emitted X-ray photons is very broad and extends up to the maximum energy of the incident electrons. In contrast, a cobalt-60 nucleus emits two gamma rays simultaneously, which have well-defined energies. Another significant difference is the angular distribution of the radiation. Nuclear gamma rays are emitted in all directions, but high-energy bremsstrahlung photons are concentrated in the direction of the incident electrons when they strike the target material. This property enables an X-ray processing facility to be more compact than a gamma-ray processing facility with similar throughput capacity, and it increases the penetration and the efficiency for absorbing the emitted X-ray energy in the irradiated material. Recent increases in the electron energy and the electron beam power from modern industrial accelerators have increased the throughput rates in X-ray processing facilities, so that this irradiation method is now economically competitive with large cobalt-60

  9. Phase contrast imaging with coherent high energy X-rays

    SciTech Connect

    Snigireva, I.

    1997-02-01

    X-ray imaging concern high energy domain (>6 keV) like a contact radiography, projection microscopy and tomography is used for many years to discern the features of the internal structure non destructively in material science, medicine and biology. In so doing the main contrast formation is absorption that makes some limitations for imaging of the light density materials and what is more the resolution of these techniques is not better than 10-100 {mu}m. It was turned out that there is now way in which to overcome 1{mu}m or even sub-{mu}m resolution limit except phase contrast imaging. It is well known in optics that the phase contrast is realised when interference between reference wave front and transmitted through the sample take place. Examples of this imaging are: phase contrast microscopy suggested by Zernike and Gabor (in-line) holography. Both of this techniques: phase contrast x-ray microscopy and holography are successfully progressing now in soft x-ray region. For imaging in the hard X-rays to enhance the contrast and to be able to resolve phase variations across the beam the high degree of the time and more importantly spatial coherence is needed. Because of this it was reasonable that the perfect crystal optics was involved like Bonse-Hart interferometry, double-crystal and even triple-crystal set-up using Laue and Bragg geometry with asymmetrically cut crystals.

  10. The High Energy X-ray Imager Technology (HEXITEC) for Solar Hard X-ray Observations

    NASA Astrophysics Data System (ADS)

    Christe, Steven; Shih, Albert Y.; Gaskin, Jessica; Wilson-Hodge, Colleen; Seller, Paul; Wilson, Matthew

    2015-04-01

    High angular resolution HXR optics require detectors with a large number of fine pixels in order to adequately sample the telescope point spread function (PSF) over the entire field of view. Excessively over-sampling the PSF will increase readout noise and require more processing with no appreciable increase in image quality. An appropriate level of over-sampling is to have 3 pixels within the HPD. For current high resolution X-ray mirrors, the HPD is about 25 arcsec. Over a 6-m focal length this converts to 750 µm, the optimum pixel size is around 250 µm. Annother requirement are that the detectors must also have high efficiency in the HXR region, good energy resolution, low background, low power requirements, and low sensitivity to radiation damage. For solar observations, the ability to handle high counting rates is also extremely desirable. The Rutherford Appleton Laboratory (RAL) in the UK has been developing the electronics for such a detector. Dubbed HEXITEC, for High Energy X-Ray Imaging Technology, this Application Specific Integrated Circuit (ASIC), can be bonded to 1- or 2- mm-thick Cadmium Telluride (CdTe) or Cadmium-Zinc-Telluride (CZT), to create a fine (250 µm pitch) HXR detector. The NASA Marshall Space Flight CenterMSFC and the Goddard Space Flight Center (GSFC) has been working with RAL over the past few years to develop these detectors to be used with HXR focusing telescopes. We present on recent results and capabilities as applied to solar observations.

  11. High-Energy X-Ray Diffraction Analysis Tool

    Energy Science and Technology Software Center (ESTSC)

    2011-11-29

    The functionality of heRXD includes the following: distance and angular calibration and viewing flat-panel detector images used for X-ray diffraction; image (polar) rebinning or "caking"; line position fitting in powder diffraction images; image segmentation or "blob finding"; crystal orentation indesing; and lattice vector refinement. These functionalities encompass a critical set analyzing teh data for high-energy diffraction measurements that are currently performed at synchrotron sources such as the Advanced Photon Source (APS). The software design modularmore » and open source under LGPL. The intent is to provide a common framework and graphical user interface that has the ability to utillize internal as well as external subroutines to provide various optins for performing the fuctionalities listed above. The software will initially be deployed at several national user facilities--including APS, ALS, and CHESS--and then made available for download using a hosting service such as sourceforge.« less

  12. 30-Lens interferometer for high-energy X-rays.

    PubMed

    Lyubomirskiy, Mikhail; Snigireva, Irina; Kohn, Victor; Kuznetsov, Sergey; Yunkin, Vyacheslav; Vaughan, Gavin; Snigirev, Anatoly

    2016-09-01

    A novel high-energy multi-lens interferometer consisting of 30 arrays of planar compound refractive lenses is reported. Under coherent illumination each lens array creates a diffraction-limited secondary source. Overlapping such coherent beams produces an interference pattern demonstrating strong longitudinal functional dependence. The proposed multi-lens interferometer was tested experimentally at the 100 m-long ID11 ESRF beamline in the X-ray energy range from 30 to 65 keV. The interference pattern generated by the interferometer was recorded at fundamental and fractional Talbot distances. An effective source size (FWHM) of the order of 15 µm was determined from the first Talbot image, proving the concept that the multi-lens interferometer can be used as a high-resolution tool for beam diagnostics. PMID:27577763

  13. High-Energy X-Ray Diffraction Analysis Tool

    SciTech Connect

    2011-11-29

    The functionality of heRXD includes the following: distance and angular calibration and viewing flat-panel detector images used for X-ray diffraction; image (polar) rebinning or "caking"; line position fitting in powder diffraction images; image segmentation or "blob finding"; crystal orentation indesing; and lattice vector refinement. These functionalities encompass a critical set analyzing teh data for high-energy diffraction measurements that are currently performed at synchrotron sources such as the Advanced Photon Source (APS). The software design modular and open source under LGPL. The intent is to provide a common framework and graphical user interface that has the ability to utillize internal as well as external subroutines to provide various optins for performing the fuctionalities listed above. The software will initially be deployed at several national user facilities--including APS, ALS, and CHESS--and then made available for download using a hosting service such as sourceforge.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  15. Comprehensive x-ray spectral code for high energy astrophysics

    SciTech Connect

    Liedahl, D A; Fournier, K B; Mauche, C W

    2000-08-18

    The aim of this project has been to develop a spectral analysis tool with a level of quality and completeness commensurate to that expected in data from the current generation of X-ray observatories. The code is called LXSS (Livermore X-Ray Spectral Synthesizer). X-ray-emitting astrophysical plasmas are rarely, if ever, in LTE, so they have adopted the detailed level accounting approach, in which rates for processes that populate or depopulate atomic energy levels are treated explicitly. This entails the generation of a large quantity of atomic data, most of which is calculated using ''in-house'' computer codes. Calculations are benchmarked against laboratory data, and spectral models have been used to provide first-time interpretations of astrophysical X-ray spectra. The design of a versatile graphical user interface that allows access to and manipulation of the atomic database comprises the second major part of the project.

  16. High-Energy X-Ray Timing Experiment Detections of Hard X-Ray Tails in Scorpius X-1

    NASA Astrophysics Data System (ADS)

    D'Amico, Flavio; Heindl, William A.; Rothschild, Richard E.; Gruber, Duane E.

    2001-02-01

    We report the detection of a nonthermal hard X-ray component from Sco X-1 based on the analysis of 20-220 keV spectra obtained with the High-Energy X-Ray Timing Experiment on board the Rossi X-Ray Timing Explorer satellite. We find that the addition of a power-law component to a thermal bremsstrahlung model is required to achieve a good fit in five of 16 observations analyzed. Using Proportional Counter Array data, we were able to track the movement of the source along the Z diagram, and we found that the presence of the hard X-ray tail is not confined to a specific Z position. However, we do observe an indication that the power-law index hardens with increasing M, as indicated from the position on the Z diagram. We find that the derived nonthermal luminosities are ~10% of that derived for the brightest of the atoll sources.

  17. Deeply X-raying the high-energy sky

    NASA Astrophysics Data System (ADS)

    Bottacini, Eugenio; Ajello, Marco

    2016-05-01

    All-sky explorations by Fermi-LAT have revolutionized our view of the gamma-ray Universe. While its ongoing all-sky survey counts thousands of sources, essential issues related to the nature of unassociated sources call for more sensitive all-sky surveys at hard X-ray energies that allow for their identification. This latter energy band encodes the hard-tail of the thermal emission and the soft-tail of non-thermal emission thereby bridging the non-thermal and thermal emission mechanisms of gamma-ray sources. All-sky surveys at hard X-rays are best performed by current coded-mask telescopes Swift/BAT and INTEGRAL/IBIS. To boost the hard X-ray all-sky sensitivity, we have developed an ad hoc technique by combining photons from independent observations of BAT and IBIS. The resulting Swift-INTEGRAL X-ray (SIX) survey has an improved source-number density. This improvement is essential to enhance the positive hard X-ray - gamma-ray source matches. We present the results from the scientific link between the neighboring gamma-ray and hard X-ray bands in the context of galactic and extragalactic source classes of the second catalog Fermi Gamma-ray LAT (2FGL).

  18. Technology development for high-energy x-ray optics

    NASA Astrophysics Data System (ADS)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell; Kester, Thomas; Speegle, Chet

    2006-06-01

    We are developing hard-x-ray optics using an electroformed-nickel-replication process off superpolished mandrels. To date, we have fabricated over 100 shells for our HERO balloon payload with typical angular resolutions in the 13-15 arcsec range. This paper discusses the factors currently limiting this resolution and various developments geared towards the production of higher-resolution optics.

  19. High energy, high resolution X-ray optics

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Joy, Marshall; Kahn, Steven

    1990-01-01

    The scientific goals of X-ray astronomy are considered to evaluate the relative advantages of using classical Wolter-1 optics or using a different approach. The portion of the X-ray band over 10 keV is unexploited in the present X-ray optics technology, and focussing in this portion of the band is crucial because nonfocussed experiments are background limited. The basic design of 'hard' X-ray optics is described theoretically emphasizing the very small angles of incidence in the grazing-incidence optics. Optimization of the signal-to-noise ratio is found to occur at a finite angular resolution. In real applications, the effective area reduced by the efficiency of the two reflections is 80 percent at energies up to 40 keV, and the quality of the reflecting surface can be monitored to minimize scattering. Focussing optics are found to offer improvements in signal-to-noise as well as more effective scientific return because microelectronic focal-plane technology is employed.

  20. High energy X-ray observations of extragalactic objects

    NASA Technical Reports Server (NTRS)

    Baity, W. A.; Gruber, D. E.; Matteson, J. L.; Knight, F. K.; Nolan, P. L.; Scheepmaker, A.; Wheaton, W. A.; Hofman, J. A.; Primini, F. A.; Lewin, W. H. G.

    1979-01-01

    Preliminary results are reported for scanning observations of the active galaxy NGC 5128 (Cen A) and the Type 1 Seyfert galaxy NGC 4151 with the low-energy detectors of the HEAO-1 A-4 hard X-ray instrument. The X-ray spectra in the energy range from 15 to 100 keV are shown to be consistent with previous observations of these galaxies. It is noted that NGC 5128 rose in intensity from 1972 to 1975, that spectral softening occurred after early 1973, and that the source has since decreased in intensity while maintaining an E to the -1.7 photon power law. The results for NGC 4151 indicate variable absorption below 10 keV and a power-law slope of about E to the -1.4 in the range from 10 keV to 10 MeV.

  1. Scintillator Evaluation for High-Energy X-Ray Diagnostics

    SciTech Connect

    S. S. Lutz; S. A. Baker

    2001-09-01

    This report presents results derived from a digital radiography study performed using x-rays from a 2.3 MeV, rod-pinch diode. Detailed is a parameter study of cerium-doped lutetium ortho-silicate (LSO) scintillator thickness, as it relates to system resolution and detection quantum efficiency (DQE). Additionally, the detection statistics of LSO were compared with that of CsI(Tl). As a result of this study we found the LSO scintillator with a thickness of 3 mm to yield the highest system DQE over the range of spatial frequencies from 0.75 to 2.5 mm{sup -1}.

  2. Event-Driven X-Ray CCD Detectors for High Energy Astrophysics

    NASA Technical Reports Server (NTRS)

    Ricker, George R.

    2004-01-01

    A viewgraph presentation describing the Event-Driven X- Ray CCD (EDCCD) detector system for high energy astrophysics is presented. The topics include: 1) EDCCD: Description and Advantages; 2) Summary of Grant Activity Carried Out; and 3) EDCCD Test System.

  3. Application of polarized neutron reflectometry and x-ray resonant magnetic reflectometry for determining the inhomogeneous magnetic structure in Fe/Gd multilayers.

    SciTech Connect

    Kravtsov, E. A.; Haskel, D.; te Velthuis, S. G. E.; Jiang, J. S.; Kirby, B. J.

    2010-01-01

    The evolution of the magnetic structure of multilayer [Fe (35 {angstrom})/Gd (50 {angstrom}){sub 5}] with variation in temperature and an applied magnetic field was determined using a complementary approach combining polarized neutron and X-ray resonant magnetic reflectometry. Self-consistent simultaneous analysis of X-ray and neutron spectra allowed us to determine the elemental and depth profiles in the multilayer structure with unprecedented accuracy, including the identification of an inhomogeneous intralayer magnetic structure with near-atomic resolution.

  4. Evaluation of resolution performance of high energy x-ray CT

    NASA Astrophysics Data System (ADS)

    Abe, Makoto; Fujimoto, Hiroyuki; Sato, Osamu; Sato, Katsutoshi; Takatsuji, Toshiyuki

    2015-07-01

    Dimensional X-ray CT has attracted production industry due to its nature [1] enabling not only external dimensional measurement but also internal dimensional measurement which has been difficult for pre-existing dimensional measurement instruments. However, because the reconstruction process of three dimensional volume image may be affected by various kinds of error sources of the hardware and also the software, performance evaluation of dimensional X-ray CT has become one of the major issues [2], especially for X-ray CT system with higher energy such as several MeV. Resolution performance of high energy X-ray CT was evaluated by using a series of phantoms which equip regular line-and-space structures with various pitch sizes down to 100 micrometer. These phantoms were prototyped in the identical pitch sizes with three different materials. These phantoms were practically measured by a high energy X-ray CT. Results and perspective of the resolution performance is presented.

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

    PubMed Central

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

    2016-01-01

    High energy X-ray imaging has unique advantage over conventional X-ray imaging, since it enables higher penetration into materials with significantly reduced radiation damage. However, the absorption contrast in high energy region is considerably low due to the reduced X-ray absorption cross section for most materials. Even though the X-ray phase and dark-field imaging techniques can provide substantially increased contrast and complementary information, fabricating dedicated optics for high energies still remain a challenge. To address this issue, we present an alternative X-ray imaging approach to produce transmission, phase and scattering signals at high X-ray energies by using a random absorption mask. Importantly, in addition to the synchrotron radiation source, this approach has been demonstrated for practical imaging application with a laboratory-based microfocus X-ray source. This new imaging method could be potentially useful for studying thick samples or heavy materials for advanced research in materials science. PMID:27466217

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

    PubMed

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

    2016-01-01

    High energy X-ray imaging has unique advantage over conventional X-ray imaging, since it enables higher penetration into materials with significantly reduced radiation damage. However, the absorption contrast in high energy region is considerably low due to the reduced X-ray absorption cross section for most materials. Even though the X-ray phase and dark-field imaging techniques can provide substantially increased contrast and complementary information, fabricating dedicated optics for high energies still remain a challenge. To address this issue, we present an alternative X-ray imaging approach to produce transmission, phase and scattering signals at high X-ray energies by using a random absorption mask. Importantly, in addition to the synchrotron radiation source, this approach has been demonstrated for practical imaging application with a laboratory-based microfocus X-ray source. This new imaging method could be potentially useful for studying thick samples or heavy materials for advanced research in materials science. PMID:27466217

  7. High energy X-ray and radio studies of Scorpius X-1

    NASA Technical Reports Server (NTRS)

    Coe, M. J.; Dennis, B. R.; Dolan, J. F.; Crannell, C. J.; Maurer, G. S.; Frost, K. J.; Orwig, L. E.; Graf, W.; Price, K. M.

    1978-01-01

    The results from extended high energy X-ray observations of Scorpius XR-1 from the OSO-8 satellite are reported here. The source was observed for a total of 15 days in 1975, 1977 and 1978. Simultaneous 10.7 GHz and 4.75 GHz radio data were obtained during the 1978 observation, and low energy X-ray data during the 1975 and 1978 observations. The data reveals a lack of any correlation between the high energy X-rays and the other energy ranges. A three standard deviation upper limit of 22% was obtained for any modulation of the high energy flux with the binary period. No high energy tail was observed at any time.

  8. High Energy Astronomy Observatory (HEAO)-2 in the X-Ray Calibration Facility

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This photograph is of the High Energy Astronomy Observatory (HEAO)-2 telescope being evaluated by engineers in the clean room of the X-Ray Calibration Facility at the Marshall Space Flight Center (MSFC). The MSFC was heavily engaged in the technical and scientific aspects, testing and calibration, of the HEAO-2 telescope The HEAO-2 was the first imaging and largest x-ray telescope built to date. The X-Ray Calibration Facility was built in 1976 for testing MSFC's HEAO-2. The facility is the world's largest, most advanced laboratory for simulating x-ray emissions from distant celestial objects. It produced a space-like environment in which components related to x-ray telescope imaging are tested and the quality of their performance in space is predicted. The original facility contained a 1,000-foot long by 3-foot diameter vacuum tube (for the x-ray path) cornecting an x-ray generator and an instrument test chamber. Recently, the facility was upgraded to evaluate the optical elements of NASA's Hubble Space Telescope, Chandra X-Ray Observatory and Compton Gamma-Ray Observatory.

  9. Strain Measurements using High Energy White X-rays at SPring-8

    NASA Astrophysics Data System (ADS)

    Shobu, T.; Kaneko, H.; Mizuki, J.; Konishi, H.; Shibano, J.; Hirata, T.; Suzuki, K.

    2007-01-01

    The strain in the bulk of a material was evaluated using high energy white X-rays from a synchrotron radiation source at SPring-8. The specimen, which was a 5 mm thick austenitic stainless steel sample (JIS-SUS304L), was subjected to bending. The internal strain was measured using white X-rays, which ranged in energy from 60 keV to 125 keV. Highly accurate internal strain measurements were accomplished by simultaneously using strain data from several lattice planes of α -Fe. Furthermore, utilizing diffracted beams with a high energy, a high peak count, and a profile similar to a Gaussian distribution decreased the error of the strain measurement The results indicated that high energy white X-rays can effectively measure the internal strain at a millimeter depth.

  10. Catalytic Adventures in Space and Time Using High Energy X-rays

    SciTech Connect

    Newton, Mark A.; Di Michiel, Marco; Ferri, Davide; Fernàndez-Garcia, Marcos; Beale, Andrew M.; Jacques, Simon D. M.; Chupas, Peter J.; Chapman, Karena W.

    2014-09-16

    Very high energy X-rays have long offered great promise in providing great insight into the inner workings of catalysts; insights that may complement the array of techniques available to researchers in catalysis either in the laboratory or at more conventional X-ray wavelengths. This contribution aims to critically assess the diverse possibilities now available in the high energy domain as a result of the maturation of third generation synchrotron facilities and to look forward to the potential that forthcoming developments in synchrotron source technology may offer the world of catalysis in the near future.

  11. Dosimetric properties of high energy current (HEC) detector in keV x-ray beams

    NASA Astrophysics Data System (ADS)

    Zygmanski, Piotr; Shrestha, Suman; Elshahat, Bassem; Karellas, Andrew; Sajo, Erno

    2015-04-01

    We introduce a new x-ray radiation detector. The detector employs high-energy current (HEC) formed by secondary electrons consisting predominantly of photoelectrons and Auger electrons, to directly convert x-ray energy to detector signal without externally applied power and without amplification. The HEC detector is a multilayer structure composed of thin conducting layers separated by dielectric layers with an overall thickness of less than a millimeter. It can be cut to any size and shape, formed into curvilinear surfaces, and thus can be designed for a variety of QA applications. We present basic dosimetric properties of the detector as function of x-ray energy, depth in the medium, area and aspect ratio of the detector, as well as other parameters. The prototype detectors show similar dosimetric properties to those of a thimble ionization chamber, which operates at high voltage. The initial results obtained for kilovoltage x-rays merit further research and development towards specific medical applications.

  12. High-Energy X-ray Absorption Diagnostics as an Experimental Combustion Technique

    NASA Astrophysics Data System (ADS)

    Dunnmon, Jared; Sobhani, Sadaf; Hinshaw, Waldo; Fahrig, Rebecca; Ihme, Matthias

    2015-11-01

    X-ray diagnostics such as X-ray Computed Tomography (XCT) have recently been utilized for measurement of scalar concentration fields in gas-phase flow phenomena. In this study, we apply high-energy X-ray absorption techniques to visualize a laboratory-scale flame via fluoroscopic measurements by using krypton as a radiodense tracer media. Advantages of X-ray absorption diagnostics in a combustion context, including application to optically inaccessible environments and lack of ambient photon interference, are demonstrated. Analysis methods and metrics for extracting physical insights from these data are presented. The accuracy of the diagnostic is assessed via comparison to known results from canonical flame configurations, and the potential for further applications is discussed. Support from the NDSEG fellowship, Bosch, and NASA are gratefully acknolwedged.

  13. Volumetric measurement of residual stress using high energy x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Whitesell, R.; McKenna, A.; Wendt, S.; Gray, J.

    2016-02-01

    We present results and recent developments from our laboratory, bench-top high energy x-ray diffraction system (HEXRD), between diffraction energies 50 and 150 KeV, to measure internal strain of moderately sized objects. Traditional x-ray strain measurements are limited to a few microns depth due to the use of Cu Kα1 Mo Kα1 radiation. The use of high energy x-rays for volumetric measurements of strain is typically the domain of synchrotron sources. We discuss the use of industrial 320kVp tube sources to generate a brighter x-ray beam along with a method using the intrinsic 43 eV width of the Kα1 characteristic peak of tungsten to measure volumetric strains in a number of industrially relevant materials. We will present volumetric strain measurements from two examples, first, additive manufacturing (AM) parts with various build configurations and, secondly, residual strain depth profiles from shot peened surface treatments. The spatial resolution of these depth profiles is ˜75 microns. The development of a faster method as compared to energy dispersive or θ-2θ scans is based on the intensity variation measurement of the strain using the aforementioned 43 eV characteristic tungsten kα line. We will present recent results on the development of this new tool and on x-ray diffraction measurements at high energy.

  14. HEAO 1 observations of high-energy X-rays from 3C273. [quasar emissions

    NASA Technical Reports Server (NTRS)

    Primini, F. A.; Cooke, B. A.; Dobson, C. A.; Howe, S. K.; Scheepmaker, A.; Wheaton, W. A.; Lewin, W. H. G.; Baity, W. A.; Gruber, D. E.; Matteson, J. L.

    1979-01-01

    The first detection of high energy (13 to 120 keV) X rays from the quasar 3C273, made by the HEAO 1 satellite, is reported. Observations were made with the 13 to 180 keV slat collimated detectors of the high energy X-ray and low energy gamma-ray (A4) experiment during December 1977-January 1978 and June-July 1978. Results are consistent with the previously observed X-ray flux variability on a scale of months. Photon count rates are presented for each of five energy bands and count rate and photon spectra for the June through July 1978 observations are derived. A comparison of the data obtained with that at lower X-ray energies and higher gamma-ray energies indicates that there is an overall spectral steepening from low to high energies and a possible break near 20 keV, which may be due to the gamma rays originating from a different region than that of the X rays.

  15. High-energy processes in Young Stellar Objects -- the radio--X-ray (dis)connection

    NASA Astrophysics Data System (ADS)

    Forbrich, Jan; Wolk, Scott; Osten, Rachel

    2009-09-01

    Low-mass young stellar objects show high levels of magnetic activity in a wide spectral range. Powerful flares have been observed from X-ray to radio wavelengths. It has been expected that radio and X-ray emission from YSOs are correlated if magnetic fields close to the star are responsible for both nonthermal radio emission (usually gyrosynchrotron radiation) and thermal hot-plasma X-ray emission (see Guedel & Benz 1994). These high-energy processes strongly influence the surroundings of the YSOs, including irradiation of their disks. A deeper understanding of these processes requires taking into account their manifestations in different spectral ranges. However, the strong variability of YSOs ideally necessitates simultaneous multi-wavelength observations or at least a large sample of sources. While a general correlation of radio and X-ray luminosities of phenomena ranging from solar flares to active stars has been found for more evolved stars, it remains unclear to what degree it applies to YSOs -- particularly their earliest evolutionary stages. Drawing from the latest simultaneous X-ray and radio observations of star-forming regions as well as on archival data from the Chandra Orion Ultra-deep project, we present an update on the question of whether and how the radio and X-ray properties of YSOs are correlated and what this tells us about high-energy processes in YSOs compared to other classes of active stars. We mostly find a very limited relation between the X-ray and radio fluxes indicating a non-magnetic origin for some of the radio or X-ray emission.

  16. Calculating the X-Ray Fluorescence from the Planet Mercury Due to High-Energy Electrons

    NASA Technical Reports Server (NTRS)

    Burbine, T. H.; Trombka, J. I.; Bergstrom, P. M., Jr.; Christon, S. P.

    2005-01-01

    The least-studied terrestrial planet is Mercury due to its proximity to the Sun, which makes telescopic observations and spacecraft encounters difficult. Our lack of knowledge about Mercury should change in the near future due to the recent launching of MESSENGER, a Mercury orbiter. Another mission (BepiColombo) is currently being planned. The x-ray spectrometer on MESSENGER (and planned for BepiColombo) can characterize the elemental composition of a planetary surface by measuring emitted fluorescent x-rays. If electrons are ejected from an atom s inner shell by interaction with energetic particles such as photons, electrons, or ions, electrons from an outer shell can transfer to the inner shell. Characteristic x-rays are then emitted with energies that are the difference between the binding energy of the ion in its excited state and that of the ion in its ground state. Because each element has a unique set of energy levels, each element emits x-rays at a unique set of energies. Electrons and ions usually do not have the needed flux at high energies to cause significant x-ray fluorescence on most planetary bodies. This is not the case for Mercury where high-energy particles were detected during the Mariner 10 flybys. Mercury has an intrinsic magnetic field that deflects the solar wind, resulting in a bow shock in the solar wind and a magnetospheric cavity. Electrons and ions accelerated in the magnetosphere tend to follow its magnetic field lines and can impact the surface on Mercury s dark side Modeling has been done to determine if x-ray fluorescence resulting from the impact of high-energy electrons accelerated in Mercury's magnetosphere can be detected by MESSENGER. Our goal is to understand how much bulk chemical information can be obtained from x-ray fluorescence measurements on the dark side of Mercury.

  17. Plasma Diagnostic Calibration and Characterizations with High Energy X-rays

    SciTech Connect

    Zaheer Ali

    2009-06-05

    National Security Technologies’ High Energy X-ray (HEX) Facility is unique in the U.S. Department of Energy complex. The HEX provides fluorescent X-rays of 5 keV to 100 keV with fluence of 10^5–10^6 photons/cm^2/second at the desired line energy. Low energy lines can be filtered, and both filters and fluorescers can be changed rapidly. We present results of calibrating image plates (sensitivity and modulation transfer function), a Bremsstrahlung spectrometer (stacked filters and image plates), and the National Ignition Facility’s Filter- Fluorescer Experiment (FFLEX) high energy X-ray spectrometer. We also show results of a scintillator light yield and alignment study for a neutron imaging system.

  18. Quantitative simulation and density reconstruction in high-energy X-ray radiograph

    NASA Astrophysics Data System (ADS)

    Tang, Li; Xu, Haibo

    2014-03-01

    Numerical radiograph using Monte Carlo method is used to study fidelity of density reconstruction in high-energy X-ray radiography. A density reconstruction method for a polyenergetic X-ray source and an object composed of different materials is proposed. The method includes energy spectrum, angular spectrum and spot size of photon source. And it includes mass absorption coefficients explicitly in density reconstruction as well. A constrained conjugate gradient algorithm and variation regularization are applied to determine material edges and density reconstruction of a French test object. It shows that the method is valid for density reconstruction and energy spectrum of imaging photons is important in obtaining accurate material densities in high-energy X-ray radiograph.

  19. Observation of solar high energy gamma and X-ray emission and solar energetic particles

    NASA Astrophysics Data System (ADS)

    Struminsky, A.; Gan, W.

    2015-08-01

    We considered 18 solar flares observed between June 2010 and July 2012, in which high energy >100 MeV γ-emission was registered by the Large Area Telescope (LAT) aboard FermiGRO. We examined for these γ-events soft X-ray observations by GOES, hard X-ray observations by the Anti-Coincidence Shield of the SPectrometer aboard INTEGRAL (ACS SPI) and the Gamma-Ray burst Monitor (GBM) aboard FermiGRO. Hard X-ray and π0-decay γ-ray emissions are used as tracers of electron and proton acceleration, respectively. Bursts of hard X-ray were observed by ACS SPI during impulsive phase of 13 events. Bursts of hard X- ray >100 keV were not found during time intervals, when prolonged hard y-emission was registered by LAT/FermiGRO. Those events showing prolonged high-energy gamma-ray emission not accompanied by >100 keV hard X-ray emission are interpreted as an indication of either different acceleration processes for protons and electrons or as the presence of a proton population accelerated during the impulsive phase of the flare and subsequently trapped by some magnetic structure. In-situ energetic particle measurements by GOES and STEREO (High Energy Telescope, HET) shows that five of these y-events were not accompanied by SEP events at 1 AU, even when multi-point measurements including STEREO are taken into account. Therefore accelerated protons are not always released into the heliosphere. A longer delay between the maximum temperature and the maximum emission measure characterises flares with prolonged high energy γ-emission and solar proton events.

  20. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy.

    PubMed

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10(13) photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV. PMID:27131669

  1. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>1013 photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

  2. ICF ignition capsule neutron, gamma ray, and high energy x-ray images

    NASA Astrophysics Data System (ADS)

    Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

    2003-03-01

    Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

  3. Demonstration of x-ray fluorescence imaging of a high-energy-density plasma

    SciTech Connect

    MacDonald, M. J. Gamboa, E. J.; Keiter, P. A.; Fein, J. R.; Klein, S. R.; Kuranz, C. C.; LeFevre, H. J.; Manuel, M. J.-E.; Wan, W. C.; Drake, R. P.; Montgomery, D. S.; Biener, M. M.; Fournier, K. B.; Streit, J.

    2014-11-15

    Experiments at the Trident Laser Facility have successfully demonstrated the use of x-ray fluorescence imaging (XRFI) to diagnose shocked carbonized resorcinol formaldehyde (CRF) foams doped with Ti. One laser beam created a shock wave in the doped foam. A second laser beam produced a flux of vanadium He-α x-rays, which in turn induced Ti K-shell fluorescence within the foam. Spectrally resolved 1D imaging of the x-ray fluorescence provided shock location and compression measurements. Additionally, experiments using a collimator demonstrated that one can probe specific regions within a target. These results show that XRFI is a capable alternative to path-integrated measurements for diagnosing hydrodynamic experiments at high energy density.

  4. A Review of X-ray Diagnostic Calibrations in the 2 to 100 keV Region Using the High Energy X-ray Calibration Facility (HEX)

    SciTech Connect

    Ali, Zaheer; Pond, T; Buckles, R A; Maddox, B R; Chen, C D; DeWald, E L; Izumi, N; Stewart, R

    2010-05-19

    The precise and accurate measurement of X-rays in the 2 keV to 100 keV region is crucial to the understanding of HED plasmas and warm dense matter in general. With the emergence of inertially confined plasma facilities as the premier platforms for ICF, laboratory astrophysics, and national security related plasma experiments, the need to calibrate diagnostics in the high energy X-ray regime has grown. At National Security Technologies High Energy X-ray Calibration Facility (HEX) in Livermore, California, X-ray imagers, filter-fluorescer spectrometers, crystal spectrometers, image plates, and nuclear diagnostics are calibrated. The HEX can provide measurements of atomic line radiation, X-ray flux (accuracy within 10%), and X-ray energy (accuracy within 1%). The HEX source is comprised of a commercial 160 kV X-ray tube, a fluorescer wheel, a filter wheel, and a lead encasement. The X-ray tube produces a Tungsten bremsstrahlung spectrum which causes a foil to fluoresce line radiation. To minimize bremsstrahlung in the radiation for calibration we also provide various foils as filters. For experimental purposes, a vacuum box capable of 10{sup -7} Torr, as well as HPGe and CdTe radiation detectors, are provided on an optical table. Most geometries and arrangements can be changed to meet experimental needs.

  5. Effects of High-Energy X-Ray Radiation on MoS2 FETs

    NASA Astrophysics Data System (ADS)

    Rai, Amritesh; Thoutam, Laxman; Zhang, Wei; Kovi, Kiran; Banerjee, Sanjay; Das, Saptarshi

    FETs based on semiconducting MoS2 nanosheets are currently being extensively explored for various nanoelectronic device applications. In real-life, several of these applications mandate the exposure of devices to X-ray radiation. In this study, we investigate the effects of high-energy X-ray radiation on few-layer MoS2 transistors. Back-gated MoS2 FETs on SiO2 substrates were fabricated and exposed to X-ray radiation in an enclosed X-ray tube utilizing tungsten as the X-ray source. The devices were exposed to successive radiation doses up to a cumulative dose of 1500 kilorads (Krads). Even after high radiation doses, the devices maintained acceptable electrical performance with high ION/IOFF ratios and good current saturation. The subthreshold swing remained similar to initial values. There was, however, a slight reduction in the ON-currents after each successive radiation, concomitant with a positive threshold voltage shift that can be attributed to the formation of negative-fixed charges in the substrate. Moreover, the maximum transconductance (gm) of the devices decreased slightly with increasing radiation dose. Finally, Raman spectroscopy revealed practically no change in the in-plane and out-of-plane Raman modes of MoS2 after radiation.

  6. High-energy synchrotron radiation x-ray microscopy: Present status and future prospects

    SciTech Connect

    Jones, K.W.; Gordon, B.M.; Spanne, P. ); Rivers, M.L.; Sutton, S.R. )

    1991-01-01

    High-energy radiation synchrotron x-ray microscopy is used to characterize materials of importance to the chemical and materials sciences and chemical engineering. The x-ray microscope (XRM) forms images of elemental distributions fluorescent x rays or images of mass distributions by measurement of the linear attenuation coefficient of the material. Distributions of sections through materials are obtained non-destructively using the technique of computed microtomography. The energy range of the x rays used for the XRM ranges from a few keV at the minimum value to more than 100 keV, which is sufficient to excite the K-edge of all naturally occurring elements. The work in progress at the Brookhaven NSLS X26 and X17 XRM is described in order to show the current status of the XRM. While there are many possible approaches to the XRM instrumentation, this instrument gives state-of-the-art performance in most respects and serves as a reasonable example of the present status of the instrumentation in terms of the spatial resolution and minimum detection limits obtainable. The examples of applications cited give an idea of the types of research fields that are currently under investigation. They can be used to illustrate how the field of x-ray microscopy will benefit from the use of bending magnets and insertion devices at the Advanced Photon Source. 8 refs., 5 figs.

  7. High-energy neutrino fluxes from AGN populations inferred from X-ray surveys

    NASA Astrophysics Data System (ADS)

    Jacobsen, Idunn B.; Wu, Kinwah; On, Alvina Y. L.; Saxton, Curtis J.

    2015-08-01

    High-energy neutrinos and photons are complementary messengers, probing violent astrophysical processes and structural evolution of the Universe. X-ray and neutrino observations jointly constrain conditions in active galactic nuclei (AGN) jets: their baryonic and leptonic contents, and particle production efficiency. Testing two standard neutrino production models for local source Cen A (Koers & Tinyakov and Becker & Biermann), we calculate the high-energy neutrino spectra of single AGN sources and derive the flux of high-energy neutrinos expected for the current epoch. Assuming that accretion determines both X-rays and particle creation, our parametric scaling relations predict neutrino yield in various AGN classes. We derive redshift-dependent number densities of each class, from Chandra and Swift/BAT X-ray luminosity functions (Silverman et al. and Ajello et al.). We integrate the neutrino spectrum expected from the cumulative history of AGN (correcting for cosmological and source effects, e.g. jet orientation and beaming). Both emission scenarios yield neutrino fluxes well above limits set by IceCube (by ˜4-106 × at 1 PeV, depending on the assumed jet models for neutrino production). This implies that: (i) Cen A might not be a typical neutrino source as commonly assumed; (ii) both neutrino production models overestimate the efficiency; (iii) neutrino luminosity scales with accretion power differently among AGN classes and hence does not follow X-ray luminosity universally; (iv) some AGN are neutrino-quiet (e.g. below a power threshold for neutrino production); (v) neutrino and X-ray emission have different duty cycles (e.g. jets alternate between baryonic and leptonic flows); or (vi) some combination of the above.

  8. The high-energy detector of the New Hard X-ray Mission (NHXM): design concept

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Brez, A.; Minuti, M.; Pinchera, M.; Spandre, G.; Argan, A.; Catalano, O.; Costa, E.; Fiorini, C.; Malaguti, G.; Pareschi, G.; Tagliaferri, G.; Uslenghi, M.

    2010-07-01

    The New Hard X-ray Mission (NHXM) is conceived to extend the grazing-angle reflection imaging capability up to 80 keV energy. The payload of the mission consists of four telescopes: three of the them having at their focal plane an identical spectral-imaging camera operating between 0.2 and 80 keV, while the fourth one is equipped with a X-ray imaging polarimeter. The three cameras consist of two detection layers: a Low Energy Detector (LED) and a High Energy Detector (HED) surrounded by an Anti Coincidence (AC) system. Here we present the preliminary design and the solutions that we are currently studying to meet the requirements for the high energy detectors. These detectors will be based on Cadmium Telluride (CdTe) pixel sensors coupled to pixel read-out electronics using custom CMOS ASICs.

  9. Transient structure in the high-energy X-ray light curve of NP 0532

    NASA Technical Reports Server (NTRS)

    Ryckman, S. G.; Ricker, G. R.; Scheepmaker, A.; Ballintine, J. E.; Doty, J. P.; Downey, P. M.; Lewin, W. H. G.

    1977-01-01

    The paper reports the observation of pulsed fractions in the primary and secondary peaks, as well as in the interpulse region, of the high-energy X-ray light curve of NP 0532. A statistical analysis of light-curve data is performed, and a similar analysis is carried out using simulated data. It is concluded that a previously reported third peak in the light curve was transient in nature.

  10. Mapping spatially inhomogeneous electrochemical reactions in battery electrodes using high energy X-rays.

    PubMed

    Borkiewicz, Olaf J; Chapman, Karena W; Chupas, Peter J

    2013-06-14

    The spatial distribution of a reaction through a lithium-ion battery electrode has been resolved using micro-beam high-energy X-ray scattering measurements coupled with Pair Distribution Function (PDF) analysis. The electrochemical reaction was most advanced at the interface between the electrode and electrolyte-soaked separator, with linear variation in reaction progress with distance from this interface. PMID:23598687

  11. AAS HIGH-ENERGY ASTROPHYSICS DIVISION: X-rays Hit the Spot for Astrophysicists.

    PubMed

    Irion, R

    2000-12-01

    About 500 astronomers flocked to Waikiki Beach from 6 to 10 November for a meeting of the American Astronomical Society's High-Energy Astrophysics Division. Looking splendid in their complimentary aloha shirts, speakers told tales of intense radiation from deep space, including x-rays from baby stars and from quasars, which could help refine estimates of how quickly the universe is expanding. PMID:17742051

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

    SciTech Connect

    Harrison, Fiona A.; Cook, W. Rick; Forster, Karl; Grefenstette, Brian W.; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa; Craig, William W.; Pivovaroff, Michael J.; Christensen, Finn E.; Hailey, Charles J.; Koglin, Jason E.; Mori, Kaya; Zhang, William W.; Boggs, Steven E.; Stern, Daniel; Kim, Yunjin; Giommi, Paolo; Perri, Matteo; and others

    2013-06-20

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

  13. The Nuclear Spectroscopic Telescope Array (NuSTAR) High-Energy X-ray Mission

    NASA Technical Reports Server (NTRS)

    Harrison, Fiona A.; Craig, Willliam W.; Christensen, Finn E.; Hailey, Charles J.; Zhang, William W.; Boggs, Steven E.; Stern, Daniel; Cook, W. Rick; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W.; Kim, Yunjin; Kitaguchi, Takao; Koglin, Jason E.; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa; Mori, Kaya; Perri, Matteo; Markwardt, Craig B.; Wik, Daniel R.; Hornschemeier, Anne E.; Ptak, Andrew; Rigby, Jane R.

    2013-01-01

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

  14. High-Energy Density science with an ultra-bright x-ray laser

    NASA Astrophysics Data System (ADS)

    Glenzer, Siegfried

    2015-11-01

    This talk will review recent progress in high-energy density physics using the world's brightest x-ray source, the Linac Coherent Light Source, SLAC's free electron x-ray laser. These experiments investigate laser-driven matter in extreme conditions where powerful x-ray scattering and imaging techniques have been applied to resolve ionic interactions at atomic (Ångstrom) scale lengths and to visualize the formation of dense plasma states. Major research areas include dynamic compression experiments of solid targets to determine structural properties and to discover and characterize phase transitions at mega-bar pressures. A second area studies extreme fields produced by high-intensity radiation where fundamental questions of laboratory plasmas can be related to cosmological phenomena. Each of these areas takes advantage of the unique properties of the LCLS x-ray beam. They include small foci for achieving high intensity or high spatial resolution, high photon flux for dynamic structure factor measurements in single shots, and high spectral bandwidth to resolve plasmon (Langmuir) waves or ion acoustic waves in dense plasmas. We will further describe new developments of ultrafast pump-probe technique at high repetition rates. These include studies on dense cryogenic hydrogen that have begun providing fundamental insights into the physical properties of matter in extreme conditions that are important for astrophysics, fusion experiments and generation of radiation sources. This work was supported by DOE Office of Science, Fusion Energy Science under FWP 100182.

  15. A first look at the distant high energy X-ray population with NuSTAR

    NASA Astrophysics Data System (ADS)

    Civano, Francesca M.; the NuSTAR Team

    2014-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR), launched in June 2012, is opening the high energy X-ray sky for sensitive study for the first time. NuSTAR focusing X-ray optics are resolving the sources contributing to the peak of the X-ray background at >10 keV. To provide a sensitive census of this population, NuSTAR is performing an extragalactic survey, using a 3 tier approach: a very deep 200 ks, pencil-beam survey of the Extended Chandra Deep Field-South (ECDFS), a moderate depth 50 ks survey of the COSMOS field, and a shallow survey suing serendipitous sources detected in target local bright sources. In this talk, I will report on the first results from this survey, including now about 200 sources in the three fields combined. The NuSTAR sources are approximately 100 times fainter than those previously detected at >10 keV by Swift/BAT and have a very broad range in redshift and luminosity (z=0.02-3). The sources are characterized on the basis of their X-ray properties (hardness ratio and luminosity), optical spectroscopy and optical to mid -infrared spectral energy distributions.

  16. Dosimetric properties of high energy current (HEC) detector in keV x-ray beams.

    PubMed

    Zygmanski, Piotr; Shrestha, Suman; Elshahat, Bassem; Karellas, Andrew; Sajo, Erno

    2015-04-01

    We introduce a new x-ray radiation detector. The detector employs high-energy current (HEC) formed by secondary electrons consisting predominantly of photoelectrons and Auger electrons, to directly convert x-ray energy to detector signal without externally applied power and without amplification. The HEC detector is a multilayer structure composed of thin conducting layers separated by dielectric layers with an overall thickness of less than a millimeter. It can be cut to any size and shape, formed into curvilinear surfaces, and thus can be designed for a variety of QA applications. We present basic dosimetric properties of the detector as function of x-ray energy, depth in the medium, area and aspect ratio of the detector, as well as other parameters. The prototype detectors show similar dosimetric properties to those of a thimble ionization chamber, which operates at high voltage. The initial results obtained for kilovoltage x-rays merit further research and development towards specific medical applications. PMID:25789488

  17. Talbot-Lau X-ray Moiré deflectometry Diagnostic for High Energy Density Plasmas

    NASA Astrophysics Data System (ADS)

    Valdivia Leiva, Maria Pia; Stutman, Dan; Finkenthal, Michael

    2013-10-01

    A Talbot-Lau (TL) x-ray interferometer measures beam angular deviations due to refraction index gradients within objects along its path. By tilting one of the gratings in the interferometer by small angles, Moiré patterns which enable the detection of density gradients in low-Z matter are obtained. In addition to the detection of both sharp and smooth density gradients this technique makes also possible the identification of micro structures within an object. The sensitivity and spatial resolution is adequate to characterize High Energy Density Laboratory Plasmas (HEDLP). The technique allows for the simultaneous acquisition of x-ray attenuation, refraction, and scatter information from a single x-ray image. Experimental and simulated results acquired show a clear advantage of the TL Moiré single image based phase-retrieval technique over the attenuation and propagation methods. Additionally, the method makes use of extended, polychromatic, incoherent, line and continuum x-ray sources, thus allowing for less demanding backlighters than those typically used in HEDLP radiography. Work supported by U.S. DOE/NNSA grant DENA0001835.

  18. Superiority of Low Energy 160 KV X-Rays Compared to High Energy 6 MV X-Rays in Heavy Element Radiosensitization for Cancer Treatment

    NASA Astrophysics Data System (ADS)

    Lim, Sara N.; Pradhan, Anil K.; Nahar, Sultana N.; Barth, Rolf F.; Yang, Weilian; Nakkula, Robin J.; Palmer, Alycia; Turro, Claudia

    2013-06-01

    High energy X-rays in the MeV range are generally employed in conventional radiation therapy from linear accelerators (LINAC) to ensure sufficient penetration depths. However, lower energy X-rays in the keV range may be more effective when coupled with heavy element (high-Z or HZ) radiosensitizers. Numerical simulations of X-ray energy deposition for tumor phantoms sensitized with HZ radiosensitizers were performed using the Monte Carlo code Geant4. The results showed enhancement in energy deposition to radiosensitized phantoms relative to unsensitized phantoms for low energy X-rays in the keV range. In contrast, minimal enhancement was seen using high energy X-rays in the MeV range. Dose enhancement factors (DEFs) were computed and showed radiosensitization only in the low energy range < 200 keV, far lower than the energy of the majority of photons in the LINAC energy range. In vitro studies were carried to demonstrate the tumoricidal effects of HZ sensitized F98 rat glioma cells following irradiation with both low energy 160 kV and high energy 6 MV X-ray sources. The platinum compound, pyridine terpyridine Pt(II) nitrate, was initially used because it was 7x less toxic that an equivalent amount of carboplatin in vitro studies. This would allow us to separate the radiotoxic and the chemotoxic effects of HZ sensitizers. Results from this study showed a 10-fold dose dependent reduction in surviving fractions (SF) of radiosensitized cells treated with low energy 160 kV X-rays compared to those treated with 6 MV X-rays. This is in agreement with our simulations that show an increase in dose deposition in radiosensitized tumors for low energy X-rays. Due to unforeen in vivo toxicity, however, another in vitro study was performed using the commonly used, Pt-based chemotherapeutic drug carboplatin which confirmed earlier results. This lays the ground work for a planned in vivo study using F98 glioma bearing rats. This study demonstrates that while high energy X-rays are

  19. High Energy Neutrino Flash From Far-UV/X-Ray Flares of Gamma-Ray Bursts

    SciTech Connect

    Murase, Kohta; Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park

    2006-04-25

    The recent observations of bright optical and X-ray flares by the Swift satellite suggest these are produced by the late activities of the central engine. We study the neutrino emission from far-UV/X-ray flares under the late internal shock model. Since the efficiency of pion production in the highest energy is higher than that of the prompt bursts, such neutrino flashes from flares can give comparable or larger contributions to a diffuse very high energy neutrino background if the total energy input into flares is comparable to the radiated energy of the prompt bursts. These signals are very important because they have possibility to probe the nature of flares (baryonic or magnetic, the photon field, the magnetic field, and so on).

  20. High contrast Kr gas jet Kα x-ray source for high energy density physics experimentsa)

    NASA Astrophysics Data System (ADS)

    Kugland, N. L.; Neumayer, P.; Döppner, T.; Chung, H.-K.; Constantin, C. G.; Girard, F.; Glenzer, S. H.; Kemp, A.; Niemann, C.

    2008-10-01

    A high contrast 12.6keV Kr Kα source has been demonstrated on the petawatt-class Titan laser facility using strongly clustering Kr gas jet targets. The contrast ratio (Kα to continuum) is 65, with a competitive ultrashort pulse laser to x-ray conversion efficiency of 10-5. Filtered shadowgraphy indicates that the Kr Kα and Kβ x rays are emitted from a roughly 1×2mm2 emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temperature of 50-70eV (i.e., mean ionization state 13-16), based on the observed ratio of Kα to Kβ. Kr gas jets provide a debris-free high energy Kα source for time-resolved diagnosis of dense matter.

  1. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Shimazoe, K.; Yan, X.; Ueda, O.; Ishikura, T.; Fujiwara, T.; Uesaka, M.; Ohno, M.; Tomita, H.; Yoshihara, Y.; Takahashi, H.

    2016-09-01

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  2. High-energy gamma-rays from GRB X-ray flares

    SciTech Connect

    Wang, X. Y.; Li, Z.; Meszaros, P.

    2007-07-12

    The recent detection of X-ray flares during the afterglow phase of gamma-ray bursts (GRBs) suggests an inner-engine origin, at radii inside the forward shock. There must be inverse Compton (IC) emission arising from such flare photons scattered by forward shock afterglow electrons when they are passing through the forward shock. We find that this IC emission produces high energy gamma-ray flares, which may be detected by AGILE, GLAST and ground-based TeV telescopes. The anisotropic IC scattering between flare photons and forward shock electrons does not affect the total IC component intensity, but cause a time delay of the IC component peak relative to the flare peak. We speculate that this IC component may already have been detected by EGRET from a very strong burst--GRB940217. Future observations by GLAST may help to distinguish whether X-ray flares originate from late central engine activity or from external shocks.

  3. Advanced Solid State Pixel Detectors for Future High Energy X-ray Missions

    NASA Astrophysics Data System (ADS)

    Harrison, Fiona

    We propose to advance the state of the art in solid state high energy X-ray pixel detectors for astrophysics. This program builds on advanced readout technology developed for suborbital and the NuSTAR space mission, and combines newly-developed CdTe PIN sensors and materials characterization techniques to achieve detectors broad band (1 - 200 keV), sub-keV energy resolution, and 300 micron spatial resolution. The low-noise readout technology will also be taken to the next generation with reduced pixel size, lower noise and significantly reduced dead time.

  4. UCSD High Energy X-ray Timing Experiment magnetic shield design and test results

    NASA Technical Reports Server (NTRS)

    Rothschild, Richard E.; Pelling, Michael R.; Hink, Paul L.

    1991-01-01

    Results are reported from an effort to define a passive magnetic field concept for the High Energy X-ray Timing Experiment (HEXTE), in the interest of reducing the detector-gain variations due to 0.5-1.0-sec timescale magnetic field variations. This will allow a sensitivity of the order of 1 percent of the HEXTE background. While aperture modulation and automatic gain control will minimize effects on timescales of tens of seconds and longer, passive magnetic shielding of the photomultiplier tubes will address 1-sec timescale variations due to aperture motions.

  5. Large-aperture prism-array lens for high-energy X-ray focusing.

    PubMed

    Zhang, Weiwei; Liu, Jing; Chang, Guangcai; Shi, Zhan; Li, Ming; Ren, Yuqi; Zhang, Xiaowei; Yi, Futing; Liu, Peng; Sheng, Weifan

    2016-09-01

    A new prism-array lens for high-energy X-ray focusing has been constructed using an array of different prisms obtained from different parabolic structures by removal of passive parts of material leading to a multiple of 2π phase variation. Under the thin-lens approximation the phase changes caused by this lens for a plane wave are exactly the same as those caused by a parabolic lens without any additional corrections when they have the same focal length, which will provide good focusing; at the same time, the total transmission and effective aperture of this lens are both larger than those of a compound kinoform lens with the same focal length, geometrical aperture and feature size. This geometry can have a large aperture that is not limited by the feature size of the lens. Prototype nickel lenses with an aperture of 1.77 mm and focal length of 3 m were fabricated by LIGA technology, and were tested using CCD camera and knife-edge scan method at the X-ray Imaging and Biomedical Application Beamline BL13W1 at Shanghai Synchrotron Radiation Facility, and provided a focal width of 7.7 µm and a photon flux gain of 14 at an X-ray energy of 50 keV. PMID:27577761

  6. The HEAO 1 A-4 catalog of high-energy X-ray sources

    NASA Technical Reports Server (NTRS)

    Levine, A. M.; Lang, F. L.; Lewin, W. H. G.; Primini, F. A.; Dobson, C. A.; Doty, J. P.; Hoffman, J. A.; Howe, S. K.; Scheepmaker, A.; Wheaton, W. A.

    1984-01-01

    Results are reported from an all-sky survey carried out at high X-ray energies (13-180 keV) from August 1977 until January 1979 using data obtained with the UCSD/MIT Hard X-Ray and Low-Energy Gamma-Ray Instrument on the HEAO 1 satellite. Visual displays are presented which indicate qualitatively the location, intensities, and time variability of the detected high-energy X-ray sources. A model-dependent procedure for the quantitative analysis of the sky survey data is described. The results of this procedure are presented in tabular form and include fitted count rates in four broad energy bands for about 70 sources. All sources which were detected at a level of statistical significance of not less than about 6 sigma were clearly evident in the visual displays of sky survey data. The survey is therefore complete, except in regions of source confusion, down to an intensity level of about 1/75 of the Crab Nebula in the 13-80 keV band. Forty-four sources were detected in the 40-80 keV energy band, and 14 were detected in the 80-180 keV band. Although most of the detected sources are galactic, seven are extragalactic.

  7. HIGH ENERGY, HIGH BRIGHTNESS X-RAYS PRODUCED BY COMPTON BACKSCATTERING AT THE LIVERMORE PLEIADES FACILITY

    SciTech Connect

    Tremaine, A M; Anderson, S G; Betts, S; Crane, J; Gibson, D J; Hartemann, F V; Jacob, J S; Frigola, P; Lim, J; Rosenzweig, J; Travish, G

    2005-05-19

    PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and up to 10{sup 7} photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 {micro}m with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 100 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verified the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials.

  8. Internal strain gradients quantified in bone under load using high-energy X-ray scattering.

    SciTech Connect

    Stock, S.R.; Yuan, F.; Brinson, L.C.; Almer, J.D.

    2011-01-01

    High-energy synchrotron X-ray scattering (>60 keV) allows noninvasive quantification of internal strains within bone. In this proof-of-principle study, wide angle X-ray scattering maps internal strain vs position in cortical bone (murine tibia, bovine femur) under compression, specifically using the response of the mineral phase of carbonated hydroxyapatite. The technique relies on the response of the carbonated hydroxyapatite unit cells and their Debye cones (from nanocrystals correctly oriented for diffraction) to applied stress. Unstressed, the Debye cones produce circular rings on the two-dimensional X-ray detector while applied stress deforms the rings to ellipses centered on the transmitted beam. Ring ellipticity is then converted to strain via standard methods. Strain is measured repeatedly, at each specimen location for each applied stress. Experimental strains from wide angle X-ray scattering and an attached strain gage show bending of the rat tibia and agree qualitatively with results of a simplified finite element model. At their greatest, the apatite-derived strains approach 2500 {micro}{var_epsilon} on one side of the tibia and are near zero on the other. Strains maps around a hole in the femoral bone block demonstrate the effect of the stress concentrator as loading increased and agree qualitatively with the finite element model. Experimentally, residual strains of approximately 2000 {micro}{var_epsilon} are present initially, and strain rises to approximately 4500 {micro}{var_epsilon} at 95 MPa applied stress (about 1000 {micro}{var_epsilon} above the strain in the surrounding material). The experimental data suggest uneven loading which is reproduced qualitatively with finite element modeling.

  9. Star Factory Near Galactic Center Bathed In High-Energy X-Rays

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Near the crowded core of the Milky Way galaxy, where stars shine so brightly and plentifully that planets there would never experience nighttime, astronomers have found a new phenomenon: a cauldron of 60-million-degree gas enveloping a cluster of young stars. Professor Farhad Zadeh of Northwestern University and his collaborators used NASA's Chandra X-ray Observatory to trace the gas around the Arches cluster, a well-studied region of star formation that is home to some of our Galaxy's largest and youngest stars. "This is the first time we have seen a young cluster of stars surrounded by such a halo of high-energy X-rays," said Zadeh in a press conference at the American Astronomical Society in Pasadena, CA. "This supports theoretical predictions that stellar winds from massive stars can collide with each other and generate very hot gas." Massive stars, newborn stars, and stellar winds have long been known to emit X-rays. The Chandra results are significant because they identify this new type of mechanism of colliding winds to generate X-rays as energetic as those seen in distant starburst galaxies, which are known for their furious pace of star production. The Arches cluster is about 26,000 light years from Earth and only about 1 to 2 million years old. It is also less than 100 light years from what is thought to be a supermassive black hole in the center of our Galaxy. The cluster contains 150 hot, young stars, known as "O" stars, concentrated within a diameter of one light year, making it the most compact cluster known in the Milky Way galaxy. The density of stars makes the region in and around the Arches cluster a microcosm of what is likely occurring in starburst galaxies. "The Arches cluster is one of the best 'local' analogues of starburst galaxies-- the most prodigious stellar nurseries known," said Casey Law of the Harvard-Smithsonian Center for Astrophysics. "Yet the Arches cluster is in our backyard, not millions of light years away." The Arches Cluster

  10. High energy X-ray observations of Sco-like sources with Ariel V

    NASA Technical Reports Server (NTRS)

    Greenhill, J. G.; Coe, M. J.; Burnell, S. J. B.; Strong, K. T.; Carpenter, G. F.

    1979-01-01

    Results are reported for observations of Sco X-1 and the similar sources 4U 1702-36 (GX 349+2, Sco X-2), 4U 1813-14 (GX 17+2), and 4U 1758-25 (GX 5-1) by several of the X-ray telescopes aboard the Ariel 5 satellite over the energy range from 2 to approximately 100 keV. The results confirm the existence of a high-energy tail in the spectrum of Sco X-1, demonstrate that 4U 1702-36 has a similar spectrum, and provide evidence for a variation of the 26-56-keV flux from 4U 1702-36 by more than a factor of four with no related change in the 2.9-7.6-keV flux. The high-energy emission from Sco X-1 is found to be one to two orders of magnitude above the extrapolated low-energy emission. Observed X-ray, radio, and optical properties of these four sources, as well as two additional Sco-like sources, are summarized.

  11. Characterizing high energy spectra of NIF ignition Hohlraums using a differentially filtered high energy multipinhole x-ray imager.

    PubMed

    Park, Hye-Sook; Dewald, E D; Glenzer, S; Kalantar, D H; Kilkenny, J D; MacGowan, B J; Maddox, B R; Milovich, J L; Prasad, R R; Remington, B A; Robey, H F; Thomas, C A

    2010-10-01

    Understanding hot electron distributions generated inside Hohlraums is important to the national ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with target materials. We used an array of 18 pinholes with four independent filter combinations to image entire Hohlraums with a magnification of 0.87× during the Hohlraum energetics campaign on NIF. Comparing our results with Hohlraum simulations indicates that the characteristic 10-40 keV hot electrons are mainly generated from backscattered laser-plasma interactions rather than from Hohlraum hydrodynamics. PMID:21034047

  12. Characterizing high energy spectra of NIF ignition Hohlraums using a differentially filtered high energy multipinhole x-ray imager

    SciTech Connect

    Park, Hye-Sook; Dewald, E. D.; Glenzer, S.; Kalantar, D. H.; Kilkenny, J. D.; MacGowan, B. J.; Maddox, B. R.; Milovich, J. L.; Prasad, R. R.; Remington, B. A.; Robey, H. F.; Thomas, C. A.

    2010-10-15

    Understanding hot electron distributions generated inside Hohlraums is important to the national ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with target materials. We used an array of 18 pinholes with four independent filter combinations to image entire Hohlraums with a magnification of 0.87x during the Hohlraum energetics campaign on NIF. Comparing our results with Hohlraum simulations indicates that the characteristic 10-40 keV hot electrons are mainly generated from backscattered laser-plasma interactions rather than from Hohlraum hydrodynamics.

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

    SciTech Connect

    Lacki, Brian C.; Thompson, Todd A.

    2013-01-01

    The origin of the diffuse hard X-ray (2-10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10-100 TeV electrons and positrons (e {sup {+-}}) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e {sup {+-}} at these energies: (1) primary electrons directly accelerated by supernova remnants, (2) pionic secondary e {sup {+-}} created by inelastic collisions between cosmic ray (CR) protons and gas nuclei in the dense interstellar medium of starbursts, and (3) pair e {sup {+-}} produced between the interactions between 10 and 100 TeV {gamma}-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic center (R {<=} 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power-law injection spectrum for electrons and protons. We consider different injection spectral slopes, magnetic field strengths, CR acceleration efficiencies, and diffusive escape times, and include advective escape, radiative cooling processes, and secondary and pair e {sup {+-}}. We compare these models to extant radio and GeV and TeV {gamma}-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and inverse Compton (IC) luminosities of these starbursts in the models which satisfy multiwavelength constraints. If the primary electron spectrum extends to {approx}PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron emission contributes 2%-20% of their unresolved, diffuse hard X-ray emission. However, there is great uncertainty in this conclusion because of the limited information on the CR electron spectrum at these high energies. IC emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic center to 10% in Arp 220's nuclei, with the main uncertainty being the starbursts

  14. Diffuse Hard X-Ray Emission in Starburst Galaxies as Synchrotron from Very High Energy Electrons

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.; Thompson, Todd A.

    2013-01-01

    The origin of the diffuse hard X-ray (2-10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10-100 TeV electrons and positrons (e ±) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e ± at these energies: (1) primary electrons directly accelerated by supernova remnants, (2) pionic secondary e ± created by inelastic collisions between cosmic ray (CR) protons and gas nuclei in the dense interstellar medium of starbursts, and (3) pair e ± produced between the interactions between 10 and 100 TeV γ-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic center (R <= 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power-law injection spectrum for electrons and protons. We consider different injection spectral slopes, magnetic field strengths, CR acceleration efficiencies, and diffusive escape times, and include advective escape, radiative cooling processes, and secondary and pair e ±. We compare these models to extant radio and GeV and TeV γ-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and inverse Compton (IC) luminosities of these starbursts in the models which satisfy multiwavelength constraints. If the primary electron spectrum extends to ~PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron emission contributes 2%-20% of their unresolved, diffuse hard X-ray emission. However, there is great uncertainty in this conclusion because of the limited information on the CR electron spectrum at these high energies. IC emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic center to 10% in Arp 220's nuclei, with the main uncertainty being the starbursts' magnetic field. We also model generic starbursts, including

  15. Image quality and dose efficiency of high energy phase sensitive x-ray imaging: Phantom studies

    PubMed Central

    Wong, Molly Donovan; Wu, Xizeng; Liu, Hong

    2014-01-01

    The goal of this preliminary study was to perform an image quality comparison of high energy phase sensitive imaging with low energy conventional imaging at similar radiation doses. The comparison was performed with the following phantoms: American College of Radiology (ACR), contrast-detail (CD), acrylic edge and tissue-equivalent. Visual comparison of the phantom images indicated comparable or improved image quality for all phantoms. Quantitative comparisons were performed through ACR and CD observer studies, both of which indicated higher image quality in the high energy phase sensitive images. The results of this study demonstrate the ability of high energy phase sensitive imaging to overcome existing challenges with the clinical implementation of phase contrast imaging and improve the image quality for a similar radiation dose as compared to conventional imaging near typical mammography energies. In addition, the results illustrate the capability of phase sensitive imaging to sustain the image quality improvement at high x-ray energies and for – breast – simulating phantoms, both of which indicate the potential to benefit fields such as mammography. Future studies will continue to investigate the potential for dose reduction and image quality improvement provided by high energy phase sensitive contrast imaging. PMID:24865208

  16. Mesoscale Science with High Energy X-ray Diffraction Microscopy at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Suter, Robert

    2014-03-01

    Spatially resolved diffraction of monochromatic high energy (> 50 keV) x-rays is used to map microstructural quantities inside of bulk polycrystalline materials. The non-destructive nature of High Energy Diffraction Microscopy (HEDM) measurements allows tracking of responses as samples undergo thermo-mechanical or other treatments. Volumes of the order of a cubic millimeter are probed with micron scale spatial resolution. Data sets allow direct comparisons to computational models of responses that frequently involve long-ranged, multi-grain interactions; such direct comparisons have only become possible with the development of HEDM and other high energy x-ray methods. Near-field measurements map the crystallographic orientation field within and between grains using a computational reconstruction method that simulates the experimental geometry and matches orientations in micron sized volume elements to experimental data containing projected grain images in large numbers of Bragg peaks. Far-field measurements yield elastic strain tensors through indexing schemes that sort observed diffraction peaks into sets associated with individual crystals and detect small radial motions in large numbers of such peaks. Combined measurements, facilitated by a new end station hutch at Advanced Photon Source beamline 1-ID, are mutually beneficial and result in accelerated data reduction. Further, absorption tomography yields density contrast that locates secondary phases, void clusters, and cracks, and tracks sample shape during deformation. A collaboration led by the Air Force Research Laboratory and including the Advanced Photon Source, Lawrence Livermore National Laboratory, Carnegie Mellon University, Petra-III, and Cornell University and CHESS is developing software and hardware for combined measurements. Examples of these capabilities include tracking of grain boundary migrations during thermal annealing, tensile deformation of zirconium, and combined measurements of nickel

  17. High-energy x-ray diffraction study of pure amorphous silicon

    SciTech Connect

    Laaziri, K.; Kycia, S.; Roorda, S.; Chicoine, M.; Robertson, J.L.; Wang, J.; Moss, S.C.

    1999-11-01

    Medium and high-energy x-ray diffraction has been used to study the atomic structure of pure amorphous Si prepared by MeV Si implantation into crystalline silicon. Both as-implanted and annealed samples were studied. The inelastically scattered x rays were removed by fitting the energy spectrum for the scattered x rays. The atomic scattering factor of silicon, previously known reliably up to 20 {Angstrom}{sup {minus}1}, has been extended to 55 {Angstrom}{sup {minus}1}. The radial distribution function of amorphous Si, before and after annealing, has been determined through an unbiased Fourier transformation of the normalized scattering data. Gaussian fits to the first neighbor peak in these functions shows that scattering data out to at least 40 {Angstrom}{sup {minus}1} is required to reliably determine the radial distribution function. The first-shell coordination number increases from 3.79 to 3.88 upon thermal annealing at 600{degree}C, whereas that of crystalline Si determined from similar measurements on a Si powder analyzed using the same technique is 4.0. Amorphous Si is therefore under coordinated relative to crystalline Si. Noise in the distribution function, caused by statistical variations in the scattering data at high-momentum transfer, has been reduced without affecting the experimental resolution through filtering of the interference function after subtracting the contribution of the first-neighbor peak. The difference induced by thermal annealing in the remainder of the radial distribution functions, thus revealed, is much smaller than previously believed. {copyright} {ital 1999} {ital The American Physical Society}

  18. High energy resolution x-ray spectrometer for high count rate XRF applications

    SciTech Connect

    Rossington, C.S.; Madden, N.W.; Chapman, K.

    1993-08-01

    A new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) pr- eamplifier. The spectrometer operates at high count rates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 {mu}sec and a throughput count rate of 145,000 counts sec{sup {minus}1}, the energy resolution at 5.9 key is 220 eV FWHM. Commercially available spectrometers utilizing conventional geometry Si(Li) detectors with areas equivalent to the new detector have resolutions on the order of 540 eV under the same conditions. Conventional x-ray spectrometers offering high energy resolution must employ detectors with areas one-tenth the size of the new LBL detector (20 mm{sup 2} compared with 200 mm{sup 2}). However, even with the use of the smaller area detectors, the energy resolution of a commercial system is typically limited to approximately 300 eV (again, at 1 {mu}sec and 5.9 keV) due to the noise of the commercially available JFET`S. The new large area detector is useful in high count rate applications, but is also useful in the detection of weak photon signals, in which it is desirable to subtend as large an angle of the available photon flux as possible, while still maintaining excellent energy resolution. X-ray fluorescence data from the new spectrometer is shown in comparison to a commercially available system in the analysis of a dilute multi-element material, and also in conjunction with high count rate synchrotron EXAMS applications.

  19. On filtration for high-energy phase-contrast x-ray imaging

    NASA Astrophysics Data System (ADS)

    Riess, Christian; Mohamed, Ashraf; Hinshaw, Waldo; Fahrig, Rebecca

    2015-03-01

    Phase-sensitive x-ray imaging promises unprecedented soft-tissue contrast and resolution. However, several practical challenges have to be overcome when using the setup in a clinical environment. The system design that is currently closest to clinical use is the grating-based Talbot-Lau interferometer (GBI).1-3 The requirements for patient imaging are low patient dose, fast imaging time, and high image quality. For GBI, these requirements can be met most successfully with a narrow energy width, high- ux spectrum. Additionally, to penetrate a human-sized object, the design energy of the system has to be well above 40 keV. To our knowledge, little research has been done so far to investigate optimal GBI filtration at such high x-ray energies. In this paper, we study different filtration strategies and their impact on high-energy GBI. Specifically, we compare copper filtration at low peak voltage with equal-absorption, equal-imaging time K-edge filtration of spectra with higher peak voltage under clinically realistic boundary conditions. We specifically focus on a design energy of 59 keV and investigate combinations of tube current, peak voltage, and filtration that lead to equal patient absorption. Theoretical considerations suggest that the K edge of tantalum might provide a transmission pocket at around 59 keV, yielding a well-shaped spectrum. Although one can observe a slight visibility benefit when using tungsten or tantalum filtration, experimental results indicate that visibility benefits most from a low x-ray tube peak voltage.

  20. Characterization of amorphous selenium alloy detectors for x-rays and high energy nuclear radiation detection

    NASA Astrophysics Data System (ADS)

    Mandal, Krishna C.; Mehta, Abhinav; Chaudhuri, Sandeep K.; Cui, Yunlong; Groza, Michael; Burger, Arnold

    2013-09-01

    Synthesized amorphous selenium (a-Se) alloy materials have been characterized for room temperature high-energy nuclear radiation detector and x-ray detection applications. The alloy composition has been optimized to ensure good charge transport properties and detector performance. The synthesis of a-Se (As, Cl) alloys has been carried out by thoroughly mixing zone-refined (ZR) Se (~7N) with previously synthesized a-Se(As) and a-Se(Cl) master alloys (MS). The synthesized alloys have been characterized by x-ray diffraction (XRD), glow discharge mass spectroscopy (GDMS), differential scanning calorimetry (DSC), x-ray photoelectron spectroscopy (XPS), and current-voltage (I-V) characteristics measurements. Raman spectroscopy demonstrated that the a-Se(As) master alloy samples were in metastable monoclinic Se8 states, in which seven vibrational modes are located at 40(41), 59(60), 77, 110, 133, 227(228) and 251(252) cm-1. However, a-Se(Cl) master alloy samples are in stable form of trigonal structure of Se8 ring, in which two modes at 142 and 234 cm-1 were found. Both Raman and energy dispersive spectroscopy (EDS) exhibited that a small amount of tellurium (Te) existed in a-Se (As, Cl) master alloy samples. DSC measurements showed that a-Se (Cl) MS and a-Se (As) MS samples have one melting point, located at ~219.6°C, whereas a-Se-As (0.52%)-Cl and Se- As(10.2%)-Cl(60 ppm) both possess two melting points, located at 221 and 220.3°C respectively. The a-Se alloy plate detectors have been fabricated and tested and the results showed high dark resistivity (1012 - 1013 Ω-cm) with good charge transport properties and cost-effective large-area scalability.

  1. Development of a dual MCP framing camera for high energy x-rays

    SciTech Connect

    Izumi, N. Hall, G. N.; Carpenter, A. C.; Allen, F. V.; Cruz, J. G.; Felker, B.; Hargrove, D.; Holder, J.; Lumbard, A.; Montesanti, R.; Palmer, N. E.; Piston, K.; Stone, G.; Thao, M.; Vern, R.; Zacharias, R.; Landen, O. L.; Tommasini, R.; Bradley, D. K.; Bell, P. M.; and others

    2014-11-15

    Recently developed diagnostic techniques at LLNL require recording backlit images of extremely dense imploded plasmas using hard x-rays, and demand the detector to be sensitive to photons with energies higher than 50 keV [R. Tommasini et al., Phys. Phys. Plasmas 18, 056309 (2011); G. N. Hall et al., “AXIS: An instrument for imaging Compton radiographs using ARC on the NIF,” Rev. Sci. Instrum. (these proceedings)]. To increase the sensitivity in the high energy region, we propose to use a combination of two MCPs. The first MCP is operated in a low gain regime and works as a thick photocathode, and the second MCP works as a high gain electron multiplier. We tested the concept of this dual MCP configuration and succeeded in obtaining a detective quantum efficiency of 4.5% for 59 keV x-rays, 3 times larger than with a single plate of the thickness typically used in NIF framing cameras.

  2. Performance of Gas Scintillation Proportional Counter Array for High-Energy X-Ray Observatory

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail; Ramsey, Brian; Apple, Jeffery

    2004-01-01

    A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a High Energy X-Ray Observatory (HERO) is developed at the Marshall Space Flight Center. The array is consisted from eight GSPCs and is a part of balloon born payload scheduled to flight in May 2004. These detectors have an active area of approximately 20 square centimeters, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approximately 500 microns. The detector's energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Results of the on-earth detector calibration will be presented and in-flight detector performance will be provided, as available.

  3. In situ energy dispersive x-ray reflectometry measurements on organic solar cells upon working

    NASA Astrophysics Data System (ADS)

    Paci, B.; Generosi, A.; Albertini, V. Rossi; Perfetti, P.; de Bettignies, R.; Firon, M.; Leroy, J.; Sentein, C.

    2005-11-01

    The change in the morphology of plastic solar cells was studied by means of time-resolved energy dispersive x-ray reflectivity (XRR). This unconventional application of the XRR technique allowed the follow up of in situ morphological evolution of an organic photovoltaic device upon working. The study consisted of three steps: A preliminary set of XRR measurements on various samples representing the intermediate stages of cell construction, which provided accurate data regarding the electronic densities of the different layers; the verification of the morphological stability of the device under ambient condition; a real-time collection of XRR patterns, both in the dark and during 15h in artificial light conditions which allowed the changes in the system morphology at the electrode-active layer interface to be monitored. In this way, a progressive thickening of this interface, responsible for a reduction in the performances of the device, was observed directly.

  4. High transmission Ni compound refractive lens for high energy X-rays

    NASA Astrophysics Data System (ADS)

    Brancewicz, M.; Itou, M.; Sakurai, Y.; Andrejczuk, A.; Chiba, S.; Kayahara, Y.; Inoue, T.; Nagamine, M.

    2016-08-01

    We present a new planar Ni compound refractive lens for high energy X-rays (116 keV). The lens is composed of identical plano-concave elements with longitudinal parabolic grooves manufactured by a punch technique. In order to increase the lens transmission, the thickness of the single lens at the parabolic groove vertex was reduced to less than 5 μm and the radius of curvature was reduced to about 20 μm. The small radius of curvature allowed us to reduce the number of single elements needed to get the focal length of 3 m to 54 single lenses. The gain parameter has been significantly improved compared to the previous lenses due to higher transmission, but the focused beam size and its gain are not as good as expected, mostly due to the aberrations caused by the lens shape imperfections.

  5. High transmission Ni compound refractive lens for high energy X-rays.

    PubMed

    Brancewicz, M; Itou, M; Sakurai, Y; Andrejczuk, A; Chiba, S; Kayahara, Y; Inoue, T; Nagamine, M

    2016-08-01

    We present a new planar Ni compound refractive lens for high energy X-rays (116 keV). The lens is composed of identical plano-concave elements with longitudinal parabolic grooves manufactured by a punch technique. In order to increase the lens transmission, the thickness of the single lens at the parabolic groove vertex was reduced to less than 5 μm and the radius of curvature was reduced to about 20 μm. The small radius of curvature allowed us to reduce the number of single elements needed to get the focal length of 3 m to 54 single lenses. The gain parameter has been significantly improved compared to the previous lenses due to higher transmission, but the focused beam size and its gain are not as good as expected, mostly due to the aberrations caused by the lens shape imperfections. PMID:27587159

  6. Performance of bent-crystal x-ray microscopes for high energy density physics research

    NASA Astrophysics Data System (ADS)

    Schollmeier, M.; Geissel, M.; Shores, J. E.; Smith, I. C.; Porter, J. L.

    2015-11-01

    We present calculations for the field of view (FOV), image fluence, image monochromaticity, spectral acceptance, and image aberrations for spherical crystal microscopes, which are used as self-emission imaging or backlighter systems at large-scale high energy density physics facilities. Our analytic results are benchmarked with ray-tracing calculations as well as with experimental measurements from the 6.151 keV backlighter system at Sandia National Laboratories. The analytic expressions can be used for x-ray source positions anywhere between the Rowland circle and object plane. This enables quick optimization of the performance of proposed but untested, bent-crystal microscope systems to find the best compromise between FOV, image fluence, and spatial resolution for a particular application.

  7. Pixellated Cd(Zn)Te high-energy X-ray instrument

    PubMed Central

    Seller, P.; Bell, S.; Cernik, R.J.; Christodoulou, C.; Egan, C.K.; Gaskin, J.A.; Jacques, S.; Pani, S.; Ramsey, B.D.; Reid, C.; Sellin, P.J.; Scuffham, J.W.; Speller, R.D.; Wilson, M.D.; Veale, M.C.

    2012-01-01

    We have developed a pixellated high energy X-ray detector instrument to be used in a variety of imaging applications. The instrument consists of either a Cadmium Zinc Telluride or Cadmium Telluride (Cd(Zn)Te) detector bump-bonded to a large area ASIC and packaged with a high performance data acquisition system. The 80 by 80 pixels each of 250 μm by 250 μm give better than 1 keV FWHM energy resolution at 59.5 keV and 1.5 keV FWHM at 141 keV, at the same time providing a high speed imaging performance. This system uses a relatively simple wire-bonded interconnection scheme but this is being upgraded to allow multiple modules to be used with very small dead space. The readout system and the novel interconnect technology is described and how the system is performing in several target applications. PMID:22737179

  8. Performance of bent-crystal x-ray microscopes for high energy density physics research

    DOE PAGESBeta

    Schollmeier, Marius S.; Geissel, Matthias; Shores, Jonathon E.; Smith, Ian C.; Porter, John L.

    2015-05-29

    We present calculations for the field of view (FOV), image fluence, image monochromaticity, spectral acceptance, and image aberrations for spherical crystal microscopes, which are used as self-emission imaging or backlighter systems at large-scale high energy density physics facilities. Our analytic results are benchmarked with ray-tracing calculations as well as with experimental measurements from the 6.151 keV backlighter system at Sandia National Laboratories. Furthermore, the analytic expressions can be used for x-ray source positions anywhere between the Rowland circle and object plane. We discovered that this enables quick optimization of the performance of proposed but untested, bent-crystal microscope systems to findmore » the best compromise between FOV, image fluence, and spatial resolution for a particular application.« less

  9. Performance of bent-crystal x-ray microscopes for high energy density physics research

    SciTech Connect

    Schollmeier, Marius S.; Geissel, Matthias; Shores, Jonathon E.; Smith, Ian C.; Porter, John L.

    2015-05-29

    We present calculations for the field of view (FOV), image fluence, image monochromaticity, spectral acceptance, and image aberrations for spherical crystal microscopes, which are used as self-emission imaging or backlighter systems at large-scale high energy density physics facilities. Our analytic results are benchmarked with ray-tracing calculations as well as with experimental measurements from the 6.151 keV backlighter system at Sandia National Laboratories. Furthermore, the analytic expressions can be used for x-ray source positions anywhere between the Rowland circle and object plane. We discovered that this enables quick optimization of the performance of proposed but untested, bent-crystal microscope systems to find the best compromise between FOV, image fluence, and spatial resolution for a particular application.

  10. High energy neutrino absorption and its effects on stars in close X-ray binaries

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.; Stecker, F. W.

    1986-01-01

    The physics and astrophysics of high energy neutrino production and interactions in close X-ray binary systems are studied. These studies were stimulated by recent observations of ultrahigh energy gamma-rays and possibly other ultrahigh energy particles coming from the directions of Cygnus X-3 and other binary systems and possessing the periodicity characteristics of these systems. Systems in which a compact object, such as a neutron star, is a strong source of high energy particles which, in turn, produce photons, neutronos and other secondary particles by interactions in the atmosphere of the companion star were considered. The highest energy neutrinos are absorbed deep in the companion and the associated energy deposition may be large enough to effect its structure or lead to its ultimate disruption. This neutrino heating was evaluated, starting with a detailed numerical calculation of the hadronic cascade induced in the atmosphere of the companion star. For some theoretical models, the resulting energy deposition from neutrino absorption may be so great as to disrupt the companion star over an astronomically small timescale of the order of 10,000 years. Even if the energy deposition is smaller, it may still be high enough to alter the system substantially, perhaps leading to quenching of high energy signals from the source. Given the cosmic ray luminosities required to produce the observed gamma rays from cygnus X-3 and LMX X-4, such a situation may occur in these sources.

  11. High-energy x-ray optics with silicon saw-tooth refractive lenses.

    SciTech Connect

    Shastri, S. D.; Almer, J. A.; Ribbing, C. R.; Cederstrom, B. C.; X-Ray Science Division; Uppsala Univ.; Royal Inst. of Tech.

    2007-01-01

    Silicon saw-tooth refractive lenses have been in successful use for vertical focusing and collimation of high-energy X-rays (50-100 keV) at the 1-ID undulator beamline of the Advanced Photon Source. In addition to presenting an effectively parabolic thickness profile, as required for aberration-free refractive optics, these devices allow high transmission and continuous tunability in photon energy and focal length. Furthermore, the use of a single-crystal material (i.e. Si) minimizes small-angle scattering background. The focusing performance of such saw-tooth lenses, used in conjunction with the 1-ID beamline's bent double-Laue monochromator, is presented for both short ({approx}1:0.02) and long ({approx}1:0.6) focal-length geometries, giving line-foci in the 2 {micro}m-25 {micro}m width range with 81 keV X-rays. In addition, a compound focusing scheme was tested whereby the radiation intercepted by a distant short-focal-length lens is increased by having it receive a collimated beam from a nearer (upstream) lens. The collimation capabilities of Si saw-tooth lenses are also exploited to deliver enhanced throughput of a subsequently placed small-angular-acceptance high-energy-resolution post-monochromator in the 50-80 keV range. The successful use of such lenses in all these configurations establishes an important detail, that the pre-monochromator, despite being comprised of vertically reflecting bent Laue geometry crystals, can be brilliance-preserving to a very high degree.

  12. Radio and Hard X-Ray Images of High-Energy Electrons in an X-Class Solar Flare

    NASA Technical Reports Server (NTRS)

    White, S. M.; Krucker, S.; Shibasaki, K.; Yokoyama, T.; Shimojo, M.; Kundu, Mukul R.

    2003-01-01

    We present the first comparison between radio images of high-energy electrons accelerated by a solar flare and images of hard X-rays produced by the same electrons at photon energies above 100 keV. The images indicate that the high-energy X-rays originate at the footpoints of the loops dominating the radio emission. The radio and hard X-ray light curves match each other well and are quantitatively consistent with an origin in a single population of nonthermal electrons with a power-law index of around 4.5-5. The high-frequency radio spectral index suggests a flatter energy spectrum, but this is ruled out by the X-ray spectrum up to 8 MeV.

  13. Position-Sensitive CZT Detectors for High Energy X-Ray Astronomy

    NASA Astrophysics Data System (ADS)

    Matteson, J.; Coburn, W.; Heindl, W.; Peterson, L.; Pelling, M.; Rothschild, R.; Skelton, R.; Hink, P.; Slavis, K.

    1998-05-01

    We report recent progress on CZT (Cadmium Zinc Telluride) detectors by the UCSD/WU collaboration. CZT, a room- temperature semiconductor, is a very promising detector material for high energy X-ray astronomy. It can operate from <10 keV to >200 keV, and give sub-keV energy resolution and sub-mm spatial resolution. We have developed an advanced CZT detector that uses two innovations to improve spectral response, give it 3-D localization of energy loss events, and reduce background at high altitudes and in space. The detector measures 12 x 12 x 2 mm(3) and was manufactured by eV Products. Each face has a strip readouts with 500 micron pitch electrodes. The 2 faces' strips are orthogonal, which provides x-y localization into 500 micron pixels. One innovation is "steering electrodes", which are located between the anode strips. They improve the anode charge collection and energy resolution, and tailing due to hole trapping is nearly totally eliminated. The energy resolution at 60 keV is 4 keV and the peak to valley ratio is 50. The other innovation is 3-D localization of energy losses. This is done by comparing the signals from the anode strips, cathode strips, and steering electrodes. There is a strong depth of interaction signature, which can be used to accept events which interact close to the cathode strips (where X-rays of interest are incident) and reject deeper interactions (which are likely to be background). The detector was tested in a balloon flight at 108,000 feet in October 1997. Background was reduced by passive shielding, consisting of lead graded with tin and copper. The lead thickness was changed by command during the flight, and was 7, 2, and 0 mm thick. With the 2 mm thickness the 20 - 40 keV background for the central 30 pixels was 8x10(-4) c/cm(2) -s-keV when the depth of interaction signature was used to reject background, and 7 times greater when this information was not used. The lower background is 12 times less than other workers have obtained

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

    SciTech Connect

    Simon, M.; Altapova, V.; Baumbach, T.; Kluge, M.; Last, A.; Marschall, F.; Mohr, J.; Nazmov, V.; Vogt, H.

    2012-05-17

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

  15. The Effects of Low- and High-Energy Cutoffs on Solar Flare Microwave and Hard X-Ray Spectra

    NASA Technical Reports Server (NTRS)

    Holman, G. D.; Oegerle, William (Technical Monitor)

    2002-01-01

    Microwave and hard x-ray spectra provide crucial information about energetic electrons and their environment in solar flares. These spectra are becoming better determined with the Owens Valley Solar Array (OVSA) and the recent launch of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The proposed Frequency Agile Solar Radiotelescope (FASR) promises even greater advances in radio observations of solar flares. Both microwave and hard x-ray spectra are sensitive to cutoffs in the electron distribution function. The determination of the high-energy cutoff from these spectra establishes the highest electron energies produced by the acceleration mechanism, while determination of the low-energy cutoff is crucial to establishing the total energy in accelerated electrons. This paper will show computations of the effects of both high- and low-energy cutoffs on microwave and hard x-ray spectra. The optically thick portion of a microwave spectrum is enhanced and smoothed by a low-energy cutoff, while a hard x-ray spectrum is flattened below the cutoff energy. A high-energy cutoff steepens the microwave spectrum and increases the wavelength at which the spectrum peaks, while the hard x-ray spectrum begins to steepen at photon energies roughly an order of magnitude below the electron cutoff energy. This work discusses how flare microwave and hard x-ray spectra can be analyzed together to determine these electron cutoff energies. This work is supported in part by the NASA Sun-Earth Connection Program.

  16. Internal strains and stresses measured in cortical bone via high-energy X-ray diffraction.

    PubMed

    Almer, J D; Stock, S R

    2005-10-01

    High-energy synchrotron X-ray diffraction was used to study internal stresses in bone under in situ compressive loading. A transverse cross-section of a 12-14 year old beagle fibula was studied with 80.7 keV radiation, and the transmission geometry was used to quantify internal strains and corresponding stresses in the mineral phase, carbonated hydroxyapatite. The diffraction patterns agreed with tabulated patterns, and the distribution of diffracted intensity around 00.2/00.4 and 22.2 diffraction rings was consistent with the imperfect 00.1 fiber texture expected along the axis of a long bone. Residual compressive stress along the bone's longitudinal axis was observed in the specimen prior to testing: for 22.2 this stress equaled -95 MPa and for 00.2/00.4 was between -160 and -240 MPa. Diffraction patterns were collected for applied compressive stresses up to -110 MPa, and, up to about -100 MPa, internal stresses rose proportionally with applied stress but at a higher rate, corresponding to stress concentration in the mineral of 2.8 times the stress applied. The widths of the 00.2 and 00.4 diffraction peaks indicated that crystallite size perpendicular to the 00.1 planes increased from t=41 nm before stress was applied to t=44 nm at -118 MPa applied stress and that rms strain epsilon(rms) rose from 2200 muepsilon before loading to 4600 muepsilon at the maximum applied stress. Small angle X-ray scattering of the unloaded sample, recorded after deformation was complete, showed a collagen D-period of 66.4 nm (along the bone axis). PMID:16183302

  17. High-energy X-ray diffraction of melts and amorphous solids at extreme conditions

    NASA Astrophysics Data System (ADS)

    Prescher, C.; Yu, T.; Wang, Y.; Eng, P. J.; Skinner, L. B.; Stubbs, J.; Prakapenka, V.

    2015-12-01

    The structural analysis of amorphous materials, glasses and liquids at extreme conditions using X-ray diffraction is a very challenging endeavor. The samples are typically very small and surrounded by pressure vessels, which result in a huge background signal which may be orders of magnitude stronger than the actual sample signal. Furthermore, the background signal changes during compression in diamond anvil cells (DAC), making analysis of the diffraction data impossible at large pressures (>60 GPa). A key factor for obtaining high quality structural data is the maximum obtainable Q of the data collection. While at ambient conditions a maximum Q of more than 20 Å-1 has become standard, at high pressures data have been reported and analyzed with a maximum Q as low as 7 Å-1, which significantly reduces the resolution of the obtained real space data for multicomponent systems. In order to overcome those challenges, we have successfully installed a multichannel collimator (MCC) for the DAC setup at APS/GSECARS 13-IDD and for the Paris Edinburgh Press (PEP) at 13-IDC. The MCC leads to a significant increase in signal to background ratio and the background remains almost constant during compression in a DAC and removes the additional diffraction signal from the pressure media in the PEP. The combination of MCC and the high-energy X-ray optics of the 13ID beamline enables data collection of melts, glasses and amorphous materials up to 10 GPa in the PEP with a maximum Q of about 16 Å-1 and the collection of amorphous materials and glasses up to pressures above 150 GPa with a maximum Q of about 13 Å-1, thus, enabling the structural investigation of amorphous materials at much larger pressures than previously achievable. Further, we have developed several new user-friendly software packages for the analysis of X-ray diffraction data with specific data reduction and optimization algorithms for the analysis of amorphous materials at high-pressure. In order to show the

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

    PubMed

    Shade, Paul A; Blank, Basil; Schuren, Jay C; Turner, Todd J; Kenesei, Peter; Goetze, Kurt; Suter, Robert M; Bernier, Joel V; Li, Shiu Fai; Lind, Jonathan; Lienert, Ulrich; Almer, Jonathan

    2015-09-01

    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. PMID:26429452

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

    SciTech Connect

    Shade, Paul A. Schuren, Jay C.; Turner, Todd J.; Blank, Basil; Kenesei, Peter; Goetze, Kurt; Lienert, Ulrich; Almer, Jonathan; Suter, Robert M.; Bernier, Joel V.; Li, Shiu Fai; Lind, Jonathan

    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.

  20. Studying X-Ray Binaries with High Energy Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Kaaret, P.

    2003-01-01

    The goal of this investigation is to further our understanding of the dynamics of accreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fields. The main focus of this work has been a multi-year program of simultaneous millisecond x-ray timing and spectral observations carried out with the Rossi X-Ray Timing Explorer (RXTE) to perform the x-ray timing and one of the satellites Asca, BeppoSAX, or Chandra to perform x-ray spectral measurements. With the advent of Chandra, we have extended our work to include imaging of X-ray jets from binaries and the study of extragalactic X-ray binaries. Significant progress was made over the past year.

  1. Studying X-Ray Binaries with High Energy Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; West, Donald K. (Technical Monitor)

    2002-01-01

    The goal of this investigation is to further our understanding of the dynamics of secreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fetus. The main focus of this work has been a multi-year program of simultaneous millisecond X-ray timing and spectral observations carried out with the Rossi X-Ray Timing Explorer (RXTE) to perform the X-ray timing and one of the satellites Asca, BeppoSAX, or Chandra to perform X-ray spectral measurements. With the advent of Chandra, we have extended our work to incLude extragalactic X-ray binaries. We conducted a comprehensive study of the X-ray and radio behavior of the Black Hole Candidate (BHC) X-ray transient XTE J1550-564 using RXTE, Chandra, and the Australian Telescope Compact Array (ATCA). We showed that strong radio emission is associated with major X-ray outbursts involving an X-ray state transition, while a compact radio jet is seen in the low/hard X-ray state found in the outburst decay. Interesting, the total energy required to produce the compact jet may be a substantial fraction of the total accretion energy of the system in that state. We also performed a detailed study of the spectral and timing properties of the decay. In joint RXTE/BeppoSAX observations of the neutron-star X-ray binary Cyg X-2, we discovered a correlation between the timing properties (the frequency of the horizontal branch oscillations) and the properties of a soft, thermal component of the X-ray spectrum. d e showed that more detX- ray from accreting neutron stars. We have completed analysis of RXTE observations of the X-ray transient SAX J1750.8-2900 made after detection of X-ray bursts from the source with the BeppoSAX Wide-Field Camera. We discovered millisecond oscillations in both the persistent emission and in the X-ray bursts.

  2. Strain measurements and imaging of metal matrix composites using high-energy X-rays

    NASA Astrophysics Data System (ADS)

    Young, Marcus L.

    Metal matrix composites (MMCs) are of technological importance for a variety of applications [1, 2]. One important aspect of MMCs is their unique mechanical behavior, which is controlled by the load transfer occurring between matrix and reinforcement. Load transfer is affected by the mismatch in stiffness between matrix and reinforcement, by plastic deformation of the metallic matrix and by damage of the ceramic reinforcement or its interface with the matrix. The goal of this thesis is to study the micromechanics of load transfer in MMC by a combination of x-ray diffraction and imaging, using high-energy synchrotron x-rays in conjunction with in-situ mechanical loading. Diffraction was used for direct measurements of internal elastic strains of all phases within the bulk (rather than near surface) of MMCs during in-situ mechanical loading. Imaging was done using an edge-enhanced, phase-contrast technique providing high spatial resolution radiographic images providing insight into the macro- and micro-mechanical evolution of damage. Three MMC systems with widely different architectures, composition, and end-use were studied: ultrahigh-carbon steels, superconducting fiber composites, and co-continuous composites. First, ultrahigh-carbon steels exhibiting spherical Fe3C particles in a Fe matrix are characterized by no load transfer in the elastic range, followed by marked load transfer in the plastic range of the matrix. Second, superconducting composites consisting of continuous MgB2 fibers in a Mg matrix show mostly elastic (and somewhat plastic) load transfer from matrix to reinforcement, which is complicated by the presence of cracks and a WB4 core in the fibers. Finally, a complex three-dimensional (3-D) Al2O3 preform infiltrated with an Al matrix, like the superconducting composites, show mostly elastic load transfer from matrix to reinforcement. For the latter two composites, differences were found between average bulk measurements and spatially

  3. High Energy Observations of X-Ray Binaries and Gamma-Ray Blazars

    NASA Technical Reports Server (NTRS)

    Vestrand, W. Thomas

    1999-01-01

    The report discusses the CGRO observation of X-ray binary systems and studies of gamma-ray blasars. Numerous authors have suggested mechanisms for particle acceleration within X-Ray Binary (XRB) systems. Among the acceleration mechanisms that have been applied are pulsar acceleration, shock acceleration at an accretion shock front, shock acceleration at a pulsar wind termination shock, plasma turbulence excited by the accretion flow, and a number of electrodynamic mechanisms. There are therefore many mechanisms which are capable of generating very energetic particles in the XRB environment. If the reports of TeV/PeV gamma-ray generation in XRBs are correct, then one can show that the accelerated particles must be hadrons and that the most likely gamma-ray production mechanism is the decay of collisionally-produced (or photoproduced) neutral pions. At these ultra-high energies, the emission is so strongly beamed that the target conditions are constrained by the requirement that the column depth be large enough to efficiently generate gamma-rays, but not so large that the gamma-rays are absorbed. These constraints naturally lead to models that explain the periodic, narrow duty-cycle pulses observed at TeV/PeV energies as arising from interactions with, either, the atmosphere of the binary companion, an accretion column, or an accretion disk. The production of these TeV/PeV gamma-rays by the decay of pions from "leading isobars" must also be accompanied by a more isotropic emission component in the EGRET energy band from the decay of slower pions (i.e. the "pionization" component). Since the attenuation of 35 MeV-1 GeV photons by photon-photon pair production is not likely to be significant in most XRBs, the TeV/PeV reports therefore strongly suggest sporadic emission in the EGRET energy band. One of the key unresolved issues for understanding AGN is the relationship between XBLs and RBLs.To test the "reunification" hypothesis, authors conducted a multiwavelength

  4. A comparison between fine grain and epitaxial superconducting tunneling junctions for use as high energy resolution x-ray detectors

    NASA Astrophysics Data System (ADS)

    Saulnier, Gregory Gerard

    1994-01-01

    Superconducting tunneling junctions (STJ) show great promise in high energy resolution x-ray spectroscopy for use in x-ray astrophysics. An STJ is a sandwich of an insulator between two superconductors (S-I-S). Such a device has an intrinsic energy resolution an order of magnitude better than any existing semiconductor device, including the charge coupled device (CCD). The potential impact on x-ray astrophysics is enormous, with possible future use on sounding rockets and other as yet undefined satellite missions. This thesis compares two STJ's that have been fabricated using Nb/Al/Al2O3/Nb in the same ultra-high vacuum chamber with the same layer thicknesses with the only difference being that the base layers are either fine grain (polycrystalline) or epitaxial. The testing was done at temperatures between 0.4 K and 4.2 K. The comparison included subgap spectra from an Fe-55 x-ray source. The findings showed that the fine grain junction had a tunnel barrier of much higher quality and yielded higher energy resolution. It was determined that the epitaxial junction was much more sensitive to substrate events. Two peaks were found in the x-ray spectra. Each peak was attributed to x-ray interactions within one or the other superconducting films of the junction.

  5. Development of a CdTe pixel detector with a window comparator ASIC for high energy X-ray applications

    NASA Astrophysics Data System (ADS)

    Hirono, T.; Toyokawa, H.; Furukawa, Y.; Honma, T.; Ikeda, H.; Kawase, M.; Koganezawa, T.; Ohata, T.; Sato, M.; Sato, G.; Takagaki, M.; Takahashi, T.; Watanabe, S.

    2011-09-01

    We have developed a photon-counting-type CdTe pixel detector (SP8-01). SP8-01 was designed as a prototype of a high-energy X-ray imaging detector for experiments using synchrotron radiation. SP8-01 has a CdTe sensor of 500 μm thickness, which has an absorption efficiency of almost 100% up to 50 keV and 45% even at 100 keV. A full-custom application specific integrated circuit (ASIC) was designed as a readout circuit of SP8-01, which is equipped with a window-type discriminator. The upper discriminator realizes a low-background measurement, because X-ray beams from the monochromator contain higher-order components beside the fundamental X-rays in general. ASIC chips were fabricated with a TSMC 0.25 μm CMOS process, and CdTe sensors were bump-bonded to the ASIC chips by a gold-stud bonding technique. Beam tests were performed at SPring-8. SP8-01 detected X-rays up to 120 keV. The capability of SP8-01 as an imaging detector for high-energy X-ray synchrotron radiation was evaluated with its performance characteristics.

  6. The high energy X-ray spectrum of the Crab Nebula observed from OSO 8

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Crannell, L. J.; Dennis, B. R.; Orwig, L. E.; Maurer, G. S.; Frost, K. J.

    1977-01-01

    The X-ray spectrum of the Crab Nebula was measured with the scintillation spectrometer on board the OSO-8 satellite. The total emission of the X-ray source shows no long term variability. The spectrum itself can be described by a single power law out to energies of at least 500 keV.

  7. Probing the micro-mechanical behavior of bone via high-energy x-rays.

    SciTech Connect

    Almer, J.; Stock, S. R.; X-Ray Science Division; Northwestern Univ.

    2006-01-01

    the sample. While under load, high-energy x-rays (80.7 keV) of transverse size 0.05(x) x 0.05(y) mm{sup 2} were used to sample through the entire thickness (z) of the sample. Wide-angle scattering patterns at multiple x-positions (y=0) were collected using a large area detector, with each 2D pattern containing data in a plane approximately parallel to the sample x-y plane. Internal strains along the longitudinal/loading direction ({var_epsilon}{sub yy}) are shown for the apatite (002) reflection in Fig. 1. Values for five different lateral positions are shown, with x = -1 mm near the convex side of the sample and x = +1 near the concave side. Also shown are value from the strain gage located on the concave side of the specimen. All internal strains are non-zero before unloading and {var_epsilon}{sub yy} {approx} -700 {mu}{var_epsilon}. When stress is applied, strain response varies substantially across the sample, with {var_epsilon}{sub yy} (x = 1) showing the highest compression while {var_epsilon}{sub yy} (x = -1) slightly more tensile values. The macroscopic strain increases similar to, but at a higher degree than, {var_epsilon}{sub yy} (x = -1). At the maximum applied stress of {approx}33 MPa the sample experienced multiple cracks, as verified via post-mortem analysis. Upon unloading the macroscopic strain was primarily elastic, as values (nearly) returned to those seen upon loading.

  8. Metrology for the Development of High Energy X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell; Dpeegle, Chet

    2005-01-01

    We are developing grazing incidence x-ray optics for a balloon-borne hard-x-ray telescope (HERO). The instrument will have 200 sq cm effective collecting area at 40 keV and an angular resolution goal of 15 arcsec. The HERO mirror shells are fabricated using electroform-nickel replication off super-polished cylindrical mandrels. The angular resolution goal puts stringent requirements on the quality of x-ray mirrors and, hence, on mandrel quality. We used metrology in an iterative approach to monitor and refine the x- ray mirror fabrication process. Comparison of surface figure and microroughness measurements of the mandrel and the shells will be presented together with results from x-ray tests.

  9. High-energy x-ray backlighter spectrum measurements using calibrated image plates

    SciTech Connect

    Maddox, B.R.; Park, H.S.; Remington, B.A.; Izumi, N.; Chen, S.; Chen, C.; Kimminau, G.; Ali, Z.; Haugh, M.J.; Ma, Q.

    2012-10-10

    The x-ray spectrum between 18 and 88 keV generated by a petawatt laser driven x-ray backlighter target was measured using a 12-channel differential filter pair spectrometer. The spectrometer consists of a series of filter pairs on a Ta mask coupled with an x-ray sensitive image plate. A calibration of Fuji{trademark} MS and SR image plates was conducted using a tungsten anode x-ray source and the resulting calibration applied to the design of the Ross pair spectrometer. Additionally, the fade rate and resolution of the image plate system were measured for quantitative radiographic applications. The conversion efficiency of laser energy into silver K{alpha} x rays from a petawatt laser target was measured using the differential filter pair spectrometer and compared to measurements using a single photon counting charge coupled device.

  10. Metrology for the development of high-energy x-ray optics

    NASA Astrophysics Data System (ADS)

    Gubarev, Mikhail; Ramsey, Brian; Engelhaupt, Darell; Speegle, Chet; Smithers, Martin

    2005-08-01

    We are developing grazing-incidence x-ray optics for a balloon-borne hard-x-ray telescope (HERO). The instrument will have 200 cm2 effective collecting area at 40 keV and an angular resolution goal of 15 arcsec. The HERO mirror shells are fabricated using electroformed-nickel replication off super-polished cylindrical mandrels. The angular resolution goal puts stringent requirements on the quality of the x-ray mirrors and, hence, on mandrel quality. We used metrology in an iterative approach to monitor and refine the x-ray mirror fabrication process. Comparison of axial slope measurements of the mandrel and the shells will be presented together with results from x-ray tests.

  11. Determination of preferential molecular orientation in porphyrin-fullerene dyad ZnDHD6ee monolayers by the X-ray standing-wave method and X-ray reflectometry

    SciTech Connect

    Seregin, A. Yu. D'yakova, Yu. A.; Yakunin, S. N.; Makhotkin, I. A.; Alekseev, A. S.; Klechkovskaya, V. V.; Tereschenko, E. Yu.; Tkachenko, N. V.; Lemmetyinen, H.; Feigin, L. A.; Kovalchuk, M. V.

    2013-11-15

    Monolayers of porphyrin-fullerene dyad molecules with zinc atoms incorporated into the porphyrin ring (ZnDHD6ee) on the surface of aqueous subphase and on Si substrates have been investigated by the X-ray standing-wave method and X-ray reflectometry. The experiments have been performed under laboratory conditions and on synchrotron radiation sources (KMC-2 station of BESSY II (Berlin) and Langmuir station at the National Research Centre 'Kurchatov Institute'). Depth distributions of Zn atoms and electron density in the monolayer film are calculated. On the basis of the analysis of these distributions, it is concluded that ZnDHD6ee dyad molecules in monolayers have preferential orientation. The data obtained indicate that the molecules in monolayer film retain their orientation when the monolayer is transferred from a liquid subphase surface onto a solid substrate.

  12. Characterization of spatially resolved high resolution x-ray spectrometers for high energy density physics and light source experiments

    SciTech Connect

    Hill, K. W. Bitter, M.; Delgado-Aparacio, L.; Efthimion, P.; Pablant, N. A.; Lu, J.; Beiersdorfer, P.; Chen, H.; Magee, E.

    2014-11-15

    A high resolution 1D imaging x-ray spectrometer concept comprising a spherically bent crystal and a 2D pixelated detector is being optimized for diagnostics of small sources such as high energy density physics (HEDP) and synchrotron radiation or x-ray free electron laser experiments. This instrument is used on tokamak experiments for Doppler measurements of ion temperature and plasma flow velocity profiles. Laboratory measurements demonstrate a resolving power, E/ΔE of order 10 000 and spatial resolution better than 10 μm. Initial tests of the high resolution instrument on HEDP plasmas are being performed.

  13. Hard X-Ray Flare Source Sizes Measured with the Ramaty High Energy Solar Spectroscopic Imager

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Pernak, Rick L.

    2009-01-01

    Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations of 18 double hard X-ray sources seen at energies above 25 keV are analyzed to determine the spatial extent of the most compact structures evident in each case. The following four image reconstruction algorithms were used: Clean, Pixon, and two routines using visibilities maximum entropy and forward fit (VFF). All have been adapted for this study to optimize their ability to provide reliable estimates of the sizes of the more compact sources. The source fluxes, sizes, and morphologies obtained with each method are cross-correlated and the similarities and disagreements are discussed. The full width at half-maximum (FWHM) of the major axes of the sources with assumed elliptical Gaussian shapes are generally well correlated between the four image reconstruction routines and vary between the RHESSI resolution limit of approximately 2" up to approximately 20" with most below 10". The FWHM of the minor axes are generally at or just above the RHESSI limit and hence should be considered as unresolved in most cases. The orientation angles of the elliptical sources are also well correlated. These results suggest that the elongated sources are generally aligned along a flare ribbon with the minor axis perpendicular to the ribbon. This is verified for the one flare in our list with coincident Transition Region and Coronal Explorer (TRACE) images. There is evidence for significant extra flux in many of the flares in addition to the two identified compact sources, thus rendering the VFF assumption of just two Gaussians inadequate. A more realistic approximation in many cases would be of two line sources with unresolved widths. Recommendations are given for optimizing the RHESSI imaging reconstruction process to ensure that the finest possible details of the source morphology become evident and that reliable estimates can be made of the source dimensions.

  14. Alignment, Assembly and Testing of High Energy X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail; Ramsey, Brian

    2005-01-01

    We are developing grazing-incidence x-ray imaging optics for a balloon-borne hard x-ray telescope (HERO). The HERO payload, scheduled for launch in May 2005, currently consists of 8 mirror modules each containing 12 mirror shells fabricated using electroform-nickel replication off super-polished cylindrical mandrels. An optical system developed for aligning and assembling the shells in the modules will be described. Sources for systematic errors associated with this process will be discussed and results from on-ground x-ray testing of each module will be presented.

  15. Design and performance of an Automatic Gain Control system for the High Energy X-Ray Timing Experiment

    NASA Technical Reports Server (NTRS)

    Pelling, Michael R.; Rothschild, Richard E.; Macdonald, Daniel R.; Hertel, Robert; Nishiie, Edward

    1991-01-01

    The High Energy X-Ray Timing Experiment (HEXTE), currently under development for the X-Ray Timing Explorer (XTE) mission, employs a closed loop gain control system to attain 0.5 percent stabilization of each of eight-phoswich detector gains. This Automatic Gain Control (AGC) system utilizes a split window discriminator scheme to control the response of each detector pulse height analyzer to gated Am-241 X-ray events at 60 keV. A prototype AGC system has been implemented and tested within the gain perturbation environment expected to be experienced by the HEXTE instrument in flight. The AGC system and test configuration are described. Response, stability and noise characteristics are measured and compared with theoretical predictions. The system is found to be generally suitable for the HEXTE application.

  16. Optimizing the Operation of a Vertical Johann Spectrometer Using a High Energy Fluorescer X-ray Source

    SciTech Connect

    Haugh, Michael; Stewart, Richard

    2010-10-01

    This paper describes the operation and testing for a Vertical Johann Spectrometer (VJS) operating in the 13 keV range. The spectrometer is designed to use thin curved mica crystals or thick germanium crystals. The VJS must have a resolution E/ΔE=3000 or better to measure Doppler broadening of highly ionized krypton and operate at a small X-ray angle in order to be used as a diagnostic in a laser plasma target chamber. The VJS was aligned, tested, and optimized using a fluorescer type high energy X-ray (HEX) source located at National Security Technologies, LLC (NSTec), in Livermore, California. The HEX uses a 160 kV X-ray tube to excite fluorescence from various targets. Both rubidium and bismuth fluorescers were used for this effort. This presentation describes the NSTec HEX system and the methods used to optimize and characterize the VJS performance.

  17. Optimizing the operation of a high resolution vertical Johann spectrometer using a high energy fluorescer x-ray source

    SciTech Connect

    Haugh, Michael; Stewart, Richard

    2010-10-15

    This paper describes the operation and testing for a vertical Johann spectrometer (VJS) operating in the 13 keV range. The spectrometer is designed to use thin curved mica crystals or thick germanium crystals. The VJS must have a resolution of E/{Delta}E=3000 or better to measure the Doppler broadening of highly ionized krypton and operate at a small x-ray angle in order to be used as a diagnostic in a laser plasma target chamber. The VJS was aligned, tested, and optimized using a fluorescer type high energy x-ray (HEX) source located at National Security Technologies (NSTec), LLC, in Livermore, CA. The HEX uses a 160 kV x-ray tube to excite fluorescence from various targets. Both rubidium and bismuth fluorescers were used for this effort. This presentation describes the NSTec HEX system and the methods used to optimize and characterize the VJS performance.

  18. Deterministic Computer-Controlled Polishing Process for High-Energy X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Khan, Gufran S.; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian

    2010-01-01

    A deterministic computer-controlled polishing process for large X-ray mirror mandrels is presented. Using tool s influence function and material removal rate extracted from polishing experiments, design considerations of polishing laps and optimized operating parameters are discussed

  19. MeV per nucleon ion irradiation of nuclear materials with high energy synchrotron X-ray characterization

    NASA Astrophysics Data System (ADS)

    Pellin, M. J.; Yacout, Abdellatif M.; Mo, Kun; Almer, Jonathan; Bhattacharya, S.; Mohamed, Walid; Seidman, D.; Ye, Bei; Yun, D.; Xu, Ruqing; Zhu, Shaofei

    2016-04-01

    The combination of MeV/Nucleon ion irradiation (e.g. 133 MeV Xe) and high energy synchrotron x-ray characterization (e.g. at the Argonne Advanced Photon Source, APS) provides a powerful characterization method to understand radiation effects and to rapidly screen materials for the nuclear reactor environment. Ions in this energy range penetrate ∼10 μm into materials. Over this range, the physical interactions vary (electronic stopping, nuclear stopping and added interstitials). Spatially specific x-ray (and TEM and nanoindentation) analysis allow individual quantification of these various effects. Hard x-rays provide the penetration depth needed to analyze even nuclear fuels. Here, this combination of synchrotron x-ray and MeV/Nucleon ion irradiation is demonstrated on U-Mo fuels. A preliminary look at HT-9 steels is also presented. We suggest that a hard x-ray facility with in situ MeV/nucleon irradiation capability would substantially accelerate the rate of discovery for extreme materials.

  20. Sub-second variations of high energy ( 300 keV) hard X-ray emission from solar flares

    NASA Technical Reports Server (NTRS)

    Bai, Taeil

    1986-01-01

    Subsecond variations of hard X-ray emission from solar flares were first observed with a balloon-borne detector. With the launch of the Solar Maximum Mission (SMM), it is now well known that subsecond variations of hard X-ray emission occur quite frequently. Such rapid variations give constraints on the modeling of electron energization. Such rapid variations reported until now, however, were observed at relatively low energies. Fast mode data obtained by the Hard X-ray Burst Spectrometer (HXRBS) has time resolution of approximately 1 ms but has no energy resolution. Therefore, rapid fluctuations observed in the fast-mode HXRBS data are dominated by the low energy hard X-rays. It is of interest to know whether rapid fluctuations are observed in high-energy X-rays. The highest energy band at which subsecond variations were observed is 223 to 1057 keV. Subsecond variations observed with HXRBS at energies greater than 300 keV are reported, and the implications discussed.

  1. Measurement of high energy x-ray beam penumbra with Gafchromic trade mark sign EBT radiochromic film

    SciTech Connect

    Cheung Tsang; Butson, Martin J.; Yu, Peter K. N.

    2006-08-15

    High energy x-ray beam penumbra are measured using Gafchromic trade mark sign EBT film. Gafchromic trade mark sign EBT, due to its limited energy dependence and high spatial resolution provide a high level of accuracy for dose assessment in penumbral regions. The spatial resolution of film detector systems is normally limited by the scanning resolution of the densitometer. Penumbral widths (80%/20%) measured at D{sub max} were found to be 2.8, 3.0, 3.2, and 3.4 mm ({+-}0.2 mm) using 5, 10, 20, and 30 cm square field sizes, respectively, for a 6 MV linear accelerator produced x-ray beam. This is compared to 3.2 mm{+-}0.2 mm (Kodak EDR2) and 3.6 mm{+-}0.2 mm (Kodak X-Omat V) at 10 cmx10 cm measured using radiographic film. Using a zero volume extrapolation technique for ionization chamber measurements, the 10 cmx10 cm field penumbra at D{sub max} was measured to be 3.1 mm, a close match to Gafchromic trade mark sign EBT results. Penumbral measurements can also be made at other depths, including the surface, as the film does not suffer significantly from dosimetric variations caused by changing x-ray energy spectra. Gafchromic trade mark sign EBT film provides an adequate measure of penumbral dose for high energy x-ray beams.

  2. Z-pinches as intense x-ray sources for high energy density physics application

    SciTech Connect

    Matzen, M.K.

    1997-02-01

    Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator at Sandia National Laboratories, for example, currents of 6 to 8 MA with a risetime of less than 50 ns are driven through cylindrically-symmetric loads, producing implosions velocities as high as 100 cm/{mu}s and x-ray energies as high as 500 kJ. The keV component of the resulting x-ray spectrum has been used for many years 8 a radiation source for material response studies. Alternatively, the x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a large cylindrical radiation case. These large volume, long-lived radiation sources have recently been used for ICF-relevant ablator physics experiments as well as astrophysical opacity and radiation-material interaction experiments. Hydromagnetic Rayleigh-Taylor instabilities and cylindrical load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray pulse widths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using uniform-fill gas puff loads or by using wire arrays with as many a 192 wires. These techniques produced significant improvements in the pinched plasma quality, Zn reproducibility, and x-ray output power. X-ray pulse widths of less than 5 ns and peak powers of 75{+-}10 TW have been achieved with arrays of 120 tungsten wires. These powers represent greater than a factor of three in power amplification over the electrical power of the Saturn n accelerator, and are a record for x-ray powers in the laboratory.

  3. Through-thickness determination of phase composition and residual stresses in thermall barrier coatings using high- energy x-rays.

    SciTech Connect

    Weyant, , C. M.; Almer, J. D.; Faber, K. T.; Stony Brook Univ.

    2009-01-01

    High-energy X-rays were used to determine the local phase composition and residual stresses through the thickness of as-sprayed and heat-treated plasma-sprayed thermal barrier coatings consisting of a NiCoCrAlY bond coat and an yttria-stabilized zirconia (YSZ) topcoat produced with through-thickness segmentation cracks. The as-sprayed residual stresses reflected the combined influence of quenching stresses from the plasma spray process, thermal expansion mismatch between the topcoat, bond coat and substrate, and stress relief from the segmentation cracks. Heat treatments led to the formation of a thermally grown oxide (TGO) which was in compression in the plane, as well as relief of quenching stresses and development of a stress gradient in the YSZ topcoat. The high-energy X-ray technique used in this study revealed the effects that TGO and segmentation cracks have on the in-plane stress state of the entire coating.

  4. Gamma-ray, neutron, and hard X-ray studies and requirements for a high-energy solar physics facility

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Dennis, B. R.; Emslie, A. G.

    1988-01-01

    The requirements for future high-resolution spatial, spectral, and temporal observation of hard X-rays, gamma rays and neutrons from solar flares are discussed in the context of current high-energy flare observations. There is much promise from these observations for achieving a deep understanding of processes of energy release, particle acceleration and particle transport in a complicated environment such as the turbulent and highly magnetized atmosphere of the active sun.

  5. INTEGRAL high-energy monitoring of the X-ray burster KS 1741-293

    NASA Astrophysics Data System (ADS)

    De Cesare, G.; Bazzano, A.; Martínez Núñez, S.; Stratta, G.; Tarana, A.; Del Santo, M.; Ubertini, P.

    2007-09-01

    KS 1741-293, discovered in 1989 by the X-ray camera TTM on the Kvant module of the Mir space station and identified as an X-ray burster, had not been detected in the hard X-ray band until the advent of the INTEGRAL observatory. Moreover, this source has recently been the object of scientific discussion, being also associated with a nearby extended radio source that in principle could be the supernova remnant produced by the accretion-induced collapse in the binary system. Our long-term monitoring with INTEGRAL, covering the period from 2003 February to 2005 May, confirms that KS 1741-293 is transient in the soft and hard X-ray bands. When the source is active, from a simultaneous JEM-X and IBIS data analysis, we provide a wide-band spectrum from 5 to 100 keV, which can be fitted by a two-component model: a multiple blackbody for the soft emission and a Comptonized or a cut-off power-law model for the hard component. Finally, by the detection of two X-ray bursters with JEM-X, we confirm the bursting nature of KS 1741-293, including this source in the class of hard-tailed X-ray bursters. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), the Czech Republic and Poland, and with the participation of Russia and the USA. E-mail: giovanni.decesare@iasf-roma.inaf.it ‡ INAF personnel resident at ASDC.

  6. High energy resolution inelastic x-ray scattering at the SRI-CAT

    SciTech Connect

    Macrander, A.T.

    1996-08-01

    This report is a combination of vugraphs and two papers. The vugraphs give information on the beamline at the APS for IXS and the science addressable by IXS. They also cover the 10 milli-eV resolution spectrometer and the 200 milli-eV resolution spectrometer. The first paper covers the performance of the focusing Ge(444) backscattering analyzers for the inelastic x-ray scattering. The second paper discusses inelastic x-ray scattering from TiC and Ti single crystals.

  7. The high energy X-ray detector on the Ariel-5 satellite

    NASA Technical Reports Server (NTRS)

    Engel, A. R.; Coe, M. J.

    1977-01-01

    The Imperial College hard X-ray detector which is used to make spectral measurements in the 26 keV to 1.2 MeV energy range on celestial X-ray sources from the Ariel-5 satellite is described. Details are given of the design, calibration and in-orbit performance of the detector. A modulation process is used to detect weak signals against a background and we give details of the spectrum unfolding techniques used to convert the measured spectra into corrected incident spectra.

  8. High energy X-ray observations of the 38-second pulsar

    NASA Technical Reports Server (NTRS)

    Byrne, P. F.; Levine, A. M.; Bautz, M.; Howe, S. K.; Lang, F. L.; Primini, F. A.; Lewin, W. H. G.; Gruber, D. E.; Knight, F. K.; Nolan, P. L.

    1981-01-01

    The results of observations of the 38-second pulsar obtained at high X-ray energies (13-180 keV) with the UCSD/MIT instrument aboard HEAO 1 are reported. The results include a measurement of the source location, measurement of the pulse profile, and determination of the average intensity and spectrum during each of three time intervals spanning a baseline of 1 year. The total intensity of the pulsar is seen to vary on a 6-month time scale. The spectrum is hard but, like other X-ray pulsars, steepens at energies above 20 keV.

  9. NuSTAR Detection of High-energy X-Ray Emission and Rapid Variability from Sagittarius Asstarf Flares

    NASA Astrophysics Data System (ADS)

    Barrière, Nicolas M.; Tomsick, John A.; Baganoff, Frederick K.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Dexter, Jason; Grefenstette, Brian; Hailey, Charles J.; Harrison, Fiona A.; Madsen, Kristin K.; Mori, Kaya; Stern, Daniel; Zhang, William W.; Zhang, Shuo; Zoglauer, Andreas

    2014-05-01

    Sagittarius Asstarf harbors the supermassive black hole that lies at the dynamical center of our Galaxy. Sagittarius Asstarf spends most of its time in a low luminosity emission state but flares frequently in the infrared and X-ray, increasing up to a few hundred fold in brightness for up to a few hours at a time. The physical processes giving rise to the X-ray flares are uncertain. Here we report the detection with the NuSTAR observatory in Summer and Fall 2012 of four low to medium amplitude X-ray flares to energies up to 79 keV. For the first time, we clearly see that the power-law spectrum of Sagittarius Asstarf X-ray flares extends to high energy, with no evidence for a cutoff. Although the photon index of the absorbed power-law fits are in agreement with past observations, we find a difference between the photon index of two of the flares (significant at the 95% confidence level). The spectra of the two brightest flares (~55 times quiescence in the 2-10 keV band) are compared to simple physical models in an attempt to identify the main X-ray emission mechanism, but the data do not allow us to significantly discriminate between them. However, we confirm the previous finding that the parameters obtained with synchrotron models are, for the X-ray emission, physically more reasonable than those obtained with inverse Compton models. One flare exhibits large and rapid (<100 s) variability, which, considering the total energy radiated, constrains the location of the flaring region to be within ~10 Schwarzschild radii of the black hole.

  10. High Energy X-Ray System Specification for the Device Assembly Facility (DAF) at the NNSS

    SciTech Connect

    Fry, David A.

    2012-08-10

    This specification establishes requirements for an X-Ray System to be used at the Device Assembly Facility (DAF) at the Nevada National Security Site (NNSS) to support radiography of experimental assemblies for Laboratory (LANL, LLNL, SNL) programs conducting work at the NNSS.

  11. Coded apertures allow high-energy x-ray phase contrast imaging with laboratory sources

    NASA Astrophysics Data System (ADS)

    Ignatyev, K.; Munro, P. R. T.; Chana, D.; Speller, R. D.; Olivo, A.

    2011-07-01

    This work analyzes the performance of the coded-aperture based x-ray phase contrast imaging approach, showing that it can be used at high x-ray energies with acceptable exposure times. Due to limitations in the used source, we show images acquired at tube voltages of up to 100 kVp, however, no intrinsic reason indicates that the method could not be extended to even higher energies. In particular, we show quantitative agreement between the contrast extracted from the experimental x-ray images and the theoretical one, determined by the behavior of the material's refractive index as a function of energy. This proves that all energies in the used spectrum contribute to the image formation, and also that there are no additional factors affecting image contrast as the x-ray energy is increased. We also discuss the method flexibility by displaying and analyzing the first set of images obtained while varying the relative displacement between coded-aperture sets, which leads to image variations to some extent similar to those observed when changing the crystal angle in analyzer-based imaging. Finally, we discuss the method's possible advantages in terms of simplification of the set-up, scalability, reduced exposure times, and complete achromaticity. We believe this would helpful in applications requiring the imaging of highly absorbing samples, e.g., material science and security inspection, and, in the way of example, we demonstrate a possible application in the latter.

  12. Construction and evaluation of a high-energy grating-based x-ray phase-contrast imaging setup

    NASA Astrophysics Data System (ADS)

    Hauke, Christian; Horn, Florian; Pelzer, Georg; Rieger, Jens; Lachner, Sebastian; Ludwig, Veronika; Seifert, Maria; Schuster, Max; Wandner, Johannes; Wolf, Andreas; Weber, Thomas; Michel, Thilo; Anton, Gisela

    2016-03-01

    Interferometric x-ray imaging becomes more and more attractive for applications such as medical imaging or non-destructive testing, because it provides the opportunity to obtain additional information on the internal structure of radiographed objects.12 Therefore, three types of images are acquired: An attenuation image like in conventional x-ray imaging, an image of the differential phase-shift generated by the object and the so called dark-field image, which contains information about the object's granularity even on sub-pixel scale.3 However, most experiments addressing grating-based x-ray phase-contrast imaging with polychromatic sources are restricted to energies up to about 40 keV. For the application of this imaging method to thicker objects like human specimens or dense components, higher tube voltages are required. This is why we designed and constructed a laboratory setup for high energies, which is able to image larger objects.4 To evaluate the performance of the setup, the mean visibility of the field of view was measured for several tube voltages. The result shows that the mean visibility has a peak value of 23% at a tube voltage of 60 kV and is constantly greater than 16% up to a tube voltage of 120 kV. Thus, good image quality is provided even for high energies. To further substantiate the performance of the setup at high energies, a human ex-vivo foot was examined at a tube voltage of 75 kV. The interferometric x-ray images show a good image quality and a promising diagnostic power.

  13. Synchrotron x-ray high energy PDF and tomography studies for gallium melts under high-pressure conditions

    NASA Astrophysics Data System (ADS)

    Liu, H.; Liu, L. L.; Li, R.; Li, L.

    2015-12-01

    Liquid gallium exhibits unusual and unique physical properties. A rich polymorphism and metastable modifications of solid Ga have been discovered and a number of studies of liquid gallium under high pressure conditions were reported. However, some fundamental properties, such as the equation of state (EoS) of Ga melt under extreme conditions remain unclear. To compare to the previous reports, we performed the pair distribution function (PDF) study using diamond anvil cell, in which synchrotron high-energy x-ray total scattering data, combined with reverse Monte Carlo simulation, was used to study the microstructure and EoS of liquid gallium under high pressure at room temperature conditions. The EoS of Ga melt, which was measured from synchrotron x-ray tomography method at room temperature, was used to avoid the potential relatively big errors for the density estimation from the reverse Monte Carlo simulation with the mathematical fit to the measured structure factor data. The volume change of liquid gallium have been studied as a function of pressure and temperature up to 5 GPa at 370 K using synchrotron x-ray microtomography combined with energy dispersive x-ray diffraction (EDXRD) techniques using Drickamer press. The directly measured P-V-T curves were obtained from 3D tomography reconstruction data. The existence of possible liquid-liquid phase transition regions is proposed based on the abnormal compressibility and local structure change in Ga melts.

  14. X-ray polarimetry and new prospects in high-energy astrophysics

    NASA Astrophysics Data System (ADS)

    Sgrò, C.

    2016-07-01

    Polarimetry is universally recognized as one of the new frontiers in X-ray astrophysics. It is a powerful tool to investigate a variety of astrophysical processes, as well as a mean to study fundamental physics in space. A renewed interest is testified by dedicated missions approved for phase A by ESA and NASA. The main advance is the availability of a gas pixel detector that is able to add polarization measurement to imaging and spectroscopy, and can be used at the focus of a conventional X-ray optics. The detector exploits the photoelectric effect in gas and a finely segmented ASIC as a collecting anode. In this work I will describe in detail the experimental technique and the detector concept, and illustrate the scientific prospects of these new missions.

  15. Experimental comparison of various techniques for spot size measurement of high-energy X-ray

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Li, Qin; Chen, Nan; Cheng, Jin-Ming; Li, Cheng-Gang; Li, Hong; Long, Quan-Hong; Shi, Jin-Shui; Deng, Jian-Jun

    2016-08-01

    In flash-radiography experiments, the quality of the acquired image strongly depends on the focal size of the X-ray source spot. A variety of techniques based on imaging of the pinhole, the slit and the rollbar are adopted to measure the focal spot size of the Dragon-I linear induction accelerator. The image of the pinhole provides a two-dimensional distribution of the X-ray spot, while those of the slit and the rollbar give a line-spread distribution and an edge-spread distribution, respectively. The spot size characterized by the full-width at half-maximum and that characterized by the LANL definition are calculated for comparison.

  16. Microstructures for high-energy x-ray and particle-imaging applications

    SciTech Connect

    Ceglio, N.M.; Stone, G.F.; Hawryluk, A.M.

    1981-05-01

    Coded imaging techniques using thick, micro-Fresnel zone plates as coded apertures have been used to image x-ray emissions (2-20 keV) and 3.5 MeV Alpha particle emissions from laser driven micro-implosions. Image resolution in these experiments was 3-8 ..mu..m. Extension of this coded imaging capability to higher energy x-rays (approx. 100 keV) and more penetrating charged particles (e.g. approx. 15 MeV protons) requires the fabrication of very thick (50-200 ..mu..m), high aspect ratio (10:1), gold Fresnel zone plates with narrow linewidths (5-25 ..mu..m) for use as coded aperatures. A reactive ion etch technique in oxygen has been used to produce thick zone plate patterns in polymer films. The polymer patterns serve as electroplating molds for the subsequent fabrication of the free-standing gold zone plate structures.

  17. Gas Scintillation Proportional Counters for High-Energy X-ray Astronomy

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail; Ramsey, Brian; Apple, Jeffery

    2003-01-01

    A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a balloon-borne hard-x-ray telescope is under development at the Marshall Space Flight Center. These detectors have an active area of approx. 20 sq cm, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approx. 500 microns. The detector s energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Full details of the instrument and its performance will be provided.

  18. In-situ High-energy X-ray Diffraction Study of the Local Structure of Supercooled Liquid Si

    NASA Technical Reports Server (NTRS)

    Lee, G. W.; Kim, T. H.; Sieve, B.; Gangopadhyay, A. K.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, D. S.; Kelton, K. F.; Goldman, A. I.

    2005-01-01

    While changes in the coordination number for liquid silicon upon supercooling, signaling an underlying liquid-liquid phase transition, have been predicted, x-ray and neutron measurements have produced conflicting reports. In particular some studies have found an increase in the first shell coordination as temperature decreases in the supercooled regime, while others have reported increases in the coordination number with decreasing temperature. Employing the technique of electrostatic levitation coupled with high energy x-ray diffraction (125 keV), and rapid data acquisition (100ms collection times) using an area detector, we have obtained high quality structural data more deeply into the supercooled regime than has been possible before. No change in coordination number is observed in this temperature region, calling into question previous experimental claims of structural evidence for the existence of a liquid-liquid phase transition.

  19. Talbot-Lau X-ray Deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments

    DOE PAGESBeta

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Mileham, C.; Begishev, I.; Theobald, W.; Bromage, J.; Regan, S. P.; Klein, S. R.; Munoz-Cordoves, G.; et al

    2016-04-21

    Talbot-Lau X-ray Deflectometry has been developed as an electron density diagnostic for High Energy Density plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping was demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moire pattern formation and grating survival was also observed using a copper x-pinch driven at 400 kA, ~1 kA/ns. Lastly, these results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

  20. Quantifying the Nucleation and Growth Kinetics of Microwave Nanochemistry Enabled by in Situ High-Energy X-ray Scattering.

    PubMed

    Liu, Qi; Gao, Min-Rui; Liu, Yuzi; Okasinski, John S; Ren, Yang; Sun, Yugang

    2016-01-13

    The fast reaction kinetics presented in the microwave synthesis of colloidal silver nanoparticles was quantitatively studied, for the first time, by integrating a microwave reactor with in situ X-ray diffraction at a high-energy synchrotron beamline. Comprehensive data analysis reveals two different types of reaction kinetics corresponding to the nucleation and growth of the Ag nanoparticles. The formation of seeds (nucleation) follows typical first-order reaction kinetics with activation energy of 20.34 kJ/mol, while the growth of seeds (growth) follows typical self-catalytic reaction kinetics. Varying the synthesis conditions indicates that the microwave colloidal chemistry is independent of concentration of surfactant. These discoveries reveal that the microwave synthesis of Ag nanoparticles proceeds with reaction kinetics significantly different from the synthesis present in conventional oil bath heating. The in situ X-ray diffraction technique reported in this work is promising to enable further understanding of crystalline nanomaterials formed through microwave synthesis. PMID:26625184

  1. Calibration of the High Energy Replicated Optics to Explore the Sun (HEROES) Hard X-ray Telescope

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.; Gaskin, Jessica; Christe, Steven; Shih, Albert; Tennant, Allyn; Swartz, Doug; Kilaru, Kiranmayee; Elsner, Ron; Kolodziejczak, Jeff; Ramsey, Brian

    2014-01-01

    On September 21-22, 2013, the High Energy Replicated Optics to Explore the Sun (HEROES) hard X-ray telescope, flew as a balloon payload from Ft. Sumner, N.M. HEROES observed the Sun, the black hole binary GRS 1915+105, and the Crab Nebula during its 27 hour flight. In this paper we describe laboratory calibration measurements of the HEROES detectors using line and continuum sources, applications of these measurements to define channel to energy (gain) corrections for observed events and to define detector response matrices. We characterize the HEROES X-ray grazing incidence optics using measurements taken in the Stray-Light (SLF) Facility in Huntsville, AL, and using ray traces.

  2. A broadband high-resolution elliptical crystal x-ray spectrometer for high energy density physics experiments

    SciTech Connect

    Anderson, S G; Heeter, R F; Booth, R; Emig, J; Fulkerson, S; McCarville, T; Norman, D; Young, B F

    2006-03-31

    Spectroscopic investigation of high temperature laser produced plasmas in general, and x-ray opacity experiments in particular, often requires instruments with both a broad coverage of x-ray energies and high spectral, spatial, and temporal resolution. We analyze the design, model the response, and report the commissioning of a spectrometer using elliptical crystals in conjunction with a large format, gated microchannel plate detector. Measurements taken with this instrument at the JANUS laser facilities demonstrate the designed spectral range of 0.24 to 5.8 keV, and spectral resolution E/{Delta}E > 500, resulting in 2 to 3 times more spectral data than achieved by previous spectrometer designs. The observed 100 picosecond temporal resolution and 35 {micro}m spatial resolution are consistent with the requirements of high energy density opacity experiments.

  3. Detection of High-energy Gamma-Ray Emission During the X-Ray Flaring Activity in GRB 100728A

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bhat, P. N.; Bissaldi, E.; Blandford, R. D.; Bonamente, E.; Bonnell, J.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Connaughton, V.; Conrad, J.; Cutini, S.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Favuzzi, C.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Granot, J.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lubrano, P.; Mazziotta, M. N.; McEnery, J. E.; Mészáros, P.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Naumann-Godo, M.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Paciesas, W. S.; Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reyes, L. C.; Roth, M.; Sadrozinski, H. F.-W.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Sonbas, E.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Strickman, M. S.; Takahashi, H.; Tanaka, T.; Tanaka, Y.; Thayer, J. G.; Thayer, J. B.; Torres, D. F.; Tosti, G.; Troja, E.; Uehara, T.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vilchez, N.; Vitale, V.; von Kienlin, A.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yamazaki, R.; Yang, Z.; Ziegler, M.; Piro, L.

    2011-06-01

    We present the simultaneous Swift and Fermi observations of the bright GRB 100728A and its afterglow. The early X-ray emission is dominated by a vigorous flaring activity continuing until 1 ks after the burst. In the same time interval, high-energy emission is significantly detected by the Fermi/Large Area Telescope. Marginal evidence of GeV emission is observed up to later times. We discuss the broadband properties of this burst within both the internal and external shock scenarios, with a particular emphasis on the relation between X-ray flares, the GeV emission, and a continued long-duration central engine activity as their power source.

  4. Calibration of the High Energy Replicated Optics to Explore the Sun (HEROES) Hard X-ray Telescope

    NASA Astrophysics Data System (ADS)

    Wilson-Hodge, Colleen A.; Gaskin, Jessica; Christe, Steven; Shih, Albert; Tennant, Allyn; Swartz, Doug; Kilaru, Kiranmayee; Elsner, Ron; Kolodziejczak, Jeff; Ramsey, Brian

    On 2013 September 21-22, the High Energy Replicated Optics to Explore the Sun (HEROES) hard X-ray telescope flew as a balloon payload from Ft. Sumner, NM. HEROES observed the Sun, the black hole binary GRS 1915+105, and the Crab Nebula during its 27 h flight. In this paper, we describe laboratory calibration measurements of the HEROES detectors using line and continuum sources and applications of these measurements to define channel to energy (gain) corrections for observed events and to define detector response matrices. We characterize the HEROES X-ray grazing incidence optics using measurements taken in the Stray Light Facility (SLF) in Huntsville, AL, and using ray traces. We describe the application of our calibration measurements to in-flight observations of the Crab Nebula.

  5. Radiological safety of food irradiation with high energy X-rays: theoretical expectations and experimental evidence

    NASA Astrophysics Data System (ADS)

    Grégoire, O.; Cleland, M. R.; Mittendorfer, J.; Dababneh, S.; Ehlermann, D. A. E.; Fan, X.; Käppeler, F.; Logar, J.; Meissner, J.; Mullier, B.; Stichelbaut, F.; Thayer, D. W.

    2003-06-01

    The radiological safety of red meat irradiated with 7.5 MeV X-rays (bremsstrahlung) has been investigated theoretically and verified by dedicated experiments. Samples of meat and meat ash were located in a large volume of fresh meat at the position of the highest photoneutron fluence and irradiated to an X-ray dose of 15 kGy, twice the maximum dose allowed by the US FDA for meat irradiation. In order to evaluate the safety of treatment with any kind of electron accelerators, two experiments have been performed with different accelerators delivering electrons with a narrow and a broad energy spread. The measured activities and theoretical estimates are of the same order of magnitude. An evaluation of the corresponding radiation exposure from ingestion of the irradiated product has been compared to natural background radiation. The paper concludes that the risk to individuals from intake of food irradiated with X-rays from 7.5 MeV electrons, even with a broad energy spectrum, would be trivial.

  6. High energy X-ray spectra of cygnus XR-1 observed from OSO-8

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.

    1978-01-01

    X-ray spectra of Cygnus XR-1 were measured with the scintillation spectrometer on board the OSO-8 satellite during a period of one and one-half to three weeks in each of the years from 1975 to 1977. Observations were made when the source was both in a high state and in a low state. Typical spectra of the source between 15 and 250 keV are presented. The observed pivoting effect is consistent with two temperature accretion disk models of the X-ray emitting region. No significant break in the spectrum occurred at energies up to 150 keV. The high state as defined in the 3 to 6 keV bandwidth was found to be the higher luminosity state of the X-ray source. One transition from a low to a high state occurred during observations. The time of occurrence of this and other transitions is consistent with the hypothesis that all intensity transitions occur near periastron of the binary system, and that such transitions are caused by changes in the mass transfer rate between the primary and the accretion disk around the secondary.

  7. The UCSD high energy X-ray timing experiment cosmic ray particle anticoincidence detector

    NASA Technical Reports Server (NTRS)

    Hink, P. L.; Rothschild, R. E.; Pelling, M. R.; Macdonald, D. R.; Gruber, D. E.

    1991-01-01

    The HEXTE, part of the X-Ray Timing Explorer (XTE), is designed to make high sensitivity temporal and spectral measurements of X-rays with energies between 15 and 250 keV using NaI/CsI phoswich scintillation counters. To achieve the required sensitivity it is necessary to provide anticoincidence of charged cosmic ray particles incident upon the instrument, some of which interact to produce background X-rays. The proposed cosmic ray particle anticoincidence shield detector for HEXTE uses a novel design based on plastic scintillators and wavelength-shifter bars. It consists of five segments, each with a 7 mm thick plastic scintillator, roughly 50 cm x 50 cm in size, coupled to two wavelength-shifter bars viewed by 1/2 inch photomultiplier tubes. These segments are configured into a five-sided, box-like structure around the main detector system. Results of laboratory testing of a model segment, and calculations of the expected performance of the flight segments and particle anticoincidence detector system are presented to demonstrate that the above anticoincidence detector system satisfies its scientific requirements.

  8. High-energy x-ray grating-based phase-contrast radiography of human anatomy

    NASA Astrophysics Data System (ADS)

    Horn, Florian; Hauke, Christian; Lachner, Sebastian; Ludwig, Veronika; Pelzer, Georg; Rieger, Jens; Schuster, Max; Seifert, Maria; Wandner, Johannes; Wolf, Andreas; Michel, Thilo; Anton, Gisela

    2016-03-01

    X-ray grating-based phase-contrast Talbot-Lau interferometry is a promising imaging technology that has the potential to raise soft tissue contrast in comparison to conventional attenuation-based imaging. Additionally, it is sensitive to attenuation, refraction and scattering of the radiation and thus provides complementary and otherwise inaccessible information due to the dark-field image, which shows the sub-pixel size granularity of the measured object. Until recent progress the method has been mainly limited to photon energies below 40 keV. Scaling the method to photon energies that are sufficient to pass large and spacious objects represents a challenging task. This is caused by increasing demands regarding the fabrication process of the gratings and the broad spectra that come along with the use of polychromatic X-ray sources operated at high acceleration voltages. We designed a setup that is capable to reach high visibilities in the range from 50 to 120 kV. Therefore, spacious and dense parts of the human body with high attenuation can be measured, such as a human knee. The authors will show investigations on the resulting attenuation, differential phase-contrast and dark-field images. The images experimentally show that X-ray grating-based phase-contrast radiography is feasible with highly absorbing parts of the human body containing massive bones.

  9. Dose and detectability improvements with high energy phase sensitive x-ray imaging in comparison to low energy conventional imaging

    PubMed Central

    Wong, Molly Donovan; Yan, Aimin; Ghani, Muhammad; Li, Yuhua; Fajardo, Laurie; Wu, Xizeng; Liu, Hong

    2014-01-01

    The objective of this study was to demonstrate the potential benefits of using high energy x-rays for phase sensitive breast imaging through a comparison with conventional mammography imaging. We compared images of a contrast-detail (CD) phantom acquired on a prototype phase sensitive x-ray imaging system with images acquired on a commercial flat panel digital mammography unit. The phase contrast images were acquired using a micro-focus x-ray source with a 50 μm focal spot at 120 kVp and 4.5 mAs, with a magnification factor of 2.46 and a 50 μm pixel pitch. A phase attenuation duality (PAD)-based phase retrieval algorithm that requires only a single phase contrast image was applied. Conventional digital mammography images were acquired at 27 kVp, 131 mAs and 28 kVp, 54 mAs. For the same radiation dose, both the observer study and SNR/FOM comparisons indicated a large improvement by the phase retrieved image as compared to the clinical system for the larger disk sizes, but the improvement was not enough to detect the smallest disks. Compared to the double dose image acquired with the clinical system, the observer study also indicated that the phase retrieved image provided improved detection capabilities for all disk sizes except the smallest disks. Thus the SNR improvement provided by phase contrast imaging is not yet enough to offset the noise reduction provided by the clinical system at the doubled dose level. However, the potential demonstrated by this study for high energy phase sensitive x-ray imaging to improve lesion detection and reduce radiation dose in mammography warrants further investigation of this technique. PMID:24732108

  10. Dose and detectability improvements with high energy phase sensitive x-ray imaging in comparison to low energy conventional imaging

    NASA Astrophysics Data System (ADS)

    Donovan Wong, Molly; Yan, Aimin; Ghani, Muhammad; Li, Yuhua; Fajardo, Laurie; Wu, Xizeng; Liu, Hong

    2014-05-01

    The objective of this study was to demonstrate the potential benefits of using high energy x-rays for phase sensitive breast imaging through a comparison with conventional mammography imaging. We compared images of a contrast-detail phantom acquired on a prototype phase sensitive x-ray imaging system with images acquired on a commercial flat panel digital mammography unit. The phase contrast images were acquired using a micro-focus x-ray source with a 50 µm focal spot at 120 kVp and 4.5 mAs, with a magnification factor of 2.46 and a 50 µm pixel pitch. A phase attenuation duality-based phase retrieval algorithm that requires only a single phase contrast image was applied. Conventional digital mammography images were acquired at 27 kVp, 131 mAs and 28 kVp, 54 mAs. For the same radiation dose, both the observer study and signal-to-noise ratio (SNR)/figure of merit comparisons indicated a large improvement by the phase retrieved image as compared to the clinical system for the larger disc sizes, but the improvement was not enough to detect the smallest discs. Compared to the double dose image acquired with the clinical system, the observer study also indicated that the phase retrieved image provided improved detection capabilities for all disc sizes except the smallest discs. Thus the SNR improvement provided by phase contrast imaging is not yet enough to offset the noise reduction provided by the clinical system at the doubled dose level. However, the potential demonstrated by this study for high energy phase sensitive x-ray imaging to improve lesion detection and reduce radiation dose in mammography warrants further investigation of this technique.

  11. High energy x-ray phase contrast CT using glancing-angle grating interferometers

    SciTech Connect

    Sarapata, A.; Stayman, J. W.; Siewerdsen, J. H.; Finkenthal, M.; Stutman, D.; Pfeiffer, F.

    2014-02-15

    Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code the authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as

  12. High energy x-ray phase contrast CT using glancing-angle grating interferometers

    PubMed Central

    Sarapata, A.; Stayman, J. W.; Finkenthal, M.; Siewerdsen, J. H.; Pfeiffer, F.; Stutman, D.

    2014-01-01

    Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code the authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as

  13. Circular multilayer zone plate for high-energy x-ray nano-imaging.

    PubMed

    Koyama, Takahisa; Takano, Hidekazu; Konishi, Shigeki; Tsuji, Takuya; Takenaka, Hisataka; Ichimaru, Satoshi; Ohchi, Tadayuki; Kagoshima, Yasushi

    2012-01-01

    A circular multilayer zone plate (MZP) was fabricated and its focusing performance was evaluated using 20-keV x-rays. MoSi(2) and Si layers were alternately deposited by DC magnetron sputtering on a wire core; all the interfaces satisfied the Fresnel zone condition. The measured line spread function was converted to a point spread function by tomographic reconstruction. The results suggest that the MZP has the potential to realize the diffraction-limited resolving power, which is calculated to be 35 nm using the diffraction integral. Furthermore, scanning transmission microscopy using the MZP could resolve a 50-nm line-and-space pattern. PMID:22299960

  14. A Bright Source of High-Energy X-rays: Final Report on LDRD Project 04-FS-007

    SciTech Connect

    Colvin, J D; Felter, T E; Searson, P C; Chen, M

    2005-02-03

    We have demonstrated the feasibility of fabricating pure-metal foams via a novel four-step technique based upon ion beam lithography. In this report we discuss why and how such foams are useful as bright, high-photon-energy x-ray sources; the details of the fabrication technique we employed to make such foams; the results obtained; and what we plan to do in the future to improve the technique and turn the foams so fabricated into real laser targets for high-brightness, high-energy back lighting.

  15. High-energy x-ray microscopy of laser-fusion plasmas at the National Ignition Facility

    SciTech Connect

    Koch, J.A.; Landen, O.L.; Hammel, B.A.

    1997-08-26

    Multi-keV x-ray microscopy will be an important laser-produced plasma diagnostic at future megajoule facilities such as the National Ignition Facility (NIF).In preparation for the construction of this facility, we have investigated several instrumentation options in detail, and we conclude that near normal incidence single spherical or toroidal crystals may offer the best general solution for high-energy x-raymicroscopy at NIF and at similar large facilities. Kirkpatrick-Baez microscopes using multi-layer mirrors may also be good secondary options, particularly if apertures are used to increase the band-width limited field of view.

  16. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

    NASA Astrophysics Data System (ADS)

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Mileham, C.; Begishev, I. A.; Bromage, J.; Regan, S. P.

    2016-02-01

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 1023 cm-3 in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. The 50 ± 15 μm spatial resolution achieved across the full field of view was found to be limited by the x-ray source-size, similar to conventional radiography.

  17. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

    DOE PAGESBeta

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Mileham, C.; Begishev, I. A.; Bromage, J.; Regan, S. P.

    2016-02-10

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 1023 cm₋3 in amore » low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. We found the 50 ± 15 μm spatial resolution achieved across the full field of view was limited by the x-ray source-size, similar to conventional radiography.« less

  18. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics.

    PubMed

    Valdivia, M P; Stutman, D; Stoeckl, C; Theobald, W; Mileham, C; Begishev, I A; Bromage, J; Regan, S P

    2016-02-01

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 10(23) cm(-3) in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. The 50 ± 15 μm spatial resolution achieved across the full field of view was found to be limited by the x-ray source-size, similar to conventional radiography. PMID:26931847

  19. HEAO 1 high energy X-ray observations of the Virgo cluster and A2142

    NASA Technical Reports Server (NTRS)

    Lea, S. M.; Reichert, G.; Mushotzky, R.; Baity, W. A.; Gruber, D. E.; Rothschild, R.; Primini, F. A.

    1981-01-01

    Observations are reported of the Virgo cluster and Abell 2142 in the energy range of 15-150 keV, detected by using hard X-ray and low energy gamma-ray instruments on board the HEAO-1 spacecraft, during 1977 and 1978. The Virgo cluster was detected at a mean flux of (1.3 + or - 0.3) x 10 to the 0.001 photons/sq cm-s in the 20-100 keV band, and A2142 was detected marginally at a flux of (2 + or - 0.8) x 10 to the 0.001 photons/sq cm-s in the 15-40 keV band. Inverse Compton emission was not observed in these clusters. Results are used to derive limits to the intracluster magnetic field of B approximately greater than 5 x 10 to the -7th gauss and B approximately 5 x 10 to the -8th gauss in the Virgo cluster and A1242, respectively. There is some evidence for variability in these sources, which implies that the hard X-ray emission originates in a relatively compact object or region rather than from the cluster as a whole.

  20. Calibration of the NuSTAR High-energy Focusing X-ray Telescope.

    NASA Astrophysics Data System (ADS)

    Madsen, Kristin K.; Harrison, Fiona A.; Markwardt, Craig B.; An, Hongjun; Grefenstette, Brian W.; Bachetti, Matteo; Miyasaka, Hiromasa; Kitaguchi, Takao; Bhalerao, Varun; Boggs, Steve; Christensen, Finn E.; Craig, William W.; Forster, Karl; Fuerst, Felix; Hailey, Charles J.; Perri, Matteo; Puccetti, Simonetta; Rana, Vikram; Stern, Daniel; Walton, Dominic J.; Jørgen Westergaard, Niels; Zhang, William W.

    2015-09-01

    We present the calibration of the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray satellite. We used the Crab as the primary effective area calibrator and constructed a piece-wise linear spline function to modify the vignetting response. The achieved residuals for all off-axis angles and energies, compared to the assumed spectrum, are typically better than ±2% up to 40 keV and 5%-10% above due to limited counting statistics. An empirical adjustment to the theoretical two-dimensional point-spread function (PSF) was found using several strong point sources, and no increase of the PSF half-power diameter has been observed since the beginning of the mission. We report on the detector gain calibration, good to 60 eV for all grades, and discuss the timing capabilities of the observatory, which has an absolute timing of ±3 ms. Finally, we present cross-calibration results from two campaigns between all the major concurrent X-ray observatories (Chandra, Swift, Suzaku, and XMM-Newton), conducted in 2012 and 2013 on the sources 3C 273 and PKS 2155-304, and show that the differences in measured flux is within ˜10% for all instruments with respect to NuSTAR.

  1. High energy x-ray radiography and computed tomography of bridge pins

    SciTech Connect

    Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

    1999-05-01

    Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL.

  2. Characterizing high energy spectra of NIF ignition hohlraums using a differentially filtered high energy multi-pinhole X-ray imager

    SciTech Connect

    Park, H; Dewald, E D; Glenzer, S; Kalantar, D H; Kilkenny, J D; MacGowan, B J; Maddox, B R; Milovich, J L; Prasad, R R; Remington, B A; Thomas, C A

    2010-05-11

    Understanding hot electron distributions generated inside hohlraums is important to the ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with the target materials. We used an array of 18 pinholes, with four independent filter combinations, to image entire hohlraums with a magnification of 0.87x during the hohlraum energetics campaign on NIF. Comparing our results with hohlraum simulations indicates that the characteristic 30 keV hot electrons are mainly generated from backscattered laser plasma interactions rather than from hohlraum hydrodynamics.

  3. High real-space resolution structure of materials by high-energy x-ray diffraction

    SciTech Connect

    Petkov, V.; Billinge, S. J. L.; Heising, J.; Kanatzidis, M. G.; Shastri, S.; Kycia, S.

    1999-12-10

    Results of high-energy synchrotrons radiation experiments are presented demonstrating the advantages of the atomic Pair Distribution Function technique in determining the structure of materials with high resolution.

  4. Internal structure of copper(II)-phthalocyanine thin films on SiO{sub 2}/Si substrates investigated by grazing incidence x-ray reflectometry

    SciTech Connect

    Brieva, A. C.; Jenkins, T. E.; Jones, D. G.; Stroessner, F.; Evans, D. A.; Clark, G. F.

    2006-04-01

    The internal structure of copper(II)-phthalocyanine (CuPc) thin films grown on SiO{sub 2}/Si by organic molecular beam deposition has been studied by grazing incidence x-ray reflectometry (GIXR) and atomic force microscopy. The electronic density profile is consistent with a structure formed by successive monolayers of molecules in the {alpha} form with the b axis lying in the substrate surface plane. The authors present an electronic density profile model of CuPc films grown on SiO{sub 2}/Si. The excellent agreement between the model and experimental data allows postdeposition monitoring of the internal structure of the CuPc films with the nondestructive GIXR technique, providing a tool for accurate control of CuPc growth on silicon-based substrates. In addition, since the experiments have been carried out ex situ, they show that these structures can endure ambient conditions.

  5. X-ray spectra of Hercules X-1. 3: Pulse phase dependence in high energy continuum

    NASA Technical Reports Server (NTRS)

    Pravdo, S. H.; Bussard, R. W.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    Pulse phase-dependent spectral changes in the high energy (less than 20 keV) continuum of Hercules X-1 were observed. Cyclotron absorption of underlying continua can reproduce the observed angular dependence in the high energy cutoff. Implications of this model, which include the possibility of determining the angular separation between the line of sight and the neutron star magnetic field if the absorbing electron spectrum is known are discussed.

  6. Effects of high-energy x-ray irradiation of selected scintillating fibers

    NASA Astrophysics Data System (ADS)

    Margulies, Seymour; Chung, Manho

    1993-10-01

    Tracking detectors based on scintillating-fiber technology are being developed for the Solenoidal Detector Collaboration at the Superconducting Super Collider and for the D0 collaboration at Fermilab. An important aspect of this work is the effect of the intense radiation environment existing in the detector cores on the fibers. This paper presents preliminary results of a 2 MeV x-ray irradiation of selected fibers to a dose of 140 Krad, corresponding to some ten years of detector operation. Primary emphasis was placed on studying new Kuraray multiclad scintillating and clear fibers which have superior brightness, attenuation lengths, and mechanical robustness. Two types of Bicron single-clad scintillating fibers were also investigated.

  7. High-energy gamma-ray and hard X-ray observations of Cyg X-3

    NASA Technical Reports Server (NTRS)

    Hermsen, W.; Bloemen, J. B. G. M.; Jansen, F. A.; Bennett, K.; Buccheri, R.; Mastichiadis, A.; Mayer-Hasselwander, H. A.; Strong, A. W.; Oezel, M. E.; Pollock, A. M. T.

    1987-01-01

    COS-B viewed the Cyg X-3 region seven times between November, 1975, and February, 1982; a search for steady gamma-ray emission pulsed at the characteristic 4.8-hour period did not reveal its source. Leiden-MIT balloon experiment observations of Cyg X-3 in May, 1979 show the 4.8-hour modulation with sinusoidal light curve and modulation depth of 0.30, for energies of up to about 140 keV. The strong variability of Cyg X-3 over more than one order of magnitude at energies below 20 keV does not emerge in the data collected at hard X-ray energies.

  8. ROSI and GEANT4 - A comparison in the context of high energy X-ray physics

    NASA Astrophysics Data System (ADS)

    Kiunke, Markus; Stritt, Carina; Schielein, Richard; Sukowski, Frank; Hölzing, Astrid; Zabler, Simon; Hofmann, Jürgen; Flisch, Alexander; Kasperl, Stefan; Sennhauser, Urs; Hanke, Randolf

    2016-06-01

    This work compares two popular MC simulation frameworks ROSI (Roentgen Simulation) and GEANT4 (Geometry and Tracking in its fourth version) in the context of X-ray physics. The comparison will be performed with the help of a parameter study considering energy, material and length variations. While the total deposited energy as well as the contribution of Compton scattering show a good accordance between all simulated configurations, all other physical effects exhibit large deviations in a comparison of data-sets. These discrepancies between simulations are shown to originate from the different cross sectional databases used in the frameworks, whereas the overall simulation mechanics seem to not have an influence on the agreement of the simulations. A scan over energy, length and material shows that the two parameters energy and material have a significant influence on the agreement of the simulation results, while the length parameter shows no noticeable influence on the deviations between the data-sets.

  9. High-energy radiation from thunderstorms and lightning with the Large Observatory for x-ray Timing (LOFT) mission

    NASA Astrophysics Data System (ADS)

    Marisaldi, Martino; Smith, David M.; Brandt, Søren; Briggs, Michael S.; Budz-Jørgensen, Carl; Campana, Riccardo; Carlson, Brant E.; Celestin, Sebastien; Connaughton, Valerie; Cummer, Steven A.; Dwyer, Joseph R.; Fishman, Gerald J.; Fullekrug, Martin; Fuschino, Fabio; Gjesteland, Thomas; Neubert, Torsten; Østgaard, Nikolai; Tavani, Marco

    2015-04-01

    We explore the possible contributions of the Large Observatory for X-ray Timing (LOFT) mission to the study of high-energy radiation from thunderstorms and lightning. LOFT is a mission dedicated to X-ray timing studies of astrophysical sources, characterised by a very large effective area of about 8.5 square meters at 8 keV. Although the main scientific target of the mission is the fundamental physics of matter under extreme conditions, the peculiar instrument concept allows significant contributions to a wide range of other science topics, including the cross-disciplinary field of high-energy atmospheric physics, at the crossroad between geophysics, space physics and astrophysics. In this field we foresee the following major contributions: detect ˜ 700 Terrestrial Gamma-ray Flashes (TGFs) per year, probing the TGF intensity distribution at low fluence values and providing an unbiased sample of bright events thanks to the intrinsic robustness against dead-time and pile-up; provide the largest TGF detection rate surface density above the equator, allowing for correlation studies with lightning activity on short time scales and small regional scales, to probe the TGF / lightning relationship; lower by a factor ˜ 5 the minimum detectable fluence for Terrestrial Electron Beams (TEBs), an additional tool to probe TGF production mechanism and the lower edge of TGF intensity distribution; open up a discovery space for the detection of high-altitude electron beams and weak X-ray emissions associated to Transient Luminous Events (TLEs). LOFT has been studied as a candidate ESA M3 mission during an extensive assessment phase. The high level of readiness and maturity of the mission, as well as the clean and solid assessment of its unique science case, make LOFT a competitive mission with a compelling science case. For this reason, its development has been continued, aiming at new launch opportunities.

  10. A stochastic approach to quantifying the blur with uncertainty estimation for high-energy X-ray imaging systems

    SciTech Connect

    Fowler, Michael J.; Howard, Marylesa; Luttman, Aaron; Mitchell, Stephen E.; Webb, Timothy J.

    2015-06-03

    One of the primary causes of blur in a high-energy X-ray imaging system is the shape and extent of the radiation source, or ‘spot’. It is important to be able to quantify the size of the spot as it provides a lower bound on the recoverable resolution for a radiograph, and penumbral imaging methods – which involve the analysis of blur caused by a structured aperture – can be used to obtain the spot’s spatial profile. We present a Bayesian approach for estimating the spot shape that, unlike variational methods, is robust to the initial choice of parameters. The posterior is obtained from a normal likelihood, which was constructed from a weighted least squares approximation to a Poisson noise model, and prior assumptions that enforce both smoothness and non-negativity constraints. A Markov chain Monte Carlo algorithm is used to obtain samples from the target posterior, and the reconstruction and uncertainty estimates are the computed mean and variance of the samples, respectively. Lastly, synthetic data-sets are used to demonstrate accurate reconstruction, while real data taken with high-energy X-ray imaging systems are used to demonstrate applicability and feasibility.

  11. A stochastic approach to quantifying the blur with uncertainty estimation for high-energy X-ray imaging systems

    DOE PAGESBeta

    Fowler, Michael J.; Howard, Marylesa; Luttman, Aaron; Mitchell, Stephen E.; Webb, Timothy J.

    2015-06-03

    One of the primary causes of blur in a high-energy X-ray imaging system is the shape and extent of the radiation source, or ‘spot’. It is important to be able to quantify the size of the spot as it provides a lower bound on the recoverable resolution for a radiograph, and penumbral imaging methods – which involve the analysis of blur caused by a structured aperture – can be used to obtain the spot’s spatial profile. We present a Bayesian approach for estimating the spot shape that, unlike variational methods, is robust to the initial choice of parameters. The posteriormore » is obtained from a normal likelihood, which was constructed from a weighted least squares approximation to a Poisson noise model, and prior assumptions that enforce both smoothness and non-negativity constraints. A Markov chain Monte Carlo algorithm is used to obtain samples from the target posterior, and the reconstruction and uncertainty estimates are the computed mean and variance of the samples, respectively. Lastly, synthetic data-sets are used to demonstrate accurate reconstruction, while real data taken with high-energy X-ray imaging systems are used to demonstrate applicability and feasibility.« less

  12. High-Energy X-ray Studies of Real Materials Under Real Conditions and in Real Time

    SciTech Connect

    Almer, Jonathan

    2011-05-11

    High-energy x-rays from 3rd generation synchrotron sources, including the APS, possess a unique combination of high penetration power and high spatial, reciprocal space, and temporal resolution. These characteristics can be exploited to non-destructively measure phase, texture and strain distributions under extreme environments including thermo-mechanical loading, high-pressure, irradiation and supercritical environments. Over the past several years, the 1-ID beamline has developed a number of programs for these purposes, namely (i) high-energy diffraction microscopy, in which grain and sub-grain volumes are mapped in polycrystalline aggregates, and (ii) combined small-and wide-angle x-ray scattering which permits information over a broad range of length scales to be collected from the same (micron-level) volume. These programs have been increasingly used to test and extend predictive simulations of materials behavior over size scales ranging from nm to mm. Select studies will be presented including nucleation and growth of nanomaterials, void and structural evolution in complex composites under thermo-mechanical and irradiated environments, and microstructural changes in layered systems including thermal-barrier coatings, batteries and fuel cells. Finally, extension of these programs, through the planned APS upgrade, to higher spatio-temporal resolution will be described.

  13. High Energy Laboratory Astrophysics using an X-Ray Microcalorimeter with an Electron Beam Ion Trap

    NASA Astrophysics Data System (ADS)

    Porter, Frederick

    Since the summer of 2000 we have successfully deployed a high-resolution x-ray microcalorimeter spectrometer, based on the spaceflight XRS instrument, at the Electron Beam Ion Trap (EBIT) facility at the Lawrence Livermore National Laboratory. Over the last 15 years, this highly successful partnership has made fundamental measurements in laboratory astrophysics including the measurements of the absolute cross sections of all the Fe L shell transitions from Fe XVII to Fe XXIV, line ratios in Fe and Ni L shell transitions, measurements of Fe K shell emission over a wide range of electron energies, and direct measurements of charge exchange emission from highly ionized Fe, O, N, and most recently L shell S, using a variety of donor gases. This work has resulted in the publication of over 40 peer-reviewed articles with many more either submitted or in preparation. The newest addition to the facility, the ECS microcalorimeter spectrometer, developed under this program, has performed flawlessly as a facility-class instrument since 2007. We propose here to continue our highly successful partnership and deploy new technology to resolve lines in the important 1/4 keV band that encompasses the M-shell iron emission and the L shell emission, including charge exchange, of many of the lower-Z elements, such as Si, S, Mg, Ne, Ca, and Ar. This work is highly relevant to NASA objectives as it allows for the unambiguous connection between spectroscopic observations with Chandra, XMM, Astro-H, and future spectrometers aboard missions like Athena, and the physics occurring in the cosmological source. Our program aids these measurements by benchmarking the spectroscopic synthesis models used to interpret all x-ray observations. Without laboratory measurements to support these models, it is not a priori certain that the models are correct, and the observational data correctly interpreted. This is especially true for charge exchange measurements, where there are substantially

  14. The Micro-X High-Energy-Resolution Microcalorimeter X-ray Imaging Rocket

    NASA Astrophysics Data System (ADS)

    Figueroa-Feliciano, Enectali

    2014-08-01

    The 2015 flight of the Micro-X Sounding Rocket Payload will obtain the first broad-band high-resolution X-ray spectrum of the diffuse emission from a supernova remnant. Its 128-pixel Transition-Edge-Sensor array is coupled to a 300 cm^2 grazing-incidence optic with a bandpass between 0.2-3 keV. An energy resolution between 2-4 eV will provide the unprecedented ability to measure plasma properties on an element-by-element basis. Measurements of the temperature, bulk velocity, turbulence, and ionization equilibrium can be individually done for O, Ne, Fe, Mg, Si, and S. Spatial correlations in our 11.8 arcmin field of view can be made with our 2.4 arcmin imaging resolution. Our first target is the Bright Eastern Knot, a complex cloud-shock interaction region in the Puppis A supernova remnant. Other targets for future flights include a Si-rich ejecta region in Puppis A as well as the Cas A supernova remnant. We overview the science and present results from the integration tests of the payload as we prepare for our first flight.

  15. Saw-tooth refractive lens for high energy x-ray focusing

    NASA Astrophysics Data System (ADS)

    Antimonov, Mikhail A.; Khounsary, Ali M.

    2014-09-01

    Saw-tooth refractive lens (SRL) provides a comparatively attractive option for X-ray focusing. An SRL assembly consists of two parts, each with an array of triangular structures (prisms), set tilted symmetrically with respect to the incoming beam. Its main advantage is a simple, continuous tunability in energy and focal length. SRLs can be used for both long and short focal length focusing. Long focal distance focusing of an SRL can accurately be predicted using simple analytical relations. However, the focus size at short focal distances focusing may deviate appreciably from the expected demagnified source size when: (1) the length of the SRL is comparable with the focusing distance, (2) the incident beam is not monochromatic, and (3) and the distance between adjacent prism tips, the tip step, is large . The first factor was considered in a previous work while the other two are addressed is this paper. This preliminary work is aimed at a better understanding of the SRL lenses for focusing an undulator beamline at the Advanced Photon Source (APS).

  16. X-Ray And Polarized Neutron Reflectometry: Characterization Of Si/Co/Si And Si/Ni/Si Systems

    SciTech Connect

    Bhattacharya, Debarati; Basu, Saibal; Poswal, A. K.; Roy, S.; Dev, B. N.

    2010-12-01

    Technologically important metal silicides formed through interdiffusion in metal/Si systems has been probed using two complementary techniques viz. x-ray reflectivity (XRR) and polarized neutron reflectivity (PNR). Both structural and magnetic characterization with good depth resolution has been achieved in these systems. We have studied two systems Si/Co/Si and Si/Ni/Si which relate to important applications in ferromagnetic/ non-magnetic semiconductor layered structures for memory devices.

  17. In situ characterization of Grade 92 steel during tensile deformation using concurrent high energy X-ray diffraction and small angle X-ray scattering

    NASA Astrophysics Data System (ADS)

    Wang, Leyun; Li, Meimei; Almer, Jonathan

    2013-09-01

    The tensile deformation in Grade 92 steel was studied in situ using simultaneous high energy X-ray diffraction (HE-XRD), radiography, and small angle X-ray scattering (SAXS) at room temperature (RT), 400, and 650 °C. Temperature-dependent elastic properties, i.e. Young's modulus and Poisson's ratio, were measured for α-Fe matrix, M23C6 and Nb(C,N) phases in various crystallographic orientation. Significant differences in the evolution of lattice strain, peak broadening/sharpening, and void development in the α-Fe matrix, M23C6 and Nb(C,N) precipitates revealed markedly different deformation and damage mechanisms at low and high temperature in the alloy. The strengthening effect of each type of precipitates measured by lattice strain agrees with the dislocation pile-up model at room temperature, while a different dislocation behavior was observed at 650 °C. Void volume fraction as a function of strain measured by SAXS can be described by a classic void nucleation and growth model at room temperature but not at 650 °C, implying a different damage process at high temperature. The ultimate tensile strength is ordered as RT > 400 °C > 650 °C; strain to failure is ordered as 650 °C > RT > 400 °C. For the 650 °C test, there was a long softening stage between the UTS and specimen necking. M23C6 and Nb(C,N) precipitates were identified in the Fe matrix. At RT and 400 °C, apparent load transfer from the matrix to the precipitates took place after the matrix's early yielding. Measured von Mises stresses in the precipitates can be quantitatively explained using the established models of precipitate strengthening. Increase of dislocation density with deformation caused peak broadening in both matrix and precipitates. At 650 °C, load transfer was much less, and peak broadening was also largely subdued at 650 °C. Anisotropy of lattice strains was observed both in the matrix and precipitates. The elastic modulus of Fe (2 0 0) is lower than Fe (2 1 1) and Fe (2 2 0

  18. High-energy density experiments on planetary materials using high-power lasers and X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Ozaki, Norimasa

    2015-06-01

    Laser-driven dynamic compression allows us to investigate the behavior of planetary and exoplanetary materials at extreme conditions. Our high-energy density (HED) experiments for applications to planetary sciences began over five years ago. We measured the equation-of-state of cryogenic liquid hydrogen under laser-shock compression up to 55 GPa. Since then, various materials constituting the icy giant planets and the Earth-like planets have been studied using laser-driven dynamic compression techniques. Pressure-volume-temperature EOS data and optical property data of water and molecular mixtures were obtained at the planetary/exoplanetary interior conditions. Silicates and oxides data show interesting behaviors in the warm-dense matter regime due to their phase transformations. Most recently the structural changes of iron were observed for understanding the kinetics under the bcc-hcp transformation phenomena on a new HED science platform coupling power-lasers and the X-ray free electron laser (SACLA). This work was performed under the joint research project at the Institute of Laser Engineering, Osaka University. It was partially supported by a Grant-in-Aid for Scientific Research (Grant Nos. 20654042, 22224012, 23540556, and 24103507) and also by grants from the Core-to-Core Program of JSPS on International Alliance for Material Science in Extreme States with High Power Laser and XFEL, and the X-ray Free Electron Laser Priority Strategy Program of MEXT.

  19. Thermal gradient crystals as tuneable monochromator for high energy X-rays

    SciTech Connect

    Ruett, U.; Schulte-Schrepping, H.; Heuer, J.; Zimmermann, M. von

    2010-06-23

    At the high energy synchrotron radiation beamline BW5 at DORIS III at DESY a new monochromator providing broad energy bandwidth and high reflectivity is in use. On a small 10x10x5 mm{sup 3} silicon crystal scattering at the (311) reflection a thermal gradient is applied, which tunes the scattered energy bandwidth. The (311) reflection strongly suppresses the higher harmonics allowing the use of an image plate detector for crystallography. The monochromator can be used at photon energies above 60 keV.

  20. A High-Energy, Ultrashort-Pulse X-Ray System for the Dynamic Study of Heavy, Dense Materials

    SciTech Connect

    Gibson, D J

    2004-09-17

    Thomson-scattering based x-ray radiation sources, in which a laser beam is scattered off a relativistic electron beam resulting in a high-energy x-ray beam, are currently being developed by several groups around the world to enable studies of dynamic material properties which require temporal resolution on the order of tens of femtoseconds to tens of picoseconds. These sources offer pulses that are shorter than available from synchrotrons, more tunable than available from so-called Ka sources, and more penetrating and more directly probing than ultrafast lasers. Furthermore, Thomson-scattering sources can scale directly up to x-ray energies in the few MeV range, providing peak brightnesses far exceeding any other sources in this regime. This dissertation presents the development effort of one such source at Lawrence Livermore National Laboratory, the Picosecond Laser-Electron InterAction for the Dynamic Evaluation of Structures (PLEIADES) project, designed to target energies from 30 keV to 200 keV, with a peak brightness on the order of 10{sup 18} photons {center_dot} s{sup -1} {center_dot} mm{sup -2} {center_dot} mrad{sup -2} {center_dot} 0.01% bandwidth{sup -1}. A 10 TW Ti:Sapphire based laser system provides the photons for the interaction, and a 100 MeV accelerator with a 1.6 cell S-Band photoinjector at the front end provides the electron beam. The details of both these systems are presented, as is the initial x-ray production and characterization, validating the theory of Thomson scattering. In addition to the systems used to enable PLEIADES, two alternative systems are discussed. An 8.5 GHz X-Band photoinjector, capable of sustaining higher accelerating gradients and producing lower emittance electron beams in a smaller space than the S-Band gun, is presented, and the initial operation and commissioning of this gun is presented. Also, a hybrid chirped-pulse amplification system is presented as an alternative to the standard regenerative amplifier technology

  1. High Energy Replicated Optics to Explore the Sun: Hard X-ray balloon-borne telescope

    NASA Astrophysics Data System (ADS)

    Gaskin, J.; Apple, J.; Chavis, K. S.; Dietz, K.; Holt, M.; Koehler, H.; Lis, T.; O'Connor, B.; Otero, M. R.; Pryor, J.; Ramsey, B.; Rinehart-Dawson, M.; Smith, L.; Sobey, A.; Wilson-Hodge, C.; Christe, S.; Cramer, A.; Edgerton, M.; Rodriguez, M.; Shih, A.; Gregory, D.; Jasper, J.; Bohon, S.

    Set to fly in the Fall of 2013 from Ft. Sumner, NM, the High Energy Replicated Optics to Explore the Sun (HEROES) mission is a collaborative effort between the NASA Marshall Space Flight Center and the Goddard Space Flight Center to upgrade an existing payload, the High Energy Replicated Optics (HERO) balloon-borne telescope, to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES science payload consists of 8 mirror modules, housing a total of 109 grazing-incidence optics. These modules are mounted on a carbon-fiber - and Aluminum optical bench 6 m from a matching array of high pressure xenon gas scintillation proportional counters, which serve as the focal-plane detectors. The HERO gondola utilizes a differential GPS system (backed by a magnetometer) for coarse pointing in the azimuth and a shaft angle encoder plus inclinometer provides the coarse elevation. The HEROES payload will incorporate a new solar aspect system to supplement the existing star camera, for fine pointing during both the day and night. A mechanical shutter will be added to the star camera to protect it during solar observations. HEROES will also implement two novel alignment monitoring system that will measure the alignment between the optical bench and the star camera and between the optics and detectors for improved pointing and post-flight data reconstruction. The overall payload will also be discussed. This mission is funded by the NASA HOPE (Hands On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  2. High Energy Replicated Optics to Explore the Sun: Hard X-Ray Balloon-Borne Telescope

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Apple, Jeff; StevensonChavis, Katherine; Dietz, Kurt; Holt, Marlon; Koehler, Heather; Lis, Tomasz; O'Connor, Brian; RodriquezOtero, Miguel; Pryor, Jonathan; Ramsey, Brian; Rinehart-Dawson, Maegan; Smith, Leigh; Sobey, Alexander; Wilson-Hodge, Colleen; Christe, Steven; Cramer, Alexander; Edgerton, Melissa; Rodriquez, Marcello; Shih, Albert; Gregory, Don; Jasper, John; Bohon, Steven

    2013-01-01

    Set to fly in the Fall of 2013 from Ft. Sumner, NM, the High Energy Replicated Optics to Explore the Sun (HEROES) mission is a collaborative effort between the NASA Marshall Space Flight Center and the Goddard Space Flight Center to upgrade an existing payload, the High Energy Replicated Optics (HERO) balloon-borne telescope, to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES science payload consists of 8 mirror modules, housing a total of 109 grazing-incidence optics. These modules are mounted on a carbon-fiber - and Aluminum optical bench 6 m from a matching array of high pressure xenon gas scintillation proportional counters, which serve as the focal-plane detectors. The HERO gondola utilizes a differential GPS system (backed by a magnetometer) for coarse pointing in the azimuth and a shaft angle encoder plus inclinometer provides the coarse elevation. The HEROES payload will incorporate a new solar aspect system to supplement the existing star camera, for fine pointing during both the day and night. A mechanical shutter will be added to the star camera to protect it during solar observations. HEROES will also implement two novel alignment monitoring system that will measure the alignment between the optical bench and the star camera and between the optics and detectors for improved pointing and post-flight data reconstruction. The overall payload will also be discussed. This mission is funded by the NASA HOPE (Hands On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist

  3. Characterization of the Decaheme c-Type Cytochrome OmcA in Solution and on Hematite Surfaces by Small Angle X-Ray Scattering and Neutron Reflectometry

    PubMed Central

    Johs, A.; Shi, L.; Droubay, T.; Ankner, J.F.; Liang, L.

    2010-01-01

    Abstract The outer membrane protein OmcA is an 85 kDa decaheme c-type cytochrome located on the surface of the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1. It is assumed to mediate shuttling of electrons to extracellular acceptors that include solid metal oxides such as hematite (α-Fe2O3). No information is yet available concerning OmcA structure in physiologically relevant conditions such as aqueous environments. We purified OmcA and characterized its solution structure by small angle x-ray scattering (SAXS), and its interaction at the hematite-water interface by neutron reflectometry. SAXS showed that OmcA is a monomer that adopts a flat ellipsoidal shape with an overall dimension of 34 × 90 × 65 Å3. To our knowledge, we obtained the first direct evidence that OmcA undergoes a redox state-dependent conformational change in solution whereby reduction decreases the overall length of OmcA by ∼7 Å (the maximum dimension was 96 Å for oxidized OmcA, and 89 Å for NADH and dithionite-reduced OmcA). OmcA was also found to physically interact with electron shuttle molecules such as flavin mononucleotide, resulting in the formation of high-molecular-weight assemblies. Neutron reflectometry showed that OmcA forms a well-defined monomolecular layer on hematite surfaces, where it assumes an orientation that maximizes its contact area with the mineral surface. These novel insights into the molecular structure of OmcA in solution, and its interaction with insoluble hematite and small organic ligands, demonstrate the fundamental structural bases underlying OmcA's role in mediating redox processes. PMID:20550916

  4. Characterization of the Decaheme c-Type Cytochrome OmcA in Solution and on Hematite Surfaces by Small Angle X-Ray Scattering and Neutron Reflectometry

    SciTech Connect

    Johs, Alexander; Shi, Liang; Droubay, Timothy C.; Ankner, John F.; Liang, L.

    2010-06-01

    The outer membrane protein OmcA is an 85 kDa decaheme c-type cytochrome located on the surface of the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1. It is assumed to mediate shuttling of electrons to extracellular acceptors that include solid metal oxides such as hematite (a-Fe2O3). No information is yet available concerning OmcA structure in physiologically relevant conditions such as aqueous environments. We purified OmcA and characterized its solution structure by small angle x-ray scattering (SAXS), and its interaction at the hematite-water interface by neutron reflectometry. SAXS showed that OmcA is a monomer that adopts a flat ellipsoidal shape with an overall dimension of 34 x 90 x 65A˚ 3. To our knowledge, we obtained the first direct evidence that OmcA undergoes a redox state-dependent conformational change in solution whereby reduction decreases the overall length of OmcA by ~7 A˚ (the maximum dimension was 96 A˚ for oxidized OmcA, and 89 A˚ for NADH and dithionite-reduced OmcA). OmcA was also found to physically interact with electron shuttle molecules such as flavin mononucleotide, resulting in the formation of high-molecular-weight assemblies. Neutron reflectometry showed that OmcA forms a well-defined monomolecular layer on hematite surfaces, where it assumes an orientation that maximizes its contact area with the mineral surface. These novel insights into the molecular structure of OmcA in solution, and its interaction with insoluble hematite and small organic ligands, demonstrate the fundamental structural bases underlying OmcA’s role in mediating redox processes.

  5. Revisiting the blocking force test on ferroelectric ceramics using high energy x-ray diffraction

    SciTech Connect

    Daniel, L.; Hall, D. A.; Withers, P. J.; Koruza, J.; Webber, K. G.; King, A.

    2015-05-07

    The blocking force test is a standard test to characterise the properties of piezoelectric actuators. The aim of this study is to understand the various contributions to the macroscopic behaviour observed during this experiment that involves the intrinsic piezoelectric effect, ferroelectric domain switching, and internal stress development. For this purpose, a high energy diffraction experiment is performed in-situ during a blocking force test on a tetragonal lead zirconate titanate (PZT) ceramic (Pb{sub 0.98}Ba{sub 0.01}(Zr{sub 0.51}Ti{sub 0.49}){sub 0.98}Nb{sub 0.02}O{sub 3}). It is shown that the usual macroscopic linear interpretation of the test can also be performed at the single crystal scale, allowing the identification of local apparent piezoelectric and elastic properties. It is also shown that despite this apparent linearity, the blocking force test involves significant non-linear behaviour mostly due to domain switching under electric field and stress. Although affecting a limited volume fraction of the material, domain switching is responsible for a large part of the macroscopic strain and explains the high level of inter- and intra-granular stresses observed during the course of the experiment. The study shows that if apparent piezoelectric and elastic properties can be identified for PZT single crystals from blocking stress curves, they may be very different from the actual properties of polycrystalline materials due to the multiplicity of the physical mechanisms involved. These apparent properties can be used for macroscopic modelling purposes but should be considered with caution if a local analysis is aimed at.

  6. Developing a bright 17 keV x-ray source for probing high-energy-density states of matter at high spatial resolution

    SciTech Connect

    Huntington, C. M.; Park, H.-S.; Maddox, B. R.; Barrios, M. A.; Benedetti, R.; Braun, D. G.; Landen, O. L.; Wehrenberg, C. E.; Remington, B. A.; Hohenberger, M.; Regan, S. P.

    2015-04-15

    A set of experiments were performed on the National Ignition Facility (NIF) to develop and optimize a bright, 17 keV x-ray backlighter probe using laser-irradiated Nb foils. High-resolution one-dimensional imaging was achieved using a 15 μm wide slit in a Ta substrate to aperture the Nb He{sub α} x-rays onto an open-aperture, time integrated camera. To optimize the x-ray source for imaging applications, the effect of laser pulse shape and spatial profile on the target was investigated. Two laser pulse shapes were used—a “prepulse” shape that included a 3 ns, low-intensity laser foot preceding the high-energy 2 ns square main laser drive, and a pulse without the laser foot. The laser spatial profile was varied by the use of continuous phase plates (CPPs) on a pair of shots compared to beams at best focus, without CPPs. A comprehensive set of common diagnostics allowed for a direct comparison of imaging resolution, total x-ray conversion efficiency, and x-ray spectrum between shots. The use of CPPs was seen to reduce the high-energy tail of the x-ray spectrum, whereas the laser pulse shape had little effect on the high-energy tail. The measured imaging resolution was comparably high for all combinations of laser parameters, but a higher x-ray flux was achieved without phase plates. This increased flux was the result of smaller laser spot sizes, which allowed us to arrange the laser focal spots from multiple beams and produce an x-ray source which was more localized behind the slit aperture. Our experiments are a first demonstration of point-projection geometry imaging at NIF at the energies (>10 keV) necessary for imaging denser, higher-Z targets than have previously been investigated.

  7. Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine.

    PubMed

    Liang, Xue; Zhang, Jing Yang; Cheng, Iek Ka; Li, Ji Yao

    2016-01-01

    Radiotherapy for malignancies in the head and neck can cause common complications that can result in tooth damage that are also known as radiation caries. The aim of this study was to examine damage to the surface topography and calculate changes in friction behavior and the nano-mechanical properties (elastic modulus, nanohardness and friction coefficient) of enamel and dentine from extracted human third molars caused by exposure to radiation. Enamel and dentine samples from 50 human third molars were randomly assigned to four test groups or a control group. The test groups were exposed to high energy X-rays at 2 Gy/day, 5 days/week for 5 days (10 Gy group), 15 days (30 Gy group), 25 days (50 Gy group), 35 days (70 Gy group); the control group was not exposed. The nanohardness, elastic modulus, and friction coefficient were analyzed using a Hysitron Triboindenter. The nano-mechanical properties of both enamel and dentine showed significant dose-response relationships. The nanohardness and elastic modulus were most variable between 30-50 Gy, while the friction coefficient was most variable between 0-10 Gy for dentine and 30-50 Gy for enamel. After exposure to X-rays, the fracture resistance of the teeth clearly decreased (rapidly increasing friction coefficient with increasing doses under the same load), and they were more fragile. These nano-mechanical changes in dental hard tissue may increase the susceptibility to caries. Radiotherapy caused nano-mechanical changes in dentine and enamel that were dose related. The key doses were 30-50 Gy and the key time points occurred during the 15th-25th days of treatment, which is when application of measures to prevent radiation caries should be considered. PMID:26676192

  8. Reconsideration of the Iwasaki-Waggener iterative perturbation method for reconstructing high-energy X-ray spectra.

    PubMed

    Iwasaki, Akira; Kimura, Shigenobu; Sutoh, Kohji; Kamimura, Kazuo; Sasamori, Makoto; Seino, Morio; Komai, Fumio; Terashima, Singo; Kubota, Mamoru; Narita, Yuichiro; Hosokawa, Yoichiro; Miyazawa, Masanori

    2012-07-01

    We have reviewed applicable ranges for attenuating media and off-axis distances regarding the high-energy X-ray spectra reconstructed via the Iwasaki-Waggener iterative perturbation method for 4-20 MV X-ray beams. Sets of in-air relative transmission data used for reconstruction of spectra were calculated for low- and high-Z attenuators (acrylic and lead, respectively) by use of a functional spectral formula. More accurate sets of spectra could be reconstructed by dividing the off-axis distances of R = 0-20 cm into two series of R = 0-10 cm and R = 10-20 cm, and by taking into account the radiation attenuation and scatter in the buildup cap of the dosimeter. We also incorporated in the reconstructed spectra an adjustment factor (f (adjust) ≈ 1) that is determined by the attenuating medium, the acceleration voltage, and the set of off-axis distances. This resulted in calculated in-air relative transmission data to within ±2 % deviation for the low-Z attenuators water, acrylic, and aluminum (Al) with 0-50 cm thicknesses and R = 0-20 cm; data to within ±3 % deviation were obtained for high-Z attenuators such as iron (Fe), copper (Cu), silver (Ag), tungsten (W), platinum (Pt), gold (Au), lead (Pb), thorium (Th), and uranium (U) having thicknesses of 0-10 cm and R = 0-20 cm. By taking into account the radiation attenuation and scatter in the buildup cap, we could analyze the in-air chamber response along a line perpendicular to the isocenter axis. PMID:22696171

  9. Strategies for efficient scanning and reconstruction methods on very large objects with high-energy x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Reims, Nils; Schoen, Tobias; Boehnel, Michael; Sukowski, Frank; Firsching, Markus

    2014-09-01

    X-ray computed tomography (CT) is an established tool for industrial non-destructive testing purposes. Yet conventional CT devices pose limitations regarding specimen dimensions and material thicknesses. Here we introduce a novel CT system capable of inspecting very large objects (VLO) like automobiles or sea freight containers in 3-D and discuss strategies for efficient scanning and reconstruction methods. The system utilizes a 9 MeV linear accelerator to achieve high penetration lengths in both dense and high-Z materials. The line detector array has an overall length of 4 meters. The presented system allows for reconstruction volumes of 3.2 meters in diameter and 5 meters in height. First we outline the general capabilities of high energy CT imaging and compare it with state of the art 450 kV X-ray systems. The imaging performance is shown based on experimental results. The second part addresses the problem of considerably higher scanning times when using line detectors compared to area detectors. Reducing the number of projections considerably causes image artifacts with standard reconstruction methods like filtered back projection (FBP). Alternative methods which can provide significantly better results are algebraic reconstruction techniques (ART). One of these is compressed sensing (CS) based ART which we discuss regarding its suitability in respect to FBP. We could prove the feasibility of inspecting VLOs like complete automobiles based on experimental data. CS allows for achieving sufficient image quality in terms of spatial and contrast resolution while reducing the number of projections significantly resulting in faster scanning times.

  10. Evaluating the solid electrolyte interphase formed on silicon electrodes: a comparison of ex situ X-ray photoelectron spectroscopy and in situ neutron reflectometry.

    PubMed

    Fears, T M; Doucet, M; Browning, J F; Baldwin, J K S; Winiarz, J G; Kaiser, H; Taub, H; Sacci, R L; Veith, G M

    2016-05-18

    This work details the in situ characterization of the interface between a silicon electrode and an electrolyte using a linear fluorinated solvent molecule, 0.1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in deuterated dimethyl perfluoroglutarate (d6-PF5M2) (1.87 × 10(-2) mS cm(-1)). The solid electrolyte interphase (SEI) composition and thickness determined via in situ neutron reflectometry (NR) and ex situ X-ray photoelectron spectroscopy (XPS) were compared. The data show that SEI expansion and contraction (breathing) during electrochemical cycling were observed via both techniques; however, ex situ XPS suggests that the SEI thickness increases during Si lithiation and decreases during delithiation, while in situ NR suggests the opposite. The most likely cause of this discrepancy is the selective removal of SEI components (top 20 nm of the SEI) during the electrode rinse process, which is required to remove the electrolyte residue prior to ex situ analysis, demonstrating the necessity of performing SEI characterization in situ. PMID:27149427

  11. Evaluating the solid electrolyte interphase formed on silicon electrodes: A comparison of ex situ X-ray photoelectron spectroscopy and in situ neutron reflectometry

    DOE PAGESBeta

    Doucet, Mathieu; Browning, Jim; Baldwin, J. K.; Winiarz, Jeffrey; Kaiser, Helmut; Taub, H.; Veith, Gabriel M.

    2016-04-15

    This work details the in situ characterization of the interface between a silicon electrode and an electrolyte using a linear fluorinated solvent molecule, 0.1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in deuterated dimethyl perfluoroglutarate (d6-PF5M2) (1.87 x 10-2 mS/cm-1). The solid electrolyte interphase (SEI) composition and thickness determined via in situ neutron reflectometry (NR) and ex situ X-ray photoelectron spectroscopy (XPS) were compared. The data show that SEI expansion and contraction (breathing) during electrochemical cycling was observed via both techniques; however, ex situ XPS suggests that the SEI thickness increases during Si lithiation and decreases during delithiation, while in situ NR suggestsmore » the opposite. The most likely cause of this discrepancy is the selective removal of SEI components (top 20 nm of the SEI) during the electrode rinse process, required to remove electrolyte residue prior to ex situ analysis, demonstrating the necessity of performing SEI characterizations in situ.« less

  12. X-ray reflectometry studies on the effect of water on the surface structure of [C4mpyr][NTf2] ionic liquid.

    PubMed

    Lauw, Y; Horne, M D; Rodopoulos, T; Webster, N A S; Minofar, B; Nelson, A

    2009-12-28

    The effect of water on the surface structure of 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonylimide [C(4)mpyr][NTf(2)] ionic liquid was investigated using X-ray reflectometry. The measured reflectivity data suggests a significant amount of water is adsorbed at the surface, with the first layer from the gas (nitrogen)-liquid phase boundary mainly occupied by a mixture of cations and water. Beyond the cation + water layer, the scattering length density increases towards the bulk value, indicating a decreasing amount of water and cations, and/or an increasing amount of anions. The orientation of the butyl chain of cation at the phase boundary and the population of water at the surface were described based on results from an independent molecular dynamics (MD) simulation. We show that the presence of water in the ionic liquid has a non-monotonic effect on the overall thickness of the surface. At low water content, the addition of water does not change the surface thickness since water is mainly present in the bulk. As the water content increases, the surface swells before eventually shrinking down close to the solubility limit of water. The non-monotonic surface thickness is used to explain the anomalous trend of surface tension in ionic liquid-water mixtures reported in the literature. PMID:20024422

  13. Characterization of neutron-irradiated HT-UPS steel by high-energy X-ray diffraction microscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Park, Jun-Sang; Almer, Jonathan; Li, Meimei

    2016-04-01

    This paper presents the first measurement of neutron-irradiated microstructure using far-field high-energy X-ray diffraction microscopy (FF-HEDM) in a high-temperature ultrafine-precipitate-strengthened (HT-UPS) austenitic stainless steel. Grain center of mass, grain size distribution, crystallographic orientation (texture), diffraction spot broadening and lattice constant distributions of individual grains were obtained for samples in three different conditions: non-irradiated, neutron-irradiated (3dpa/500 °C), and irradiated + annealed (3dpa/500 °C + 600 °C/1 h). It was found that irradiation caused significant increase in grain-level diffraction spot broadening, modified the texture, reduced the grain-averaged lattice constant, but had nearly no effect on the average grain size and grain size distribution, as well as the grain size-dependent lattice constant variations. Post-irradiation annealing largely reversed the irradiation effects on texture and average lattice constant, but inadequately restored the microstrain.

  14. 3D Atomic Arrangement at Functional Interfaces Inside Nanoparticles by Resonant High-Energy X-ray Diffraction.

    PubMed

    Petkov, Valeri; Prasai, Binay; Shastri, Sarvjit; Chen, Tsan-Yao

    2015-10-21

    With current science and technology moving rapidly into smaller scales, nanometer-sized materials, often referred to as NPs, are produced in increasing numbers and explored for numerous useful applications. Evidence is mounting, however, that useful properties of NPs can be improved further and even new NP functionality achieved by not only controlling the NP size and shape but also interfacing chemically or structurally distinct entities into single, so-called "composite" NPs. A typical example is core-shell NPs wherein the synergy of distinct atoms at the core\\shell interface endows the NPs with otherwise unachievable functionality. However, though advantageous, the concept of functional interfaces inside NPs is still pursued largely by trial-and-error. That is because it is difficut to assess the interfaces precisely at the atomic level using traditional experimental techniques and, hence, difficult to take control of. Using the core\\shell interface in less than 10 nm in size Ru core-Pt shells NPs as an example, we demonstrate that precise knowledge of the 3D atomic arrangement at functional interfaces inside NPs can be obtained by resonant high-energy X-ray diffraction (XRD) coupled to element-specific atomic pair distribution function (PDF) analysis. On the basis of the unique structure knowledge obtained, we scrutinize the still-debatable influence of core\\shell interface on the catalytic functionality of Ru core-Pt shell NPs, thus evidencing the usefulness of this nontraditional technique for practical applications. PMID:26415142

  15. Characterization of Cr poisoning in a solid oxide fuel cell cathode using a high-energy x-ray microbeam.

    SciTech Connect

    Liu, D. J.; Almer, J.; Cruse, T.

    2010-01-01

    A key feature of planar solid oxide fuel cells (SOFCs) is the feasibility of using metallic interconnects made of high temperature ferritic stainless steels, which reduce system cost while providing excellent electric conductivity. Such interconnects, however, contain high levels of chromium, which has been found to be associated with SOFC cathode performance degradation at SOFC operating temperatures; a phenomenon known as Cr poisoning. Here, we demonstrate an accurate measurement of the phase and concentration distributions of Cr species in a degraded SOFC, as well as related properties including deviatoric strain, integrated porosity, and lattice parameter variation, using high energy microbeam X-ray diffraction and radiography. We unambiguously identify (MnCr){sub 3}O{sub 4} and Cr{sub 2}O{sub 3} as the two main contaminant phases and find that their concentrations correlate strongly with the cathode layer composition. Cr{sub 2}O{sub 3} deposition within the active cathode region reduces porosity and produces compressive residual strains, which hinders the reactant gas percolation and can cause structural breakdown of the SOFC cathode. The information obtained through this study can be used to better understand the Cr-poisoning mechanism and improve SOFC design.

  16. Beamline electrostatic levitator for in situ high energy x-ray diffraction studies of levitated solids and liquids

    SciTech Connect

    Gangopadhyay, A.K.; Lee, G.W.; Kelto, K.F.; Rogers, J.R.; Goldman, A.I.; Robinson, D.S.; Rathz, T.J.; Hyers, R.W.

    2010-07-19

    Determinations of the phase formation sequence, crystal structures and the thermo-physical properties of materials at high temperatures are hampered by contamination from the sample container and environment. Containerless processing techniques, such as electrostatic (ESL), electromagnetic, aerodynamic, and acoustic levitation, are most suitable for these studies. An adaptation of ESL for in situ structural studies of a wide range of materials using high energy (30-130 keV) x rays at a synchrotron source is described here. This beamline ESL (BESL) allows the in situ determination of the atomic structures of equilibrium solid and liquid phases, undercooled liquids and time-resolved studies of solid-solid and liquid-solid phase transformations. The use of area detectors enables the rapid acquisition of complete diffraction patterns over a wide range (0.5-14 {angstrom}{sup -1}) of reciprocal space. The wide temperature range (300-2500 K), containerless processing environment under high vacuum (10{sup -7}-10{sup -8} Torr), and fast data acquisition capability, make BESL particularly well suited for phase stability studies of high temperature solids and liquids. An additional, but important, feature of BESL is the capability for simultaneous measurements of a host of thermo-physical properties including the specific heat, enthalpy of transformation, solidus and liquidus temperatures, density, viscosity, and surface tension, all on the same sample during the structural measurements.

  17. An accelerator scenario for a hard X-ray free electron laser combined with high energy electron radiography

    NASA Astrophysics Data System (ADS)

    Wei, Tao; Li, Yiding; Yang, Guojun; Pang, Jian; Li, Yuhui; Li, Peng; Pflueger, Joachim; He, Xiaozhong; Lu, Yaxin; Wang, Ke; Long, Jidong; Zhang, Linwen; Wu, Qiang

    2016-08-01

    In order to study the dynamic response of the material and the physical mechanism of fluid dynamics, an accelerator scenario which can be applied to both hard X-ray free electron laser and high energy electron radiography is proposed. This accelerator is mainly composed of a 12 GeV linac, an undulator branch and an eRad beamline. In order to characterize a sample’s dynamic behavior in situ and real-time with XFEL and eRad simultaneously, the linac should be capable of accelerating the two kinds of beam within the same operation mode. Combining in-vacuum and tapering techniques, the undulator branch can produce more than 1011 photons per pulse in 0.1% bandwidth at 42 keV. Finally, an eRad amplifying beamline with 1:10 ratio is proposed as an important complementary tool for the wider view field and density identification ability. Supported by China Academy of Engineering Physics (2014A0402016) and Institute of Fluid Physics (SFZ20140201)

  18. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    NASA Astrophysics Data System (ADS)

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

    2016-02-01

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K-B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10-15 μm) has been achieved at energies of 66 and 81 keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DAC can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71 GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. The coupling of sagittally bent Laue crystals with K-B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source.

  19. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    DOE PAGESBeta

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

    2016-02-23

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K–B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10–15 μm) has been achieved at energies of 66 and 81keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DACmore » can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. In conclusion, the coupling of sagittally bent Laue crystals with K–B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source.« less

  20. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures.

    PubMed

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S; Weidner, Donald J

    2016-01-01

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K-B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10-15 μm) has been achieved at energies of 66 and 81 keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DAC can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71 GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. The coupling of sagittally bent Laue crystals with K-B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source. PMID:26902122

  1. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    PubMed Central

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

    2016-01-01

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K–B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10–15 μm) has been achieved at energies of 66 and 81 keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DAC can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71 GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. The coupling of sagittally bent Laue crystals with K–B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source. PMID:26902122

  2. High energy x-ray diffraction/x-ray fluorescence spectroscopy for high-throughput analysis of composition spread thin films

    SciTech Connect

    Gregoire, John M.; Dale, Darren; Kazimirov, Alexander; DiSalvo, Francis J.; Dover, R. Bruce van

    2009-12-15

    High-throughput crystallography is an important tool in materials research, particularly for the rapid assessment of structure-property relationships. We present a technique for simultaneous acquisition of diffraction images and fluorescence spectra on a continuous composition spread thin film using a 60 keV x-ray source. Subsequent noninteractive data processing provides maps of the diffraction profiles, thin film fiber texture, and composition. Even for highly textured films, our diffraction technique provides detection of diffraction from each family of Bragg reflections, which affords direct comparison of the measured profiles with powder patterns of known phases. These techniques are important for high throughput combinatorial studies as they provide structure and composition maps which may be correlated with performance trends within an inorganic library.

  3. The structure of molten CuCl: Reverse Monte Carlo modeling with high-energy X-ray diffraction data and molecular dynamics of a polarizable ion model.

    PubMed

    Alcaraz, Olga; Trullàs, Joaquim; Tahara, Shuta; Kawakita, Yukinobu; Takeda, Shin'ichi

    2016-09-01

    The results of the structural properties of molten copper chloride are reported from high-energy X-ray diffraction measurements, reverse Monte Carlo modeling method, and molecular dynamics simulations using a polarizable ion model. The simulated X-ray structure factor reproduces all trends observed experimentally, in particular the shoulder at around 1 Å(-1) related to intermediate range ordering, as well as the partial copper-copper correlations from the reverse Monte Carlo modeling, which cannot be reproduced by using a simple rigid ion model. It is shown that the shoulder comes from intermediate range copper-copper correlations caused by the polarized chlorides. PMID:27609000

  4. A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays Final Technical Report

    SciTech Connect

    Jeremy Weiss

    2012-08-02

    This is the final technical report for the SBIR Phase I project titled 'A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays.' Experiments using diffraction of synchrotron radiation that help scientists understand engineering material failure modes, such as fracture and fatigue, require specialized machinery. This machinery must be able to induce these failure modes in a material specimen while adhering to strict size, weight, and geometric limitations prescribed by diffraction measurement techniques. During this Phase I project, Mechanical Solutions, Inc. (MSI) developed one such machine capable of applying uniaxial mechanical loading to a material specimen in both tension and compression, with zero backlash while transitioning between the two. Engineers currently compensate for a lack of understanding of fracture and fatigue by employing factors of safety in crucial system components. Thus, mechanical and structural parts are several times bigger, thicker, and heavier than they need to be. The scientific discoveries that result from diffraction experiments which utilize sophisticated mechanical loading devices will allow for broad material, weight, fuel, and cost savings in engineering design across all industries, while reducing the number of catastrophic failures in transportation, power generation, infrastructure, and all other engineering systems. With an existing load frame as the starting point, the research focused on two main areas: (1) the design of a specimen alignment and gripping system that enables pure uniaxial tension and compression loading (and no bending, shear, or torsion), and (2) development of a feedback control system that is adaptive and thus can maintain a load set point despite changing specimen material properties (e.g. a decreasing stiffness during yield).

  5. Research relative to high energy astrophysics. [large area modular array of reflectors, X-ray spectroscopy, and thermal control

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.

    1984-01-01

    Various parameters which affect the design of the proposed large area modular array of reflectors (LAMAR) are considered, including thermal control, high resolution X-ray spectroscopy, pointing control, and mirror performance. The LAMAR instrument is to be a shuttle-launched X-ray observatory to carry out cosmic X-ray investigations. The capabilities of LAMAR are enumerated. Angular resolution performance of the mirror module prototype was measured to be 30 sec of ARC for 50% of the power. The LAMAR thermal pre-collimator design concepts and test configurations are discussed in detail.

  6. The fast Z-scan method for studying working catalytic reactors with high energy X-ray diffraction: ZSM-5 in the methanol to gasoline process.

    PubMed

    Wragg, David S; Bleken, Francesca L; O'Brien, Matthew G; Di Michiel, Marco; Fjellvåg, Helmer; Olsbye, Unni

    2013-06-14

    The methanol to gasoline process over the zeolite catalyst ZSM-5 in a lab-sized reactor bed (4 mm diameter) has been studied in operando with high energy synchrotron X-ray diffraction. The fast z-scan method was used, scanning the reactor repeatedly and at speed through the X-ray beam. The X-ray diffraction data were processed using high throughput parametric Rietveld refinement to obtain real structural parameters. The diffraction data show only very subtle changes during the process and this allows us to demonstrate the combination of very large data volumes with parametric Rietveld methods to study weak features of the data. The different possible data treatment methodologies are discussed in detail and their effects on the results obtained are demonstrated. The trends in unit cell volume, zeolite channel occupancy and crystallite strain indicate that more or larger reaction intermediates are present close to the reactor outlet. PMID:23575962

  7. Development of 4.5 keV monochromatic X-ray radiography using the high-energy, picosecond LFEX laser

    NASA Astrophysics Data System (ADS)

    Sawada, H.; Fujioka, S.; Hosoda, T.; Zhang, Z.; Arikawa, Y.; Nagatomo, H.; Nishimura, H.; Sunahara, A.; Theobald, W.; Patel, P. K.; Beg, F. N.

    2016-05-01

    Development of a monochromatic x-ray imaging system using a high-energy short- pulse laser LFEX and a spherical crystal is reported. Irradiation of the intense short-pulse laser produces a flash of 4.51 keV Ti K-alpha x-ray while the spherically bent quartz crystal provides a narrow spectral bandwidth and high spatial resolution. This high spatiotemporal imaging technique was applied for recording 2-D monochromatic x-ray images of laser-driven Fast Ignition targets. The results show a sufficiently high spatial resolution to characterize the implosion core, suggesting that the core information extracted from the radiograph images can be used to benchmark a 2-D radiation-hydrodynamic code for accurate hydrodynamic modelling and optimization of FI fuel assembly in the asymmetrical implosion.

  8. High-energy X-ray detection by hafnium-doped organic-inorganic hybrid scintillators prepared by sol-gel method

    SciTech Connect

    Sun, Yan; Koshimizu, Masanori Yahaba, Natsuna; Asai, Keisuke; Nishikido, Fumihiko; Kishimoto, Shunji; Haruki, Rie

    2014-04-28

    With the aim of enhancing the efficiency with which plastic scintillators detect high-energy X-rays, hafnium-doped organic-inorganic hybrid scintillators were fabricated via a sol-gel method. Transmission electron microscopy of sampled material reveals the presence of Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles, dispersed in a polymer matrix that constitutes the active material of the X-ray detector. With Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles incorporated in the polymer matrix, the absorption edge and the luminescence wavelength is shifted, which we attribute to Mie scattering. The detection efficiency for 67.4-keV X-rays in a 0.6-mm-thick piece of this material is two times better than the same thickness of a commercial plastic scintillator-NE142.

  9. Differential Effects of X-Rays and High-Energy {sup 56}Fe Ions on Human Mesenchymal Stem Cells

    SciTech Connect

    Kurpinski, Kyle; Jang, Deok-Jin; Bhattacharya, Sanchita; Rydberg, Bjorn; Chu, Julia; So, Joanna; Wyrobek, Andy; Li Song; Wang Daojing

    2009-03-01

    Purpose: Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) {sup 56}Fe ions on human mesenchymal stem cells (hMSC). Methods and Materials: A multi-functional comparison was carried out to investigate the differential effects of X-rays and {sup 56}Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. Results: X-rays and {sup 56}Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and {sup 56}Fe ions, with more significant effects from {sup 56}Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy {sup 56}Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. Conclusions: {sup 56}Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation.

  10. Clinopyroxenes still trapped in diamonds: high-energy synchrotron X-ray diffraction as a chemical probe

    NASA Astrophysics Data System (ADS)

    Casati, Nicola; Nestola, Fabrizio; Alvaro, Matteo; Wilhelm, Heribert; Kleppe, Annette; Nimis, Paolo; Harris, Jeffrey W.

    2014-05-01

    Clinopyroxenes are mainly Ca-Na-Fe-Mg-silicates constituting a significant portion of the Earth's upper mantle up to 20% of such shell of our planet. They could be found as typical mineral inclusions in diamonds being diopsidic and omphacitic in composition and, together with garnets, cover a key role in providing indications concerning the source rock in which the diamond crystallize. In detail, it is well known that eclogitic diamonds are characterized by clinopyroxenes with omphacitic compositions (about Ca0.5Na0.5Mg0.5Al0.5Si2O6) whereas peridotitic diamonds show clinopyroxenes very rich in the diopside end-member (CaMgSi2O6). In order to get direct chemical composition on the inclusions, and therefore on the diamond origin source, it is obviously necessary to extract them breaking and/or polishing the diamond host. However, a non-destructive investigation of an inclusion still trapped in a diamond is useful and important for different reasons: (1) the inclusions could be under pressure and their crystal structure can be modified if the pressure is released by the extraction; (2) the residual pressure on the inclusion can provide information about the formation pressure of the diamond (e.g. Nestola et al. 2011 and references therein); (3) the morphology and growth relationships of the inclusion with the host diamond can provide indications about its protogenetic vs. syngenetic and/or epigenetic nature; and (4) preservation of the diamond surface growth features can maintain crucial information on late oxidation processes (Fedortchouk et al. 2011). However the available methods to measure the composition of the inclusions implies to destroy the sample. The aim of this work is to obtain chemical information on the inclusions still trapped in their diamond host and therefore to indicate the diamond origin without extracting the inclusions. The work was carried out by single crystal X-ray diffraction using a new experimental approach by high energy synchrotron

  11. Study of Mechanical Properties of Bone by Measuring Load Transfer via High-energy X-ray Diffraction

    NASA Astrophysics Data System (ADS)

    Singhal, Anjali

    Synchrotron high-energy X-ray scattering is used to investigate the in situ strains in hydroxyapatite (HAP) platelets and mineralized collagen fibrils in bovine cortical bone. Compressive load-unload tests at room temperature (27°C) and body temperature (37°C) show that the load transfer to the stiff nano-sized platelets from the surrounding compliant protein matrix does not vary significantly with temperature. This emphasizes that the stiffness of bone is controlled by the stiffness of the HAP phase, which remains unaffected by this change in temperature. Monotonic loading tests in compression and tension, conducted at 37°C, illustrate the spatial variation of properties within a single femur, which is correlated to the mineral content, porosity and microstructure of the samples. The average apparent modulus of HAP and fibrils (EappHAP and Eappfib, respectively), defined as the ratio of applied stress and phase strain, is obtained as 27.5 ± 6.6 and 18.5 ± 8.9 GPa, respectively, in compression. These values are significantly higher than the values of 20.0 ± 5.4 and 4.1 ± 2.6 GPa obtained for HAP and fibrils, respectively, in tension. The difference between the two types of loading is attributed to greater plastic deformation of collagen in tension, which results in greater strains in the collagen fibril, and concomitant greater load transfer to the HAP. Increasing synchrotron X-ray doses (5-3880 kGy) affect neither apparent HAP nor fibrillar modulus, up to stresses of -60 MPa (measured during in situ loading and unloading). However, the residual elastic strains in the HAP phase decrease markedly with increased irradiation, indicating damage at the HAP-collagen interface. Analysis of the X-ray diffraction peak widths shows that unit cells of HAP which are under the highest initial residual strains are most able to relax due to irradiation, resulting in a net decrease in the strain

  12. MEASUREMENT OF THE HIGH ENERGY COMPONENT OF THE X-RAY SPECTRA INTHE VENUS ECR ION SOURCE

    SciTech Connect

    Leitner, Daniela; Benitez, Janilee Y.; Lyneis, Claude M.; Todd,Damon S.; Ropponen,Tommi; Ropponen,Janne; Koivisto, Hannu; Gammino, Santo

    2007-11-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (Versatile ECR for Nuclear Science), produce large amounts of x-rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental set-up to measure bremsstrahlung spectra from ECR ion sources is somewhat different than for the traditional nuclear physics measurements these detectors are generally used for. In particular the collimation and background shielding can be problematic. In this paper we will discuss the experimental set-up for such a measurement, the energy calibration and background reduction, the correction for detector efficiency, the shielding of the detector and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates in dependence of various ion source parameters such as confinement fields, minimum B-field, rf power and heating frequency.

  13. Measurement of the high energy component of the x-ray spectra in the VENUS electron cyclotron resonance ion source

    SciTech Connect

    Leitner, D.; Benitez, J. Y.; Lyneis, C. M.; Todd, D. S.; Ropponen, T.; Ropponen, J.; Koivisto, H.; Gammino, S.

    2008-03-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (Versatile ECR for NUclear Science), produce large amounts of x-rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet, adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental setup to measure bremsstrahlung spectra from ECR ion sources is somewhat different from that for the traditional nuclear physics measurements these detectors are generally used for. In particular, the collimation and background shielding can be problematic. In this paper, we will discuss the experimental setup for such a measurement, the energy calibration and background reduction, the shielding of the detector, and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates depending on various ion source parameters, such as confinement fields, minimum B-field, rf power, and heating frequency.

  14. Development of Si-APD Timing Detectors for Nuclear Resonant Scattering using High-energy Synchrotron X-rays

    SciTech Connect

    Kishimoto, Shunji; Zhang Xiaowei

    2007-01-19

    A timing detector with silicon avalanche photodiodes (Si-APDs) has been developed for nuclear resonant scattering using synchrotron x-rays. The detector had four pairs of a germanium plate 0.1mm thick and a Si-APD (3 mm in dia., a depletion layer of 30-{mu}m thickness). Using synchrotron x-rays of 67.4 keV, the efficiency increased to 1.5% for the incident beam, while the efficiency was 0.76 % without the germanium converters. A measurement of SR-PAC on Ni-61 was executed by using the detector. Some other types of timing detectors are planned for x-rays of E>20 keV.

  15. Searching Ultimate Nanometrology for AlOx Thickness in Magnetic Tunnel Junction by Analytical Electron Microscopy and X-ray Reflectometry

    NASA Astrophysics Data System (ADS)

    Song, Se Ahn; Hirano, Tatsumi; Park, Jong Bong; Kaji, Kazutoshi; Kim, Ki Hong; Terada, Shohei

    2005-10-01

    Practical analyses of the structures of ultrathin multilayers in tunneling magneto resistance (TMR) and Magnetic Random Access Memory (MRAM) devices have been a challenging task because layers are very thin, just 1-2 nm thick. Particularly, the thinness ([similar]1 nm) and chemical properties of the AlOx barrier layer are critical to its magnetic tunneling property. We focused on evaluating the current TEM analytical methods by measuring the thickness and composition of an AlOx layer using several TEM instruments, that is, a round robin test, and cross-checked the thickness results with an X-ray reflectometry (XRR) method. The thickness measured by using HRTEM, HAADF-STEM, and zero-loss images was 1.1 nm, which agreed with the results from the XRR method. On the other hand, TEM-EELS measurements showed 1.8 nm for an oxygen 2D-EELS image and 3.0 nm for an oxygen spatially resolved EELS image, whereas the STEM-EDS line profile showed 2.5 nm in thickness. However, after improving the TEM-EELS measurements by acquiring time-resolved images, the measured thickness of the AlOx layer was improved from 1.8 nm to 1.4 nm for the oxygen 2D-EELS image and from 3.0 nm to 2.0 nm for the spatially resolved EELS image, respectively. Also the observed thickness from the EDS line profile was improved to 1.4 nm after more careful optimization of the experimental parameters. We found that EELS and EDS of one-dimensional line scans or two-dimensional elemental mapping gave a larger AlOx thickness even though much care was taken. The reasons for larger measured values can be found from several factors such as sample drift, beam damage, probe size, beam delocalization, and multiple scattering for the EDS images, and chromatic aberration, diffraction limit due to the aperture, delocalization, alignment between layered direction in samples, and energy dispersion direction in the EELS instrument for EELS images. In the case of STEM-EDS mapping with focused nanoprobes, it is always necessary

  16. Silicon saw-tooth refractive lens for high-energy x-rays made using a diamond saw.

    SciTech Connect

    Said, A. H.; Shastri, S. D.; X-Ray Science Division

    2010-01-01

    Silicon is a material well suited for refractive lenses operating at high X-ray energies (>50 keV), particularly if implemented in a single-crystal form to minimize small-angle scattering. A single-crystal silicon saw-tooth refractive lens, fabricated by a dicing process using a thin diamond wheel, was tested with 115 keV X-rays, giving an ideal 17 {mu}m line focus width in a long focal length, 2:1 ratio demagnification geometry, with a source-to-focus distance of 58.5 m. The fabrication is simple, using resources typically available at any synchrotron facility's optics shop.

  17. Photonuclear reaction based high-energy x-ray spectrometer to cover from 2 MeV to 20 MeV

    SciTech Connect

    Sakata, S. Arikawa, Y.; Kojima, S.; Ikenouchi, T.; Nagai, T.; Abe, Y.; Inoue, H.; Morace, A.; Utsugi, M.; Nishimura, H.; Nakai, M.; Shiraga, H.; Fujioka, S.; Azechi, H.; Kato, R.

    2014-11-15

    A photonuclear-reaction-based hard x-ray spectrometer is developed to measure the number and energy spectrum of fast electrons generated by interactions between plasma and intense laser light. In this spectrometer, x-rays are converted to neutrons through photonuclear reactions, and the neutrons are counted with a bubble detector that is insensitive to x-rays. The spectrometer consists of a bundle of hard x-ray detectors that respond to different photon-energy ranges. Proof-of-principle experiment was performed on a linear accelerator facility. A quasi-monoenergetic electron bunch (N{sub e} = 1.0 × 10{sup −6} C, E{sub e} = 16 ± 0.32 MeV) was injected into a 5-mm-thick lead plate. Bremsstrahlung x-rays, which emanate from the lead plate, were measured with the spectrometer. The measured spectral shape and intensity agree fairly well with those computed with a Monte Carlo simulation code. The result shows that high-energy x-rays can be measured absolutely with a photon-counting accuracy of 50%–70% in the energy range from 2 MeV to 20 MeV with a spectral resolution (Δhν/hν) of about 15%. Quantum efficiency of this spectrometer was designed to be 10{sup −7}, 10{sup −4}, 10{sup −5}, respectively, for 2–10, 11–15, and 15–25 MeV of photon energy ranges.

  18. NuSTAR Detection of High-Energy X-Ray Emission and Rapid Variability from Sagittarius A(star) Flares

    NASA Technical Reports Server (NTRS)

    Barriere, Nicolas M.; Tomsick, John A.; Baganoff, Frederick K.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Dexter, Jason; Grefenstette, Brian; Hailey, Charles J.; Zhang, William W.

    2014-01-01

    Sagittarius A(star) harbors the supermassive black hole that lies at the dynamical center of our Galaxy. Sagittarius A(star) spends most of its time in a low luminosity emission state but flares frequently in the infrared and X-ray, increasing up to a few hundred fold in brightness for up to a few hours at a time. The physical processes giving rise to the X-ray flares are uncertain. Here we report the detection with the NuSTAR observatory in Summer and Fall 2012 of four low to medium amplitude X-ray flares to energies up to 79 keV. For the first time, we clearly see that the power-law spectrum of Sagittarius A(star) X-ray flares extends to high energy, with no evidence for a cut off. Although the photon index of the absorbed power-law fits are in agreement with past observations, we find a difference between the photon index of two of the flares (significant at the 95% confidence level). The spectra of the two brightest flares (approx. 55 times quiescence in the 2- 10 keV band) are compared to simple physical models in an attempt to identify the main X-ray emission mechanism, but the data do not allow us to significantly discriminate between them. However, we confirm the previous finding that the parameters obtained with synchrotron models are, for the X-ray emission, physically more reasonable than those obtained with inverse-Compton models. One flare exhibits large and rapid (less than 100 s) variability, which, considering the total energy radiated, constrains the location of the flaring region to be within approx. 10 Schwarzschild radii of the black hole.

  19. NuSTAR detection of high-energy X-ray emission and rapid variability from Sagittarius A{sup *} flares

    SciTech Connect

    Barrière, Nicolas M.; Tomsick, John A.; Boggs, Steven E.; Craig, William W.; Zoglauer, Andreas; Baganoff, Frederick K.; Christensen, Finn E.; Dexter, Jason; Grefenstette, Brian; Harrison, Fiona A.; Madsen, Kristin K.; Hailey, Charles J.; Mori, Kaya; Zhang, Shuo; Stern, Daniel; Zhang, William W.

    2014-05-01

    Sagittarius A{sup *} harbors the supermassive black hole that lies at the dynamical center of our Galaxy. Sagittarius A{sup *} spends most of its time in a low luminosity emission state but flares frequently in the infrared and X-ray, increasing up to a few hundred fold in brightness for up to a few hours at a time. The physical processes giving rise to the X-ray flares are uncertain. Here we report the detection with the NuSTAR observatory in Summer and Fall 2012 of four low to medium amplitude X-ray flares to energies up to 79 keV. For the first time, we clearly see that the power-law spectrum of Sagittarius A{sup *} X-ray flares extends to high energy, with no evidence for a cutoff. Although the photon index of the absorbed power-law fits are in agreement with past observations, we find a difference between the photon index of two of the flares (significant at the 95% confidence level). The spectra of the two brightest flares (∼55 times quiescence in the 2-10 keV band) are compared to simple physical models in an attempt to identify the main X-ray emission mechanism, but the data do not allow us to significantly discriminate between them. However, we confirm the previous finding that the parameters obtained with synchrotron models are, for the X-ray emission, physically more reasonable than those obtained with inverse Compton models. One flare exhibits large and rapid (<100 s) variability, which, considering the total energy radiated, constrains the location of the flaring region to be within ∼10 Schwarzschild radii of the black hole.

  20. Imaging of High-Energy X-Ray Emission from Cryogenic Thermonuclear Fuel Implosions on the NIF

    SciTech Connect

    Ma, T

    2012-05-01

    Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide spectrally resolved time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered targets. Using bremsstrahlung assumptions, the measured absolute x-ray brightness allows for the inference of electron temperature, electron density, hot spot mass, mix mass, and pressure. Current inertial confinement fusion (ICF) experiments conducted on the National Ignition Facility (NIF) seek to indirectly drive a spherical implosion, compressing and igniting a deuterium-tritium fuel. This DT fuel capsule is cryogenically prepared as a solid ice layer surrounded by a low-Z ablator material. Ignition will occur when the hot spot approaches sufficient temperature ({approx}3-4 keV) and {rho}R ({approx}0.3 g/cm{sup 2}) such that alpha deposition can further heat the hot spot and generate a self-sustaining burn wave. During the implosion, the fuel mass becomes hot enough to emit large amounts of x-ray radiation, the spectra and spatial variation of which contains key information that can be used to evaluate the implosion performance. The Ross filter diagnostic employs differential filtering to provide spectrally resolved, time-integrated, absolute x-ray self-emission images of the imploded core of cryogenic layered targets.

  1. The X-ray behaviour of the high-energy peaked BL Lacertae source PKS 2155-304 in the 0.3-10 keV band

    NASA Astrophysics Data System (ADS)

    Kapanadze, B.; Romano, P.; Vercellone, S.; Kapanadze, S.

    2014-10-01

    We present the results of our monitoring of the high-energy peaked BL Lac object PKS 2155-304 by the Swift/X-Ray Telescope (XRT) during 2005-2012. Our timing study shows that the source was highly variable both on longer (weeks-to-months) and intra-day time-scales, up to a factor of 7 in flux, and 30 per cent in fractional variability amplitudes, with no periodic variations. The X-ray spectra are mainly curved with broad ranges of photon index, curvature parameter, and hardness ratio which exhibit significant variability with the flux on different time-scales. Our study of multi-wavelength cross-correlations has revealed that the one-zone SSC scenario seems to be valid for the most optical-to-gamma-ray flares observed during 2006-2012. An `orphan' X-ray flare with no counterpart in other spectral bands suggests the existence of different electron populations. Based on the absence of a correlation between photon index and curvature parameter (expected from the energy-dependent acceleration probability scenario), the observed distribution of curvature parameter from the XRT spectra peaking at b = 0.37, and the observed anti-correlation between the curvature parameter and the 0.3-10 keV flux (i.e. lower curvatures in flaring states), we conclude that the most likely mechanism responsible for producing X-ray emission during the flares is the stochastic acceleration of the electrons.

  2. Effects of high energy x ray and proton irradiation on lead zirconate titanate thin films' dielectric and piezoelectric response

    SciTech Connect

    Bastani, Y.; Cortes-Pena, A. Y.; Wilson, A. D.; Gerardin, S.; Bagatin, M.; Paccagnella, A.; Bassiri-Gharb, N.

    2013-05-13

    The effects of irradiation by X rays and protons on the dielectric and piezoelectric response of highly (100)-textured polycrystalline Pb(Zr{sub x}Ti{sub 1-x})O{sub 3} (PZT) thin films have been studied. Low-field dielectric permittivity, remanent polarization, and piezoelectric d{sub 33,f} response all degraded with exposure to radiation, for doses higher than 300 krad. At first approximation, the degradation increased at higher radiation doses, and was stronger in samples exposed to X rays, compared to the proton-irradiated ones. Nonlinear and high-field dielectric characterization suggest a radiation-induced reduction of the extrinsic contributions to the response, attributed to increased pinning of the domain walls by the radiation-induced point defects.

  3. A scanning modulation collimator observation of the high-energy X-ray source in the Crab Nebula

    NASA Technical Reports Server (NTRS)

    Pelling, R. M.; Paciesas, W. S.; Peterson, L. E.; Makishima, K.; Oda, M.

    1987-01-01

    Two-dimensional maps of the 22-64 keV emission from the Crab Nebula with an angular resolution of 15 arcsec has been synthesized. The maps are generated by application of a maximum entropy method operating on a series of one-dimensional scans obtained with a balloon-borne modulation collimator telescope. The two-dimensional size, shape and orientation of the hard X-ray nebula relative to the pulsar have been measured for the first time. The implications of these results for models of electron transport in the Crab are discussed, and the geometry of the observed X-ray nebula is related to other features of the Crab Nebula system.

  4. Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF.

    PubMed

    Ma, T; Izumi, N; Tommasini, R; Bradley, D K; Bell, P; Cerjan, C J; Dixit, S; Döppner, T; Jones, O; Kline, J L; Kyrala, G; Landen, O L; LePape, S; Mackinnon, A J; Park, H-S; Patel, P K; Prasad, R R; Ralph, J; Regan, S P; Smalyuk, V A; Springer, P T; Suter, L; Town, R P J; Weber, S V; Glenzer, S H

    2012-10-01

    Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure. PMID:23126937

  5. Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF

    SciTech Connect

    Ma, T.; Izumi, N.; Tommasini, R.; Bradley, D. K.; Bell, P.; Cerjan, C. J.; Dixit, S.; Doeppner, T.; Jones, O.; Landen, O. L.; LePape, S.; Mackinnon, A. J.; Park, H.-S.; Patel, P. K.; Prasad, R. R.; Ralph, J.; Smalyuk, V. A.; Springer, P. T.; Suter, L.; Town, R. P. J.; and others

    2012-10-15

    Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.

  6. Correlating Fischer-Tropsch activity to Ru nanoparticle surface structure as probed by high-energy X-ray diffraction.

    PubMed

    Quek, Xian-Yang; Filot, Ivo A W; Pestman, Robert; van Santen, Rutger A; Petkov, Valeri; Hensen, Emiel J M

    2014-06-01

    Synchrotron X-ray diffraction coupled to atomic pair distribution function analysis and Reverse Monte Carlo simulations is used to determine the atomic-scale structure of Ru nanoparticle catalysts for the Fischer-Tropsch reaction. The rate of CO hydrogenation strongly correlates with the abundance of surface atoms with coordination numbers of 10 and 11. DFT calculations confirm that CO dissociation proceeds with a low barrier on these Ru surface atom ensembles. PMID:24763733

  7. High-Resolution Spectroscopy of the X-Ray-photoionized Wind in Cygnus X-3 with the Chandra High-Energy Transmission Grating Spectrometer.

    PubMed

    Paerels; Cottam; Sako; Liedahl; Brinkman; van Der Meer RL; Kaastra; Predehl

    2000-04-20

    We present a preliminary analysis of the 1-10 keV spectrum of the massive X-ray binary Cygnus X-3, obtained with the high-energy transmission grating spectrometer on the Chandra X-Ray Observatory. The source reveals a richly detailed discrete emission spectrum, with clear signatures of photoionization-driven excitation. Among the spectroscopic novelties in the data are the first astrophysical detections of a number of He-like "triplets" (Si, S, Ar) with emission-line ratios characteristic of photoionization equilibrium, fully resolved narrow radiative recombination continua of Mg, Si, and S, the presence of the H-like Fe Balmer series, and a clear detection of an approximately 800 km s-1 large-scale velocity field as well as an approximately 1500 km s-1 FWHM Doppler broadening in the source. We briefly touch on the implications of these findings for the structure of the Wolf-Rayet wind. PMID:10770708

  8. High energy X-ray observations of CYG X-3 from from OSO-8: Further evidence of a 34.1 day period

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.

    1981-01-01

    The X-ray source Cyg X-3 (=4U2030+40) was observed with the high energy X-ray spectrometer on OSO-8 for two weeks in 1975 and in 1976 and for one week in 1977. No change in spectral shape and intensity above 23 keV was observed from year to year. No correlation is observed between the source's intensity and the phase of the 34.1 day period discovered by Molteni, et al. (1980). The pulsed fraction of the 4.8 hour light curve between 23 and 73 keV varies from week to week, however, and the magnitude of the pulsed fraction appears to be correlated with the 34.1 day phase. No immediate explanation of this behavior is apparent in terms of previously proposed models of the source.

  9. Observations of celestial X-ray sources above 20 keV with the high-energy scintillation spectrometer on board OSO 8

    NASA Technical Reports Server (NTRS)

    Crannell, C. J.; Dennis, B. R.; Dolan, J. H.; Frost, K. J.; Orwig, L. E.; Beall, J. H.; Maurer, G. S.

    1977-01-01

    High-energy X-ray spectra of the Crab Nebula, Cyg- XR-1, and Cen A were determined from observations with the scintillation spectrometer on board the OSO-8 satellite, launched in June, 1975. Each of these sources was observed over two periods of 8 days or more, enabling a search for day-to-day and year to year variations in the spectral and temporal characteristics of the X-ray emission. No variation in the light curve of the Crab pulsar was found from observations which span a 15-day period in March 1976, with demonstrable phase stability. Transitions associated with the binary phase of Cyg XR-1 and a large change in the emission from Con A are reported.

  10. A furnace and environmental cell for the in situ investigation of molten salt electrolysis using high-energy X-ray diffraction.

    PubMed

    Styles, Mark J; Rowles, Matthew R; Madsen, Ian C; McGregor, Katherine; Urban, Andrew J; Snook, Graeme A; Scarlett, Nicola V Y; Riley, Daniel P

    2012-01-01

    This paper describes the design, construction and implementation of a relatively large controlled-atmosphere cell and furnace arrangement. The purpose of this equipment is to facilitate the in situ characterization of materials used in molten salt electrowinning cells, using high-energy X-ray scattering techniques such as synchrotron-based energy-dispersive X-ray diffraction. The applicability of this equipment is demonstrated by quantitative measurements of the phase composition of a model inert anode material, which were taken during an in situ study of an operational Fray-Farthing-Chen Cambridge electrowinning cell, featuring molten CaCl(2) as the electrolyte. The feasibility of adapting the cell design to investigate materials in other high-temperature environments is also discussed. PMID:22186642

  11. Morphometrics of cellular damage in mice testis receiving X-ray and high-energy particle irradiation

    NASA Technical Reports Server (NTRS)

    Sapp, Walter J.

    1987-01-01

    Murine tests were exposed to single, low doses of either X-ray, helium, or argon radiation. Animals were sacrificed seventy-two hours later. Testes were fixed for transmission electron microscopy (TEM) and sectioned at either 60 nm for TEM observation or at 2 micron for counting using routine light microscope methods. Counts of the total population of surviving spermatogonia, including all type A cells, intermediate, and type B cells, were taken from tubule cross sections identified as Stage 6 and Stage 1 according to spermatogonial configuration. The surviving fraction of spermatogonia as compared to control, S/S sub o, was calculated for each dose. For both ions and X-rays, there was a rapid decline in survival at dose levels of .10 to .15 Gy in Stage 6 tubules. This was followed by a more gradual decrease in population. At higher doses, 0.30 Gy for argon and 0.80 Gy for helium and X-rays, the cell survival rates declined rapidly. Pre-leptotene spermatocytes in Stage 1 tubules exhibited a different survival curve indicating the extreme radio-sensitivity of type B spermatogonia. Data verify that the seminiferous tubules are composed of a heterogeneous population of cells with different radio-sensitivities and that these differences are manifested even at very low doses.

  12. From EXOSAT to the High Energy Astrophysics Science Archive (HEASARC): X-ray Astronomy Comes of Age

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.

    2012-01-01

    In May 1983 the European Space Agency launched EXOSAT, its first X-ray astronomy observatory. Even though it lasted only 3 short years, this mission brought not only new capabilities that resulted in unexpected discoveries, but also a pioneering approach to operations and archiving that changed X-ray astronomy from observations led by small instrument teams, to an observatory approach open to the entire community through a guest observer program. The community use of the observatory was supported by a small dedicated team of scientists, the precursor to the data center activities created to support e.g. Chandra and XMM-Newton. The new science capabilities of EX OS AT included a 90 hr highly eccentric high earth orbit that allow unprecedented continuous coverage of sources as well as direct communication with the satellite that allowed real time decisions to respond to unexpected events through targets of opportunity. The advantages of this orbit demonstrated by EXOSAT resulted in Chandra and XMM-Newton selecting similar orbits. The three instruments on board the EXOSAT observatory were complementary, designed to give complete coverage over a wide energy band pass of 0.05-50 keY. An onboard processor could be programmed to give multiple data modes that could be optimized in response to science discoveries: These new capabilities resulted in many new discoveries including the first comprehensive study of AGN variability, new orbital periods in X-ray binaries and cataclysmic variables, new black holes, quasi-periodic oscillations from neutron stars and black holes and broad band X-ray spectroscopy. The EXOSAT team generated a well-organized database accessible worldwide over the nascent internet, allowing remote selection of data products, making samples and undertaking surveys from the data. The HEASARC was established by NASA at Goddard Space Flight Center in 1990 as the repository of NASA X-ray and Gamma-ray data. The proven EXOSAT database system became the core

  13. From EXOSAT to the High Energy Astrophysics Science Archive (HEASARC): X-ray Astronomy Comes of Age

    NASA Astrophysics Data System (ADS)

    White, Nicholas E.

    2013-01-01

    In May 1983 the European Space Agency launched EXOSAT, its first X-ray astronomy observatory. Even though it lasted only 3 short years, this mission brought not only new capabilities that resulted in unexpected discoveries, but also a pioneering approach to operations and archiving that changed X-ray astronomy from observations led by small instrument teams, to an observatory approach open to the entire community through a guest observer program. The community use of the observatory was supported by a small dedicated team of scientists, the precursor to the data center activities created to support e.g. Chandra and XMM-Newton. The new science capabilities of EXOSAT included a 90 hr highly eccentric high earth orbit that allow unprecedented continuous coverage of sources as well as direct communication with the satellite that allowed real time decisions to respond to unexpected events through targets of opportunity. The advantages of this orbit demonstrated by EXOSAT resulted in Chandra and XMM-Newton selecting similar orbits. The three instruments on board the EXOSAT observatory were complementary, designed to give complete coverage over a wide energy band pass of 0.05-50 keV. An onboard processor could be programed to give multiple data modes that could be optimized in response to science discoveries. These new capabilities resulted in many new discoveries including the first comprehensive study of AGN variability, new orbital periods in X-ray binaries and cataclysmic variables, new black holes, quasi-periodic oscillations from neutron stars and black holes and broad band X-ray spectroscopy. The EXOSAT team generated a well-organized database accessible worldwide over the nascent internet, allowing remote selection of data products, making samples and undertaking surveys from the data. The HEASARC was established by NASA at Goddard Space Flight Center in 1990 as the repository of NASA X-ray and Gamma-ray data. The proven EXOSAT database system became the core of

  14. Exchange of Coordinated Solvent During Crystallization of a Metal-Organic Framework Observed by In Situ High-Energy X-ray Diffraction.

    PubMed

    Wu, Yue; Breeze, Matthew I; Clarkson, Guy J; Millange, Franck; O'Hare, Dermot; Walton, Richard I

    2016-04-11

    Using time-resolved monochromatic high energy X-ray diffraction, we present an in situ study of the solvothermal crystallisation of a new MOF [Yb2 (BDC)3 (DMF)2 ]⋅H2 O (BDC=benzene-1,4-dicarboxylate and DMF=N,N-dimethylformamide) under solvothermal conditions, from mixed water/DMF solvent. Analysis of high resolution powder patterns obtained reveals an evolution of lattice parameters and electron density during the crystallisation process and Rietveld analysis shows that this is due to a gradual topochemical replacement of coordinated solvent molecules. The water initially coordinated to Yb(3+) is replaced by DMF as the reaction progresses. PMID:26959076

  15. A new approach to the determination of atomic-architecture of amorphous zeolite precursors by high-energy X-ray diffraction technique.

    PubMed

    Wakihara, Toru; Kohara, Shinji; Sankar, Gopinathan; Saito, Seijiro; Sanchez-Sanchez, Manuel; Overweg, Arian R; Fan, Wei; Ogura, Masaru; Okubo, Tatsuya

    2006-01-14

    The structure of amorphous precursor species formed under hydrothermal conditions, prior to the onset of crystallization of microporous aluminosilicate zeolites, is determined employing high-energy X-ray diffraction (HEXRD). The investigation, combined with the use of reverse Monte Carlo modelling suggests that even numbered rings, especially 4R (R: ring) and 6R, which are the dominant aluminosilicate rings in zeolite A, have already been produced in the precursor. The model implies that the formation of double 4Rs occurs at the final step of the crystallization of zeolite A. PMID:16482264

  16. HIGH-ENERGY OBSERVATIONS OF PSR B1259–63/LS 2883 THROUGH THE 2014 PERIASTRON PASSAGE: CONNECTING X-RAYS TO THE GeV FLARE

    SciTech Connect

    Tam, P. H. T.; Li, K. L.; Kong, A. K. H.; Takata, J.; Okazaki, A. T.; Hui, C. Y.

    2015-01-01

    The binary system PSR B1259–63/LS 2883 is well sampled in radio, X-rays, and TeV γ-rays, and shows orbital-phase-dependent variability in these frequencies. The first detection of GeV γ-rays from the system was made around the 2010 periastron passage. In this Letter, we present an analysis of X-ray and γ-ray data obtained by the Swift/XRT, NuSTAR/FPM, and Fermi/LAT, through the recent periastron passage which occurred on 2014 May 4. While PSR B1259–63/LS 2883 was not detected by the Large Area Telescope before and during this passage, we show that the GeV flares occurred at a similar orbital phase as in early 2011, thus establishing the repetitive nature of the post-periastron GeV flares. Multiple flares each lasting for a few days have been observed and short-term variability is seen as well. We also found X-ray flux variation contemporaneous with the GeV flare for the first time. Strong evidence of the keV-to-GeV connection came from the broadband high-energy spectra, which we interpret as synchrotron radiation from the shocked pulsar wind.

  17. Fast scintillation timing detector using proportional-mode avalanche photodiode for nuclear resonant scattering experiments in high-energy synchrotron X-ray region

    NASA Astrophysics Data System (ADS)

    Inoue, Keisuke; Kishimoto, Shunji

    2016-01-01

    To obtain both a high count rate of >107 s-1 and a detection efficiency sufficient for high-energy X-rays of >30 keV, we propose a scintillation timing detector using a proportional-mode silicon avalanche photodiode (Si-APD) for synchrotron radiation nuclear resonant scattering. We here present results obtained with a prototype detector using a lead-loaded plastic scintillator (EJ-256) mounted on a proportional-mode Si-APD (active area size: 3 mm in diameter). The detector was operated at ‒35 °C for a better signal-to-noise ratio. Using synchrotron X-rays of 67.41 keV, which is the same energy as the first excited level of 61Ni, we successfully measured pulse-height and time spectra of the scintillation light. A good time resolution of 0.50±0.06 ns (full width at half-maximum) was obtained for 67.41 keV X-rays with a scintillator 3 mm in diameter and 2 mm thick.

  18. Nanophase evolution at semiconductor/electrolyte interface in situ probed by time-resolved high-energy synchrotron x-ray diffraction.

    SciTech Connect

    Sun, Y.; Ren, Y.; Haeffner, D. R.; Almer, J. D.; Wang, L.; Yang, W.; Truong, T. T.

    2010-09-01

    Real-time evolution of nanoparticles grown at the semiconductor/electrolyte interface formed between a single crystalline n-type GaAs wafer and an aqueous solution of AgNO{sub 3} has been studied by using high-energy synchrotron X-ray diffraction. The results reveal the distinct nucleation and growth steps involved in the growth of anisotropic Ag nanoplates on the surface of the GaAs wafer. For the first time, a quick transit stage is observed to be responsible for the structural transformation of the nuclei to form structurally stable seeds that are critical for guiding their anisotropic growth into nanoplates. Reaction between a GaAs wafer and AgNO{sub 3} solution at room temperature primarily produces Ag nanoplates on the surface of the GaAs wafer in the dark and at room temperature. In contrast, X-ray irradiation can induce charge separation in the GaAs wafer to drive the growth of nanoparticles made of silver oxy salt (Ag{sub 7}NO{sub 11}) and silver arsenate (Ag{sub 3}AsO{sub 4}) at the semiconductor/electrolyte interface if the GaAs wafer is illuminated by the X-ray and reaction time is long enough.

  19. Exploring the interfacial structure of protein adsorbates and the kinetics of protein adsorption: an in situ high-energy X-ray reflectivity study.

    PubMed

    Evers, Florian; Shokuie, Kaveh; Paulus, Michael; Sternemann, Christian; Czeslik, Claus; Tolan, Metin

    2008-09-16

    The high energy X-ray reflectivity technique has been applied to study the interfacial structure of protein adsorbates and protein adsorption kinetics in situ. For this purpose, the adsorption of lysozyme at the hydrophilic silica-water interface has been chosen as a model system. The structure of adsorbed lysozyme layers was probed for various aqueous solution conditions. The effect of solution pH and lysozyme concentration on the interfacial structure was measured. Monolayer formation was observed for all cases except for the highest concentration. The adsorbed protein layers consist of adsorbed lysozyme molecules with side-on or end-on orientation. By means of time-dependent X-ray reflectivity scans, the time-evolution of adsorbed proteins was monitored as well. The results of this study demonstrate the capabilities of in situ X-ray reflectivity experiments on protein adsorbates. The great advantages of this method are the broad wave vector range available and the high time resolution. PMID:18715021

  20. A new method of observing weak extended x-ray sources with the Reuven Ramaty high-energy solar spectroscopic imager.

    PubMed

    Hannah, Iain G; Hurford, Gordon J; Hudson, Hugh S; Lin, Robert P

    2007-02-01

    We present a new method, fan-beam modulation, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This space-based solar x-ray and gamma-ray telescope has much greater sensitivity than previous experiments in the 3-25 keV range, but is normally not well suited to detecting extended sources since their signal is not modulated by RHESSI's rotating grids. When the spacecraft is offpointed from the target source, however, the fan-beam modulation time-modulates the transmission by shadowing resulting from exploiting the finite thickness of the grids. In this article we detail how the technique is implemented and verify its consistency with sources with clear known signals that have occurred during RHESSI offpointing: microflares and the Crab Nebula. In both cases the results are consistent with previous and complementary measurements. Preliminary work indicates that this new technique allows RHESSI to observe the integrated hard x-ray spectrum of weak extended sources on the quiet Sun. PMID:17578130

  1. Technical Note: Synchrotron-based high-energy x-ray phase sensitive microtomography for biomedical research

    SciTech Connect

    Liu, Huiqiang; Wu, Xizeng E-mail: tqxiao@sinap.ac.cn; Xiao, Tiqiao E-mail: tqxiao@sinap.ac.cn

    2015-10-15

    Purpose: Propagation-based phase-contrast CT (PPCT) utilizes highly sensitive phase-contrast technology applied to x-ray microtomography. Performing phase retrieval on the acquired angular projections can enhance image contrast and enable quantitative imaging. In this work, the authors demonstrate the validity and advantages of a novel technique for high-resolution PPCT by using the generalized phase-attenuation duality (PAD) method of phase retrieval. Methods: A high-resolution angular projection data set of a fish head specimen was acquired with a monochromatic 60-keV x-ray beam. In one approach, the projection data were directly used for tomographic reconstruction. In two other approaches, the projection data were preprocessed by phase retrieval based on either the linearized PAD method or the generalized PAD method. The reconstructed images from all three approaches were then compared in terms of tissue contrast-to-noise ratio and spatial resolution. Results: The authors’ experimental results demonstrated the validity of the PPCT technique based on the generalized PAD-based method. In addition, the results show that the authors’ technique is superior to the direct PPCT technique as well as the linearized PAD-based PPCT technique in terms of their relative capabilities for tissue discrimination and characterization. Conclusions: This novel PPCT technique demonstrates great potential for biomedical imaging, especially for applications that require high spatial resolution and limited radiation exposure.

  2. A high energy phase retarder for the simultaneous production of right- and left-handed circularly polarized x-rays

    SciTech Connect

    Venkataraman, C.T.; Lang, J.C.; Nelson, C.S.; Srajer, G.; Haeffner, D.R.; Shastri, S.D.

    1997-09-01

    The authors have fabricated and characterized the performance of a monolithic Ge Bragg-Laue phase retarder capable of simultaneously producing both right- and left-handed circularly polarized x rays. The energy range of operation of the phase retarder is between 50 and 100 keV making it well suited to the measurement of spin-dependent Compton profiles within the impulse approximation, primarily because of the increased momentum resolution and larger Compton scattering cross section available at these higher incident energies. Although the phase retarder was optimized for operation at 86 keV, it can produce highly circularly polarized x rays over a substantial energy range. The performance of the phase retarder was tested via magnetic Compton scattering measurements on an Fe sample at the undulator A of the Advanced Photon Source. It was found to perform well in terms of flux and degree of circular polarization thereby greatly reducing the data collection times required for this inherently weak scattering process.

  3. Low Dose High Energy X-ray In-Line Phase Sensitive Imaging Prototype: Investigation of Optimal Geometric Conditions and Design Parameters

    PubMed Central

    Ghani, Muhammad. U.; Yan, Aimin; Wong, Molly. D.; Li, Yuhua; Ren, Liqiang; Wu, Xizeng; Liu, Hong

    2016-01-01

    The objective of this study was to investigate the optimization of a high energy in-line phase sensitive x-ray imaging prototype under different geometric and operating conditions for mammography application. A phase retrieval algorithm based on phase attenuation duality (PAD) was applied to the phase contrast images acquired by the prototype. Imaging performance was investigated at four magnification values of 1.67, 2, 2.5 and 3 using an acrylic edge, an American College of Radiology (ACR) mammography phantom and contrast detail (CD) phantom with tube potentials of 100, 120 and 140 kVp. The ACR and CD images were acquired at the same mean glandular dose (MGD) of 1.29 mGy with a computed radiography (CR) detector of 43.75 µm pixel pitch at a fixed source to image distance (SID) of 170 cm. The x-ray tube focal spot size was kept constant as 7 µm while a 2.5 mm thick aluminum (Al) filter was used for beam hardening. The performance of phase contrast and phase retrieved images were compared with computer simulations based on the relative phase contrast factor (RPF) at high x-ray energies. The imaging results showed that the x-ray tube operated at 100 kVp under the magnification of 2.5 exhibits superior imaging performance which is in accordance to the computer simulations. As compared to the phase contrast images, the phase retrieved images of the ACR and CD phantoms demonstrated improved imaging contrast and target discrimination. We compared the CD phantom images acquired in conventional contact mode with and without the anti-scatter grid using the same prototype at 1.295 mGy and 2.59 mGy using 40 kVp, a 25 µm rhodium (Rh) filter. At the same radiation dose, the phase sensitive images provided improved detection capabilities for both the large and small discs, while compared to the double dose image acquired in conventional mode, the observer study also indicated that the phase sensitive images provided improved detection capabilities for the large discs. This

  4. Low dose high energy x-ray in-line phase sensitive imaging prototype: Investigation of optimal geometric conditions and design parameters.

    PubMed

    Ghani, Muhammad U; Yan, Aimin; Wong, Molly D; Li, Yuhua; Ren, Liqiang; Wu, Xizeng; Liu, Hong

    2015-01-01

    The objective of this study was to investigate the optimization of a high energy in-line phase sensitive x-ray imaging prototype under different geometric and operating conditions for mammography application. A phase retrieval algorithm based on phase attenuation duality (PAD) was applied to the phase contrast images acquired by the prototype. Imaging performance was investigated at four magnification values of 1.67, 2, 2.5 and 3 using an acrylic edge, an American College of Radiology (ACR) mammography phantom and contrast detail (CD) phantom with tube potentials of 100, 120 and 140 kVp. The ACR and CD images were acquired at the same mean glandular dose (MGD) of 1.29 mGy with a computed radiography (CR) detector of 43.75 μm pixel pitch at a fixed source to image distance (SID) of 170 cm. The x-ray tube focal spot size was kept constant as 7 μm while a 2.5 mm thick aluminum (Al) filter was used for beam hardening. The performance of phase contrast and phase retrieved images were compared with computer simulations based on the relative phase contrast factor (RPF) at high x-ray energies. The imaging results showed that the x-ray tube operated at 100 kVp under the magnification of 2.5 exhibits superior imaging performance which is in accordance to the computer simulations. As compared to the phase contrast images, the phase retrieved images of the ACR and CD phantoms demonstrated improved imaging contrast and target discrimination. We compared the CD phantom images acquired in conventional contact mode with and without the anti-scatter grid using the same prototype at 1.295 mGy and 2.59 mGy using 40 kVp, a 25 μm rhodium (Rh) filter. At the same radiation dose, the phase sensitive images provided improved detection capabilities for both the large and small discs, while compared to the double dose image acquired in conventional mode, the observer study also indicated that the phase sensitive images provided improved detection capabilities for the large discs. This

  5. Fingerprinting analysis of non-crystalline pharmaceutical compounds using high energy X-rays and the total scattering pair distribution function

    NASA Astrophysics Data System (ADS)

    Davis, Timur D.

    2011-12-01

    In the development of new medicinal products, poor oral bioavailability, due to the low solubilities of many active pharmaceutical ingredients (APIs), is increasingly a barrier for treatments to be administered using tablet or capsule formulations and one of the main challenges facing the pharmaceutical industry. Non-crystalline phases such as the amorphous and nanostructured states can confer increased solubility to a drug, and therefore, have recently garnered a lot of interest from pharmaceutical researchers. However, little is known about local ordering in non-crystalline pharmaceuticals due to the lack of reliable experimental probes, hindering the clinical application of these compounds. The powerful tools of crystallography begin to lose their potency for structures on the nanoscale; conventional X-ray powder diffraction (XRPD) patterns become broad and featureless in these cases and are not useful for differentiating between different local molecular packing arrangements. In this thesis, we introduce the use of high energy X-rays coupled with total scattering pair distribution function (TSPDF) and fingerprinting analysis to investigate the local structures of non-crystalline pharmaceutical compounds. The high energy X-rays allow us to experimentally collect diffuse scattering intensities, which contain information about a sample's local ordering, in addition to the Bragg scattering available in conventional XRPD experiments, while the TSPDF allows us to view the intra- and inter-molecular correlations in real space. The goal of this study was to address some fundamental problems involving fingerprinting non-crystalline APIs using TSPDF in order to lay the groundwork for the proper use of the technique by the pharmaceutical community. We achieved this by developing the methodology as well as the exploring the scientific implications. On the methodology side, we introduced PDFGetX3, a new software program for calculating TSPDFs that simplifies the procedure

  6. OZSPEC-2: An improved broadband high-resolution elliptical crystal x-ray spectrometer for high-energy density physics experiments (invited)

    SciTech Connect

    Heeter, R. F.; Anderson, S. G.; Booth, R.; Brown, G. V.; Emig, J.; Fulkerson, S.; McCarville, T.; Norman, D.; Schneider, M. B.; Young, B. K. F.

    2008-10-15

    A novel time, space, and energy-resolved x-ray spectrometer has been developed which produces, in a single snapshot, a broadband and relatively calibrated spectrum of the x-ray emission from a high-energy density laboratory plasma. The opacity zipper spectrometer (OZSPEC-1) records a nearly continuous spectrum for x-ray energies from 240 to 5800 eV in a single shot. The second-generation OZSPEC-2, detailed in this work, records fully continuous spectra on a single shot from any two of these three bands: 270-650, 660-1580, and 1960-4720 eV. These instruments thus record thermal and line radiation from a wide range of plasmas. These instruments' single-shot bandwidth is unmatched in a time-gated spectrometer; conversely, other broadband instruments are either time-integrated (using crystals or gratings), lack spectral resolution (diode arrays), or cover a lower energy band (gratings). The OZSPECs are based on the zipper detector, a large-format (100x35 mm) gated microchannel plate detector, with spectra dispersed along the 100 mm dimension. OZSPEC-1 and -2 both use elliptically bent crystals of OHM, RAP, and/or PET. Individual spectra are gated in 100 ps. OZSPEC-2 provides one-dimensional spatial imaging with 30-50 {mu}m resolution over a 1500 {mu}m field of view at the source. The elliptical crystal design yields broad spectral coverage with resolution E/{delta}E>500, strong rejection of hard x-ray backgrounds, and negligible source broadening for extended sources. Near-term applications include plasma opacity measurements, detailed spectra of inertial fusion Hohlraums, and laboratory astrophysics experiments.

  7. Analysis of Flow Cytometry DNA Damage Response Protein Activation Kinetics Following X-rays and High Energy Iron Nuclei Exposure

    SciTech Connect

    Universities Space Research Association; Chappell, Lori J.; Whalen, Mary K.; Gurai, Sheena; Ponomarev, Artem; Cucinotta, Francis A.; Pluth, Janice M.

    2010-12-15

    We developed a mathematical method to analyze flow cytometry data to describe the kinetics of {gamma}H2AX and pATF2 phosphorylations ensuing various qualities of low dose radiation in normal human fibroblast cells. Previously reported flow cytometry kinetic results for these DSB repair phospho-proteins revealed that distributions of intensity were highly skewed, severely limiting the detection of differences in the very low dose range. Distributional analysis reveals significant differences between control and low dose samples when distributions are compared using the Kolmogorov-Smirnov test. Radiation quality differences are found in the distribution shapes and when a nonlinear model is used to relate dose and time to the decay of the mean ratio of phosphoprotein intensities of irradiated samples to controls. We analyzed cell cycle phase and radiation quality dependent characteristic repair times and residual phospho-protein levels with these methods. Characteristic repair times for {gamma}H2AX were higher following Fe nuclei as compared to X-rays in G1 cells (4.5 {+-} 0.46 h vs 3.26 {+-} 0.76 h, respectively), and in S/G2 cells (5.51 {+-} 2.94 h vs 2.87 {+-} 0.45 h, respectively). The RBE in G1 cells for Fe nuclei relative to X-rays for {gamma}H2AX was 2.05 {+-} 0.61 and 5.02 {+-} 3.47, at 2 h and 24-h postirradiation, respectively. For pATF2, a saturation effect is observed with reduced expression at high doses, especially for Fe nuclei, with much slower characteristic repair times (>7 h) compared to X-rays. RBEs for pATF2 were 0.66 {+-} 0.13 and 1.66 {+-} 0.46 at 2 h and 24 h, respectively. Significant differences in {gamma}H2AX and pATF2 levels comparing irradiated samples to control were noted even at the lowest dose analyzed (0.05 Gy) using these methods of analysis. These results reveal that mathematical models can be applied to flow cytometry data to uncover important and subtle differences following exposure to various qualities of low dose radiation.

  8. High-Energy Nanoscale-Resolution X-ray Microscopy Based on Refractive Optics on a Long Beamline

    SciTech Connect

    Snigireva, I.; Vaughan, G. B. M.; Snigirev, A.

    2011-09-09

    The long length and good coherence properties of ID11 at the ESRF have led to the development of x-ray microscopy based on compound refractive lenses (CRLs). For the highest resolution full-field microscopy, the sample is placed {approx}40 m from the source, which can be micro-focused by a transfocator as a condenser. Due to the long length of the beamline and consequent long sample-detector distance, a CRL objective can be placed up to a meter behind the sample and still allow for magnification of 60x on a detector located at 99 m--enough to achieve easily 100-nm resolution with a typical high-resolution detector.

  9. A high-spatial-resolution fiber-optic-coupled CMOS imager with novel scintillator for high-energy x-ray applications

    NASA Astrophysics Data System (ADS)

    Baur, Robin M.; Tate, Mark W.; Dale, Darren S.; Gruner, Sol M.

    2013-03-01

    A fast, high-spatial-resolution detector for high-energy microscopy work is presented. The detector uses a 2160 × 2560 CMOS chip for fast framing (up to 100 Hz in full-frame mode), coupled by a fiber optic taper to a scintillating Terbium-doped fiber optic plate for excellent stopping power even at high energies. The field of view is 7mm × 8.6mm with a resolution of 9 microns. The sensitivity is 1 e-/x-ray at 35 keV, with a read noise of 2.5 e-/pixel. Standard characterization metrics including dark current, sensitivity, modulation transfer function, and detective quantum efficiency are presented, along with preliminary experimental results.

  10. Faradaurate-940: synthesis, mass spectrometry, electron microscopy, high-energy X-ray diffraction, and X-ray scattering study of Au∼940±20(SR)∼160±4 nanocrystals.

    PubMed

    Kumara, Chanaka; Zuo, Xiaobing; Cullen, David A; Dass, Amala

    2014-06-24

    Obtaining monodisperse nanocrystals and determining their composition to the atomic level and their atomic structure is highly desirable but is generally lacking. Here, we report the discovery and comprehensive characterization of a 2.9 nm plasmonic nanocrystal with a composition of Au940±20(SCH2CH2Ph)160±4, which is the largest mass spectrometrically characterized gold thiolate nanoparticle produced to date. The compositional assignment has been made using electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry (MS). The MS results show an unprecedented size monodispersity, where the number of Au atoms varies by only 40 atoms (940 ± 20). The mass spectrometrically determined composition and size are supported by aberration-corrected scanning transmission electron microscopy (STEM) and synchrotron-based methods such as atomic pair distribution function (PDF) and small-angle X-ray scattering (SAXS). Lower-resolution STEM images show an ensemble of particles-1000s per frame-visually demonstrating monodispersity. Modeling of SAXS data on statistically significant nanoparticle population-approximately 10(12) individual nanoparticles-shows that the diameter is 3.0 ± 0.2 nm, supporting mass spectrometry and electron microscopy results on monodispersity. Atomic PDF based on high-energy X-ray diffraction experiments shows decent match with either a Marks decahedral or truncated octahedral structure. Atomic resolution STEM images of single particles and their fast Fourier transform suggest face-centered cubic arrangement. UV-visible spectroscopy data show that Faradaurate-940 supports a surface plasmon resonance peak at ̃505 nm. These monodisperse plasmonic nanoparticles minimize averaging effects and have potential application in solar cells, nano-optical devices, catalysis, and drug delivery. PMID:24813022

  11. Monochromatic x-ray radiography of laser-driven spherical targets using high-energy, picoseconds LFEX laser

    NASA Astrophysics Data System (ADS)

    Sawada, Hiroshi; Fujioka, S.; Lee, S.; Arikawa, Y.; Shigemori, K.; Nagatomo, H.; Nishimura, H.; Sunahara, A.; Theobald, W.; Perez, F.; Patel, P. K.; Beg, F. N.

    2015-11-01

    Formation of a high density fusion fuel is essential in both conventional and advanced Inertial Confinement Fusion (ICF) schemes for the self-sustaining fusion process. In cone-guided Fast Ignition (FI), a metal cone is attached to a spherical target to maintain the path for the injection of an intense short-pulse ignition laser from blow-off plasma created when nanoseconds compression lasers drive the target. We have measured a temporal evolution of a compressed deuterated carbon (CD) sphere using 4.5 keV K-alpha radiography with the Kilo-Joule, picosecond LFEX laser at the Institute of Laser Engineering. A 200 μm CD sphere attached to the tip of a Au cone was directly driven by 9 Gekko XII beams with 300 J/beam in a 1.3 ns Gaussian pulse. The LFEX laser irradiated on a Ti foil to generate 4.51 Ti K-alpha x-ray. By varying the delay between the compression and backlighter lasers, the measured radiograph images show an increase of the areal density of the imploded target. The detail of the quantitative analyses to infer the areal density and comparisons to hydrodynamics simulations will be presented. This work was performed with the support and under the auspices of the NIFS Collaboration Research program (NIFS13KUGK072). H.S. was supported by the UNR's International Activities Grant program.

  12. New Science Case for the Micro-X High Energy Resolution Microcalorimeter X-ray Imaging Rocket

    NASA Astrophysics Data System (ADS)

    Figueroa-Feliciano, E.; Adams, J. S.; Baker, R.; Bandler, S. R.; DeLaney, T. A.; Dewey, D.; Doriese, W. B.; Eckart, M. E.; Galeazzi, M.; Goeke, R.; Hamersma, R.; Hilton, G. C.; Hwang, U.; Irwin, K. D.; Kelley, R. L.; Kilbourne, C. A.; Leman, S. W.; McCammon, D.; Okajima, T.; Porter, F. S.; Reintsema, C. D.; Rutherford, J. M.; Saab, T.; Serlemitsos, P.; Soong, Y.; Trowbridge, S. N.; Wikus, P.

    2009-12-01

    The Micro-X sounding rocket payload will be launched on January 18, 2011 to make the first observation of an astronomical target with Transition-Edge Sensor (TES) X-ray microcalorimeters. The 128 pixel TES array lies at the focus of a 2.165 m focal length conical imaging mirror with a 0.2-3.0 keV bandpass. The spectral resolution of the TES array will be between 2 and 4 eV at 1 keV. Our scientific program is focused on high-spectral resolution observations of extended sources. For supernova remnants (SNRs) our scientific objectives are to map the velocity structure of the ejecta, and study both elemental abundances and the thermodynamic and ionization state of the plasma through plasma line diagnostics. For clusters of galaxies, Micro-X can uniquely study turbulence, velocities, and the temperature phases of the plasma. For our initial flight, we have changed our target from the bright eastern knot to a recently discovered ejecta region in the Puppis A SNR. The target of the second flight in mid-2012 is M87, the center of the Virgo Cluster. The third flight, in early 2014, will make an observation of the Cas A SNR. In this contribution we discuss the science objectives of our first flight.

  13. An Observation of the Soft X-ray Diffuse Background with High Energy Resolution Micro-calorimeters

    NASA Astrophysics Data System (ADS)

    Galeazzi, M.; Almy, R.; Apodaca, E.; Bergmann Tiest, W.; Deiker, S.; Lesser, A.; McCammon, D.; Sanders, W. T.; Figueroa, E.; Kelley, R. L.; Porter, F. S.; Stahle, C. K.; Szymkowiak, A. E.

    2000-10-01

    A high spectral resolution observation of the diffuse X-ray background in the energy range 30-1000 eV has been performed using an array of thirty-six cryogenic micro-calorimeters flown on a sounding rocket. The effective area of the detectors is 0.308 cm2 and a composite spectrum of ~1 steradian of the background centered at l=90o, b=+60o was obtained with a net energy resolution of ~9 eV FWHM. The target area includes bright 1/4 keV regions, but avoids Loop I and the North Polar Spur. With 100 s of on-target observation it has been possible to clearly detect lines of C VI, O VII, and O VIII with intensities of 5.4 +/- 2.3, 5.0 +/- 0.9, and 1.6 +/- 0.4 photons cm2 s-1 sr-1 respectively. The oxygen lines alone account for a majority of the diffuse background observed in the ROSAT R4 band that is not due to extragalactic discrete sources. Upper limits on Fe lines appear inconsistent with normal abundances. The interpretation of the spectrum below 300 eV is still under investigation. Preliminary results on emission from the local hot bubble and an observation on the possible existence of interacting dark matter will be presented.

  14. Observational Signatures of High-Energy Emission during the Shallow Decay Phase of Gamma-Ray Burst X-Ray Afterglows

    NASA Astrophysics Data System (ADS)

    Yu, Y. W.; Liu, X. W.; Dai, Z. G.

    2007-12-01

    The widely existing shallow decay phase of the X-ray afterglows of gamma-ray bursts (GRBs) is generally accepted to be due to long-lasting energy injection. The outflows carrying the injecting energy, based on the component that is dominant in energy, fall into two possible types: baryon-dominated and lepton-dominated ones. The former type of outflow could be ejecta that is ejected during the prompt phase of a GRB and consists of a series of baryonic shells with a distribution of Lorentz factors, and the latter type could be an electron-positron pair wind that is driven by the postburst central engine. We here provide a unified description for the dynamics of fireballs based on these two types of energy injection and calculate the corresponding high-energy photon emission by considering synchrotron radiation and inverse Compton scattering (including synchrotron self-Compton and combined inverse Compton) of electrons. We find that, in the two energy-injection models, there is a plateau (even a hump) in high-energy light curves during the X-ray shallow decay phase. In particular, a considerable fraction of the injecting energy in the lepton-dominated model can be shared by the long-lasting reverse shock since it is relativistic. Furthermore, almost all of the energy of the reverse shock is carried by leptons, and thus, the inverse Compton emission is enhanced dramatically. Therefore, this model predicts more significant high-energy afterglow emission than the baryon-dominated model. We argue that these observational signatures would be used to discriminate between different energy-injection models in the upcoming Gamma-Ray Large Area Space Telescope (GLAST) era.

  15. Comparative Studies of Hard X-Ray Spectral Evolution in Solar Flares with High-Energy Proton Events Observed at Earth

    NASA Astrophysics Data System (ADS)

    Kiplinger, Alan L.

    1995-11-01

    This paper presents the results of two extensive studies of hard X-ray spectral evolution in solar flares and their associations with energetic interplanetary proton events. The focus of this work is to establish the degree to which events that display progressively hardening hard X-ray spectra, at any time and over all observable timescales, are associated with high-energy interplanetary proton events. The first study examined a sample of 152 hard X-ray flares well observed with the HXRBS instrument on the Solar Maximum Mission (SMM). The study showed that 22 events revealed a progressive spectral hardening either over flux peaks (i.e., a soft-hard- harder spectral evolution) or during flux decays and that 18 of these 22 events (82%) had associated 10 MeV proton events or enhancements. Conversely, the absence of spectral hardening is associated with the absence of interplanetary protons with 124 of the 130 remaining flares (95.4%). Since the hard X-ray counting rate threshold of the first study was sufficiently high (5000 counts s-1) to exclude many flares (more than 36%) associated with the largest interplanetary proton events, a second study was conducted using 193 less intense HXRBS events (a one out of three sample) and their associations with only large proton events. This study also identifies events with progressive spectral hardening. It also employs selection criteria suggested by the results of the first study to "predict" which flares would or would not have associated large proton events. This prescription for "predicting" proton events did so correctly for four large (SESC qualified) proton events, missed none, and produced only one "false alarm" in which the criteria were met but only a small proton event was seen at earth. Thus, a correct "prediction" was made for all but one of the 193 events. The results of the first study are then combined with the weighted results of the one out of three study, using the same selection criteria, to project

  16. High Energy Resolution Hard X-Ray and Gamma-Ray Imagers Using CdTe Diode Devices

    NASA Astrophysics Data System (ADS)

    Watanabe, Shin; Ishikawa, Shin-Nosuke; Aono, Hiroyuki; Takeda, Shin'ichiro; Odaka, Hirokazu; Kokubun, Motohide; Takahashi, Tadayuki; Nakazawa, Kazuhiro; Tajima, Hiroyasu; Onishi, Mitsunobu; Kuroda, Yoshikatsu

    2009-06-01

    We developed CdTe double-sided strip detectors (DSDs or cross strip detectors) and evaluated their spectral and imaging performance for hard X-rays and gamma-rays. Though the double-sided strip configuration is suitable for imagers with a fine position resolution and a large detection area, CdTe diode DSDs with indium (In) anodes have yet to be realized due to the difficulty posed by the segmented In anodes. CdTe diode devices with aluminum (Al) anodes were recently established, followed by a CdTe device in which the Al anodes could be segmented into strips. We developed CdTe double-sided strip devices having Pt cathode strips and Al anode strips, and assembled prototype CdTe DSDs. These prototypes have a strip pitch of 400 micrometer. Signals from the strips are processed with analog ASICs (application specific integrated circuits). We have successfully performed gamma-ray imaging spectroscopy with a position resolution of 400 micrometer. Energy resolution of 1.8 keV (FWHM: full width at half maximum) was obtained at 59.54 keV. Moreover, the possibility of improved spectral performance by utilizing the energy information of both side strips was demonstrated. We designed and fabricated a new analog ASIC, VA32TA6, for the readout of semiconductor detectors, which is also suitable for DSDs. A new feature of the ASIC is its internal ADC function. We confirmed this function and good noise performance that reaches an equivalent noise charge of 110 e- under the condition of 3-4 pF input capacitance.

  17. Local structure and lattice dynamics study of low dimensional materials using atomic pair distribution function and high energy resolution inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Shi, Chenyang

    Structure and dynamics lie at the heart of the materials science. A detailed knowledge of both subjects would be foundational in understanding the materials' properties and predicting their potential applications. However, the task becomes increasingly dicult as the particle size is reduced to the nanometer scale. For nanostructured materials their laboratory x-ray scattering patterns are overlapped and broadened, making structure determination impossible. Atomic pair distribution function technique based on either synchrotron x-ray or neutron scattering data is known as the tool of choice for probing local structures. However, to solve the "structure problem" in low-dimensional materials with PDF is still challenging. For example for 2D materials of interest in this thesis the crystallographic modeling approach often yields unphysical thermal factors along stacking direction where new chemical intuitions about their actual structures and new modeling methodology/program are needed. Beyond this, lattice dynamical investigations on nanosized particles are extremely dicult. Laboratory tools such as Raman and infra-red only probe phonons at Brillouin zone center. Although in literature there are a great number of theoretical studies of their vibrational properties based on either empirical force elds or density functional theory, various approximations made in theories make the theoretical predictions less reliable. Also, there lacks the direct experiment result to validate the theory against. In this thesis, we studied the structure and dynamics of a wide variety of technologically relevant low-dimensional materials through synchrotron based x-ray PDF and high energy resolution inelastic x-ray scattering (HERIX) techniques. By collecting PDF data and employing advanced modeling program such as DiPy-CMI, we successfully determined the atomic structures of (i) emerging Ti3C2, Nb4C3 MXenes (transition metal carbides and/or nitrides) that are promising for energy storage

  18. XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465

    SciTech Connect

    Funk, S.; Hinton, J.A.; Puhlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.; Funk, S.; Hinton, J.A.; Puehlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.

    2007-03-05

    We present X-ray observations of the as of yet unidentified very high-energy (VHE) {gamma}-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ksec XMM-Newton observation of HESS J1640-465 in September 2005 represents a significant improvement in sensitivity and angular resolution over previous ASCA studies in this region. These new data show a hard-spectrum X-ray emitting object at the centroid of the H.E.S.S. source, within the shell of the radio Supernova Remnant (SNR) G338.3-0.0. This object is consistent with the position and flux previously measured by both ASCA and Swift-XRT but is now shown to be significantly extended. We argue that this object is very likely the counterpart to HESS J1640-465 and that both objects may represent the Pulsar Wind Nebula of an as of yet undiscovered pulsar associated with G338.3-0.0.

  19. Ex-Situ Stress Measurements in Polycrystalline Ceramics Using Photo-Stimulated Luminescence Spectroscopy and High-Energy X-Rays

    SciTech Connect

    Raghavan, Seetha; Imbrie, Peter K.

    2009-09-14

    The photo-stimulated luminescence spectroscopy (PSLS) technique provides the means to establish stress dependencies of the well-known R-line peak positions in polycrystalline alumina. The uniaxial compression tests presented in this paper, which determine the coefficients describing this piezospectroscopic (PS) behavior, tackle two previously unexplored areas. Firstly, the vibronic band peaks in the emission spectrum are introduced here, and the PS coefficients of several peaks within these bands are established. These results set the foundation for the exploitation of vibronic band peakshifts, along with the R-lines, in order to provide the non-symmetric components of the stress tensor and therefore the measurement of the complete stress state in polycrystalline alumina. Secondly, high-energy X-rays serve as an ex-situ stress measurement method upon which the optical fluorescence shifts are based, thereby advancing the accuracy of PS coefficient determination in a unique approach. The results of PSLS and synchrotron X-ray experiments are presented here and used in conjunction to reveal new information on the PS behavior of polycrystalline alumina.

  20. Gamma-ray emission from globular clusters. Shock high energy emission from the Be-Star/Pulsar System PSR 1259-63. Echoes in x-ray novae

    NASA Technical Reports Server (NTRS)

    Kaaret, Philip

    1995-01-01

    This grant covers work on the Compton phase 3 investigation, 'Shock High Energy Emission from the Be- Star/Pulsar System PSR 1259-63' and cycle 4 investigations 'Diffuse Gamma-Ray Emission at High Latitudes' and 'Echoes in X-Ray Novae'. Work under the investigation 'Diffuse Gamma-Ray Emission at High Latitudes' has lead to the publication of a paper (attached), describing gamma-ray emissivity variations in the northern galactic hemisphere. Using archival EGRET data, we have found a large irregular region of enhanced gamma-ray emissivity at energies greater 100 MeV. This is the first observation of local structure in the gamma-ray emissivity. Work under the investigation 'Echoes in X-Ray Novae' is proceeding with analysis of data from OSSE from the transient source GRO J1655-40. The outburst of this source last fall triggered this Target of Opportunity investigation. Preliminary spectral analysis shows emission out to 600 keV and a pure power low spectrum with no evidence of an exponential cutoff. Work is complete on the analysis of BATSE data from the Be-Star/Pulsar Sustem PSR 1259-63.

  1. High-Energy X-Ray Detection of G359.89-0.08 (SGR A-E): Magnetic Flux Tube Emission Powered by Cosmic Rays?

    NASA Technical Reports Server (NTRS)

    Zhang, Shuo; Hailey, Charles J.; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Mori, Kaya; Nynka, Melania; Stern, Daniel; Tomsick, John A; Zhang, Will

    2014-01-01

    We report the first detection of high-energy X-ray (E (is) greater than 10 keV) emission from the Galactic center non-thermal filament G359.89-0.08 (Sgr A-E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to approximately 50 keV during a NuSTAR Galactic center monitoring campaign. The featureless power-law spectrum with a photon index gamma approximately equals 2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is F(sub X) = (2.0 +/- 0.1) × 10(exp -12)erg cm(-2) s(-1) , corresponding to an unabsorbed X-ray luminosity L(sub X) = (2.6+/-0.8)×10(exp 34) erg s(-1) assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A-E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to (is) approximately 100 kyr) with low surface brightness and radii up to (is) approximately 30 pc or MCs illuminated by cosmic rays (CRs) from CR accelerators such as SNRs or Sgr A*.

  2. MAXI INVESTIGATION INTO THE LONG-TERM X-RAY VARIABILITY FROM THE VERY-HIGH-ENERGY γ-RAY BLAZAR Mrk 421

    SciTech Connect

    Isobe, Naoki; Sato, Ryosuke; Ueda, Yoshihiro; Hayashida, Masaaki; Shidatsu, Megumi; Kawamuro, Taiki; Ueno, Shiro; Matsuoka, Masaru; Sugizaki, Mutsumi; Sugimoto, Juri; Mihara, Tatehiro; Negoro, Hitoshi

    2015-01-01

    The archetypical very-high-energy γ-ray blazar Mrk 421 was monitored for more than three years with the Gas Slit Camera on board Monitor of All Sky X-ray Image (MAXI), and its long-term X-ray variability was investigated. The MAXI light curve in the 3-10 keV range was transformed into the periodogram in the frequency range f = 1 × 10{sup –8}-2 × 10{sup –6} Hz. The artifacts on the periodogram, resulting from data gaps in the observed light curve, were extensively simulated for variations with a power-law-like power spectrum density (PSD). By comparing the observed and simulated periodograms, the PSD index was evaluated as α = 1.60 ± 0.25. This index is smaller than that obtained in the higher-frequency range (f ≳ 1 × 10{sup –5} Hz), namely, α = 2.14 ± 0.06 in the 1998 ASCA observation of the object. The MAXI data impose a lower limit on the PSD break at f {sub b} = 5 × 10{sup –6} Hz, consistent with the break of f {sub b} = 9.5 × 10{sup –6} Hz suggested from the ASCA data. The low-frequency PSD index of Mrk 421 derived with MAXI falls well within the range of typical values among nearby Seyfert galaxies (α = 1-2). The physical implications from these results are briefly discussed.

  3. The high energy replicated optics to explore the sun mission: a hard x-ray balloon-borne telescope

    NASA Astrophysics Data System (ADS)

    Christe, Steven D.; Shih, Albert; Rodriguez, Marcello; Cramer, Alex; Gregory, Kyle; Edgerton, Melissa; Gaskin, Jessica; Wilson-Hodge, Colleen; Apple, Jeff; Stevenson Chavis, Katherine; Jackson, Amanda; Smith, Leigh; Dietz, Kurt; O'Connor, Brian; Sobey, Alex; Koehler, Heather; Ramsey, Brian

    2013-09-01

    Set to fly in the Fall of 2013 from Ft. Sumner, NM, the High Energy Replicated Optics to Explore the Sun (HEROES) mission is a collaborative effort between the NASA Marshall Space Flight Center and the Goddard Space Flight Center to upgrade an existing payload, the High Energy Replicated Optics (HERO) balloon-borne telescope, to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES science payload consists of 8 mirror modules, housing a total of 109 grazing-incidence optics. These modules are mounted on a carbon-fiber and Aluminum optical bench 6 m from a matching array of high pressure xenon gas scintillation proportional counters, which serve as the focal-plane detectors. The HEROES gondola utilizes a differential GPS system (backed by a magnetometer) for coarse pointing in the azimuth and a shaft angle encoder plus inclinometer provides the coarse elevation. The HEROES payload will incorporate a new solar aspect system to supplement the existing star camera, for fine pointing during both the day and night. The overall payload will be discussed as well as the new solar aspect system. This mission is funded by the NASA HOPE (Hands On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  4. High-energy x-ray scattering quantification of in-situ-loading-related strain gradients spanning the dentinoenamel junction (DEJ) in bovine tooth specimens.

    SciTech Connect

    Almer, J. D.; Stock, S. R.; Northeastern Univ.

    2010-08-26

    High energy X-ray scattering (80.7keV photons) at station 1-ID of the Advanced Photon Source quantified internal strains as a function of applied stress in mature bovine tooth. These strains were mapped from dentin through the dentinoenamel junction (DEJ) into enamel as a function of applied compressive stress in two small parallelepiped specimens. One specimen was loaded perpendicular to the DEJ and the second parallel to the DEJ. Internal strains in enamel and dentin increased and, as expected from the relative values of the Young's modulus, the observed strains were much higher in dentin than in enamel. Large strain gradients were observed across the DEJ, and the data suggest that the mantle dentin-DEJ-aprismatic enamel structure may shield the near-surface volume of the enamel from large strains. In the enamel, drops in internal strain for applied stresses above 40MPa also suggest that this structure had cracked.

  5. Structural investigations of interfaces in Fe{sub 90}Sc{sub 10} nanoglasses using high-energy x-ray diffraction

    SciTech Connect

    Ghafari, M.; Gleiter, H.; Feng, T.; Kohara, S.; Kamali, S.

    2012-03-26

    High-resolution diffraction experiments of Fe{sub 90}Sc{sub 10} nanoglasses and rapidly quenched metallic glasses as reference materials have been performed using high-energy x-rays with a wavelength of 0.21 Angst from a synchrotron radiation source. Nanoglasses are amorphous alloys with a significant fraction of interfaces on the nanometer scale. The short- and intermediate-range orders of a nanoglass are different from the well known amorphous materials produced by rapid quenching from the melt. These structural modifications have significant influence on the physical properties. In this paper, the short- and intermediate-range orders of the nanoglass Fe{sub 90}Sc{sub 10} and the reference metallic glass Fe{sub 90}Sc{sub 10} alloy prepared by rapid quenching are discussed.

  6. Monte Carlo characterizations mapping of the (γ,n) and (n,γ) photonuclear reactions in the high energy X-ray radiation therapy

    PubMed Central

    Ghiasi, Hosein

    2013-01-01

    Aim The aim of this work was to map the characteristics of (n,γ) and (γ,n) reactions in a high energy photon radiation therapy. Background Photoneutrons produced in the high energy X-Ray radiation therapy may damage patients and staff. It is due to high RBE of the produced neutrons according to their energy and isotropic emission. Characterization of the photoneutrons can help us in appropriate shielding. Materials and methods This study focused on the photoneutron and capture gamma ray phenomena. Characteristics such as dose value, fluence and spectra of both the neutrons and the by produced prompt gamma ray were described. Results and discussion Neutron and prompt gamma spectra in different points showed the neutrons to be thermalized when increasing the distance from the linac. Energy of the neutrons changed from about 0.6 MeV at the isocentre to around 10−08 MeV at the outer door position. Although the neutrons were found as fast neutrons, their spectra showed they were thermal neutrons at the outer door position. Additionally, it was seen that the energy of the gamma rays is higher than the scattered X-ray energy. The energy of gamma rays was seen to be up to 10 MeV while the linac photons had energy lower than 1 MeV. Neutron source strength obtained in this work was in good agreement with the published data, which may be a confirmation of our simulation accuracy. Conclusion The study showed that the Monte Carlo simulation can be applied in the radiotherapy and industrial radiation works as a useful and precise estimator. We also concluded that the dose from the prompt gamma ray at the outer door location is higher than the scattered radiation from the linac and should be considered in the shielding. PMID:24936317

  7. Predicting Fracture Toughness of TRIP 800 using Phase Properties Characterized by In-Situ High Energy X-Ray Diffraction

    SciTech Connect

    Soulami, Ayoub; Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Ren, Yang; Wang, Yan-Dong

    2010-05-01

    TRansformation Induced Plasticity (TRIP) steel is a typical representative of 1st generation advanced high strength steel (AHSS) which exhibits a combination of high strength and excellent ductility due to its multiphase microstructure. In this paper, we study the crack propagation behavior and fracture resistance of a TRIP 800 steel using a microstructure-based finite element method with the various phase properties characterized by in-situ high energy Xray diffraction (HEXRD) technique. Uniaxial tensile tests on the notched TRIP 800 sheet specimens were also conducted, and the experimentally measured tensile properties and R-curves (Resistance curves) were used to calibrate the modeling parameters and to validate the overall modeling results. The comparison between the simulated and experimentally measured results suggests that the micromechanics based modeling procedure can well capture the overall complex crack propagation behaviors and the fracture resistance of TRIP steels. The methodology adopted here may be used to estimate the fracture resistance of various multiphase materials.

  8. Determination of platinum, palladium, and rhodium in automotive catalysts using high-energy secondary target X-ray fluorescence spectrometry.

    PubMed

    Van Meel, Katleen; Smekens, Anne; Behets, Marc; Kazandjian, Paul; Van Grieken, René

    2007-08-15

    A fast and direct determination procedure for precious metals in spent automotive catalyst was developed using the novel high-energy polarized-beam XRF. A sample preparation method working directly on the ground material was optimized. The material was pressed as a pellet using wax as a binder; no internal standard was added. The standards for this application were available spent automotive catalyst, previously analyzed by ICP-OES to verify their concentration, prepared in the same way as the unknown samples. The investigated concentration ranged from nearly 0 to approximately 2700 ppm for Pt, to 500 ppm for Rh, and to 7500 ppm for Pd. The repeatability of the XRF measurement appeared to be better than 0.5%, while the precision of the whole method was approximately 1%. The accuracy of the XRF method was verified with the well-established (but very time-consuming) ICP-OES method; a good agreement (no difference when using the 95% confidence interval) was found for the results. When using an irradiation time of 500 s for the CsI secondary target and the Zr secondary target, the detection limits for Pt, Pd, and Rh were found to be better than 5 ppm. PMID:17628117

  9. High-energy monitoring of NGC 4593 with XMM-Newton and NuSTAR. X-ray spectral analysis

    NASA Astrophysics Data System (ADS)

    Ursini, F.; Petrucci, P.-O.; Matt, G.; Bianchi, S.; Cappi, M.; De Marco, B.; De Rosa, A.; Malzac, J.; Marinucci, A.; Ponti, G.; Tortosa, A.

    2016-08-01

    We present results from a joint XMM-Newton/NuSTAR monitoring of the Seyfert 1 NGC 4593, consisting of 5 × 20 ks simultaneous observations spaced by two days, performed in January 2015. The source is variable, both in flux and spectral shape, on time-scales down to a few ks and with a clear softer-when-brighter behaviour. In agreement with past observations, we find the presence of a warm absorber well described by a two-phase ionized outflow. The source exhibits a cold, narrow and constant Fe K α line at 6.4 keV, and a broad component is also detected. The broad-band (0.3-79 keV) spectrum is well described by a primary power law with Γ ≃ 1.6 - 1.8 and an exponential cut-off varying from 90^{+ 40}_{- 20} keV to >700 keV, two distinct reflection components, and a variable soft excess correlated with the primary power law. This campaign shows that probing the variability of Seyfert 1 galaxies on different time-scales is of prime importance to investigate the high-energy emission of AGNs.

  10. The high energy spherical grating monochromator minus A new source of soft x rays at Daresbury (abstract)

    SciTech Connect

    Surman, M.; Cragg-Hine, I.; Singh, J.; Bowler, B.; Padmore, H.A.; Norman, D. ); Johnson, A.L.; Atrei, A.; Walter, W.K.; King, D.A. ); Davis, R.; Purcell, K.G.; Thornton, G. )

    1992-01-01

    In this article we report the characteristics of the new High Energy Spherical Grating Monochromator beam line on the SRS. The instrument, which has no entrance slit, was designed to provide high photon flux with small spot size, in the energy range covering the 1s binding energies of carbon, nitrogen, oxygen, and fluorine. Radiation from a bending magnet is horizontally focused onto the exit slit by a long, Pt-coated meridian cylinder ({ital R}=299 m, 2 mrad horiz. aperture, 2{degree} glancing angle). The light is vertically diffracted and focused by one of three interchangeable spherical gratings (1050, 1500, and 1800 lines mm{sup {minus}1}) operating in negative order. Finally, the light is refocused by an ellipsoidal mirror. The photon flux, determined with copper and carbon photocathodes, is presented for the three gratings. Useful flux is obtained in the range 250--1200 eV, with intensity maxima for each grating at 600, 700, and 800 eV of 11, 9, and 5{times}10{sup 10} photons s{sup {minus}1} per 100-mA stored beam into a band pass of 0.05%. The influence of contaminants which are present on the optical elements is discussed, together with details of beam line operating conditions which minimize the build up of such contaminants. Photoabsorption and photoemission measurements indicate a high (up to 30%) second order and some third order light content. Resolution determinations obtained from photoabsorption measurements are presented. Although features as narrow as 250 meV have been resolved, the resolving power of the instrument is found to depend strongly on stored beam current. We suggest this may be due to electron beam (i.e., source) blow-up. We critically discuss the suitability of the new facility for surface EXAFS of low {ital Z} adsorbates, in particular above the carbon, nitrogen, and oxygen 1s edges, using examples from recent studies which have been undertaken on the beamline.

  11. High-energy resolution X-ray absorption and emission spectroscopy reveals insight into unique selectivity of La-based nanoparticles for CO2

    PubMed Central

    Hirsch, Ofer; Kvashnina, Kristina O.; Luo, Li; Süess, Martin J.; Glatzel, Pieter; Koziej, Dorota

    2015-01-01

    The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications. PMID:26668362

  12. High-energy magnetic excitations in overdoped La2 -xSrxCuO4 studied by neutron and resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Wakimoto, S.; Ishii, K.; Kimura, H.; Fujita, M.; Dellea, G.; Kummer, K.; Braicovich, L.; Ghiringhelli, G.; Debeer-Schmitt, L. M.; Granroth, G. E.

    2015-05-01

    We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L3 edge to study high-energy magnetic excitations at energy transfers of more than 100 meV for overdoped La2 -xSrxCuO4 with x =0.25 (Tc=15 K) and x =0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic excitations up to ˜250 meV for x =0.25 . Although the width in the momentum direction is large, the peak positions along the (π ,π ) direction agree with the dispersion relation of the spin wave in the nondoped La2CuO4 (LCO), which is consistent with the previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π ,π ) and (π ,0 ) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π ,0 ) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π ,π ) direction probed by RIXS appears to be less dispersive and the excitation energy is lower than the spin wave of LCO near (π /2 ,π /2 ) . Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic excitation in the (π ,π ) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge excitations exist in the same energy range of magnetic excitations, reflecting the itinerant character of the overdoped sample. A possible anisotropy in the charge excitation intensity might explain the apparent differences in the paramagnon dispersion in the (π ,π ) direction as detected by the x-ray scattering.

  13. High-energy X-ray detection of G359.89–0.08 (SGR A–E): Magnetic flux tube emission powered by cosmic rays?

    SciTech Connect

    Zhang, Shuo; Hailey, Charles J.; Gotthelf, Eric V.; Mori, Kaya; Nynka, Melania; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Tomsick, John A.; Christensen, Finn E.; Harrison, Fiona A.; Stern, Daniel; Zhang, William W.

    2014-03-20

    We report the first detection of high-energy X-ray (E > 10 keV) emission from the Galactic center non-thermal filament G359.89–0.08 (Sgr A–E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to ∼50 keV during a NuSTAR Galactic center monitoring campaign. The featureless power-law spectrum with a photon index Γ ≈ 2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is F{sub X} = (2.0 ± 0.1) × 10{sup –12} erg cm{sup –2} s{sup –1}, corresponding to an unabsorbed X-ray luminosity L{sub X} = (2.6 ± 0.8) × 10{sup 34} erg s{sup –1} assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A–E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to ∼100 kyr) with low surface brightness and radii up to ∼30 pc or MCs illuminated by cosmic rays (CRs) from CR accelerators such as SNRs or Sgr A*.

  14. Strontium complexation in aqueous solutions and silicate glasses: Insights from high energy-resolution fluorescence detection X-ray spectroscopy and ab-initio modeling

    NASA Astrophysics Data System (ADS)

    Borchert, Manuela; Wilke, Max; Schmidt, Christian; Kvashnina, Kristina; Jahn, Sandro

    2014-10-01

    Although fluid-melt partitioning of trace elements like Sr, Ba, La, and Y is known to be strongly influenced by the fluid and melt chemical composition, their speciation in silicate-saturated fluids is studied insufficiently at high temperatures and pressures. Here, high energy-resolution fluorescence detection-X-ray absorption spectroscopy (HERFD-XAS) has been applied to investigate the local environment of strontium in crystalline model compounds, silicate glasses, and aqueous solutions. Acquisition of Sr K-edge HERFD-XAS spectra of aqueous solutions of SrCl2 and Sr(OH)2, and three aqueous fluids with dissolved silicate components was done in situ at temperatures to 780 °C and pressures to ∼800 MPa using hydrothermal diamond-anvil cells. Experiments were complemented by theoretical spectroscopy calculations using the finite difference method near edge structure (FDMNES) code. This approach was validated for a number of crystalline model compounds. For the silicate glasses and aqueous solutions (SrCl2 and Sr(OH)2), small clusters were examined. Either symmetric or distorted SrO6 clusters were found to describe Sr complexation in peraluminous or peralkaline glasses. However, small ‘static’ clusters seem not to be fully suited to account for the dynamically changing atomic arrangements in aqueous solutions at high temperature. Therefore, ab-initio molecular dynamics simulations were performed and used as input for modeling of X-ray absorption spectra. Analyses of these simulations indicated [SrCl(H2O)6]+ and Sr(OH)2(H2O)4 as the most likely complexes in the chloride and hydroxide solutions, respectively. Analysis of the spectra of the silicate-rich fluids shows that both melt and fluid composition strongly influence Sr complexation. For the silicate-rich fluids, formation of Sr-Cl complexes occurs at low (Na + K)/Cl and (Si + Al)/(Na + K) ratios in the fluid, whereas Sr hydroxide and possibly silicate complexes (similar to those in the silicate glass) are

  15. High energy X-ray diffraction study of a dental ceramics–titanium functional gradient material prepared by field assisted sintering technique

    SciTech Connect

    Witte, K.; Bodnar, W.; Schell, N.; Lang, H.; Burkel, E.

    2014-09-15

    A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is α-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. The crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1) Å, while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2) Å. The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable. - Highlights: • High energy XRD studies of dental ceramics–Ti gradient material consolidated by FAST. • Phase composition, crystallinity and lattice parameters are determined. • Crystallinity increases stepwisely along the gradient following weight fraction of Ti. • Lattice mismatch leading to internal stress is calculated over the whole gradient. • Internal stress in α-Ti embedded in the gradient is smaller than its yield strength.

  16. A derivation of bulk-motion insensitive implosion metrics inferred from neutron and high-energy x-ray emission in a series of high yield implosions on the NIF

    NASA Astrophysics Data System (ADS)

    Springer, P. T.; Macphee, A. G.; Hurricane, O. A.; Callahan, D. A.; Casey, D. T.; Cerjan, C. J.; Dewald, E. L.; Dittrich, T. R.; Doeppner, T.; Edgell, D. H.; Edwards, M. J.; Gaffney, J.; Grim, G. P.; Haan, S.; Hammer, J. H.; Hinkel, D. E.; Berzak Hopkins, L. F.; Jones, O.; Kritcher, A. L.; Le Pape, S.; Ma, T.; Milovich, J.; Munro, D. H.; Pak, A.; Park, H. S.

    2015-11-01

    A suite of nuclear and x-ray data is used to deduce key implosion performance metrics at stagnation including the hotspot pressure, energy, and the role of alpha heating on producing the observed yield. Key to this analysis is a determination of the burn-averaged temperature of the hot plasma so that the nuclear reactivity and yield can then be used to deduce the plasma density and pressure. In this presentation we examine the systematics of both neutron and high-energy x-ray emission (22 keV x-ray monochromator) from a series of high yield implosions on the NIF. The advantage of incorporating high energy x-rays into the analysis is their insignificant attenuation and insensitivity to bulk flows, thus providing insight as to whether these effects complicate the interpretation of the nuclear data, and that a precipitous drop in their production is expected as the thermal temperature is reduced. A dynamic model for hotspot assembly is developed that incorporates thermal conduction, radiative losses, and alpha heating, which simultaneously matches both neutron and x-ray data with nearly identical nuclear and x-ray derived thermal temperatures. Work performed under the auspices of the USDoE by Lawrence Livermore National Laboratory under contract DE-AC52-07NA273.

  17. Finding concealed high atomic numbered materials hidden in cargo containers using dual-energy high-energy x-rays from a linear accelerator with the unique signature from photofission

    NASA Astrophysics Data System (ADS)

    Clayton, James E.; Bjorkholm, Paul

    2006-05-01

    The Dual Energy X-ray technique employs two X-ray projection images of an object with X-ray energy spectra at a low X-ray energy and a high X-ray energy. The two energies are both high enough to penetrate all cargoes. The endpoint energies for low and high will be approximately 5-6 MeV and 8-9.5 MeV respectively. These energies are chosen such that pair production is the dominant energy loss mechanism for the high energy mode. By defining the ratio of the transmitted X-ray photon R = T high/T low it can be shown that there is a difference in the ratio that will permit the detection of materials that are significantly higher in atomic number than the low to mid atomic numbered elements that normally appear in the stream of commerce. This difference can be used to assist in the automatic detection of high atomic numbered materials. These materials might be a WMD or dirty bomb. When coupled with detectors that can observe the delayed signature of photon induced fission a confirmation of a WMD may be made. The use of the delayed photons and neutrons from Photofission can confirm the presence of Special Nuclear Materials (SNM). The energy required to induce fission in SNM by a photon is approximately 6 MeV with the maximum fission production rate from X-ray photons in the energy range of 12-15 MeV.

  18. Advanced micromechanical model for transformation-induced plasticity steels with application of in-situ high energy x-ray diffraction method

    SciTech Connect

    Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Ren, Yang; Wang, Yan-Dong

    2008-12-01

    Compared to other advanced high-strength steels, TRIP (Transformation-Induced Plasticity) steels exhibit better ductility at a given strength level and can be used to produce complicated automotive parts. This enhanced formability comes from the transformation of retained austenite to martensite during plastic deformation. In this study, as a first step in predicting optimum processing parameters in TRIP steel productions, a micromechanical finite element model is developed based on the actual microstructure of a TRIP 800 steel. The method uses microstructure-based representative volume element (RVE) to capture the complex deformation behavior of TRIP steels. The mechanical properties of the constituent phases of the TRIP 800 steel and the fitting parameters of the martensite transformation kinetics are determined using the synchrotron-based in-situ high-energy X-ray diffraction (HEXRD) measurements of a uniaxial tensile test. The experimental results suggest that the HEXRD technique provides a powerful tool for characterizing the phase transformation and the microstress of each phase of TRIP steels during deformation. The computational results suggest that the response of the RVE well represents the overall macroscopic behavior of the TRIP 800 steel under deformation. The methodology described in this study may be used in studying the effects of the various processing parameters on the macroscopic behaviors of TRIP steels.

  19. Advanced micromechanical model for transformation-induced plasticity steels with application of in-situ high-energy x-ray diffraction method.

    SciTech Connect

    Choi, K. S.; Liu, W. N.; Sun, X.; Khaleel, M.A.; Ren, Y.; Wang, Y.D.; X-Ray Science Division; PNNL; Northeastern Univ.

    2008-12-01

    Compared to other advanced high-strength steels, transformation-induced plasticity (TRIP) steels exhibit better ductility at a given strength level and can be used to produce complicated automotive parts. This enhanced formability comes from the transformation of retained austenite to martensite during plastic deformation. In this study, as a first step in predicting optimum processing parameters in TRIP steel productions, a micromechanical finite element model is developed based on the actual microstructure of a TRIP 800 steel. The method uses a microstructure-based representative volume element (RVE) to capture the complex deformation behavior of TRIP steels. The mechanical properties of the constituent phases of the TRIP 800 steel and the fitting parameters describing the martensite transformation kinetics are determined using the synchrotron-based in-situ high-energy X-ray diffraction (HEXRD) experiments performed under a uniaxial tensile deformation. The experimental results suggest that the HEXRD technique provides a powerful tool for characterizing the phase transformation behavior and the microstress developed due to the phase-to-phase interaction of TRIP steels during deformation. The computational results suggest that the response of the RVE well represents the overall macroscopic behavior of the TRIP 800 steel under deformation. The methodology described in this study may be extended for studying the effects of the various processing parameters on the macroscopic behaviors of TRIP steels.

  20. High spatial resolution, high energy synchrotron x-ray diffraction characterization of residual strains and stresses in laser shock peened Inconel 718SPF alloy

    NASA Astrophysics Data System (ADS)

    Gill, Amrinder S.; Zhou, Zhong; Lienert, Ulrich; Almer, Jonathan; Lahrman, David F.; Mannava, S. R.; Qian, Dong; Vasudevan, Vijay K.

    2012-04-01

    Laser shock peening (LSP) is an advanced surface enhancement technique used to enhance the fatigue strength of metal parts by imparting deep compressive residual stresses. In the present study, LSP was performed on IN718 SPF alloy, a fine grained nickel-based superalloy, with three different power densities and depth resolved residual strain and stress characterization was conducted using high energy synchrotron x-ray diffraction in beam line 1-ID-C at the Advanced Photon Source at the Argonne National laboratory. A fine probe size and conical slits were used to non-destructively obtain data from specific gauge volumes in the samples, allowing for high-resolution strain measurements. The results show that LSP introduces deep compressive residual stresses and the magnitude and depth of these stresses depend on the energy density of the laser. The LSP induced residual stresses were also simulated using three-dimensional nonlinear finite element analysis, with employment of the Johnson-Cook model for describing the nonlinear materials constitutive behavior. Good agreement between the experimental and simulated data was obtained. These various results are presented and discussed.

  1. Analysis on explosive welded Al/Mg plates in as-received state and after heat treatment using the in situ high-energy X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Zhou, Qiang; Chen, Pengwan; Nie, Zhihua; Lan, Yazhu

    2015-06-01

    The synchrotron-based HEXRD method has a much better angular resolution in the reciprocal space than neutron or traditional laboratory XRD, which creates an opportunity that could precisely study the crystal structure and parameter from the XRD pattern. Due to the high penetration depth of high-energy X-ray, the micro-strain and phase distribution could be determined precisely. In this work, the explosive welded 2024 Al/AZ31 Mg plates, both in as-received state and after heat treatment, were investigated by HEXRD method. The XRD patterns were taken shot-by-shot, going from Al to Mg with step width of 0.1mm. The micro-strain, phase distribution and grain size of each step were estimated and analyzed within the general mechanism of explosive welding. It is interesting to find that the intense texture observed in both cladded and base materials disappeared at the welded interface. Residual stress, which was obviously detected at the interface for the as-received sample, was eliminated after heat treatment. For the as-received sample, the strain of Mg along the path from interface to free surface was different for different Azimuth angle and different crystal orientation; but such variations didn't occur for Al.

  2. Size dependence of structural parameters in fcc and hcp Ru nanoparticles, revealed by Rietveld refinement analysis of high-energy X-ray diffraction data

    NASA Astrophysics Data System (ADS)

    Song, Chulho; Sakata, Osami; Kumara, Loku Singgappulige Rosantha; Kohara, Shinji; Yang, Anli; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

    2016-08-01

    To reveal the origin of the CO oxidation activity of Ruthenium nanoparticles (Ru NPs), we structurally characterized Ru NPs through Rietveld refinement analysis of high-energy X-ray diffraction data. For hexagonal close-packed (hcp) Ru NPs, the CO oxidation activity decreased with decreasing domain surface area. However, for face-centered cubic (fcc) Ru NPs, the CO oxidation activity became stronger with decreasing domain surface area. In comparing fcc Ru NPs with hcp Ru NPs, we found that the hcp Ru NPs of approximately 2 nm, which had a smaller domain surface area and smaller atomic displacement, showed a higher catalytic activity than that of fcc Ru NPs of the same size. In contrast, fcc Ru NPs larger than 3.5 nm, which had a larger domain surface area, lattice distortion, and larger atomic displacement, exhibited higher catalytic activity than that of hcp Ru NPs of the same size. In addition, the fcc Ru NPs had larger atomic displacements than hcp Ru NPs for diameters ranging from 2.2 to 5.4 nm. Enhancement of the CO oxidation activity in fcc Ru NPs may be caused by an increase in imperfections due to lattice distortions of close-packed planes and static atomic displacements.

  3. Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine.

    PubMed

    Wakabayashi, Genichiro; Nohtomi, Akihiro; Yahiro, Eriko; Fujibuchi, Toshioh; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Nakamura, Katsumasa; Hosono, Makoto; Itoh, Tetsuo

    2015-01-01

    The applicability of the activation of an NaI scintillator for neutron monitoring at a clinical linac was investigated experimentally. Thermal neutron fluence rates are derived by measurement of the I-128 activity generated in an NaI scintillator irradiated by neutrons; β-rays from I-128 are detected efficiently by the NaI scintillator. In order to verify the validity of this method for neutron measurement, we irradiated an NaI scintillator at a research reactor, and the neutron fluence rate was estimated. The method was then applied to neutron measurement at a 10-MV linac (Varian Clinac 21EX), and the neutron fluence rate was estimated at the isocenter and at 30 cm from the isocenter. When the scintillator was irradiated directly by high-energy X-rays, the production of I-126 was observed due to photo-nuclear reactions, in addition to the generation of I-128 and Na-24. From the results obtained by these measurements, it was found that the neutron measurement by activation of an NaI scintillator has a great advantage in estimates of a low neutron fluence rate by use of a quick measurement following a short-time irradiation. Also, the future application of this method to quasi real-time monitoring of neutrons during patient treatments at a radiotherapy facility is discussed, as well as the method of evaluation of the neutron dose. PMID:25404493

  4. High energy X-ray diffraction measurement of residual stresses in a monolithic aluminum clad uranium–10 wt% molybdenum fuel plate assembly

    SciTech Connect

    D. W. Brown; M. A. Okuniewski; J. D. Almer; L. Balogh; B. Clausen; J. S. Okasinski; B. H. Rabin

    2013-10-01

    Residual stresses are expected in monolithic, aluminum clad uranium 10 wt% molybdenum (U–10Mo) nuclear fuel plates because of the large mismatch in thermal expansion between the two bonded materials. The full residual stress tensor of the U–10Mo foil in a fuel plate assembly was mapped with 0.1 mm resolution using high-energy (86 keV) X-ray diffraction. The in-plane stresses in the U–10Mo foil are strongly compressive, roughly -250 MPa in the longitudinal direction and -140 MPa in the transverse direction near the center of the fuel foil. The normal component of the stress is weakly compressive near the center of the foil and tensile near the corner. The disparity in the residual stress between the two in-plane directions far from the edges and the tensile normal stress suggest that plastic deformation in the aluminum cladding during fabrication by hot isostatic pressing also contributes to the residual stress field. A tensile in-plane residual stress is presumed to be present in the aluminum cladding to balance the large in-plane compressive stresses in the U–10Mo fuel foil, but cannot be directly measured with the current technique due to large grain size.

  5. A Census of X-ray gas in NGC 1068: Results from 450 ks of Chandra high energy transmission grating observations

    SciTech Connect

    Kallman, T.; Evans, Daniel A.; Marshall, H.; Canizares, C.; Nowak, M.; Schulz, N.; Longinotti, A.

    2014-01-10

    We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating on Chandra. The data show line and radiative recombination continuum emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation, and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(ξ) = 1 to 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3 M {sub ☉} yr{sup –1}, assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

  6. High energy X-ray diffraction study of the relationship between the macroscopic mechanical properties and microstructure of irradiated HT-9 steel

    NASA Astrophysics Data System (ADS)

    Tomchik, C.; Almer, J.; Anderoglu, O.; Balogh, L.; Brown, D. W.; Clausen, B.; Maloy, S. A.; Sisneros, T. A.; Stubbins, J. F.

    2016-07-01

    Samples harvested from an HT-9 fuel test assembly (ACO-3) irradiated for six years in the Fast Flux Test Facility (FFTF) reaching 2-147 dpa at 382-504 °C were deformed in-situ while collecting high-energy X-ray diffraction data to monitor microstructure evolution. With the initiation of plastic deformation, all samples exhibited a clear load transfer from the ferrite matrix to carbide particulate. This behavior was confirmed by modeling of the control material. The evolution of dislocation density in the material as a result of deformation was characterized through full pattern line profile analysis. The dislocation densities increased substantially after deformation, the level of dislocation evolution observed was highly dependent upon the irradiation temperature of the sample. Differences in both the yield and hardening behavior between samples irradiated at higher and lower temperatures suggest the existence of a transition in tensile behavior at an irradiation temperature near 420 °C dividing regions of distinct damage effects.

  7. Size dependence of structural parameters in fcc and hcp Ru nanoparticles, revealed by Rietveld refinement analysis of high-energy X-ray diffraction data

    PubMed Central

    Song, Chulho; Sakata, Osami; Kumara, Loku Singgappulige Rosantha; Kohara, Shinji; Yang, Anli; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

    2016-01-01

    To reveal the origin of the CO oxidation activity of Ruthenium nanoparticles (Ru NPs), we structurally characterized Ru NPs through Rietveld refinement analysis of high-energy X-ray diffraction data. For hexagonal close-packed (hcp) Ru NPs, the CO oxidation activity decreased with decreasing domain surface area. However, for face-centered cubic (fcc) Ru NPs, the CO oxidation activity became stronger with decreasing domain surface area. In comparing fcc Ru NPs with hcp Ru NPs, we found that the hcp Ru NPs of approximately 2 nm, which had a smaller domain surface area and smaller atomic displacement, showed a higher catalytic activity than that of fcc Ru NPs of the same size. In contrast, fcc Ru NPs larger than 3.5 nm, which had a larger domain surface area, lattice distortion, and larger atomic displacement, exhibited higher catalytic activity than that of hcp Ru NPs of the same size. In addition, the fcc Ru NPs had larger atomic displacements than hcp Ru NPs for diameters ranging from 2.2 to 5.4 nm. Enhancement of the CO oxidation activity in fcc Ru NPs may be caused by an increase in imperfections due to lattice distortions of close-packed planes and static atomic displacements. PMID:27506187

  8. High-energy X-ray diffuse scattering studies on deformation-induced spatially confined martensitic transformations in multifunctional Ti-24Nb-4Zr-8Sn alloy

    SciTech Connect

    Liu, J. P.; Wang, Y. D.; Hao, Y. L.; Wang, H. L.; Wang, Y.; Nie, Z. H.; Su, R.; Wang, D.; Ren, Y.; Lu, Z. P.; Wang, J. G.; Hui, X. D.; Yang, R.

    2014-12-01

    Two main explanations exist for the deformation mechanisms in Ti-Nb-based gum metals, i.e. the formation of reversible nanodisturbance and reversible stress-induced martensitic transformation. In this work, we used the in situ synchrotron-based high-energy X-ray diffuse-scattering technique to reveal the existence of a specific deformation mechanism, i.e. deformation-induced spatially confined martensitic transformations, in Ti-24Nb-4Zr-8Sn-0.10O single crystals with cubic 13 parent phase, which explains well some anomalous mechanical properties of the alloy such as low elastic modulus and nonlinear superelasticity. Two kinds of nanosized martensites with different crystal structures were found during uniaxial tensile loading along the [11 0](beta) axis at room temperature and 190 K, respectively. The detailed changes in the martensitic phase transformation characteristics and the transformation kinetics were experimentally observed at different temperatures. The domain switch from non-modulated martensite to a modulated one occurred at 190 K, with its physical origin attributed to the heterogeneity of local phonon softening depending on temperature and inhomogeneous composition in the parent phase. An in-depth understanding of the formation of stress-induced spatially confined nanosized martensites with a large gradient in chemical composition may benefit designs of high-strength and high-ductility alloys. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. In situ observation of formation and growth of oxygen nano-precipitates in silicon with high energy X-rays from a laboratory source

    NASA Astrophysics Data System (ADS)

    Grillenberger, H.; Knerer, D.; Magerl, A.

    2011-03-01

    A focusing Laue diffractometer is used to analyze the strain field in silicon in situ during different thermal treatments up to 1000 °C. A high energy X-ray tube is the source for this so-called strain field diffraction (SFD) setup. The SFD setup is utilized to monitor in situ the strain generated by growing oxygen precipitates (bulk micro defects, BMD) in Czochralski grown silicon. Subsequently, the in situ investigated samples are characterized subsequently with ex situ techniques including FT-IR, infra red light scattering tomography (IR-LST) and TEM. By correlating enhancements of the integrated intensity (EII) of an investigated 220 silicon Bragg peak with BMD diameters obtained with TEM measurements a strong dependency of the total BMD volume and EII is found. The detection limit of the SFD setup is determined at a BMD diameter of 7 nm and a density of 1013 cm-3, and at 40 nm at a density of 108 cm-3. Thus SFD reaches into a detection range only covered by TEM so far and having additional advantages in in situ capability and minimal sample preparation requirements.

  10. Photoionized plasmas induced in neon with extreme ultraviolet and soft X-ray pulses produced using low and high energy laser systems

    SciTech Connect

    Bartnik, A.; Wachulak, P.; Fok, T.; Węgrzyński, Ł.; Fiedorowicz, H.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Dudzak, R.; Dostal, J.; Krousky, E.; Skala, J.; Ullschmied, J.; Hrebicek, J.; Medrik, T.

    2015-04-15

    A comparative study of photoionized plasmas created by two soft X-ray and extreme ultraviolet (SXR/EUV) laser plasma sources with different parameters is presented. The two sources are based on double-stream Xe/He gas-puff targets irradiated with high (500 J/0.3 ns) and low energy (10 J/1 ns) laser pulses. In both cases, the SXR/EUV beam irradiated the gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Irradiation of gases resulted in formation of photoionized plasmas emitting radiation in the SXR/EUV range. The measured Ne plasma radiation spectra are dominated by emission lines corresponding to radiative transitions in singly charged ions. A significant difference concerns origin of the lines: K-shell or L-shell emissions occur in case of the high and low energy irradiating system, respectively. In high energy system, the electron density measurements were also performed by laser interferometry, employing a femtosecond laser system. A maximum electron density for Ne plasma reached the value of 2·10{sup 18 }cm{sup −3}. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.

  11. A Census of X-ray Gas in NGC 1068: Results From 450 ks of CHANDRA High Energy Transmisson Grating Observations

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Evans, Daniel A.; Marshall, H.; Canizares, C.; Longinotti, A.; Nowak, M.; Schulz, N.

    2013-01-01

    We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating on Chandra. The data show line and radiative recombination continuum emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation, and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(E ) = 1 to 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3M/yr, assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

  12. High-energy magnetic excitations in overdoped La2-xSrxCuO4 studied by neutron and resonant inelastic X-ray scattering

    DOE PAGESBeta

    Wakimoto, S.; Ishii, K.; Kimura, H.; Fujita, M.; Dellea, G.; Kummer, K.; Braicovich, L.; Ghiringhelli, G.; Debeer-Schmitt, Lisa M.; Granroth, Garrett E.

    2015-05-21

    We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L3 edge to study high-energy magnetic excitations at energy transfers of more than 100 meV for overdoped La2₋xSrxCuO4 with x=0.25 (Tc=15 K) and x=0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic excitations up to ~250 meV for x=0.25. Although the width in the momentum direction is large, the peak positions along the (π,π) direction agree with the dispersion relation of the spin wave in the nondoped La2CuO4 (LCO), which is consistent with themore » previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π,π) and (π,0) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π,0) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π,π) direction probed by RIXS appears to be less dispersive and the excitation energy is lower than the spin wave of LCO near (π/2,π/2). Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic excitation in the (π,π) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge excitations exist in the same energy range of magnetic excitations, reflecting the itinerant character of the overdoped sample. Lastly, we find a possible anisotropy in the charge excitation intensity might explain the apparent differences in the paramagnon dispersion in the (π,π) direction as detected by the x-ray scattering.« less

  13. SU-D-BRF-01: Applications of Photonuclear Activation of Biological Tissues in Clinical High-Energy X-Ray Beams

    SciTech Connect

    Veltchev, I; Fourkal, E; Ma, C

    2014-06-01

    Purpose: The commercial availability of high-energy accelerators opens new therapeutic opportunities for X-rays with energies in excess of 15MV. Three clinical beams (Varian 18MV, Elekta SL25, and Top Grade LA45) were compared by the production of photo-activated positron emitters in five types of biological tissues. Methods: The activation studies were performed using FLUKA2011 Monte Carlo suite with beam models designed for the three accelerators. Absolute activity density (Bq/ml) distribution in space was obtained from this study. Additionally, the temporal evolution of all activated species was monitored for cooling times up to 30 minutes. Results: The relative activation contrast of tissue pairs was evaluated for 2Gy of dose at 10cm depth for five tissues (normal, hypoxic, adipose, bone, and lung). In bone the sort-lived isotopes O-15 and P-30 dominated the activity at the early cooling stages. In all tissues 15 minutes post-irradiation the C-11 activity became dominant. Tissues with higher carbon-to-oxygen ratio in their elemental composition became clearly visible in a PET scan at longer cooling times. Radiation treatment of a lung tumor with a hypoxic core was simulated in an anthropomorphic phantom using the LA45 beam model. Increase in the PET counts by more than 50% was measured in the hypoxic volume 15 minutes post-irradiation, demonstrating the benefits of the relative activation contrast concept. Conclusion: LA45 beam is found to produce measurable activation distribution for 2Gy of dose, suitable for tissue type discrimination studies. Maximum activation contrast of 1.7 between hypoxic and normal tissues was measured in a simulated treatment. The absolute activity density values obtained from these Monte Carlo studies suggest that the window of opportunity for a PET scan exists up to 60 minutes after 2Gy of dose is deposited by 45MV X-ray beam. Lung-to-tissue activation contrast can be explored for treatment QA purposes as well.

  14. A K-alpha x-ray source using high energy and high repetition rate laser system for phase contrast imaging

    PubMed Central

    Fourmaux, Sylvain; Kieffer, Jean-Claude; Kincaid, Russell; Krol, Andrzej

    2009-01-01

    K-alpha x-ray sources from laser produced plasmas provide completely new possibilities for x-ray phase-contrast imaging applications. By tightly focusing intense femtosecond laser pulses onto a solid target K-alpha x-ray pulses are generated through the interaction of energetic electrons created in the plasma with the bulk target. In this paper, we present a continuous and efficient Mo K-alpha x-ray source produced by a femtosecond laser system operating at 100 Hz repetition rate with maximum pulse energy of 110 mJ before compression. The source has an x-ray conversion efficiency of greater than 10−5 into K-alpha line emission. In preparation for phase contrast imaging applications, the size of the resultant K-alpha x-ray emission spot has been also characterized. The source exhibits sufficient spatial coherence to observe phase contrast. We observe a relatively small broadening of the K-alpha source size compared to the size of the laser beam itself. Detailed characterization of the source including the x-ray spectrum and the x-ray average yield along with phase contrast images of test objects will be presented. PMID:20046807

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

    NASA Technical Reports Server (NTRS)

    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

  16. THE NuSTAR EXTRAGALACTIC SURVEY: A FIRST SENSITIVE LOOK AT THE HIGH-ENERGY COSMIC X-RAY BACKGROUND POPULATION

    SciTech Connect

    Alexander, D. M.; Del Moro, A.; Lansbury, G. B.; Aird, J.; Stern, D.; Assef, R. J.; Ajello, M.; Boggs, S. E.; Ballantyne, D. R.; Bauer, F. E.; Brandt, W. N.; Christensen, F. E.; Craig, W. W.; Civano, F.; Hickox, R. C.; Comastri, A.; Elvis, M.; Grefenstette, B. W.; Harrison, F. A.; Hailey, C. J.; and others

    2013-08-20

    We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array (NuSTAR) to provide the first sensitive census of the cosmic X-ray background source population at {approx}> 10 keV. We find that these NuSTAR-detected sources are Almost-Equal-To 100 times fainter than those previously detected at {approx}> 10 keV and have a broad range in redshift and luminosity (z = 0.020-2.923 and L{sub 10-40{sub keV}} Almost-Equal-To 4 Multiplication-Sign 10{sup 41}-5 Multiplication-Sign 10{sup 45} erg s{sup -1}); the median redshift and luminosity are z Almost-Equal-To 0.7 and L{sub 10-40{sub keV}} Almost-Equal-To 3 Multiplication-Sign 10{sup 44} erg s{sup -1}, respectively. We characterize these sources on the basis of broad-band Almost-Equal-To 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}, of which Almost-Equal-To 50% are obscured with N{sub H} {approx}> 10{sup 22} cm{sup -2}. However, none of the 10 NuSTAR sources are Compton thick (N{sub H} {approx}> 10{sup 24} cm{sup -2}) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}) selected at {approx}> 10 keV of {approx}< 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame Almost-Equal-To 10-40 keV data for all of the non-beamed sources with L{sub 10-40{sub keV}} > 10{sup 43} erg s{sup -1} to constrain the average strength of reflection; we find R < 1.4 for {Gamma} = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at {approx}> 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of Almost-Equal-To 10{sup 11} M{sub Sun }, a factor Almost-Equal-To 5 times higher than the median stellar mass of nearby high-energy

  17. The NuSTAR Extragalactic Survey: A First Sensitive Look at the High-Energy Cosmic X-Ray Background Population

    NASA Technical Reports Server (NTRS)

    Alexander, D. M.; Stern, D.; DelMoro, A.; Lansbury, G. B.; Assef, R. J.; Aird, J.; Ajello, M.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Christensen, F. E.; Civano, F.; Cosmastri, A.; Craig, W. W.; Elvis, M.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Luo, B.; Madsen, K. K.; Alexander, D. M.; Zhang, W. W.; Eisenhardt, P. R. M.

    2013-01-01

    mass of approximately 10(exp 11) solar mass, a factor approximately 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

  18. V oxidation state in Fe-Ti oxides by high-energy resolution fluorescence-detected X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Bordage, Amélie; Balan, Etienne; de Villiers, Johan P. R.; Cromarty, Robert; Juhin, Amélie; Carvallo, Claire; Calas, Georges; Sunder Raju, P. V.; Glatzel, Pieter

    2011-06-01

    The oxidation state of vanadium in natural and synthetic Fe-Ti oxides is determined using high-energy resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS). Eleven natural magnetite-bearing samples from a borehole of the Main Magnetite Layer of the Bushveld Complex (South Africa), five synthetic Fe oxide samples, and three natural hematite-bearing samples from Dharwar supergroup (India) are investigated. V K edge spectra were recorded on the ID26 beamline at the European Synchrotron Radiation Facility (Grenoble, France), and the pre-edge features were used to determine the local environment and oxidation state of vanadium. In the case of the magnetite samples (natural and synthetic), we show that vanadium is incorporated in the octahedral site of the spinel structure under two oxidation states: +III and +IV. The variations of the pre-edge area are interpreted as various proportions in V3+ and V4+ (between 9.5 and 16.3% of V4+), V3+ being the main oxidation state. In particular, the variations of the V4+/V3+ ratio along the profile of the Main Magnetite Layer seem to follow the crystallization sequence of the layer. In the case of the hematite samples from India, the pre-edge features indicate that vanadium is substituted to Fe and mainly incorporated as V4+ (between 40 and 72% of V4+). We also demonstrate the potentiality of HERFD-XAS for mineralogical studies, since it can filter out the unwanted fluorescence and give better resolved spectra than conventional XAS.

  19. The CAT-ACT Beamline at ANKA: A new high energy X-ray spectroscopy facility for CATalysis and ACTinide research

    NASA Astrophysics Data System (ADS)

    Zimina, A.; Dardenne, K.; Denecke, M. A.; Grunwaldt, J. D.; Huttel, E.; Lichtenberg, H.; Mangold, S.; Pruessmann, T.; Rothe, J.; Steininger, R.; Vitova, T.

    2016-05-01

    A new hard X-ray beamline for CATalysis and ACTinide research has been built at the synchrotron radiation facility ANKA. The beamline design is dedicated to X-ray spectroscopy, including ‘flux hungry’ photon-in/photon-out and correlative techniques with a special infrastructure for radionuclide and catalysis research. The CAT-ACT beamline will help serve the growing need for high flux/hard X-ray spectroscopy in these communities. The design, the first spectra and the current status of this project are reported.

  20. X-ray lithography source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

    1991-01-01

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

  1. X-ray lithography source

    DOEpatents

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

    1991-12-31

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

  2. High-Energy X-rays from J174545.5-285829, the Cannonball: a Candidate Pulsar Wind Nebula Associated with Sgr a East

    NASA Technical Reports Server (NTRS)

    Nynka, Melania; Hailey, Charles J.; Mori, Kaya; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Hong, Jaesub; Perez, Kerstin M.; Stern, Daniel; Zhang, Shuo; Zhang, William W.

    2013-01-01

    We report the unambiguous detection of non-thermal X-ray emission up to 30 keV from the Cannonball, a few arcsecond long diffuse X-ray feature near the Galactic Center, using the NuSTAR X-ray observatory. The Cannonball is a high-velocity (v(proj) approximately 500 km s(exp -1)) pulsar candidate with a cometary pulsar wind nebula (PWN) located approximately 2' north-east from Sgr A*, just outside the radio shell of the supernova remnant Sagittarius A (Sgr A) East. Its non-thermal X-ray spectrum, measured up to 30 keV, is well characterized by a Gamma is approximately 1.6 power law, typical of a PWN, and has an X-ray luminosity of L(3-30 keV) = 1.3 × 10(exp 34) erg s(exp -1). The spectral and spatial results derived from X-ray and radio data strongly suggest a runaway neutron star born in the Sgr A East supernova event. We do not find any pulsed signal from the Cannonball. The NuSTAR observations allow us to deduce the PWN magnetic field and show that it is consistent with the lower limit obtained from radio observations.

  3. Magnetic reflectometry of heterostructures.

    PubMed

    Macke, S; Goering, E

    2014-09-10

    Measuring the magnetic configuration at complex buried layers and interfaces is an important task, which requires especially a non-destructive probing technique. X-ray resonant magnetic reflectometry (XRMR) combines the non-destructive depth profiling potential of x-ray reflectometry with the excellent sensitivity for magnetic phenomena, utilizing the x-ray magnetic circular dichroism effect. It provides the magnetic spatial distribution with a precision down to the angstrom scale, combined with element and symmetry specificity, sub-monolayer sensitivity, and the possible separation of spin and orbital magnetic moments. This review provides an overview to the XRMR technique in a tutorial way. We focus on the introduction to the theory, measurement types, and data simulation. We provide related experimental examples and show selected applications. PMID:25121937

  4. A Possible X-Ray and Radio Counterpart of the High-Energy Gamma-Ray Source 3EG J2227+6122

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Gotthelf, E. V.; Helfand, D. J.; Leighly, K. M.; Oliversen, Ronald (Technical Monitor)

    2001-01-01

    The identity of the persistent EGRET sources in the Galactic plane is largely a mystery. For one of these, 3EG J2227+6122, our complete census of X-ray and radio sources in its error circle reveals a remarkable superposition of an incomplete radio shell with a flat radio spectrum, and a compact, power-law X-ray source with photon index Gamma = 1.5 and with no obvious optical counterpart. The radio shell is polarized at a level of approx. = 25%. The anomalous properties of the radio source prevent us from deriving a completely satisfactory theory as to its nature. Nevertheless, using data from ROSAT, ASCA, the VLA, and optical imaging and spectroscopy, we argue that the X-ray source may be a young pulsar with an associated wind-blown bubble or bow shock nebula, and an example of the class of radio-quiet pulsars which are hypothesized to comprise the majority of EGRET sources in the Galaxy. The distance to this source can be estimated from its X-ray absorption as 3 kpc. At this distance, the X-ray and gamma-ray luminosities would be approx. = 1.7 x 10(exp 33) and approx. = 3.7 x 10(exp 35) erg/s, respectively, which would require an energetic pulsar to power them. If, on the contrary, this X-ray source is not the counterpart of 3EG J2227+6122, then by process of elimination the X-ray luminosity of the latter must be less than 10(exp -4) of its gamma-ray luminosity, a condition not satisfied by any established class of gamma-ray source counterpart. This would require the existence of at least a quantitatively new type of EGRET source, as has been suggested in studies of other EGRET fields.

  5. Method for the determination of Pd-catalyst residues in active pharmaceutical ingredients by means of high-energy polarized-beam energy dispersive X-ray fluorescence.

    PubMed

    Marguí, E; Van Meel, K; Van Grieken, R; Buendía, A; Fontàs, C; Hidalgo, M; Queralt, I

    2009-02-15

    In medicinal chemistry, Pd is perhaps the most-widely utilized precious metal, as catalyst in reactions which represent key transformations toward the synthesis of new active pharmaceutical ingredients (APIs). The disadvantage of this metal-catalyzed chemistry is that expensive and toxic metal residues are invariably left bound to the desired product. Thus, stringent regulatory guidelines exist for the amount of residual Pd that a drug candidate is allowed to contain. In this work, a rapid and simple method for the determination of Pd in API samples by high-energy polarized-beam energy dispersive X-ray fluorescence spectrometry has been developed and validated according to the specification limits of current legislation (10 mg kg(-1) Pd) and the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines). Sample and calibration standards preparation includes a first step of homogenization and then, in a second step, the pressing of the powdered material into pellets without any chemical treatment. The use of several synthetic calibration standards made of cellulose to simulate the API matrix appears to be an effective means to obtain reliable calibration curves with a good spread of data points over the working range. With the use of the best measuring conditions, the limit of detection (0.11 mg kg(-1) Pd) as well as the limit of quantitation (0.37 mg kg(-1) Pd) achieved meet rigorous requirements. The repeatability of the XRF measurement appeared to be less than 2%, while the precision of the whole method was around 7%. Trueness was evaluated by analyzing spiked API samples at the level of the specification limit and calculating the recovery factor, which was better than 95%. To study the applicability of the developed methodology for the intended purpose, three batches of the studied API were analyzed for their Pd content, and the attained results were comparable to those obtained by the

  6. Measurement of the high energy component of the x-ray spectra in the VENUS electron cyclotron resonance ion source (abstract only)

    SciTech Connect

    Leitner, D.; Benitez, J. Y.; Lyneis, C. M.; Todd, D. S.; Ropponen, T.; Ropponen, J.; Koivisto, H.; Gammino, S.

    2008-02-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (versatile ECR for nuclear science), produce large amounts of x rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental setup to measure bremsstrahlung spectra from ECR ion sources is somewhat different than for the traditional nuclear physics measurements these detectors are generally used for. In particular, the collimation and background shielding can be problematic. In this paper we will discuss the experimental setup for such a measurement, the energy calibration and background reduction, the shielding of the detector, and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates in dependence of various ion source parameters such as confinement fields, minimum B-field, rf power, and heating frequency.

  7. X-ray Emission Characteristics of Ultra-High Energy Density Relativistic Plasmas Created by Ultrafast Laser Irradiation of Nanowire Arrays

    NASA Astrophysics Data System (ADS)

    Hollinger, R. C.; Bargsten, C.; Shlyaptsev, V. N.; Pukhov, A.; Purvis, M. A.; Townsend, A.; Keiss, D.; Wang, Y.; Wang, S.; Prieto, A.; Rocca, J. J.

    2014-10-01

    Irradiation of ordered nanowire arrays with high contrast femtosecond laser pulses of relativistic intensity creates volumetrically heated near solid density plasmas characterized by multi-KeV temperatures and extreme degrees of ionization. The large hydrodynamic-to-radiative lifetime ratio of these plasmas results in very efficient X-ray generation. Au nanowire array plasmas irradiated at I 5×1018 Wcm-2 are measured to convert ~ 5 percent of the laser energy into h ν > 0.9 KeV X-rays, and >1 × 10-4 into h ν > 9 KeV photons, creating bright picosecond X-ray sources. The angular distribution of the higher energy photons is measured to change from isotropic into annular as the intensity increases, while softer X-ray emission (h ν >1 KeV) remains isotropic and nearly unchanged. Model simulations suggest the unexpected annular distribution of the hard X-rays might result from bremsstrahlung of fast electrons confined in a high aspect ratio near solid density plasma in which the electron-ion collision mean free-path is of the order of the plasma thickness. Work supported by the U.S Department of Energy, Fusion Energy Sciences and the Defense Threat Reduction Agency Grant HDTRA-1-10-1-0079. A.P was supported by of DFG-funded project TR18.

  8. Hard X-ray emission from X-ray bursters.

    NASA Astrophysics Data System (ADS)

    Tavani, M.; Liang, E.

    1996-11-01

    Hard X-ray emission from compact objects has been considered a spectral signature of black hole candidates. However, SIGMA and BATSE recently detected transient emission in the energy range 30-200keV from several X-ray bursters (XRBs) believed to contain weakly magnetized neutron stars. At least seven XRBs (including Aquila X-1 and 4U 1608-52) are currently known to produce erratic hard X-ray outbursts with typical durations of several weeks. These results lead us to reconsider theoretical models of high-energy emission from compact objects, and in particular thermal Comptonization models vs. non-thermal models of particle energization and X-ray emission from weakly magnetized neutron stars. We summarize here recent results for magnetic field reconnection models of non-thermal particle acceleration and high-energy emission of accretion disks. For intermediate soft X-ray luminosities below the Eddington limit, non-thermal hard X-ray emission is predicted to have a (broken) power-law spectrum with intensity anticorrelated with the soft X-ray luminosity. Recent GINGA/BATSE data for the XRB 4U 1608-52 are in agreement with the mechanism of emission proposed here: transient hard X-ray emission consistent with a broken power-law spectrum was detected for a sub-Eddington soft X-ray luminosity.

  9. Compressibility and phase transition studies for amorphous materials under high pressure: Approach combined of synchrotron high energy x-ray diffraction and micro tomography techniques using diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Liu, H.; Wang, L.; Xiao, X.; Lee, P.; Hemley, R.; Mao, H.

    2007-12-01

    The structural evolution of amorphous materials under high pressure conditions is a virgin field that has not been extensively explored. Investigations by reaching large Q range using synchrotron high energy x-ray diffraction and diamond anvil cell (DAC) techniques were performed. The study of polyamorphism will undoubtedly broaden our horizons and perspectives of the states of matter in general, and may have a significant impact on the existing theories about the structure, formation, and evolution of amorphous materials. The procedure of the pressure- induced amorphous state to crystalline state is another interesting subject. Combine the high energy x-ray diffraction with the time resolved area detector, we not only could accurately measure the structural factors evolution of amorphous materials under pressure, but also could record the time dependence of the crystallization procedure. These will provide new insight on the nature of crystallization, provide new invitation for the electronic theoretical studies for the phase stability and competition in time and spatial domains, and improve our understanding of the kinetic process of the common pressure induced crystallization. Another technical development effort is the micro tomography study using DAC at radial geometrical setting. Although the two-dimensional imaging, i. e. x-ray radiography, is used in routine way for high pressure DAC experiments, the ¡®volume imaging', i. e. x-ray tomography, will offer us more information regarding direct volume measurement, relative density measurement, and shear deformation under high pressure. The application in high pressure conditions by using DAC will greatly push our understanding of deformation mechanism down to lower mantle conditions. Another major application for DAC tomography will be the relative density measurement for the amorphous materials, metallic glasses, and liquid or melt in DAC under pressure, which will provide better information for the density

  10. Chest x-ray

    MedlinePlus

    ... Images Aortic rupture, chest x-ray Lung cancer, frontal chest x-ray Adenocarcinoma - chest x-ray Coal ... cancer - chest x-ray Lung nodule, right middle lobe - chest x-ray Lung mass, right upper lung - ...

  11. High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline

    SciTech Connect

    Llorens, Isabelle; Lahera, Eric; Delnet, William; Proux, Olivier; Dermigny, Quentin; Gelebart, Frederic; Morand, Marc; Shukla, Abhay; Bardou, Nathalie; Ulrich, Olivier; and others

    2012-06-15

    Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.

  12. UNDERSTANDING THE UNUSUAL X-RAY EMISSION PROPERTIES OF THE MASSIVE, CLOSE BINARY WR 20a: A HIGH ENERGY WINDOW INTO THE STELLAR WIND INITIATION REGION

    SciTech Connect

    Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel

    2013-11-10

    The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.

  13. Improvement of field emission properties of α-Fe{sub 2}O{sub 3} nanoflakes due to the lowered back contact barrier after high energy X-ray irradiation

    SciTech Connect

    Wu, J. Q.; Deng, S. Z.; Xu, N. S.; Chen, Jun; Wang, B.; Yi, F. T.

    2013-11-14

    Improvement in the field emission properties of α-Fe{sub 2}O{sub 3} nanoflakes is observed after high energy X-ray irradiation from synchrotron radiation. Field emission threshold field of α-Fe{sub 2}O{sub 3} nanoflakes is found to decrease from 10.1 to 7.8 MV/m after X-ray irradiation with the dose of 9.0 × 10{sup 14} phs/cm{sup 2}. Electrical measurement reveals that the potential barrier at the back contact between the α-Fe{sub 2}O{sub 3} layer and the iron substrate changes after X-ray irradiation. The observed threshold field decrease is well explained by the changes in potential barrier at the back contact of α-Fe{sub 2}O{sub 3} nanoflakes, which indicates the back contact plays an important role in controlling the field emission properties of α-Fe{sub 2}O{sub 3} nanoflakes. Our study shows that the α-Fe{sub 2}O{sub 3} nanoflakes are a promising material for the application as field emitter under X-ray environment.

  14. Roles of the Major, Small, Acid-Soluble Spore Proteins and Spore-Specific and Universal DNA Repair Mechanisms in Resistance of Bacillus subtilis Spores to Ionizing Radiation from X Rays and High-Energy Charged-Particle Bombardment▿

    PubMed Central

    Moeller, Ralf; Setlow, Peter; Horneck, Gerda; Berger, Thomas; Reitz, Günther; Rettberg, Petra; Doherty, Aidan J.; Okayasu, Ryuichi; Nicholson, Wayne L.

    2008-01-01

    The role of DNA repair by nonhomologous end joining (NHEJ), homologous recombination, spore photoproduct lyase, and DNA polymerase I and genome protection via α/β-type small, acid-soluble spore proteins (SASP) in Bacillus subtilis spore resistance to accelerated heavy ions (high-energy charged [HZE] particles) and X rays has been studied. Spores deficient in NHEJ and α/β-type SASP were significantly more sensitive to HZE particle bombardment and X-ray irradiation than were the recA, polA, and splB mutant and wild-type spores, indicating that NHEJ provides an efficient DNA double-strand break repair pathway during spore germination and that the loss of the α/β-type SASP leads to a significant radiosensitivity to ionizing radiation, suggesting the essential function of these spore proteins as protectants of spore DNA against ionizing radiation. PMID:18055591

  15. Use of the high-energy X-ray microprobe at the advanced photon source to investigate the interactions between metals and bacteria

    NASA Astrophysics Data System (ADS)

    Kemner, K. M.; Lai, B.; Maser, J.; Schneegurt, M. A.; Cai, Z.; Ilinski, P. P.; Kulpa, C. F.; Legnini, D. G.; Nealson, K. H.; Pratt, S. T.; Rodrigues, W.; Tischler, M. Lee; Yun, W.

    2000-05-01

    Understanding the fate of heavy-metal contaminants in the environment is of fundamental importance in the development and evaluation of effective remediation and sequestration strategies. Among the factors influencing the transport of these contaminants are their chemical speciation and the chemical and physical attributes of the surrounding medium. Bacteria and the extracellular material associated with them are thought to play a key role in determining a contaminant's speciation and thus its mobility in the environment. In addition, the microenvironment at and adjacent to actively metabolizing cell surfaces can be significantly different from the bulk environment. Thus, the spatial distribution and chemical speciation of contaminants and elements that are key to biological processes must be characterized at micron and submicron resolution in order to understand the microscopic physical, geological, chemical, and biological interfaces that determine a contaminant's macroscopic fate. Hard X-ray microimaging is a powerful technique for the element-specific investigation of complex environmental samples at the needed micron and submicron resolution. An important advantage of this technique results from the large penetration depth of hard X-rays in water. This advantage minimizes the requirements for sample preparation and allows the detailed study of hydrated samples. This paper presents results of studies of the spatial distribution of naturally occurring metals and a heavy-metal contaminant (Cr) in and near hydrated bacteria (Pseudomonas fluorescens) in the early stages of biofilm development, performed at the Advanced Photon Source Sector 2 X-ray microscopy beamline.

  16. SU-D-BRF-02: In Situ Verification of Radiation Therapy Dose Distributions From High-Energy X-Rays Using PET Imaging

    SciTech Connect

    Zhang, Q; Kai, L; Wang, X; Hua, B; Chui, L; Wang, Q; Ma, C

    2014-06-01

    Purpose: To study the possibility of in situ verification of radiation therapy dose distributions using PET imaging based on the activity distribution of 11C and 15O produced via photonuclear reactions in patient irradiated by 45MV x-rays. Methods: The method is based on the photonuclear reactions in the most elemental composition {sup 12}C and {sup 16}O in body tissues irradiated by bremsstrahlung photons with energies up to 45 MeV, resulting primarily in {sup 11}C and {sup 15}O, which are positron-emitting nuclei. The induced positron activity distributions were obtained with a PET scanner in the same room of a LA45 accelerator (Top Grade Medical, Beijing, China). The experiments were performed with a brain phantom using realistic treatment plans. The phantom was scanned at 20min and 2-5min after irradiation for {sup 11}C and {sup 15}, respectively. The interval between the two scans was 20 minutes. The activity distributions of {sup 11}C and {sup 15}O within the irradiated volume can be separated from each other because the half-life is 20min and 2min for {sup 11}C and {sup 15}O, respectively. Three x-ray energies were used including 10MV, 25MV and 45MV. The radiation dose ranged from 1.0Gy to 10.0Gy per treatment. Results: It was confirmed that no activity was detected at 10 MV beam energy, which was far below the energy threshold for photonuclear reactions. At 25 MV x-ray activity distribution images were observed on PET, which needed much higher radiation dose in order to obtain good quality. For 45 MV photon beams, good quality activation images were obtained with 2-3Gy radiation dose, which is the typical daily dose for radiation therapy. Conclusion: The activity distribution of {sup 15}O and {sup 11}C could be used to derive the dose distribution of 45MV x-rays at the regular daily dose level. This method can potentially be used to verify in situ dose distributions of patients treated on the LA45 accelerator.

  17. A sample chamber for in situ high-energy X-ray studies of crystal growth at deeply buried interfaces in harsh environments

    NASA Astrophysics Data System (ADS)

    de Jong, A. E. F.; Vonk, V.; Honkimäki, V.; Gorges, B.; Vitoux, H.; Vlieg, E.

    2015-06-01

    We introduce a high pressure high temperature chamber for in situ synchrotron X-ray studies. The chamber design allows for in situ studies of thin film growth from solution at deeply buried interfaces in harsh environments. The temperature can be controlled between room temperature and 1073 K while the pressure can be set as high as 50 bar using a variety of gases including N2 and NH3. The formation of GaN on the surface of a Ga13Na7 melt at 1073 K and 50 bar of N2 is presented as a performance test.

  18. Determining Individual Phase Flow Properties in a Quench and Partitioning Steel with In Situ High-Energy X-Ray Diffraction and Multiphase Elasto-Plastic Self-Consistent Method

    NASA Astrophysics Data System (ADS)

    Hu, Xiaohua; Choi, Kyoo Sil; Sun, Xin; Ren, Yang; Wang, Yangdong

    2016-02-01

    The micromechanical properties of the constituent phases were characterized for advanced high-strength steels (AHSS) produced by a quenching and partitioning (Q&P) process with in situ tensile loading under synchrotron-based, high-energy X-ray diffraction. The constituent phases present are retained austenite and three martensites (tempered, untampered, and freshly formed martensites). For the material investigated, the 200 and 220 lattice strains of the retained austenite phase were calculated by examining the changes of the X-ray diffraction peak positions during deformation. The 200 and 211 lattice strains of the various martensitic phases with similar crystal structures were determined by separating their overlapped diffraction peaks. Apart from tempered and untempered martensite, the diffraction peaks of freshly formed martensite as a result of austenite-to-martensite transformation can also be separated due to a high initial austenite volume fraction. The phase stresses are first estimated with an empirical relationship through the X-ray diffraction elastic constants. A multiphase elasto-plastic self-consistent model is next used for more accurate determination of the constitutive behaviors of the various phases by comparing the predicted lattice strain distributions and global stress-strain curves with the measured ones. The determined constitutive laws will be used for microstructure-based modeling for sheet formability of the Q&P AHSS steel.

  19. Electromechanical x-ray generator

    DOEpatents

    Watson, Scott A; Platts, David; Sorensen, Eric B

    2016-05-03

    An electro-mechanical x-ray generator configured to obtain high-energy operation with favorable energy-weight scaling. The electro-mechanical x-ray generator may include a pair of capacitor plates. The capacitor plates may be charged to a predefined voltage and may be separated to generate higher voltages on the order of hundreds of kV in the AK gap. The high voltage may be generated in a vacuum tube.

  20. Measurement of high-energy (10–60 keV) x-ray spectral line widths with eV accuracy

    SciTech Connect

    Seely, J. F. Feldman, U.; Glover, J. L.; Hudson, L. T.; Ralchenko, Y.; Henins, Albert; Pereira, N.; Di Stefano, C. A.; Kuranz, C. C.; Drake, R. P.; Chen, Hui; Williams, G. J.; Park, J.

    2014-11-15

    A high resolution crystal spectrometer utilizing a crystal in transmission geometry has been developed and experimentally optimized to measure the widths of emission lines in the 10–60 keV energy range with eV accuracy. The spectrometer achieves high spectral resolution by utilizing crystal planes with small lattice spacings (down to 2d = 0.099 nm), a large crystal bending radius and Rowland circle diameter (965 mm), and an image plate detector with high spatial resolution (60 μm in the case of the Fuji TR image plate). High resolution W L-shell and K-shell laboratory test spectra in the 10–60 keV range and Ho K-shell spectra near 47 keV recorded at the LLNL Titan laser facility are presented. The Ho K-shell spectra are the highest resolution hard x-ray spectra recorded from a solid target irradiated by a high-intensity laser.

  1. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  2. High-Energy X-Ray Imaging of the Pulsar Wind Nebula MSH 15-52: Constraints on Particle Acceleration and Transport

    NASA Technical Reports Server (NTRS)

    An, Hongjun; Madsen, Kristin K.; Reynolds, Stephen P.; Kaspi, Victoria M.; Harrison, Fiona A.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Fryer, Chris L.; Grefenstette, Brian W.; Zhang, William W.

    2014-01-01

    We present the first images of the pulsar wind nebula (PWN) MSH 15-52 in the hard X-ray band (8 keV), as measured with the Nuclear Spectroscopic Telescope Array (NuSTAR). Overall, the morphology of the PWN as measured by NuSTAR in the 3-7 keV band is similar to that seen in Chandra high-resolution imaging. However, the spatial extent decreases with energy, which we attribute to synchrotron energy losses as the particles move away from the shock. The hard-band maps show a relative deficit of counts in the northern region toward the RCW 89 thermal remnant, with significant asymmetry. We find that the integrated PWN spectra measured with NuSTAR and Chandra suggest that there is a spectral break at 6 keV, which may be explained by a break in the synchrotron emitting electron distribution at approximately 200 TeV and/or imperfect cross calibration. We also measure spatially resolved spectra, showing that the spectrum of the PWN softens away from the central pulsar B1509-58, and that there exists a roughly sinusoidal variation of spectral hardness in the azimuthal direction. We discuss the results using particle flow models. We find non-monotonic structure in the variation with distance of spectral hardness within 50 of the pulsar moving in the jet direction, which may imply particle and magnetic-field compression by magnetic hoop stress as previously suggested for this source. We also present two-dimensional maps of spectral parameters and find an interesting shell-like structure in the N(sub H) map. We discuss possible origins of the shell-like structure and their implications.

  3. High-energy X-ray imaging of the pulsar wind nebula MSH 15–52: constraints on particle acceleration and transport

    SciTech Connect

    An, Hongjun; Kaspi, Victoria M.; Madsen, Kristin K.; Harrison, Fiona A.; Grefenstette, Brian W.; Reynolds, Stephen P.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Fryer, Chris L.; Hailey, Charles J.; Mori, Kaya; Stern, Daniel; Zhang, William W.

    2014-10-01

    We present the first images of the pulsar wind nebula (PWN) MSH 15–52 in the hard X-ray band (≳8 keV), as measured with the Nuclear Spectroscopic Telescope Array (NuSTAR). Overall, the morphology of the PWN as measured by NuSTAR in the 3-7 keV band is similar to that seen in Chandra high-resolution imaging. However, the spatial extent decreases with energy, which we attribute to synchrotron energy losses as the particles move away from the shock. The hard-band maps show a relative deficit of counts in the northern region toward the RCW 89 thermal remnant, with significant asymmetry. We find that the integrated PWN spectra measured with NuSTAR and Chandra suggest that there is a spectral break at 6 keV, which may be explained by a break in the synchrotron-emitting electron distribution at ∼200 TeV and/or imperfect cross calibration. We also measure spatially resolved spectra, showing that the spectrum of the PWN softens away from the central pulsar B1509–58, and that there exists a roughly sinusoidal variation of spectral hardness in the azimuthal direction. We discuss the results using particle flow models. We find non-monotonic structure in the variation with distance of spectral hardness within 50'' of the pulsar moving in the jet direction, which may imply particle and magnetic-field compression by magnetic hoop stress as previously suggested for this source. We also present two-dimensional maps of spectral parameters and find an interesting shell-like structure in the N {sub H} map. We discuss possible origins of the shell-like structure and their implications.

  4. Search for Hard X-Ray Emission from Aquila X-1: High Energy Emission from Gamma-ray Radio Star 2CG 135+1/LSI 61 305

    NASA Technical Reports Server (NTRS)

    Tavani, Marco

    1998-01-01

    Several investigations supported by these CCRO grant were completed or are close to completion. The study of EGRET data for the unidentified source 2CG 135+01 was very fruitful. We discovered transient gamma-ray emission by combining several data obtained since 1994 through 1997. It is the first time that time variable emission is established for this enigmatic source, and clearly an interpretation in terms of an isolated radio pulsar (Geminga-like) is disfavored now. Our preferred model is a Galactic source, probably an energetic pulsar (such as PSR129-63) in a binary system producing gamma-rays because of pulsar wind/mass outflow interaction. We also accumulated may data concerning the radio source LSI 61 303, the possible counterpart of 2CG 135+01. We show that a possible anti-correlation between radio and gamma-ray emission exists. This anticorrelation is evident only in the energy range above 100 MeV, as demonstrated by the lack of it obtained from OSSE data. If confirmed, this anti-correlation would prove to be very important for the interpretation of the hundreds of unidentified gamma-ray sources currently discovered by EGRET near the Galactic plane, and would point to a new class of sources in addition to AGNs and isolated pulsars. We also completed the analysis of several time variable gamma-ray sources near the Galactic plane, with the discussion of evidence for transient emission from 2EG J1813-12 and 2EG J1828+01. We completed several investigations regarding gamma-ray bursts (GRBs), including the study of the brightness distribution for different spectral/duration GRB sub-classes, an investigation of acceleration processes and their consequences for GRB afterglow emission [61, the application of the synchrotron shock model of GRBs to X-ray energies.

  5. X-Rays

    MedlinePlus

    X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat ...

  6. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  7. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  8. Joint x-ray

    MedlinePlus

    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 ...

  9. Comparison of Spitzer/IRAC Galactic Center Mid-IR Survey Results with X-ray and Radio Emission Due to High-Energy Processes in the Central 100 Parsecs

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Arendt, R. A.; Smith, R.; Yusef-Zadeh, F.; Stolovy, S.; Law, C.; Smith, H. A.; Moseley, Harvey; Ramirez, S.; Karr, J.

    2006-01-01

    We compare the results of a small region from our 3.6 - 8.0 micron Spitzer/IRAC imaging survey of 2 x 1.5 deg around the Galactic Center with x-ray and radio emission due to high energy processes. The region we studied covers 100 x 100 parsecs, and was chosen to include a rich collection of sources, including Sgr A* and the bright Sgr AWest infrared/radio source complex, the non-thermal radio filaments and the thermal: radio arches. In a 40 x 40 parsec subset of that region we also make a preliminary analysis of the correlation between approx.2300 x-ray sources identified by Muno et al. (2003) and 20,000 infrared sources from our survey. We also investigate the correlation between infrared and radio emission in the large-scale structures including the thermal radio arches and non-thermal radio filaments. We set constrictions on the synchrotron spectrum observed at radio and millimeter wavelengths extrapolated to 8 micons, and set limits on the midinfrared variability of Sgr A* during and after the coordinated multi-wavelength observing campaign in September 2004.

  10. The evolution of internal stress and dislocation during tensile deformation in a 9Cr ferritic/martensitic (F/M) ODS steel investigated by high-energy X-rays

    NASA Astrophysics Data System (ADS)

    Zhang, Guangming; Zhou, Zhangjian; Mo, Kun; Miao, Yinbin; Liu, Xiang; Almer, Jonathan; Stubbins, James F.

    2015-12-01

    An application of high-energy wide angle synchrotron X-ray diffraction to investigate the tensile deformation of 9Cr ferritic/martensitic (F/M) ODS steel is presented. With tensile loading and in-situ X-ray exposure, the lattice strain development of matrix was determined. The lattice strain was found to decrease with increasing temperature, and the difference in Young's modulus of six different reflections at different temperatures reveals the temperature dependence of elastic anisotropy. The mean internal stress was calculated and compared with the applied stress, showing that the strengthening factor increased with increasing temperature, indicating that the oxide nanoparticles have a good strengthening impact at high temperature. The dislocation density and character were also measured during tensile deformation. The dislocation density decreased with increasing of temperature due to the greater mobility of dislocation at high temperature. The dislocation character was determined by best-fit methods for different dislocation average contrasts with various levels of uncertainty. The results shows edge type dislocations dominate the plastic strain at room temperature (RT) and 300 °C, while the screw type dislocations dominate at 600 °C. The dominance of edge character in 9Cr F/M ODS steels at RT and 300 °C is likely due to the pinning effect of nanoparticles for higher mobile edge dislocations when compared with screw dislocations, while the stronger screw type of dislocation structure at 600 °C may be explained by the activated cross slip of screw segments.

  11. Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

    PubMed

    Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

    2015-09-01

    We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (<1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (<11°), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument. PMID:26429486

  12. Monte Carlo estimation of photoneutrons contamination from high-energy X-ray medical accelerators in treatment room and maze: a simplified model.

    PubMed

    Zabihzadeh, Mansour; Ay, Mohammad Reza; Allahverdi, Mahmoud; Mesbahi, Asghar; Mahdavi, Seyed Rabee; Shahriari, Majid

    2009-07-01

    Despite all advantages associated with high-energy radiotherapy to improve therapeutic gain, the production of photoneutron via interaction of high-energy photons with high atomic number (Z) materials increases undesired dose to the patient and staff. Owing to the limitation and complication of experimental neutron dosimetry in mixed beam environment, including photon and neutron, the Monte Carlo (MC) simulation is a gold standard method for calculation of photoneutron contaminations. On the other hand, the complexity of treatment head makes the MC simulation more difficult and time-consuming. In this study, the possibility of using a simplified MC model for the simulation of treatment head has been investigated using MCNP4C general purpose MC code. As a part of comparative assessment strategy, the fluence, average energy and dose equivalent of photoneutrons were estimated and compared with other studies for several fields and energies at different points in treatment room and maze. The mean energy of photoneutrons was 0.17, 0.19 and 0.2 MeV at the patient plan for 10, 15 and 18 MeV, respectively. The calculated values differed, respectively, by a factor of 1.4, 0.7 and 0.61 compared with the reported measured data for 10, 15 and 18 MeV. Our simulation results in the maze showed that the neutron dose equivalent is attenuated by a factor of 10 for every 4.6 m of maze length while the related factor from Kersey analytical method is 5 m. The neutron dose equivalent was 4.1 mSv Gy(-1) at the isocentre and decreased to 0.79 mSv Gy(-1) at a distance of 100 cm away from the isocentre for 40 x 40 cm(2). There is good agreement between the data calculated using simplified model in this study and measurements. Considering the reported high uncertainties (up to 50%) in experimental neutron dosimetry, it can be concluded that the simplified model can be used as a useful tool for estimation of photoneutron contamination associated with high-energy photon radiotherapy. PMID

  13. X-ray transmissive debris shield

    DOEpatents

    Spielman, Rick B.

    1994-01-01

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

  14. Chest x-ray

    MedlinePlus

    Chest radiography; Serial chest x-ray; X-ray - chest ... You stand in front of the x-ray machine. You will be told to hold your breath when the x-ray is taken. Two images are usually taken. You will ...

  15. Dental x-rays

    MedlinePlus

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film ... dentist's office. There are many types of dental x-rays. Some are: Bitewing Periapical Palatal (also called occlusal) ...

  16. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  17. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  18. X Ray Topography

    ERIC Educational Resources Information Center

    Balchin, A. A.

    1974-01-01

    Discusses some aspects in X-ray topography, including formation of dislocations, characteristics of stacking faults, x-ray contrast in defect inspection, Berg-Barrett technique, and Lang traversing crystal and Borrmann's methods. (CC)

  19. Extremity x-ray

    MedlinePlus

    ... degenerative) Bone tumor Broken bone (fracture) Dislocated bone Osteomyelitis (infection) Other conditions for which the test may ... Bone tumor Bone x-ray Broken bone Clubfoot Osteomyelitis X-ray Update Date 10/22/2014 Updated ...

  20. Recent X-ray Variability of Eta Car Approaching The X-ray Eclipse

    NASA Technical Reports Server (NTRS)

    Corcoran, M.; Swank, J. H.; Ishibashi, K.; Gull, T.; Humphreys, R.; Damineli, A.; Walborn, N.; Hillier, D. J.; Davidson, K.; White, S. M.

    2002-01-01

    We discuss recent X-ray spectral variability of the supermassive star Eta Car in the interval since the last X-ray eclipse in 1998. We concentrate on the interval just prior to the next X-ray eclipse which is expected to occur in June 2003. We compare the X-ray behavior during the 2001-2003 cycle with the previous cycle (1996-1998) and note similarities and differences in the temporal X-ray behavior. We also compare a recent X-ray observation of Eta Car obtained with the Chandra high energy transmission grating in October 2002 with an earlier observation from Nov 2002, and interpret these results in terms of the proposed colliding wind binary model for the star. In addition we discuss planned observations for the upcoming X-ray eclipse.

  1. X-Ray Imaging

    MedlinePlus

    ... Brain Surgery Imaging Clinical Trials Basics Patient Information X-Ray Imaging Print This Page X-ray imaging is perhaps the most familiar type of imaging. Images produced by X-rays are due to the different absorption rates of ...

  2. X-Rays

    MedlinePlus

    X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of your ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat and ...

  3. Hand x-ray

    MedlinePlus

    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 ...

  4. Sinus x-ray

    MedlinePlus

    Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH Schaefer- ...

  5. Element-specific structure of materials with intrinsic disorder by high-energy resonant x-ray diffraction and differential atomic pair-distribution functions: A study of PtPd nanosized catalysts

    NASA Astrophysics Data System (ADS)

    Petkov, V.; Shastri, S. D.

    2010-04-01

    We demonstrate how high-energy resonant x-ray diffraction (XRD) and differential atomic-pair-distribution function (PDF) analysis can be used to characterize the atomic ordering in materials of limited structural coherence with both excellent spatial resolution and element specificity. First we prove that this experimental approach is feasible by probing the K -absorption edge of Au(˜81keV) atoms in chemically ordered and disordered bulk Cu3Au alloys. The resulting Au-differential PDFs show very clearly the different ways Au atoms are known to occupy the sites of otherwise identical cubic lattices of those materials. Next we apply it to a more complex material: PtPd alloy and core-shell nanosized (˜2-4nm) particles by probing the K -absorption edge of Pt(˜78keV) . The resulting Pt-differential atomic PDFs reveal how exactly the atomic ordering of catalytically active Pt atoms is affected by the nanoparticles’ design, thus providing a firm structural basis for understanding their properties. The work is a step forward in expanding the limits of applicability of nontraditional XRD to the rapidly growing field of materials of unusual structural complexity.

  6. Thermal stability of wurtzite Zr{sub 1−x}Al{sub x}N coatings studied by in situ high-energy x-ray diffraction during annealing

    SciTech Connect

    Rogström, L. Ghafoor, N.; Odén, M.; Schroeder, J.; Birch, J.; Schell, N.; Ahlgren, M.

    2015-07-21

    We study the thermal stability of wurtzite (w) structure ZrAlN coatings by a combination of in situ high-energy x-ray scattering techniques during annealing and electron microscopy. Wurtzite structure Zr{sub 1−x}Al{sub x}N coatings with Al-contents from x = 0.46 to x = 0.71 were grown by cathodic arc evaporation. The stability of the w-ZrAlN phase depends on chemical composition where the higher Al-content coatings are more stable. The wurtzite ZrAlN phase was found to phase separate through spinodal decomposition, resulting in nanoscale compositional modulations, i.e., alternating Al-rich ZrAlN layers and Zr-rich ZrAlN layers, forming within the hexagonal lattice. The period of the compositional modulations varies between 1.7 and 2.5 nm and depends on the chemical composition of the coating where smaller periods form in the more unstable, high Zr-content coatings. In addition, Zr leaves the w-ZrAlN lattice to form cubic ZrN precipitates in the column boundaries.

  7. The evolution of internal stress and dislocation during tensile deformation in a 9Cr ferritic/martensitic (F/M) ODS steel investigated by high-energy X-rays

    SciTech Connect

    Zhang, Guangming; Zhou, Zhangjian; Mo, Kun; Miao, Yinbin; Liu, Xiang; Almer, Jonathan; Stubbins, James F.

    2015-12-01

    An application of high-energy wide angle synchrotron X-ray diffraction to investigate the tensile deformation of 9Cr ferritic/martensitic (F/M) ODS steel is presented. With tensile loading and in-situ Xray exposure, the lattice strain development of matrix was determined. The lattice strain was found to decrease with increasing temperature, and the difference in Young's modulus of six different reflections at different temperatures reveals the temperature dependence of elastic anisotropy. The mean internal stress was calculated and compared with the applied stress, showing that the strengthening factor increased with increasing temperature, indicating that the oxide nanoparticles have a good strengthening impact at high temperature. The dislocation density and character were also measured during tensile deformation. The dislocation density decreased with increasing of temperature due to the greater mobility of dislocation at high temperature. The dislocation character was determined by best-fit methods for different dislocation average contrasts with various levels of uncertainty. The results shows edge type dislocations dominate the plastic strain at room temperature (RT) and 300 C, while the screw type dislocations dominate at 600 C. The dominance of edge character in 9Cr F/M ODS steels at RT and 300 C is likely due to the pinning effect of nanoparticles for higher mobile edge dislocations when compared with screw dislocations, while the stronger screw type of dislocation structure at 600 C may be explained by the activated cross slip of screw segments.

  8. Element-specific structure of materials with intrinsic disorder by high-energy resonant x-ray diffraction and differential atomic pair-distribution functions : a study of PtPd nanosized catalysts.

    SciTech Connect

    Petkov, V.; Shastri, S. D.; X-Ray Science Division; Central Michigan Univ.

    2010-01-01

    We demonstrate how high-energy resonant x-ray diffraction (XRD) and differential atomic-pair-distribution function (PDF) analysis can be used to characterize the atomic ordering in materials of limited structural coherence with both excellent spatial resolution and element specificity. First we prove that this experimental approach is feasible by probing the K-absorption edge of Au({approx}81 keV) atoms in chemically ordered and disordered bulk Cu3Au alloys. The resulting Au-differential PDFs show very clearly the different ways Au atoms are known to occupy the sites of otherwise identical cubic lattices of those materials. Next we apply it to a more complex material: PtPd alloy and core-shell nanosized ({approx}2-4 nm) particles by probing the K-absorption edge of Pt({approx}78 keV). The resulting Pt-differential atomic PDFs reveal how exactly the atomic ordering of catalytically active Pt atoms is affected by the nanoparticles design, thus providing a firm structural basis for understanding their properties. The work is a step forward in expanding the limits of applicability of nontraditional XRD to the rapidly growing field of materials of unusual structural complexity.

  9. High-energy polarized-beam energy-dispersive X-ray fluorescence analysis combined with activated thin layers for cadmium determination at trace levels in complex environmental liquid samples.

    PubMed

    Marguí, Eva; Fontàs, Clàudia; Van Meel, Katleen; Van Grieken, René; Queralt, Ignasi; Hidalgo, Manuela

    2008-04-01

    In this paper, we describe a new method for trace level Cd determination in complex environmental liquid samples. Thin layers activated with the extractant Aliquat 336 were prepared either by direct impregnation of commercial polymeric supports or by physical inclusion in a cellulose triacetate matrix, and both were effectively used to collect Cd present at low concentration in different aqueous matrixes. Quantitation of Cd contained in the thin layers was performed by high-energy polarized-beam energy-dispersive X-ray fluorescence. The effects of various experimental parameters such as layer composition, equilibration time, and instrumental conditions have been investigated. The analysis of different impregnated layers contacted with solutions ranging from 5 to 8000 microg L-1 Cd showed a linear response between the Cd concentration in the aqueous solutions and the metal present in the thin layer, with a detection limit of 0.7 microg L-1. The accuracy of the proposed method was confirmed by analyzing spiked seawater samples and a synthetic water sample containing, besides Cd, high amounts of other metal pollutants such as Ni, Cu, and Pb. The attained results were comparable to those obtained by anodic stripping voltammetry or inductively coupled plasma spectrometry. PMID:18327919

  10. X-ray Polarization Probes of SNR and PWN

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2016-04-01

    X-ray synchrotron radiation traces the high energy extrema of e+/e- accelerated by pulsar magnetospheres and supernova shocks. X-ray polarization lets us probe the unresolved geometry of these relativistic shock structures. I summarize what we know about magnetic field geometries in these nebulae and the prospects for learning more from X-ray polarimetry.

  11. High-energy magnetic excitations in overdoped La2-xSrxCuO4 studied by neutron and resonant inelastic X-ray scattering

    SciTech Connect

    Wakimoto, S.; Ishii, K.; Kimura, H.; Fujita, M.; Dellea, G.; Kummer, K.; Braicovich, L.; Ghiringhelli, G.; Debeer-Schmitt, Lisa M.; Granroth, Garrett E.

    2015-05-21

    We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L3 edge to study high-energy magnetic excitations at energy transfers of more than 100 meV for overdoped La2₋xSrxCuO4 with x=0.25 (Tc=15 K) and x=0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic excitations up to ~250 meV for x=0.25. Although the width in the momentum direction is large, the peak positions along the (π,π) direction agree with the dispersion relation of the spin wave in the nondoped La2CuO4 (LCO), which is consistent with the previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π,π) and (π,0) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π,0) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π,π) direction probed by RIXS appears to be less dispersive and the excitation energy is lower than the spin wave of LCO near (π/2,π/2). Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic excitation in the (π,π) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge excitations exist in the same energy range of magnetic excitations, reflecting the itinerant character of the overdoped sample. Lastly, we find a possible anisotropy in the charge excitation intensity might explain the apparent differences in the paramagnon dispersion in the (π,π) direction as detected by the x-ray scattering.

  12. Panoramic Dental X-Ray

    MedlinePlus

    ... X-ray? What is Panoramic X-ray? Panoramic radiography , also called panoramic x-ray , is a two- ... Exams Dental Cone Beam CT X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety About this Site ...

  13. Observation of femtosecond X-ray interactions with matter using an X-ray-X-ray pump-probe scheme.

    PubMed

    Inoue, Ichiro; Inubushi, Yuichi; Sato, Takahiro; Tono, Kensuke; Katayama, Tetsuo; Kameshima, Takashi; Ogawa, Kanade; Togashi, Tadashi; Owada, Shigeki; Amemiya, Yoshiyuki; Tanaka, Takashi; Hara, Toru; Yabashi, Makina

    2016-02-01

    Resolution in the X-ray structure determination of noncrystalline samples has been limited to several tens of nanometers, because deep X-ray irradiation required for enhanced resolution causes radiation damage to samples. However, theoretical studies predict that the femtosecond (fs) durations of X-ray free-electron laser (XFEL) pulses make it possible to record scattering signals before the initiation of X-ray damage processes; thus, an ultraintense X-ray beam can be used beyond the conventional limit of radiation dose. Here, we verify this scenario by directly observing femtosecond X-ray damage processes in diamond irradiated with extraordinarily intense (∼10(19) W/cm(2)) XFEL pulses. An X-ray pump-probe diffraction scheme was developed in this study; tightly focused double-5-fs XFEL pulses with time separations ranging from sub-fs to 80 fs were used to excite (i.e., pump) the diamond and characterize (i.e., probe) the temporal changes of the crystalline structures through Bragg reflection. It was found that the pump and probe diffraction intensities remain almost constant for shorter time separations of the double pulse, whereas the probe diffraction intensities decreased after 20 fs following pump pulse irradiation due to the X-ray-induced atomic displacement. This result indicates that sub-10-fs XFEL pulses enable conductions of damageless structural determinations and supports the validity of the theoretical predictions of ultraintense X-ray-matter interactions. The X-ray pump-probe scheme demonstrated here would be effective for understanding ultraintense X-ray-matter interactions, which will greatly stimulate advanced XFEL applications, such as atomic structure determination of a single molecule and generation of exotic matters with high energy densities. PMID:26811449

  14. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  15. Chandra X-Ray Observatory Concept

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This is an artist's concept of the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), fully developed in orbit in a star field with Earth. In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-ray such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

  16. Chandra X-Ray Observatory Concept

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a computer rendering of the fully developed Chandra X-ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), in orbit in a star field. In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-rays such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

  17. Chandra X-Ray Observatory Computer Rendering

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This is a computer rendering of the fully developed Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF). In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-ray such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

  18. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  19. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

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

  20. X-ray beamsplitter

    DOEpatents

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

    1987-08-07

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

  1. X-ray - skeleton

    MedlinePlus

    A skeletal x-ray is an imaging test used to look at the bones. It is used to detect fractures , tumors, or ... in the health care provider's office by an x-ray technologist. You will lie on a table or ...

  2. Extremity x-ray

    MedlinePlus

    An extremity x-ray is an image of the hands, wrist, feet, ankle, leg, thigh, forearm humerus or upper arm, hip, shoulder ... term "extremity" often refers to a human limb. X-rays are a form of radiation that passes through ...

  3. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  4. X-ray monochromator

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B. (Inventor)

    1992-01-01

    An x-ray monochromator is described, wherin a housing supports a plurality of mirrors forming a plurality of opposed mirror faces in parallel with each other and having thereon multilayer coatings, with each of said pairs of mirror faces being provided with identical coatings which are different from the coatings on the other pairs of mirror faces such that each pair of mirror faces has a peak x-ray reflection at a different wavelength regime. The housing is moveable to bring into a polychromatic x-ray beam that pair of mirror faces having the best x-ray reflection for the desired wavelength, with the mirrors being pivotable to move the mirror faces to that angle of incidence at which the peak reflectivity of the desired wavelength x-rays occurs.

  5. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

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

  6. Paradigm Shift in Radiation Biology/Radiation Oncology-Exploitation of the "H₂O₂ Effect" for Radiotherapy Using Low-LET (Linear Energy Transfer) Radiation such as X-rays and High-Energy Electrons.

    PubMed

    Ogawa, Yasuhiro

    2016-01-01

    Most radiation biologists/radiation oncologists have long accepted the concept that the biologic effects of radiation principally involve damage to deoxyribonucleic acid (DNA), which is the critical target, as described in "Radiobiology for the Radiologist", by E.J. Hall and A.J. Giaccia [1]. Although the concepts of direct and indirect effects of radiation are fully applicable to low-LET (linear energy transfer) radioresistant tumor cells/normal tissues such as osteosarcoma cells and chondrocytes, it is believed that radiation-associated damage to DNA does not play a major role in the mechanism of cell death in low-LET radiosensitive tumors/normal tissues such as malignant lymphoma cells and lymphocytes. Hall and Giaccia describe lymphocytes as very radiosensitive, based largely on apoptosis subsequent to irradiation. As described in this review, apoptosis of lymphocytes and lymphoma cells is actually induced by the "hydrogen peroxide (H₂O₂) effect", which I propose in this review article for the first time. The mechanism of lymphocyte death via the H₂O₂ effect represents an ideal model to develop the enhancement method of radiosensitivity for radiation therapy of malignant neoplasms. In terms of imitating the high radiosensitivity of lymphocytes, osteosarcoma cells (representative of low-LET radioresistant cells) might be the ideal model for indicating the conversion of cells from radioresistant to radiosensitive utilizing the H₂O₂ effect. External beam radiation such as X-rays and high-energy electrons for use in modern radiotherapy are generally produced using a linear accelerator. We theorized that when tumors are irradiated in the presence of H₂O₂, the activities of anti-oxidative enzymes such as peroxidases and catalase are blocked and oxygen molecules are produced at the same time via the H₂O₂ effect, resulting in oxidative damage to low-LET radioresistant tumor cells, thereby rendering them highly sensitive to irradiation. In this

  7. Paradigm Shift in Radiation Biology/Radiation Oncology—Exploitation of the “H2O2 Effect” for Radiotherapy Using Low-LET (Linear Energy Transfer) Radiation such as X-rays and High-Energy Electrons

    PubMed Central

    Ogawa, Yasuhiro

    2016-01-01

    Most radiation biologists/radiation oncologists have long accepted the concept that the biologic effects of radiation principally involve damage to deoxyribonucleic acid (DNA), which is the critical target, as described in “Radiobiology for the Radiologist”, by E.J. Hall and A.J. Giaccia [1]. Although the concepts of direct and indirect effects of radiation are fully applicable to low-LET (linear energy transfer) radioresistant tumor cells/normal tissues such as osteosarcoma cells and chondrocytes, it is believed that radiation-associated damage to DNA does not play a major role in the mechanism of cell death in low-LET radiosensitive tumors/normal tissues such as malignant lymphoma cells and lymphocytes. Hall and Giaccia describe lymphocytes as very radiosensitive, based largely on apoptosis subsequent to irradiation. As described in this review, apoptosis of lymphocytes and lymphoma cells is actually induced by the “hydrogen peroxide (H2O2) effect”, which I propose in this review article for the first time. The mechanism of lymphocyte death via the H2O2 effect represents an ideal model to develop the enhancement method of radiosensitivity for radiation therapy of malignant neoplasms. In terms of imitating the high radiosensitivity of lymphocytes, osteosarcoma cells (representative of low-LET radioresistant cells) might be the ideal model for indicating the conversion of cells from radioresistant to radiosensitive utilizing the H2O2 effect. External beam radiation such as X-rays and high-energy electrons for use in modern radiotherapy are generally produced using a linear accelerator. We theorized that when tumors are irradiated in the presence of H2O2, the activities of anti-oxidative enzymes such as peroxidases and catalase are blocked and oxygen molecules are produced at the same time via the H2O2 effect, resulting in oxidative damage to low-LET radioresistant tumor cells, thereby rendering them highly sensitive to irradiation. In this review, this

  8. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  9. X-Ray Crystallography Reagent

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

    2003-01-01

    Microcapsules prepared by encapsulating an aqueous solution of a protein, drug or other bioactive substance inside a semi-permeable membrane by are disclosed. The microcapsules are formed by interfacial coacervation under conditions where the shear forces are limited to 0-100 dynes per square centimeter at the interface. By placing the microcapsules in a high osmotic dewatering solution. the protein solution is gradually made saturated and then supersaturated. and the controlled nucleation and crystallization of the protein is achieved. The crystal-filled microcapsules prepared by this method can be conveniently harvested and stored while keeping the encapsulated crystals in essentially pristine condition due to the rugged. protective membrane. Because the membrane components themselves are x-ray transparent, large crystal-containing microcapsules can be individually selected, mounted in x-ray capillary tubes and subjected to high energy x-ray diffraction studies to determine the 3-D smucture of the protein molecules. Certain embodiments of the microcapsules of the invention have composite polymeric outer membranes which are somewhat elastic, water insoluble, permeable only to water, salts, and low molecular weight molecules and are structurally stable in fluid shear forces typically encountered in the human vascular system.

  10. Lumbosacral spine x-ray

    MedlinePlus

    X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray table ...

  11. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  12. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

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

  13. Rosat and the X-ray universe

    SciTech Connect

    Beatty, J.K.

    1990-08-01

    A major new satellite (Rosat) promises to provide astronomers with a map of perhaps 100,000 beacons in the X-ray sky, fresh images of high-energy objects approaching the resolution of visible-light photographs, and a first-ever survey of the sky at extreme-ultraviolet wavelengths. The German and British governments along with NASA are participating in this program. The grazing incidence technique previously used by Einstein and other missions is used to bring the X-rays to a focus and thus to create images. The X-ray telescope is equipped with three instruments, though only one can occupy the focus at any given time. Two are redundant detectors called position-sensitive proportional counters. The whole-sky survey will yield a complete X-ray image of the celestial sphere with 1/2-arc-minute detail of sources large and small, not just crude scans by wide-angle sensors.

  14. Medical X-Rays

    MedlinePlus

    ... Diagnostic X-Ray Equipment Compliance Program Guidance Manual CP 7386.003 Field Compliance Testing of Diagnostic (Medical) ... and Exporting Electronic Products Compliance Program Guidance Manual CP 7386.003 Field Compliance Testing of Diagnostic (Medical) ...

  15. Dental x-rays

    MedlinePlus

    ... or impacted teeth The presence and extent of dental caries (cavities) Bone damage (such as from periodontitis ) Abscessed ... Dental x-rays can reveal dental cavities (tooth decay) before they ... take yearly bitewings for the early development of cavities.

  16. X-ray - skeleton

    MedlinePlus

    ... is used to look for: Fractures or broken bone Cancer that has spread to other areas of the ... 2014:chap 8. Read More Bone tumor Broken bone Cancer Metastasis Osteomyelitis X-ray Update Date 5/9/ ...

  17. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  18. Abdominal x-ray

    MedlinePlus

    An abdominal x-ray is an imaging test to look at organs and structures in the abdomen. Organs include the spleen, stomach, and intestines. When the test is done to look at the bladder and kidney structures, ...

  19. X-Ray Spectrometry.

    ERIC Educational Resources Information Center

    Macdonald, G. L.

    1980-01-01

    Reviews instrumental developments and technique improvements in X-ray spectrometry, grouped into major topic areas of excitation, dispersion and detection, instrumentation and techniques, and quantitative analyses. Cites 162 references. (CS)

  20. Bone x-ray

    MedlinePlus

    ... or broken bone Bone tumors Degenerative bone conditions Osteomyelitis (inflammation of the bone caused by an infection) ... Multiple myeloma Osgood-Schlatter disease Osteogenesis imperfecta Osteomalacia Osteomyelitis Paget disease of the bone Rickets X-ray ...

  1. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  2. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. New ...

  3. X-ray nanotomography

    NASA Astrophysics Data System (ADS)

    Sasov, Alexander

    2004-10-01

    A compact laboratory x-ray "nano-CT" scanner has been created for 3D non-invasive imaging with 150-200 nanometers 3D spatial resolution, using advanced x-ray technologies and specific physical phenomena for signal detection. This spatial resolution in volume terms is 3 orders better than can be achieved in synchrotron tomography, 5 orders better then in existing laboratory micro-CT instruments and 10-12 orders better in comparison to clinical CT. The instrument employs an x-ray source with a 300-400nm x-ray spot size and uses small-angle scattering to attain a detail detectability of 150-200nm. An object manipulator allows positioning and rotation with an accuracy of 150nm. The x-ray detector is based on an intensified CCD with single-photon sensitivity. A typical acquisition cycle for 3D reconstruction of the full object volume takes from 10 to 60 minutes, with the collection of several hundred angular views. Subsequent volumetric reconstruction produces results as a set of cross sections with isotropic voxel size down to 140 x 140 x 140nm, or as a 3D-model, which can be virtually manipulated and measured. This unique spatial resolution in non-invasive investigations gives previously unattainable 3D images in several application areas, such as composite materials, paper and wood microstructure, biomedical applications and others.

  4. Attenuation properties and percentage depth dose of tannin-based Rhizophora spp. particleboard phantoms using computed tomography (CT) and treatment planning system (TPS) at high energy x-ray beams

    NASA Astrophysics Data System (ADS)

    Yusof, M. F. Mohd; Abdullah, R.; Tajuddin, A. A.; Hashim, R.; Bauk, S.

    2016-01-01

    A set of tannin-based Rhizophora spp. particleboard phantoms with dimension of 30 cm x 30 cm was fabricated at target density of 1.0 g/cm3. The mass attenuation coefficient of the phantom was measured using 60Co gamma source. The phantoms were scanned using Computed Tomography (CT) scanner and the percentage depth dose (PDD) of the phantom was calculated using treatment planning system (TPS) at 6 MV and 10 MV x-ray and compared to that in solid water phantoms. The result showed that the mass attenuation coefficient of tannin-based Rhizohora spp. phantoms was near to the value of water with χ2 value of 1.2. The measured PDD also showed good agreement with solid water phantom at both 6 MV and 10 MV x-ray with percentage deviation below 8% at depth beyond the maximum dose, Zmax.

  5. High-resolution x-ray telescopes

    NASA Astrophysics Data System (ADS)

    O'Dell, Stephen L.; Brissenden, Roger J.; Davis, William N.; Elsner, Ronald F.; Elvis, Martin S.; Freeman, Mark D.; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhail V.; Jerius, Diab; Juda, Michael; Kolodziejczak, Jeffery J.; Murray, Stephen S.; Petre, Robert; Podgorski, William; Ramsey, Brian D.; Reid, Paul B.; Saha, Timo; Schwartz, Daniel A.; Trolier-McKinstry, Susan; Weisskopf, Martin C.; Wilke, Rudeger H. T.; Wolk, Scott; Zhang, William W.

    2010-08-01

    High-energy astrophysics is a relatively young scientific field, made possible by space-borne telescopes. During the half-century history of x-ray astronomy, the sensitivity of focusing x-ray telescopes-through finer angular resolution and increased effective area-has improved by a factor of a 100 million. This technological advance has enabled numerous exciting discoveries and increasingly detailed study of the high-energy universe-including accreting (stellarmass and super-massive) black holes, accreting and isolated neutron stars, pulsar-wind nebulae, shocked plasma in supernova remnants, and hot thermal plasma in clusters of galaxies. As the largest structures in the universe, galaxy clusters constitute a unique laboratory for measuring the gravitational effects of dark matter and of dark energy. Here, we review the history of high-resolution x-ray telescopes and highlight some of the scientific results enabled by these telescopes. Next, we describe the planned next-generation x-ray-astronomy facility-the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility-Generation X. The scientific objectives of such a mission will require very large areas (about 10000 m2) of highly-nested lightweight grazing-incidence mirrors with exceptional (about 0.1-arcsecond) angular resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  6. Young Supernova explosions in the X-rays and hard X-rays

    NASA Astrophysics Data System (ADS)

    Margutti, Raffaella

    2016-04-01

    X-ray observations are providing critical insights into Supernova explosions and the nature of their progenitors. In this talk I will highlight some recent results from our dedicated programs at high-energies that allowed us to (1) uncover the weakest engine-driven SNe and understand their link to Gamma-Ray Bursts; (2) monitor the high-energy emission from shock energy deposition into the stellar envelope as early as a few days after the onset of core-collapse; (3) put the most stringent constraints to the progenitors of Type Ia SNe by using the deepest X-ray observations ever obtained. (4) Reveal the ejection of a massive stellar envelope timed with the collapse of a stripped star. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays of ˜40 keV

  7. High-efficiency high-energy Ka source for the critically-required maximum illumination of x-ray optics on Z using Z-petawatt-driven laser-breakout-afterburner accelerated ultrarelativistic electrons LDRD .

    SciTech Connect

    Sefkow, Adam B.; Bennett, Guy R.

    2010-09-01

    Under the auspices of the Science of Extreme Environments LDRD program, a <2 year theoretical- and computational-physics study was performed (LDRD Project 130805) by Guy R Bennett (formally in Center-01600) and Adam B. Sefkow (Center-01600): To investigate novel target designs by which a short-pulse, PW-class beam could create a brighter K{alpha} x-ray source than by simple, direct-laser-irradiation of a flat foil; Direct-Foil-Irradiation (DFI). The computational studies - which are still ongoing at this writing - were performed primarily on the RedStorm supercomputer at Sandia National Laboratories Albuquerque site. The motivation for a higher efficiency K{alpha} emitter was very clear: as the backlighter flux for any x-ray imaging technique on the Z accelerator increases, the signal-to-noise and signal-to-background ratios improve. This ultimately allows the imaging system to reach its full quantitative potential as a diagnostic. Depending on the particular application/experiment this would imply, for example, that the system would have reached its full design spatial resolution and thus the capability to see features that might otherwise be indiscernible with a traditional DFI-like x-ray source. This LDRD began FY09 and ended FY10.

  8. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    NASA Astrophysics Data System (ADS)

    Romano, F. P.; Garraffo, S.; Pappalardo, L.; Rizzo, F.

    2012-07-01

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi - the important typology of coin introduced by Diocletian in his monetary reform - is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-μXRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294-333 AD) and in almost all the imperial mints operating in the Roman world.

  9. Lumbosacral spine x-ray

    MedlinePlus

    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 ...

  10. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

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

  11. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, Stephen S.

    1987-01-01

    The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

  12. Principles of X-ray Navigation

    SciTech Connect

    Hanson, John Eric; /SLAC

    2006-03-17

    X-ray navigation is a new concept in satellite navigation in which orientation, position and time are measured by observing stellar emissions in x-ray wavelengths. X-ray navigation offers the opportunity for a single instrument to be used to measure these parameters autonomously. Furthermore, this concept is not limited to missions in close proximity to the earth. X-ray navigation can be used on a variety of missions from satellites in low earth orbit to spacecraft on interplanetary missions. In 1997 the Unconventional Stellar Aspect Experiment (USA) will be launched as part of the Advanced Research and Global Observation Satellite (ARGOS). USA will provide the first platform for real-time experimentation in the field of x-ray navigation and also serves as an excellent case study for the design and manufacturing of space qualified systems in small, autonomous groups. Current techniques for determining the orientation of a satellite rely on observations of the earth, sun and stars in infrared, visible or ultraviolet wavelengths. It is possible to use x-ray imaging devices to provide arcsecond level measurement of attitude based on star patterns in the x-ray sky. This technique is explored with a simple simulation. Collimated x-ray detectors can be used on spinning satellites to provide a cheap and reliable measure of orientation. This is demonstrated using observations of the Crab Pulsar taken by the high Energy Astronomy Observatory (HEAO-1) in 1977. A single instrument concept is shown to be effective, but dependent on an a priori estimate of the guide star intensity and thus susceptible to errors in that estimate. A star scanner based on a differential measurement from two x-ray detectors eliminates the need for an a priori estimate of the guide star intensity. A first order model and a second order model of the two star scanner concepts are considered. Many of the stars that emit in the x-ray regime are also x-ray pulsars with frequency stability approaching a

  13. X-ray

    MedlinePlus

    ... Most experts feel that the benefits of appropriate x-ray imaging greatly outweigh any risks. Young children and babies ... be pregnant. Alternative Names ... CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2014: ...

  14. Gamma-Ray Emission from X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Shrader, Chris R.

    2007-01-01

    We summarize the current observational picture regarding high-energy emission from Galactic X-ray binaries, reviewing the results of the Compton Gamma Ray Observatory mission. We speculate on the prospects for the GLAST era.

  15. X-rays from the eclipsing pulsar 1957+20

    NASA Technical Reports Server (NTRS)

    Fruchter, A. S.; Bookbinder, J.; Garcia, M. R.; Bailyn, C. D.

    1992-01-01

    The detection of soft X-rays of about 1 keV energy from the eclipsing pulsar PSR1957+20 is reported. This high-energy radiation should be a valuable diagnostic of the wind in this recycled pulsar system. Possible sources of the X-ray emission are the interstellar nebula driven by the pulsar wind, the interaction between the pulsar and its evaporating companion, and the pulsar itself. The small apparent size of the X-ray object argues against the first of these possibilities and suggests that the X-rays are produced within the binary.

  16. Uses of therapeutic x rays in medicine.

    PubMed

    Orton, C G

    1995-11-01

    Treatment of diseases with x rays began within months of Roentgen's discovery, and within four years x rays were being used successfully for the treatment of skin cancers. Deep-seated cancers began to be treated successfully in the 1920's with the advent of "deep" x-ray units and, especially, once supervoltage therapy machines became available in the 1930's. The 1940's and 1950's saw significant growth of megavoltage therapy, initially with Van de Graaff generators and betatrons, and later with linear accelerators. Linear accelerators became popular during the 1960's and 1970's and, by the 1980's they began to replace 60Co units as the most common form of treatment machine. With high-energy linear accelerators, computerized treatment planning, and ingenious fractionation schemes, modern radiotherapy has become a vital component of cancer treatment. PMID:7558860

  17. [The X-Ray Fluorescence Spectrometer Based on Pyroelectric Effect].

    PubMed

    Dong, Yi-fan; Fan, Rui-rui; Guo, Dong-ya; Zhang, Chun-lei; Gao, Min; Wang, Jin-zhou; Liu, Ya-qing; Zhou, Da-wei; Wang, Huan-yu

    2016-02-01

    Pyroelectric X-ray generator is implemented, and an X-ray fluorescence spectrometer is accomplished by combining the pyroelectric X-ray generator with a high energy resolution silicon drift detector. Firstly, the parameters of the X-ray generator are decided by analyzing and calculating the influence of the thickness of the pyroelectriccrystal and the thickness of the target on emitted X-ray. Secondly, the emitted X-ray is measured. The energy of emitted X-ray is from 1 to 27 keV, containing the characteristic X-ray of Cu and Ta, and the max counting rate is more than 3 000 per second. The measurement also proves that the detector of the spectrometer has a high energy resolution which the FWMH is 210 eV at 8. 05 keV. Lastly, samples of Fe, Ti, Cr and high-Ti basalt are analyzed using the spectrometer, and the results are agreed with the elements of the samples. It shows that the spectrometer consisting of a pyroelectric X-ray generator and a silicon drift detector is effective for element analysis. Additionally, because each part of the spectrometer has a small volume, it can be easily modified to a portable one which is suitable for non-destructive, on-site and quick element analysis. PMID:27209767

  18. Transforming Our Understanding of the X-ray Universe: The Imaging X-ray Polarimeter Explorer (IXPE)

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Bellazzini, Ronaldo; Costa, Enrico; Matt, Giorgio; Marshall, Herman; ODell, Stephen L.; Pavlov, George; Ramsey, Brian; Romani, Roger

    2014-01-01

    Accurate X-ray polarimetry can provide unique information on high-energy-astrophysical processes and sources. As there have been no meaningful X-ray polarization measurements of cosmic sources since our pioneering work in the 1970's, the time is ripe to explore this new parameter space in X-ray astronomy. To accomplish this requires a well-calibrated and well understood system that-particularly for an Explorer mission-has technical, cost, and schedule credibility. The system that we shall present satisfies these conditions, being based upon completely calibrated imaging- and polarization-sensitive detectors and proven X-ray-telescope technology.

  19. Low Energy X-Ray Spectrometer

    NASA Astrophysics Data System (ADS)

    Woodruff, Wayne R.

    1981-10-01

    A subkilovolt spectrometer has been produced to permit high-energy-resolution, time-dependent x-ray intensity measurements. The diffracting element is a curved mica (d=9.95Å) crystal. To preclude higher order (n≳1) diffractions, a carbon x-ray mirror that reflects only photons with energies less than ˜1.1 keV is utilized ahead of the diffracting element. The nominal energy range of interest is 800 to 900 eV. The diffracted photons are detected by a gold-surfaced photoelectric diode designed to have a very good frequency response, and whose current is recorded on an oscilloscope. A thin, aluminum light barrier is placed between the diffracting crystal and the photoelectric diode detector to keep any UV generated on or scattered by the crystal from illuminating the detector. High spectral enegy resolution is provided by many photocathodes between 8- and 50-eV wide placed serially along the diffracted x-ray beam at the detector position. The spectrometer was calibrated for energy and energy dispersion using the Ni Lα1,2 lines produced in the LLNL IONAC accelerator and in third order using a molybdenum target x-ray tube. For the latter calibration the carbon mirror was replaced by one surfaced with rhodium to raise the cut-off energy to about 3 keV. The carbon mirror reflection dependence on energy was measured using one of our Henke x-ray sources. The curved mica crystal diffraction efficiency was measured on our Low-Energy X-ray (LEX) machine. The spectrometer performs well although some changes in the way the x-ray mirror is held are desirable.

  20. Low energy x-ray spectrometer

    SciTech Connect

    Woodruff, W.R.

    1981-06-05

    A subkilovolt spectrometer has been produced to permit high-energy-resolution, time-dependent x-ray intensity measurements. The diffracting element is a curved mica (d = 9.95A) crystal. To preclude higher order (n > 1) diffractions, a carbon x-ray mirror that reflects only photons with energies less than approx. 1.1 keV is utilized ahead of the diffracting element. The nominal energy range of interest is 800 to 900 eV. The diffracted photons are detected by a gold-surface photoelectric diode designed to have a very good frequency response, and whose current is recorded on an oscilloscope. A thin, aluminium light barrier is placed between the diffracting crystal and the photoelectric diode detector to keep any uv generated on or scattered by the crystal from illuminating the detector. High spectral energy resolution is provided by many photocathodes between 8- and 50-eV wide placed serially along the diffracted x-ray beam at the detector position. The spectrometer was calibrated for energy and energy dispersion using the Ni L..cap alpha../sub 1/ /sub 2/ lines produced in the LLNL IONAC accelerator and in third order using a molybdenum target x-ray tube. For the latter calibration the carbon mirror was replaced by one surfaced with rhodium to raise the cut-off energy to about 3 keV. The carbon mirror reflection dependence on energy was measured using one of our Henke x-ray sources. The curved mica crystal diffraction efficiency was measured on our Low-Energy x-ray (LEX) machine. The spectrometer performs well although some changes in the way the x-ray mirror is held are desirable. 16 figures.

  1. The Chandra X-Ray Observatory

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.

    2013-01-01

    The Chandra X-ray Observatory, the third of NASA's four Great Observatories and its flagship mission for X-ray astronomy, was launched by NASA's Space Shuttle Columbia on July 23, 1999. The first X-ray sources were observed on August 12, 1999. The brightest of these sources named Leon X-1 in honor of Chandra's Telescope Scientist who played the leading role in establishing the key to Chandra's great advance in angular resolution. Over the past years, the Observatory's ability to provide sub-arc second X-ray images and high resolution spectra has established it as one of the most versatile and powerful tools for astrophysical research in the 21st century. Chandra explores the high-energy regions of the universe, observing X-ray sources with fluxes ranging over more than 10 orders of magnitude. The longevity of Chandra also provides a long observing baseline enabling temporal studies over time-scales of years. I will discuss how the Observatory works, the current operational status, and scientific highlights covering a variety of objects from stars with nearby planets that impact the stellar activity to the deepest Chandra surveys.

  2. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  3. Monitoring X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, Philip

    1998-01-01

    The goal of this investigation was to use the All-Sky Monitor on the Rossi X-Ray Timing Explorer (RXTE) in combination with the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to simultaneously measure the x-ray (2-12 keV) and hard x-ray (20-100 keV) emission from x-ray bursters. The investigation was successful. We made the first simultaneous measurement of hard and soft x-ray emission and found a strong anticorrelation of hard and soft x-ray emission from the X-Ray Burster 4U 0614+091. The monitoring performed under this investigation was also important in triggering target of opportunity observations of x-ray bursters made under the investigation hard x-ray emission of x-ray bursters approved for RXTE cycles 1 and 2. These observations lead to a number of papers on high-frequency quasi-periodic oscillations and on hard x-ray emission from the x-ray bursters 4U 0614+091 and 4U 1705-44.

  4. Optimization of the genetic algorithm of jointly fitting different types of X-ray scattering curves

    SciTech Connect

    Sutyrin, A. G.; Imamov, R. M.

    2011-01-15

    A method for jointly processing X-ray scattering data of different types is developed. It is shown that, by optimizing the genetic algorithm of the joint solution of the inverse problem of X-ray diffractometry and reflectometry, one can reduce the amount of calculations and reliably determine the parameters of layers in the structure under study, even when the information about them is a priori limited.

  5. Fluctuation X-Ray Scattering

    SciTech Connect

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

    2013-01-25

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

  6. X-ray Crystallography Facility

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Edward Snell, a National Research Council research fellow at NASA's Marshall Space Flight Center (MSFC), prepares a protein crystal for analysis by x-ray crystallography as part of NASA's structural biology program. The small, individual crystals are bombarded with x-rays to produce diffraction patterns, a map of the intensity of the x-rays as they reflect through the crystal.

  7. Tunable X-ray source

    DOEpatents

    Boyce, James R.

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  8. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  9. SMM x ray polychromator

    NASA Technical Reports Server (NTRS)

    Saba, J. L. R.

    1993-01-01

    The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

  10. Soft x-ray lasers

    SciTech Connect

    Matthews, D.L.; Rosen, M.D.

    1988-12-01

    One of the elusive dreams of laser physicists has been the development of an x-ray laser. After 25 years of waiting, the x-ray laser has at last entered the scientific scene, although those now in operation are still laboratory prototypes. They produce soft x rays down to about five nanometers. X-ray lasers retain the usual characteristics of their optical counterparts: a very tight beam, spatial and temporal coherence, and extreme brightness. Present x-ray lasers are nearly 100 times brighter that the next most powerful x-ray source in the world: the electron synchrotron. Although Lawrence Livermore National Laboratory (LLNL) is widely known for its hard-x-ray laser program which has potential applications in the Strategic Defense Initiative, the soft x-ray lasers have no direct military applications. These lasers, and the scientific tools that result from their development, may one day have a place in the design and diagnosis of both laser fusion and hard x-ray lasers. The soft x-ray lasers now in operation at the LLNL have shown great promise but are still in the primitive state. Once x-ray lasers become reliable, efficient, and economical, they will have several important applications. Chief among them might be the creation of holograms of microscopic biological structures too small to be investigated with visible light. 5 figs.

  11. Beyond Chandra - the X-ray Surveyor

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Gaskin, Jessica A.; Tananbaum, Harvey; Vhiklinin, Alexey

    2015-01-01

    Over the past 16 years, NASA's Chandra X-ray Observatory has provided an unparalleled means for exploring the high energy universe with its half-arcsecond angular resolution. Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, planets, and solar system objects addressing most, if not all, areas of current interest in astronomy and astrophysics. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address even more demanding science questions, such as the formation and subsequent growth of black hole seeds at very high redshift; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, NASA Marshall Space Flight Center, together with the Smithsonian Astrophysical Observatory, has initiated a concept study for such a mission now named the X-ray Surveyor. This concept study starts with a baseline payload consisting of a high resolution X-ray telescope and an instrument set which may include an X-ray calorimeter, a wide-field imager and a dispersive grating spectrometer and readout. The telescope would consist of highly nested thin shells, for which a number of technical approaches are currently under development, including adjustable X-ray optics, differential deposition, and modern polishing techniques applied to a variety of substrates. In many areas, the mission requirements would be no more stringent than those of Chandra, and the study takes advantage of similar studies for other large area missions carried out over the past two decades. Initial assessments indicate that such an X-ray mission is scientifically compelling, technically feasible, and worthy of a high prioritization by the next American National Academy of Sciences Decadal Survey for Astronomy and Astrophysics.

  12. Accretion powered X-ray pulsars

    NASA Technical Reports Server (NTRS)

    White, N. E.; Swank, J. H.; Holt, S. S.

    1982-01-01

    A unified description of the properties of 14 X-ray pulsars is presented and compared with the current theoretical understanding of these systems. The sample extends over six orders of magnitude in luminosity, with the only trend in the phase averaged spectra being that the lower luminosity systems appear to have less abrupt high energy cutoffs. There is no correlation of luminosity with power law index, high energy cutoff energy or iron line EW. Detailed pulse phase spectroscopy is given for five systems.

  13. High-energy X-ray powder diffraction and atomic-pair distribution-function studies of charged/discharged structures in carbon-hybridized Li2MnSiO4 nanoparticles as a cathode material for lithiumion batteries

    SciTech Connect

    Moriya, Maki; Miyahara, Masahiko; Hokazono, Mana; Sasaki, Hirokazu; Nemoto, Atsushi; Katayama, Shingo; Akimoto, Yuji; Hirano, Shin-ichi; Ren, Yang

    2014-10-01

    The stable cycling performance with a high discharge capacity of similar to 190 mAh g(-1) in a carbon-hybridized Li2MnSiO4 nanostructured powder has prompted an experimental investigation of the charged/discharged structures using synchrotron-based and laboratory-based X-rays and atomic-pair distributionfunction (PDF) analyses. A novel method of in-situ spray pyrolysis of a precursor solution with glucose as a carbon source enabled the successful synthesis of the carbon-hybridized Li2(M)nSiO(4) nanoparticles. The XRD patters of the discharged (lithiated) samples exhibit a long-range ordered structure characteristic of the (beta) Li2MnSiO4 crystalline phase (space group Pmn2(1)) which dissipates in the charged (delithiated) samples. However, upon discharging the long-range ordered structure recovers in each cycle. The disordered structure, according to the PDF analysis, is mainly due to local distortions of the MnO4 tetrahedra which show a mean Mn-O nearest neighbor distance shorter than that of the long-range ordered phase. These results corroborate the notion of the smaller Mn3+/Mn4+ ionic radii in the Li extracted phase versus the larger Mn2+ ionic radius in Li inserted phase. Thus Li extraction/insertion drives the fluctuation between the disordered and the long-range ordered structures. (C) 2014 Elsevier B.V. All rights reserved.

  14. Time- and space-resolved high energy operando X-ray diffraction for monitoring the methanol to hydrocarbons reaction over H-ZSM-22 zeolite catalyst in different conditions

    NASA Astrophysics Data System (ADS)

    del Campo, Pablo; Slawinski, Wojciech Andrzej; Henry, Reynald; Erichsen, Marius Westgård; Svelle, Stian; Beato, Pablo; Wragg, David; Olsbye, Unni

    2016-06-01

    The conversion of methanol to hydrocarbons (MTH) over H-ZSM-22 was studied by operando time- and space-resolved X-ray diffraction (XRD) at 370-385 °C and WHSV = 2 g/g h at the Swiss-Norwegian Beamline at ESRF. The performance of a commercial H-ZSM-22 sample was compared before and after acid-base treatment, and with and without propanol co-feed, respectively. N2 adsorption, Scanning Electron Microscopy and propyl amine desorption experiments showed that acid-base treatment led to enhanced accessibility of acid sites, mainly due to the formation of mesopores between agglomerated H-ZSM-22 crystals. The catalytic set-up allowed us to simultaneously observe the catalyst activity and unit cell volume variations by time- and space-resolved HXRD in operando conditions. The expansion of the unit cell and final flattening at different positions in the catalytic bed matched very nicely with the catalytic activity gradients. Different scenarios provided different behaviors and gave insights in the effect of morphology and co-feed process on the activity in the MTH process. This technique is the only one which has so far been able to provide direct evidence of the behavior of the species inside the catalytic reactor.

  15. Monitoring X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Kaaret, Philip

    1999-01-01

    The scientific goal of this project was to monitor a selected sample of x-ray bursters using data from the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer together with data from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory to study the long-term temporal evolution of these sources in the x-ray and hard x-ray bands. The project was closely related to "Long-Term Hard X-Ray Monitoring of X-Ray Bursters", NASA project NAG5-3891, and and "Hard x-ray emission of x-ray bursters", NASA project NAG5-4633, and shares publications in common with both of these. The project involved preparation of software for use in monitoring and then the actual monitoring itself. These efforts have lead to results directly from the ASM data and also from Target of Opportunity Observations (TOO) made with the Rossi X-Ray Timing Explorer based on detection of transient hard x-ray outbursts with the ASM and BATSE.

  16. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  17. X-ray Production By Cosmic Muons

    NASA Astrophysics Data System (ADS)

    Mrdja, D.; Bikit, I.; Aničin, I.; Vesković, M.; Forkapić, S.

    2007-04-01

    Muons have a small cross section for interactions and high energy, so they are very penetrating and give the significant contribution to the gamma spectra of Ge detectors, even in deep underground laboratories. One of the muon interaction effects with material is X-rays production. Having in mind that gold is often used as a detectors component, in this paper the production of X-rays in gold sample is analyzed by using an coincidence system based on plastic scintillation detector and Ge detector. The Au disc-shaped sample with mass of 40.6 g, radius 3.34 cm and 0.06 cm thickness was inside 12 cm thick lead shield of extended range HPGe detector. The plastic detector of 0.5 × 0.5 × 0.05 m dimensions was placed above the lead shield at the distance of 32 cm from detector endcap. The producing rate of Kα rays per Au mass unit from coincidence gamma spectrum is determined as R ~7.1 × 10-4 g-1s-1. Taking in account the measured muon flux of Φ=54 s-1m-2, the muon cross section σKα~ 43 Barn, for Au Kα X-rays production is calculated. Also, the cross sections of X-ray production by cosmic muons in lead and tungsten are measured. Unexpectedly, the results obtained did not reveal Z dependence in the Z= 74-82 region.

  18. Anomalous nonlinear X-ray Compton scattering

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    X-ray scattering is typically used as a weak linear atomic-scale probe of matter. At high intensities, such as produced at free-electron lasers, nonlinearities can become important, and the probe may no longer be considered weak. Here we report the observation of one of the most fundamental nonlinear X-ray-matter interactions: the concerted nonlinear Compton scattering of two identical hard X-ray photons producing a single higher-energy photon. The X-ray intensity reached 4 × 1020 W cm-2, corresponding to an electric field well above the atomic unit of strength and within almost four orders of magnitude of the quantum-electrodynamic critical field. We measure a signal from solid beryllium that scales quadratically in intensity, consistent with simultaneous non-resonant two-photon scattering from nearly-free electrons. The high-energy photons show an anomalously large redshift that is incompatible with a free-electron approximation for the ground-state electron distribution, suggesting an enhanced nonlinearity for scattering at large momentum transfer.

  19. Germanium x-ray phase plates for the production of circularly polarized x-rays

    SciTech Connect

    Yahnke, C.J.; Srajer, G.; Haeffner, D.R.; Mills, D.M.; Assoufid, L.

    1993-10-01

    The authors have constructed an x-ray phase plate to produce both linearly and circularly polarized x-rays at discrete energies between 20 keV and 88 keV. The plate is a monolithic two-crystal design, constructed from germanium, which increases the resultant degree of circular polarization of the output beam. They have measured the degree of circular polarization at 65 keV to be 90% {+-} 4%, significantly better than that produced by silicon phase plates. This radiation was used to measure the magnetic Compton profile for Fe, which was found to be in good agreement with theory and previous work. The underlying x-ray optics and the characterization of the device between 62 keV and 93 keV at the Cornell High Energy Synchrotron Source are presented.

  20. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

    2002-01-01

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

  1. Solar X-ray physics

    SciTech Connect

    Bornmann, P.L. )

    1991-01-01

    Research on solar X-ray phenomena performed by American scientists during 1987-1990 is reviewed. Major topics discussed include solar images observed during quiescent times, the processes observed during solar flares, and the coronal, interplanetary, and terrestrial phenomena associated with solar X-ray flares. Particular attention is given to the hard X-ray emission observed at the start of the flare, the energy transfer to the soft X-ray emitting plasma, the late resolution of the flare as observed in soft X-ray, and the rate of occurrence of solar flares as a function of time and latitude. Pertinent aspects of nonflaring, coronal X-ray emission and stellar flares are also discussed. 175 refs.

  2. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  3. Nonthermal X-ray Microflares

    NASA Astrophysics Data System (ADS)

    Christe, S.; Rauscher, E.; Krucker, S.; Lin, R. P.

    2004-12-01

    The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) provides unique sensitivity in the 3-15 keV energy range, with an effective area ˜100 times larger than similar past instruments. Along with its high spectral resolution (1 keV) RHESSI is uniquely suited to study small events. Microflares have been observed by Benz & Grigis (2002) and Krucker et al. (2002) to have anomalously steep spectra ( spectral index between -5 and -8) extending down to ˜ 7 keV. Thermal emission is found to dominate below ˜ 7 keV. In many other respects, microflares show properties similar to larger flares. We present single event studies of different types of x-ray microflares. RHESSI observations during quiet times (04-May 10-14; GOES level low B class) reveal a set 5 microflares (>=A Class). These microflares show power law spectra (spectral index of ˜4-8) with little or no thermal emission in the 3- ˜7 keV energy range above the nonthermal part of the spectrum. Other microflares in the same GOES class range, however, have been found which show extremely hard spectra with emission up to 50 keV (power law index ˜2). At lower energies, emission is dominated by a hot thermal component (20 MK). This work was supported by NASA contract NAS5-98033.

  4. Enhanced betatron X-rays from axially modulated plasma wakefields

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-01

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  5. Enhanced betatron X-rays from axially modulated plasma wakefields

    SciTech Connect

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-15

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  6. The Hard X-Ray Sky: Recent Observational Progress

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Cannizzo, John K.

    2010-01-01

    The last fifty years have witnessed the birth, development, and maturation to full potential of hard X-ray astrophysics. The primary force driving the history of the field has been the development of space-based instrumentation optimized for getting the maximum science out of observations of high-energy photons from astrophysical sources. Hard X-ray telescopes are leading research in areas such as galactic diffuse emission, galactic transients, and active galactic nuclei.

  7. High Energy Astrophysics Program

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This report reviews activities performed by members of the USRA (Universities Space Research Association) contract team during the six months during the reporting period (10/95 - 3/96) and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA), X-ray Timing Experiment (XTE), X-ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science, Archive Research Center (HEASARC), and others.

  8. High Energy Astrophysics Program

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This report reviews activities performed-by members of the USRA contract team during the six months of the reporting period and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, visiting the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA); X-ray Timing Experiment (XTE); X-ray Spectrometer (XRS); Astro-E; High Energy Astrophysics Science Archive Research Center (HEASARC), and others.

  9. X-ray Absorption Spectroscopy

    SciTech Connect

    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. X-ray emission from high temperature plasmas

    NASA Technical Reports Server (NTRS)

    Harries, W. L.

    1977-01-01

    The physical processes occurring in plasma focus devices were investigated with particular emphasis on X-ray emission. Topics discussed include: trajectories of high energy electrons; detection of ion trajectories; spatial distribution of neutron emission; space and time resolved emission of hard X-rays from a plasma focus; the staged plasma focus as a variation of the hypocloidal pinch; formation of current sheets in a staged plasma focus; and X-ray and neutron emission from a staged plasma focus. The possibility of operating dense plasma-focus type devices in multiple arrays beyond the scaling law for a single gun is discussed.

  11. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    DOE PAGESBeta

    Burcklen, C.; Soufli, R.; Gullikson, E.; Meltchakov, E.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Jerome, A.; de Rossi, S.; et al

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (opticalmore » constants) values for Cr.« less

  12. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    NASA Astrophysics Data System (ADS)

    Burcklen, C.; Soufli, R.; Dennetiere, D.; Polack, F.; Capitanio, B.; Gullikson, E.; Meltchakov, E.; Thomasset, M.; Jérome, A.; de Rossi, S.; Delmotte, F.

    2016-03-01

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1-1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  13. Development of high resolution imaging detectors for x ray astronomy

    NASA Technical Reports Server (NTRS)

    Murray, S. S.; Schwartz, D. A.

    1992-01-01

    This final report summarizes our past activities and discusses the work performed over the period of 1 April 1990 through 1 April 1991 on x-ray optics, soft x-ray (0.1 - 10 KeV) imaging detectors, and hard x-ray (10 - 300 KeV) imaging detectors. If microchannel plates (MCPs) can be used to focus x-rays with a high efficiency and good angular resolution, they will revolutionize the field of x-ray optics. An x-ray image of a point source through an array of square MCP pores compared favorably with our ray tracing model for the MCP. Initial analysis of this image demonstrates the feasibility of MCPs for soft x-rays. Our work continues with optimizing the performance of our soft x-ray MCP imaging detectors. This work involves readout technology that should provide improved MCP readout devices (thin film crossed grid, curved, and resistive sheets), defect removal in MCPs, and photocathode optimization. In the area of hard x-ray detector development we have developed two different techniques for producing a CsI photocathode thickness of 10 to 100 microns, such that it is thick enough to absorb the high energy x-rays and still allow the photoelectrons to escape to the top MCP of a modified soft x-ray imaging detector. The methods involve vacuum depositing a thick film of CsI on a strong back, and producing a converter device that takes the place of the photocathode.

  14. X-ray radiography for container inspection

    DOEpatents

    Katz, Jonathan I.; Morris, Christopher L.

    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.

  15. Longterm lightcurves of X-ray binaries

    NASA Astrophysics Data System (ADS)

    Clarkson, William

    The X-ray Binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight ( P orb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena, indeed the resulting accretion/ outflow process is among the most efficient energy-conversion machines in the universe. The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves above 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ~3 years' overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X- 1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band. Chapters 1 & 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 & 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE

  16. X-ray Astronomy

    ERIC Educational Resources Information Center

    Giacconi, Riccardo

    1973-01-01

    This new field, generated from observations above the atmosphere, has been an unexpected gift to astronomy by giving a better understanding of the role and importance of high energy phenomena. The history, instrumentation, and types of celestial sources observed are discussed. (DF)

  17. Inner-shell photoionized x-ray lasers

    SciTech Connect

    Moon, S.J.

    1998-06-01

    The inner-shell photoionized x-ray lasing scheme is an attractive method for achieving x-ray lasing at short wavelengths, via population inversion following inner-shell photoionization (ISPI). This scheme promises both a short wavelength and a short pulse source of coherent x rays with high average power. In this dissertation a very complete study of the ISPI x-ray laser scheme is done concerning target structure, filter design and lasant medium. An investigation of the rapid rise time of x-ray emission from targets heated by an ultra-short pulse high-intensity optical laser was conducted for use as the x-ray source for ISPI x-ray lasing. Lasing by this approach in C at a wavelength of 45 {angstrom} requires a short pulse (about 50 fsec) driving optical laser with an energy of 1-5 J and traveling wave optics with an accuracy of {approximately} 15 {micro}m. The optical laser is incident on a high-Z target creating a high-density plasma which emits a broadband spectrum of x rays. This x-ray source is passed through a filter to eliminate the low-energy x rays. The remaining high-energy x rays preferentially photoionize inner-shell electrons resulting in a population inversion. Inner-shell photoionized x-ray lasing relies on the large energy of a K-{alpha} transition in the initially neutral lasant. The photo energy required to pump this scheme is only slightly greater than the photon energy of the lasing transition yielding a lasing scheme with high quantum efficiency. However, the overall efficiency is reduced due to low x-ray conversion efficiency and the large probability of Auger decay yielding an overall efficiency of {approximately} 10{sup {minus}7} resulting in an output energy of {micro}J's. They calculate that a driving laser with a pulse duration of 40 fs, a 10{micro}m x 1 cm line focus, and an energy of 1 J gives an effective gain length product (gl) of 10 in C at 45 {angstrom}. At saturation (gl {approximately} 18) they expect an output of {approximately

  18. Planetary X-ray studies: past, present and future

    NASA Astrophysics Data System (ADS)

    Branduardi-Raymont, Graziella

    2016-07-01

    relative contributions of different processes. SWCX X-ray emission from the Earth's exosphere is turning from unwanted variable background in astrophysical observations to a novel and global diagnostic tool for investigating solar-terrestrial interactions: this underpins the development of the ESA-CAS joint mission SMILE (Solar Wind Magnetosphere Ionosphere Link Explorer) due for launch in 2021. On the longer term ATHENA (Advanced Telescope for High ENergy Astrophysics, launch 2028) will provide planetary targets with vastly improved X-ray sensitivity on that currently afforded by XMM-Newton.

  19. X-ray beam pointer

    NASA Technical Reports Server (NTRS)

    Nelson, C. W.

    1980-01-01

    Inexpensive, readily assembled pointer aims X-ray machine for welded assembly radiographs. Plumb bob used for vertical alinement and yardstick used to visualize X-ray paths were inconvenient and inaccurate. Pointer cuts alinement time by one-half and eliminates necessity of retakes. For 3,000 weld radiographs, pointer will save 300 worker-hours and significant materials costs.

  20. Plug Would Collimate X Rays

    NASA Technical Reports Server (NTRS)

    Anders, Jeffrey E.; Adams, James F.

    1989-01-01

    Device creates narrow, well-defined beam for radiographic measurements of thickness. Cylindrical plug collimates and aligns X rays with respect to through holes in parts. Helps in determination of wall thickness by radiography. Lead absorbs X rays that do not pass axially through central hole. Lead/vinyl seals prevent off-axis rays from passing along periphery of plug.

  1. X-ray based extensometry

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.; Pease, D. M.

    1988-01-01

    A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

  2. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A.

    2003-07-08

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

  3. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  4. X-Ray Tomographic Reconstruction

    SciTech Connect

    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.

  5. Focusing X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

    2010-01-01

    During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  6. Solar System X-rays from Charge Exchange Processes

    NASA Astrophysics Data System (ADS)

    Lisse, Carey M.; Christian, D. J.; Bhardwaj, A.; Dennerl, K.; Wolk, S. J.; Bodewits, D.; Combi, M. R.; Zurbuchen, T. H.; Lepri, S. T.

    2013-04-01

    The discovery of high energy x-ray emission in 1996 from comet C/1996 B2 (Hyakutake) uncovered a new class of x-ray emitting objects. Subsequent detections of the morphology, spectra, and time dependence of the x-rays from more than 20 comets have shown that the very soft (E < 1 keV) emission is due to a charge-exchange interaction between highly charged solar wind minor ions and the comet's extended neutral atmosphere. Many solar system objects are now known to shine in the X-ray, including Venus, Mars, the Moon, the Earth, Jupiter, and Saturn, with total power outputs on the MW - GW scale. Like comets, the X-ray emission from the Earth's geo-corona, the Jovian & Saturnian aurorae, and the Martian halo are thought to be driven by charge exchange between highly charged minor (heavy) ions in the solar wind and gaseous neutral species in the bodies' atmosphere. The non-auroral X-ray emissions from Jupiter, Saturn, and Earth, and those from disks of Mars, Venus, and the Moon are produced by scattering of solar X-rays. The first soft X-ray observations of Earth’s aurora by Chandra shows that it is highly variable, and the giant planet aurorae are fascinating puzzles that are just beginning to yield their secrets and may be the only x-ray sources not driven directly by the Sun in the whole system as well as properties of hot exo-solar Jupiters. Observations of local solar system charge exchange processes can also help inform us about x-rays produced at more distant hot ionized gas/cold neutral gas interfaces, like the heliopause, stellar astrospheres, galactic star forming regions, and starburst galaxies.

  7. First Detection of Phase-dependent Colliding Wind X-ray Emission outside the Milky Way

    NASA Technical Reports Server (NTRS)

    Naze, Yael; Koenigsberger, Gloria; Moffat, Anthony F. J.

    2007-01-01

    After having reported the detection of X-rays emitted by the peculiar system HD 5980, we assess here the origin of this high-energy emission from additional X-ray observations obtained with XMM-Newton. This research provides the first detection of apparently periodic X-ray emission from hot gas produced by the collision of winds in an evolved massive binary outside the Milky Way. It also provides the first X-ray monitoring of a Luminous Blue Variable only years after its eruption and shows that the source of the X-rays is not associated with the ejecta.

  8. High Energy Astronomy Observatory

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An overview of the High Energy Astronomy Observatory 2 contributions to X-ray astronomy is presented along with a brief description of the satellite and onboard telescope. Observations relating to galaxies and galactic clusters, black holes, supernova remnants, quasars, and cosmology are discussed.

  9. X-ray Free-electron Lasers

    SciTech Connect

    Feldhaus, J.; Arthur, J.; Hastings, J.B.; /SLAC

    2007-02-23

    In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, and can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.

  10. Chandra X-Ray Observatory High Resolution Mirror Assembly

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This photograph shows the mirrors of the High Resolution Mirror Assembly (HRMA) for the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), being assembled in the Eastman Kodak Company in Rochester, New York. The AXAF was renamed CXO in 1999. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It observes x-rays from high-energy regions of the universe, such as hot gas in the remnants of exploded stars. The HRMA, the heart of the telescope system, is contained in the cylindrical 'telescope' portion of the observatory. Since high-energy x-rays would penetrate a normal mirror, special cylindrical mirrors were created. The two sets of four nested mirrors resemble tubes within tubes. Incoming x-rays graze off the highly polished mirror surface and are furneled to the instrument section for detection and study. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission.

  11. Future X-ray Missions to Study Relativistic Astrophysics

    NASA Astrophysics Data System (ADS)

    Takahashi, Tadayuki

    2011-09-01

    In order to revolutionize the current understanding of the high energy universe, a number of new X-ray missions are being developed and planned. Among them, e-ROSITA/SRG, NuSTAR, ASTROSAT, GEMS and ASTRO-H will be realized in the next decade. And then, much larger missions, such as IXO, have been proposed for the 2020's. NuSTAR and ASTRO-H will open up completely new field of spatial studies of non-thermal emission above 10 keV by hard X-ray telescopes. They will also uniquely allow mapping of the spatial extent of the hard X-ray emission in diffuse sources, thus tracing the sites of particle acceleration in structures ranging in size from clusters of galaxies down to supernova remnants. Multi-wavelength spectra by ASTROSAT and ASTRO-H are indispensable to understand physical processes in high energy phenomena, such as particle acceleration in the Universe. Imaging spectroscopy with an energy resolution <5-7 eV brought by the micro-calorimeter onboard ASTRO-H can reveal line broadening and Doppler shifts due to turbulent or bulk velocities in extended sources. GEMS will perform the first sensitive X-ray polarization survey of several classes of X-ray emitting sources characterized by strong gravitational or magnetic fields. Here we present the key science goals for future X-ray missions designed to address a number of fundamental questions in contemporary astrophysics.

  12. Enhancement of X-ray dose absorption for medical applications

    NASA Astrophysics Data System (ADS)

    Lim, Sara; Nahar, S.; Pradhan, A.; Barth, R.

    2013-05-01

    A promising technique for cancer treatment is radiation therapy with high-Z (HZ) nanomoities acting as radio-sensitizers attached to tumor cells and irradiated with X-rays. But the efficacy of radiosenstization is highly energy dependent. We study the physical effects in using platinum (Pt) as the radio-sensitizing agent, coupled with commonly employed broadband x-ray sources with mean energies around 100 keV, as opposed to MeV energies produced by clinical linear accelerators (LINAC) used in radiation therapy. Numerical calculations, in vitro, and in vivo studies of F98 rat glioma (brain cancer) demonstrate that irradiation from a medium energy X-ray (MEX) 160 kV source is far more effective than from a high energy x-ray (HEX) 6 MV LINAC. We define a parameter to quantify photoionization by an x-ray source, which thereby provides a measure of subsequent Auger decays. The platinum (Z = 78) results are also relevant to ongoing studies on x-ray interaction with gold (Z = 79) nanoparticles, widely studied as an HZ contrast agent. The present study should be of additional interest for a combined radiation plus chemotherapy treatment since Pt compounds such cis-Pt and carbo-Pt are commonly used in chemotherapy.

  13. Synthesis, characterization, thermal behaviour and single crystal X-ray analysis of two new insensitive high energy density materials [8-hydroxyquinolinium 5-(2,4,6-trinitrophenyl)barbiturate (I) and 8-hydroxyquinolinium 5-(5-chloro-2,4-dinitrophenyl)-1,3-dimethyl barbiturate (II)

    NASA Astrophysics Data System (ADS)

    Manickkam, V.; Devi, P. Poornima; Kalaivani, D.

    2014-12-01

    Barbiturates I and II have been synthesized as maroon red and red orange coloured solids by mixing the ethanolic solutions of 2-chloro-1,3,5-trinitrobenzene ( TNCB), pyrimidine-2,4,6(1 H,3 H,5 H)-trione [barbituric acid ( BA)] and 8-hydroxyquinoline and 1,3-dichloro-4,6-dinitrobenzene ( DCDNB), 1,3-dimethylpyrimidine-2,4,6(1 H,3 H,5 H)-trione(1,3-dimethylbarbituric acid) and 8-hydroxyquinoline respectively. The structures of these two barbiturates have been predicted from the spectral studies (UV-VIS, IR, 1H NMR, 13C NMR, mass) and elemental analysis. Qualitative tests have been carried out to infer the presence of nitrogen and nitro groups and also chlorine atom in barbiturate II. Slow evaporation of ethanol-dimethylsulphoxide/ethanol solutions of barbiturate I/barbiturate II at 293 K yielded good for X-Ray diffraction crystals. Single crystal X-ray diffraction studies of the crystals further confirm the putative structures of the barbiturates. The asymmetric unit of the barbiturate I comprises of 8-hydroxyquinolinium cation, 5-(2,4,6-trinitrophenyl) barbiturate anion and a molecule of dimethylsulphoxide (DMSO), which is used as a recrystallizing solvent. It crystallizes in the triclinic system with space group (centrosymmetric). Barbiturate II crystallizes in the orthorhombic system with space group P212121 (non-centrosymmetric). Barbiturates I and II are stable towards an impact sensitivity test, when a weight of 2 kg mass hammer is dropped from a height of 160 cm of the instrument. TGA/ DTA analyses at four different heating rates (5, 10, 20, and 40 K/min) imply that they undergo exothermic decomposition (˜85%) in three different stages between 273 and 873 K. Activation energies for these decomposition processes have been calculated by employing Kissinger and Ozawa plots. Impact sensitivity test and activation energies have revealed that the titled barbiturates are insensitive high energy density materials ( IHEDMS).

  14. X-Ray Imaging System

    NASA Astrophysics Data System (ADS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  15. X-ray burst sources

    NASA Technical Reports Server (NTRS)

    Lewin, W. H. G.

    1986-01-01

    There are about 100 bright X-ray sources in the Galaxy that are accretion-driven systems composed of a neutron star and a low mass companion that fills its critical Roche lobe. Many of these systems generate recurring X-ray bursts that are the result of thermonuclear flashes in the neutron star's surface layers, and are accompanied by a somewhat delayed optical burst due to X-ray heating of accretion disk. The Rapid Burster discovered in 1976 exhibits an interval between bursts that is strongly correlated with the energy in the preceding burst. There is no optical identification for this object.

  16. Chandra X-Ray Observatory (CXO) on Orbit Animation

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is an on-orbit animation of the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF). In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the remnants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers worldwide better understand the structure and evolution of the universe by studying powerful sources of x-rays such as exploding stars, matter falling into black holes, and other exotic celestial objects. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission.

  17. Chandra X-Ray Observatory (CXO) at Johnson Space Center

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This Quick Time movie depicts the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), in its entirety, at the orbital processing facility at the Johnson Space Center. In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the remnants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers worldwide better understand the structure and evolution of the universe by studying powerful sources of x-rays such as exploding stars, matter falling into black holes, and other exotic celestial objects. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission.

  18. X-ray and gamma ray astronomy detectors

    NASA Technical Reports Server (NTRS)

    Decher, Rudolf; Ramsey, Brian D.; Austin, Robert

    1994-01-01

    X-ray and gamma ray astronomy was made possible by the advent of space flight. Discovery and early observations of celestial x-rays and gamma rays, dating back almost 40 years, were first done with high altitude rockets, followed by Earth-orbiting satellites> once it became possible to carry detectors above the Earth's atmosphere, a new view of the universe in the high-energy part of the electromagnetic spectrum evolved. Many of the detector concepts used for x-ray and gamma ray astronomy were derived from radiation measuring instruments used in atomic physics, nuclear physics, and other fields. However, these instruments, when used in x-ray and gamma ray astronomy, have to meet unique and demanding requirements related to their operation in space and the need to detect and measure extremely weak radiation fluxes from celestial x-ray and gamma ray sources. Their design for x-ray and gamma ray astronomy has, therefore, become a rather specialized and rapidly advancing field in which improved sensitivity, higher energy and spatial resolution, wider spectral coverage, and enhanced imaging capabilities are all sought. This text is intended as an introduction to x-ray and gamma ray astronomy instruments. It provides an overview of detector design and technology and is aimed at scientists, engineers, and technical personnel and managers associated with this field. The discussion is limited to basic principles and design concepts and provides examples of applications in past, present, and future space flight missions.

  19. X-ray and gamma ray astronomy detectors

    NASA Astrophysics Data System (ADS)

    Decher, Rudolf; Ramsey, Brian D.; Austin, Robert

    X-ray and gamma ray astronomy was made possible by the advent of space flight. Discovery and early observations of celestial x-rays and gamma rays, dating back almost 40 years, were first done with high altitude rockets, followed by Earth-orbiting satellites> once it became possible to carry detectors above the Earth's atmosphere, a new view of the universe in the high-energy part of the electromagnetic spectrum evolved. Many of the detector concepts used for x-ray and gamma ray astronomy were derived from radiation measuring instruments used in atomic physics, nuclear physics, and other fields. However, these instruments, when used in x-ray and gamma ray astronomy, have to meet unique and demanding requirements related to their operation in space and the need to detect and measure extremely weak radiation fluxes from celestial x-ray and gamma ray sources. Their design for x-ray and gamma ray astronomy has, therefore, become a rather specialized and rapidly advancing field in which improved sensitivity, higher energy and spatial resolution, wider spectral coverage, and enhanced imaging capabilities are all sought. This text is intended as an introduction to x-ray and gamma ray astronomy instruments. It provides an overview of detector design and technology and is aimed at scientists, engineers, and technical personnel and managers associated with this field. The discussion is limited to basic principles and design concepts and provides examples of applications in past, present, and future space flight missions.

  20. Neutron and X-ray Detectors

    SciTech Connect

    Carini, Gabriella; Denes, Peter; Gruener, Sol; Lessner, Elianne

    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

  1. Densitometry and temperature measurement of combustion gas by X-ray Compton scattering

    PubMed Central

    Sakurai, Hiroshi; Kawahara, Nobuyuki; Itou, Masayoshi; Tomita, Eiji; Suzuki, Kosuke; Sakurai, Yoshiharu

    2016-01-01

    Measurement of combustion gas by high-energy X-ray Compton scattering is reported. The intensity of Compton-scattered X-rays has shown a position dependence across the flame of the combustion gas, allowing us to estimate the temperature distribution of the combustion flame. The energy spectra of Compton-scattered X-rays have revealed a significant difference across the combustion reaction zone, which enables us to detect the combustion reaction. These results demonstrate that high-energy X-ray Compton scattering can be employed as an in situ technique to probe inside a combustion reaction. PMID:26917151

  2. Densitometry and temperature measurement of combustion gas by X-ray Compton scattering.

    PubMed

    Sakurai, Hiroshi; Kawahara, Nobuyuki; Itou, Masayoshi; Tomita, Eiji; Suzuki, Kosuke; Sakurai, Yoshiharu

    2016-03-01

    Measurement of combustion gas by high-energy X-ray Compton scattering is reported. The intensity of Compton-scattered X-rays has shown a position dependence across the flame of the combustion gas, allowing us to estimate the temperature distribution of the combustion flame. The energy spectra of Compton-scattered X-rays have revealed a significant difference across the combustion reaction zone, which enables us to detect the combustion reaction. These results demonstrate that high-energy X-ray Compton scattering can be employed as an in situ technique to probe inside a combustion reaction. PMID:26917151

  3. Chandra X-ray grating spectra of V959 Mon

    NASA Astrophysics Data System (ADS)

    Orio, Marina; Zemko, Polina; Peretz, Uria; Behar, Ehud

    2016-07-01

    V959 Mon (Nova Mon 2012) was discovered in X-rays and gamma rays in the Summer of 2012, before it could be observed optically. It was observed twice with the Chandra gratings, by us in December of 2012 with the Low Energy Transmission Grating (LETG) and previously, in September of 2012, by another team with the Chandra High Energy Transmission Gratings. Although it seems very likely that only a small fraction of the ejecta emitted X-rays in small, dense clumps, the X-ray emission of the ejecta are very important for what the teach us about the kinematics, the chemical composition and nucleosynthesis of the nova. By December, the central source had shrunk almost to pre-outburst size and was visible in X-rays, revealing a massive, hot oxygen-neon white dwarf.

  4. Chandra X-ray Observatory (CXO): overview

    NASA Astrophysics Data System (ADS)

    Weisskopf, Martin C.; Tananbaum, Harvey D.; Van Speybroeck, Leon P.; O'Dell, Stephen L.

    2000-07-01

    The Chandra X-Ray Observatory, the x-ray component of NASA's Great Observatories, was launched early in the morning of 1999, July 23 by the Space Shuttle Columbia. The Shuttle launch was only the first step in placing the observatory in orbit. After release from the cargo bay, the Inertial Upper Stage performed two firings, and separated from the observatory as planned. Finally, after five firings of Chandra's own Integral Propulsion System--the last of which took place 15 days after launch--the observatory was placed in its highly elliptical orbit of approximately 140,000 km apogee and approximately 10,000 km perigee. After activation, the first x-rays focused by the telescope were observed on 1999, August 12. Beginning with these initial observations one could see that the telescope had survived the launch environment and was operating as expected. The month following the opening of the sun-shade door was spent adjusting the focus for each set of instrument configurations, determining the optical axis, calibrating the star camera, establishing the relative response functions, determining energy scales, and taking a series of `publicity' images. Each observation proved to be far more revealing than was expected. Finally, and despite an initial surprise and setback due to the discovery that the Chandra x-ray telescope was far more efficient for concentrating low-energy protons that had been anticipated, the observatory is performing well and is returning superb scientific data. Together with other space observations, most notably the recently activated XMM-Newton, it is clear that we are entering a new era of discovery in high-energy astrophysics.

  5. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  6. Imaging X-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Grant, P. A.; Jackson, J. W., Jr.; Alcorn, G. E.; Marshall, F. E.

    1984-09-01

    An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

  7. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  8. Picosecond x-ray science.

    SciTech Connect

    Landahl, E.; Reis, D.; Wang, J.; Young, L.

    2006-01-01

    The report discusses the exciting times for short pulse X-rays and the current users of the technology in the United States. Tracking nuclear motions with X-rays transcends scientific disciplines and includes Biology, Materials Science, Condensed Matter and Chemistry. 1 picosecond accesses many phenomena previously hidden at 100ps. Synchrotron advantage over laser plasma and LCLS is that it's easily tunable. There is a large and diverse user community of this technology that is growing rapidly. A working group is being formed to implement 'fast track' Phases 1 and 2 which includes tunable, polarized, monochromatic, focused X-rays; variable pulse length (1 to 100ps) and 1 kHz, 10{sup 9} X-rays/s with 1% bandwidth. ERL would be a major advance for ultrafast time-resolved studies.

  9. X-ray microtomographic scanners

    SciTech Connect

    Syryamkin, V. I. Klestov, S. A.

    2015-11-17

    The article studies the operating procedures of an X-ray microtomographic scanner and the module of reconstruction and analysis 3D-image of a test sample in particular. An algorithm for 3D-image reconstruction based on image shadow projections and mathematical methods of the processing are described. Chapter 1 describes the basic principles of X-ray tomography and general procedures of the device developed. Chapters 2 and 3 are devoted to the problem of resources saving by the system during the X-ray tomography procedure, which is achieved by preprocessing of the initial shadow projections. Preprocessing includes background noise removing from the images, which reduces the amount of shadow projections in general and increases the efficiency of the group shadow projections compression. In conclusion, the main applications of X-ray tomography are presented.

  10. X-Ray Exam: Finger

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... Results A radiologist, a doctor specially trained in reading and interpreting X-ray images, will look at ...

  11. X-Ray Exam: Hip

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of keeping still while the X-ray is ...

  12. X-Ray Exam: Foot

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  13. X-Ray Exam: Ankle

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  14. X-Ray Exam: Pelvis

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of keeping still while the X-ray is ...

  15. X-Ray Exam: Forearm

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  16. X-Ray Exam: Wrist

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... For older kids, be sure to explain the importance of staying still while the X-ray is ...

  17. Imaging X-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Grant, P. A.; Jackson, J. W., Jr.; Alcorn, G. E.; Marshall, F. E. (Inventor)

    1984-01-01

    An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

  18. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1980-01-01

    The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

  19. X-Rays, Pregnancy and You

    MedlinePlus

    ... and Procedures Medical Imaging Medical X-ray Imaging X-Rays, Pregnancy and You Share Tweet Linkedin Pin it ... the decision with your doctor. What Kind of X-Rays Can Affect the Unborn Child? During most x- ...

  20. Why Do I Need X-Rays?

    MedlinePlus

    ... to your desktop! more... Why Do I Need X-Rays? Article Chapters Why Do I Need X-Rays? ... of tooth decay. Updated: January 2012 Related Articles: X-Rays The Academy of General Dentistry (AGD) Sets the ...

  1. Nanometer x-ray lithography

    NASA Astrophysics Data System (ADS)

    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.

  2. Universal x-ray unit

    SciTech Connect

    Charrier, P.

    1988-04-26

    An X-ray apparatus capable of X-ray beaming in a multiplicity of directions around and through the body of a horizontally lying stationary patient is described comprising: a horizontal patient's table; a ring in circumscribing position around the table; a X-ray equipment fixedly mounted on the ring for X-ray beaming through the table and through the body of a patient when lying thereon, the X-ray equipment comprising a source of X-rays; support means for holding the ring in the circumscribing position and first drive means on the support means and on the ring for rotating the ring about a first axis perpendicular to the general plane of the ring through the ring center; a suspension member having downwardly extending side legs, second drive means for oscillating the ring support means and the ring together in unison about the second axis; a frame having a top structure above the table, the ring and the suspension member; and a carrier assembly mounted on the top structure and at the center of the suspension member.

  3. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1985-01-01

    A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

  4. Center for X-Ray Optics, 1992

    SciTech Connect

    Not Available

    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.

  5. Hard x-ray spectrometers for NIF (abstract)

    NASA Astrophysics Data System (ADS)

    Seely, John; Holland, Glenn; Brown, Charles; Deslattes, Richard; Hudson, Lawrence; Bell, Perry; Miller, Michael; Back, Christina

    2001-01-01

    A National Ignition Facility (NIF) core diagnostic instrument has been designed and will be fabricated to record x-ray spectra in the 1.2-20 keV energy range. The high-energy electronic x-ray instrument has four reflection crystals with overlapping coverage of 1.2-10.9 keV and one transmission crystal covering 8.6-20 keV. The spectral resolving power varies from approximately 1000 at low energies to 315 at 20 keV. The spectrum produced by each crystal is recorded by a modified commercial dental x-ray charge coupled device (CCD) detector. The scintillators on the CCD detectors are optimized for the energy ranges. A one-channel x-ray spectrometer, using one transmission crystal covering 12-60 keV, will be fabricated for the OMEGA laser facility. The transmission crystal spectrometers are based on instruments originally designed at National Institute for Standards and Technology for the purpose of characterizing the x-ray flux from medical radiography sources. Utilizing one of those instruments and a commercial dental x-ray CCD detector, x-ray images were recorded using a single pulse from a laboratory x-ray source with a peak charging voltage of 200 kV. A resolving power of 300 was demonstrated by recording on film the Kα1 and Kα2 characteristic x-ray lines near 17 keV from a molybdenum anode. The continuum radiation from a tungsten anode was recorded in the 20-50 keV energy range. The transmission crystal spectrometer has sufficient spectral resolution and sensitivity to record the line and continuum radiation from high-Z targets irradiated by the NIF laser and the OMEGA laser.

  6. Coherent X-ray Imaging Techniques for Shock Physics

    NASA Astrophysics Data System (ADS)

    Montgomery, David

    2015-06-01

    X-ray radiography has been used for several decades in dynamic experiments to measure material flow in extreme conditions via absorption of x-rays propagating through the materials. Image contrast in traditional radiography is determined by the absorption coefficients and areal densities of the materials at a given x-ray wavelength, and often limits these measurements to materials with sufficiently high atomic numbers and areal density, while low-Z materials and small areal density variations are completely transparent and not visible in the image. Coherent x-ray sources, such as those found at synchrotrons and x-ray free-electron lasers, provide new opportunities for imaging dynamic experiments due to their high spatial and spectral coherence, high brightness and short temporal duration (<100 ps). Phase-sensitive techniques, such as phase contrast imaging (PCI), rely on the overlap and interference of the x-rays due to spatial variations in their transmitted phase, and are enabled primarily by high spatial coherence of the x-ray source. Objects that are otherwise transparent to x-rays can be imaged with PCI, and small variations in areal density become visible that would be not observable with traditional radiography. In this talk an overview of PCI will be given, and current applications of this technique in high-energy density physics, shock physics and material dynamics will be presented. Other future uses of imaging using coherent x-ray sources in dynamic high-pressure experiments will be discussed. Work performed under the auspices of DOE by LANL under Contract DE-AC52-06NA25396.

  7. The ASTROSAT mission and study of X-ray binaries.

    NASA Astrophysics Data System (ADS)

    Somasundaram, Seetha

    2016-07-01

    The ASTROnomy SATellite (ASTROSAT) is the first Indian astronomy mission. The scientific objectives to be addressed using ASTROSAT are To understand high energy processes in binary systems containing neutron stars and black hole sources, estimate magnetic fields of neutron stars, study star birth regions and high energy processes in extragalactic systems, and detect new transient X-ray sources. To achieve this ASTROSAT has a suite of experiments to conduct Multiwavelength studies, covering the energy bands in the UV (NUV and FUV), limited optical, and X-ray regime (0.3 keV to 100keV). This will provide wide spectral coverage to study thermal and non-thermal spectra. High resolution timing capability will also enable study of periodic and aperiodic time variabilities in X-ray sources, including high frequency QPOs. This talk will provide a brief description of the instrument capabilities of ASTROSAT and some initial results.

  8. X-ray properties of planet-bearing host stars

    NASA Astrophysics Data System (ADS)

    Schmitt, Jurgen

    2007-10-01

    We propose to carry out a complete X-ray census of planet-bearing host stars with a distance limit of 30 pc. We specifically propose to obtain well-exposed EPIC spectra of those stars harboring close-in (Porb < 10 days) planets and to carry out detection experiments on planet-bearing stars hitherto not detected in X-rays. With the these data we will characterize the high-energy radiation field for a representative sample of nearby planet-bearing stars, compute the expected evaporation rates due to the host stars' X-ray and UV irradiation, study the metal abundance of the coronae of planet bearing host stars, assess the frequency of flaring events in our sample, construct luminosity distribution functions and place the high-energy environment of the Sun in the context of that for extrasolar planets.

  9. Simultaneous parameter optimization of x-ray and neutron reflectivity data using genetic algorithms

    NASA Astrophysics Data System (ADS)

    Singh, Surendra; Basu, Saibal

    2016-05-01

    X-ray and neutron reflectivity are two non destructive techniques which provide a wealth of information on thickness, structure and interracial properties in nanometer length scale. Combination of X-ray and neutron reflectivity is well suited for obtaining physical parameters of nanostructured thin films and superlattices. Neutrons provide a different contrast between the elements than X-rays and are also sensitive to the magnetization depth profile in thin films and superlattices. The real space information is extracted by fitting a model for the structure of the thin film sample in reflectometry experiments. We have applied a Genetic Algorithms technique to extract depth dependent structure and magnetic in thin film and multilayer systems by simultaneously fitting X-ray and neutron reflectivity data.

  10. A Simulation Study on the Flash X-Ray Spectra Spatial Distribution

    NASA Astrophysics Data System (ADS)

    Xu, Xiufeng; Li, Shiping; Cao, Hongrui; Xiao, Rui; Chen, Nan; Zhang, Linwen; Yin, Zejie

    2013-11-01

    Accurate measurement of flash X-ray energy spectra plays an important role in high-energy flash radiography. In this paper, by virtue of Geant4 toolkit, we simulated the generation and transport of X-ray photons resulting from the interaction of a high-energy electron beam with a solid thin target. We obtained the flash X-ray energy spectral distribution in the plane perpendicular to the electron beam incident direction. Our results indicate that the flash X-ray spectrum is almost uniform in the azimuthal direction but is quite different in the radius direction. Specifically, as the radius increases, the incident X-ray dose decreases significantly. Our work paves a theoretical basis for selecting appropriate structures and layout of the spectrometer and facilitates the measurements of flash X-ray energy spectra.

  11. Ultrafast phase contrast imaging of laser driven shocks using betatron X-rays

    NASA Astrophysics Data System (ADS)

    Chapman, D. J.; Rutherford, M. E.; White, T. G.; Eakins, D. E.; Wood, J. C.; Poder, K.; Lopes, N. C.; Bryant, J. S. J.; Mangles, S. P. D.; Najmudin, Z.; Cole, J. S.; Albert, F.; Pollack, B. B.; Behm, K. T.; Zhao, Z.; Thomas, A. G. R.; Krushelnick, K.; Schumaker, W.; Glenzer, S.

    2015-06-01

    Bright, high-energy photon sources, such as synchrotrons and more recently the new generation of X-ray free-electron lasers, offer the attractive combination of high brilliance, short pulse duration and high-energy X-rays. Betatron X-rays produced within a laser-plasma wakefield accelerator provide an exciting complementary energetic photon source to these large scale facilities. We describe the first proof-of-principle experiments imaging shock-front evolution in laser driven targets using wakefield betatron X-rays. These pioneering experiments were performed on the 400TW Gemini laser at the Rutherford Appleton Laboratory, UK. Shock waves were driven into silicon wafers along the [100] direction, and stroboscopically imaged perpendicular to the shock propagation direction using a ~ 40 fs betatron X-ray pulse. These initial results showcase a promising, potentially table top sized X-ray source suitable for probing the response of materials under extreme condition.

  12. Spectral unfolds of PITHON Flash X-ray source.

    SciTech Connect

    Zarick, Thomas Andrew; Sheridan, Timothy J.; Hartman, E. Frederick; Riordan, John C.

    2007-11-01

    Using a differential absorption spectrometer we obtained experimental spectral information for the PITHON Flash X-ray Machine located in San Leandro, California at L-3 Communications. Spectral information we obtained pertained to the 200 keV to 800 keV endpoint operation of PITHON. We also obtained data on the temporal behavior of high energy and low energy spectral content.

  13. Discovery of Spatial and Spectral Structure in the X-Ray Emission from the Crab Nebula

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Hester, J. Jeff; Tennant, Allyn F.; Elsner, Ronald F.; Schulz, Norbert S.; Marshall, Herman L.; Karovska, Margarita; Nichols, Joy S.; Swartz, Douglas A.; Kolodziejczak, Jeffery J.

    2000-01-01

    The Chandra X-Ray Observatory observed the Crab Nebula and pulsar during orbital calibration. Zeroth-order images with the High-Energy Transmission Grating (HETG) readout by the Advanced Charge Coupled Devices (CCD) Imaging Spectrometer spectroscopy array (ACIS-S) show a striking richness of X-ray structure at a resolution comparable to that of the best ground-based visible-light observations. The HETG-ACIS-S images reveal, for the first time, an X-ray inner ring within the X-ray torus, the suggestion of a hollow-tube structure for the torus, and X-ray knots along the inner ring and (perhaps) along the inward extension of the X-ray jet. Although complicated by instrumental effects and the brightness of the Crab Nebula, the spectrometric analysis shows systematic variations of the X-ray spectrum throughout the nebula.

  14. High-energy spectroscopic astrophysics

    NASA Astrophysics Data System (ADS)

    Güdel, Manuel; Walter, Roland

    After three decades of intense research in X-ray and gamma-ray astronomy, the time was ripe to summarize basic knowledge on X-ray and gamma-ray spectroscopy for interested students and researchers ready to become involved in new high-energy missions. This volume exposes both the scientific basics and modern methods of high-energy spectroscopic astrophysics. The emphasis is on physical principles and observing methods rather than a discussion of particular classes of high-energy objects, but many examples and new results are included in the three chapters as well.

  15. A novel instrument for quantitative nanoanalytics involving complementary X-ray methodologies

    SciTech Connect

    Lubeck, J.; Beckhoff, B.; Fliegauf, R.; Holfelder, I.; Hoenicke, P.; Mueller, M.; Pollakowski, B.; Reinhardt, F.; Weser, J.

    2013-04-15

    A novel ultra-high vacuum instrument for X-ray reflectometry and spectrometry-related techniques for nanoanalytics by means of synchrotron radiation has been constructed and commissioned. This versatile instrument was developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute, and includes a 9-axis manipulator that allows for an independent alignment of the samples with respect to all degrees of freedom. In addition, a rotational and translational movement of several photodiodes as well as a translational movement of an aperture system in and out of the beam is provided. Thus, the new instrument enables various analytical techniques based on energy dispersive X-ray detectors such as reference-free X-ray fluorescence analysis (XRF), total-reflection XRF, grazing-incidence XRF in addition to optional X-ray reflectometry measurements or polarization-dependent X-ray absorption fine structure analyses. With this instrument samples having a size of up to 100 mm Multiplication-Sign 100 mm can be analyzed with respect to their mass deposition, elemental or spatial composition, or the species in order to probe surface contamination, layer composition and thickness, the depth profile of matrix elements or implants, the species of nanolayers, nanoparticles or buried interfaces as well as the molecular orientation of bonds. Selected applications of this advanced ultra-high vacuum instrument demonstrate both its flexibility and capability.

  16. X-ray Echo Spectroscopy.

    PubMed

    Shvyd'ko, Yuri

    2016-02-26

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >10^{8}) with broadband ≃5-13  meV dispersing systems are introduced featuring more than 10^{3} signal enhancement. The technique is general, applicable in different photon frequency domains. PMID:26967404

  17. X-ray Echo Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri

    2016-02-01

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

  18. A short working distance multiple crystal x-ray spectrometer

    USGS Publications Warehouse

    Dickinson, B.; Seidler, G.T.; Webb, Z.W.; Bradley, J.A.; Nagle, K.P.; Heald, S.M.; Gordon, R.A.; Chou, I.-Ming

    2008-01-01

    For x-ray spot sizes of a few tens of microns or smaller, a millimeter-sized flat analyzer crystal placed ???1 cm from the sample will exhibit high energy resolution while subtending a collection solid angle comparable to that of a typical spherically bent crystal analyzer (SBCA) at much larger working distances. Based on this observation and a nonfocusing geometry for the analyzer optic, we have constructed and tested a short working distance (SWD) multicrystal x-ray spectrometer. This prototype instrument has a maximum effective collection solid angle of 0.14 sr, comparable to that of 17 SBCA at 1 m working distance. We find good agreement with prior work for measurements of the Mn K?? x-ray emission and resonant inelastic x-ray scattering for MnO, and also for measurements of the x-ray absorption near-edge structure for Dy metal using L??2 partial-fluorescence yield detection. We discuss future applications at third- and fourth-generation light sources. For concentrated samples, the extremely large collection angle of SWD spectrometers will permit collection of high-resolution x-ray emission spectra with a single pulse of the Linac Coherent Light Source. The range of applications of SWD spectrometers and traditional multi-SBCA instruments has some overlap, but also is significantly complementary. ?? 2008 American Institute of Physics.

  19. The Focusing Optics Solar X-ray Imager (FOXSI)

    NASA Astrophysics Data System (ADS)

    Christe, S.; Glesener, L.; Krucker, S.; Ramsey, B.; Ishikawa, S.; Takahashi, T.

    2009-12-01

    The Focusing Optics x-ray Solar Imager is a sounding rocket payload funded under the NASA Low Cost Access to Space program to test hard x-ray focusing optics and position-sensitive solid state detectors for solar observations. Today's leading solar hard x-ray instrument, the Reuven Ramaty High Energy Solar Spectroscopic Imager provides excellent spatial (2 arcseconds) and spectral (1~keV) resolution. Yet, due to its use of indirect imaging, the derived images have a low dynamic range (<30) and sensitivity. These limitations make it difficult to study faint x-ray sources in the solar corona which are crucial for understanding the solar flare acceleration process. Grazing-incidence x-ray focusing optics combined with position-sensitive solid state detectors can overcome both of these limitations enabling the next breakthrough in understanding particle acceleration in solar flares. The foxsi project is led by the Space Science Laboratory at the University of California. The NASA Marshall Space Flight Center, with experience from the HERO balloon project, is responsible for the grazing-incidence optics, while the Astro H team (JAXA/ISAS) will provide double-sided silicon strip detectors. FOXSI will be a pathfinder for the next generation of solar hard x-ray spectroscopic imagers. Such observatories will be able to image the non-thermal electrons within the solar flare acceleration region, trace their paths through the corona, and provide essential quantitative measurements such as energy spectra, density, and energy content in accelerated electrons.

  20. X-ray laser interferometry: A new tool for AGEX

    SciTech Connect

    Wan, A.S.; Moreno, J.C.; Libby, S.B.

    1995-10-01

    Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 4--40 nm. With the recent advances in the development of multilayer mirrors and beamsplitters in the soft x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. By employing a shorter wavelength x-ray laser, as compared to using conventional optical laser as the probe source, we can access a much higher density regime while reducing refractive effects which limit the spatial resolution and data interpretation. Using a neon-like yttrium x-ray laser which operates at a wavelength of 15.5 mn, we have performed a series of soft x-ray laser interferometry experiments, operated in the skewed Mach-Zehnder configuration, to characterize plasmas relevant to both weapons and inertial confinement fusion. The two-dimensional density profiles obtained from the interferograms allow us to validate and benchmark our numerical models used to study the physics in the high-energy density regime, relevant to both weapons and inertial confinement fusion.