WorldWideScience

Sample records for broadband x-ray spectra

  1. Broadband X-ray spectra of the ultraluminous x-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

    DEFF Research Database (Denmark)

    Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.

    2014-01-01

    We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the...

  2. Applying a physical continuum model to describe the broadband X-ray spectra of accreting pulsars at high luminosity

    Science.gov (United States)

    Pottschmidt, Katja; Hemphill, Paul B.; Wolff, Michael T.; Cheatham, Diana M.; Iwakiri, Wataru; Gottlieb, Amy M.; Falkner, Sebastian; Ballhausen, Ralf; Fuerst, Felix; Kuehnel, Matthias; Ferrigno, Carlo; Becker, Peter A.; Wood, Kent S.; Wilms, Joern

    2018-01-01

    A new window for better understanding the accretion onto strongly magnetized neutron stars in X-ray binaries is opening. In these systems the accreted material follows the magnetic field lines as it approaches the neutron star, forming accretion columns above the magnetic poles. The plasma falls toward the neutron star surface at near-relativistic speeds, losing energy by emitting X-rays. The X-ray spectral continua are commonly described using phenomenological models, i.e., power laws with different types of curved cut-offs at higher energies. Here we consider high luminosity pulsars. In these systems the mass transfer rate is high enough that the accreting plasma is thought to be decelerated in a radiation-dominated radiative shock in the accretion columns. While the theory of the emission from such shocks had already been developed by 2007, a model for direct comparison with X-ray continuum spectra in xspec or isis has only recently become available. Characteristic parameters of this model are the accretion column radius and the plasma temperature, among others. Here we analyze the broadband X-ray spectra of the accreting pulsars Centaurus X-3 and 4U 1626-67 obtained with NuSTAR. We present results from traditional empirical modeling as well as successfully apply the radiation-dominated radiative shock model. We also take the opportunity to compare to similar recent analyses of both sources using these and other observations.

  3. THE BROADBAND XMM-NEWTON AND NuSTAR X-RAY SPECTRA OF TWO ULTRALUMINOUS X-RAY SOURCES IN THE GALAXY IC 342

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Vikram; Harrison, Fiona A.; Walton, Dominic J.; Furst, Felix; Grefenstette, Brian W.; Madsen, Kristin K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Bachetti, Matteo; Barret, Didier; Webb, Natalie A. [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Miller, Jon M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Fabian, Andrew C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, Finn C. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Ptak, Andrew F.; Zhang, William W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-02-01

    We present results for two ultraluminous X-ray sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by ∼7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3-30 keV luminosities being 1.04{sub −0.06}{sup +0.08}×10{sup 40} erg s{sup –1} for IC 342 X-1 and 7.40 ± 0.20 × 10{sup 39} erg s{sup –1} for IC 342 X-2, so that both were observed in a similar, luminous state. Both sources have a high absorbing column in excess of the Galactic value. Neither source has a spectrum consistent with a black hole binary in low/hard state, and both ULXs exhibit strong curvature in their broadband X-ray spectra. This curvature rules out models that invoke a simple reflection-dominated spectrum with a broadened iron line and no cutoff in the illuminating power-law continuum. X-ray spectrum of IC 342 X-1 can be characterized by a soft disk-like blackbody component at low energies and a cool, optically thick Comptonization continuum at high energies, but unique physical interpretation of the spectral components remains challenging. The broadband spectrum of IC 342 X-2 can be fit by either a hot (3.8 keV) accretion disk or a Comptonized continuum with no indication of a seed photon population. Although the seed photon component may be masked by soft excess emission unlikely to be associated with the binary system, combined with the high absorption column, it is more plausible that the broadband X-ray emission arises from a simple thin blackbody disk component. Secure identification of the origin of the spectral components in these sources will likely require broadband spectral variability studies.

  4. Broadband X-ray spectra of the ultraluminous X-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

    Energy Technology Data Exchange (ETDEWEB)

    Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.; Fuerst, F.; Madsen, K. K.; Rana, V.; Stern, D. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Miller, J. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Bachetti, M.; Barret, D.; Webb, N. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C.; Parker, M. L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Ptak, A.; Zhang, W. W., E-mail: dwalton@srl.caltech.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-09-20

    We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the X-ray coverage of this remarkable source up to ∼30 keV. Broadband observations were undertaken at two epochs, between which Holmberg IX X-1 exhibited both flux and strong spectral variability, increasing in luminosity from L {sub X} = (1.90 ± 0.03) × 10{sup 40} erg s{sup –1} to L {sub X} = (3.35 ± 0.03) × 10{sup 40} erg s{sup –1}. Neither epoch exhibits a spectrum consistent with emission from the standard low/hard accretion state seen in Galactic black hole binaries, which would have been expected if Holmberg IX X-1 harbors a truly massive black hole accreting at substantially sub-Eddington accretion rates. The NuSTAR data confirm that the curvature observed previously in the 3-10 keV bandpass does represent a true spectral cutoff. During each epoch, the spectrum appears to be dominated by two optically thick thermal components, likely associated with an accretion disk. The spectrum also shows some evidence for a nonthermal tail at the highest energies, which may further support this scenario. The available data allow for either of the two thermal components to dominate the spectral evolution, although both scenarios require highly nonstandard behavior for thermal accretion disk emission.

  5. New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei

    Science.gov (United States)

    Baloković, M.; Brightman, M.; Harrison, F. A.; Comastri, A.; Ricci, C.; Buchner, J.; Gandhi, P.; Farrah, D.; Stern, D.

    2018-02-01

    The basic unified model of active galactic nuclei (AGNs) invokes an anisotropic obscuring structure, usually referred to as a torus, to explain AGN obscuration as an angle-dependent effect. We present a new grid of X-ray spectral templates based on radiative transfer calculations in neutral gas in an approximately toroidal geometry, appropriate for CCD-resolution X-ray spectra (FWHM ≥ 130 eV). Fitting the templates to broadband X-ray spectra of AGNs provides constraints on two important geometrical parameters of the gas distribution around the supermassive black hole: the average column density and the covering factor. Compared to the currently available spectral templates, our model is more flexible, and capable of providing constraints on the main torus parameters in a wider range of AGNs. We demonstrate the application of this model using hard X-ray spectra from NuSTAR (3–79 keV) for four AGNs covering a variety of classifications: 3C 390.3, NGC 2110, IC 5063, and NGC 7582. This small set of examples was chosen to illustrate the range of possible torus configurations, from disk-like to sphere-like geometries with column densities below, as well as above, the Compton-thick threshold. This diversity of torus properties challenges the simple assumption of a standard geometrically and optically thick toroidal structure commonly invoked in the basic form of the unified model of AGNs. Finding broad consistency between our constraints and those from infrared modeling, we discuss how the approach from the X-ray band complements similar measurements of AGN structures at other wavelengths.

  6. X-ray Emitting GHz-Peaked Spectrum Galaxies: Testing a Dynamical-Radiative Model with Broad-Band Spectra

    International Nuclear Information System (INIS)

    Ostorero, L.; Moderski, R.; Stawarz, L.; Diaferio, A.; Kowalska, I.; Cheung, C.C.; Kataoka, J.; Begelman, M.C.; Wagner, S.J.

    2010-01-01

    In a dynamical-radiative model we recently developed to describe the physics of compact, GHz-Peaked-Spectrum (GPS) sources, the relativistic jets propagate across the inner, kpc-sized region of the host galaxy, while the electron population of the expanding lobes evolves and emits synchrotron and inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the expanding lobes, and photoionized by the active nucleus, are responsible for the radio spectral turnover through free-free absorption (FFA) of the synchrotron photons. The model provides a description of the evolution of the GPS spectral energy distribution (SED) with the source expansion, predicting significant and complex high-energy emission, from the X-ray to the γ-ray frequency domain. Here, we test this model with the broad-band SEDs of a sample of eleven X-ray emitting GPS galaxies with Compact-Symmetric-Object (CSO) morphology, and show that: (i) the shape of the radio continuum at frequencies lower than the spectral turnover is indeed well accounted for by the FFA mechanism; (ii) the observed X-ray spectra can be interpreted as non-thermal radiation produced via IC scattering of the local radiation fields off the lobe particles, providing a viable alternative to the thermal, accretion-disk dominated scenario. We also show that the relation between the hydrogen column densities derived from the X-ray (N H ) and radio (N HI ) data of the sources is suggestive of a positive correlation, which, if confirmed by future observations, would provide further support to our scenario of high-energy emitting lobes.

  7. Broad-band hard X-ray reflectors

    DEFF Research Database (Denmark)

    Joensen, K.D.; Gorenstein, P.; Hoghoj, P.

    1997-01-01

    Interest in optics for hard X-ray broad-band application is growing. In this paper, we compare the hard X-ray (20-100 keV) reflectivity obtained with an energy-dispersive reflectometer, of a standard commercial gold thin-film with that of a 600 bilayer W/Si X-ray supermirror. The reflectivity...... of the multilayer is found to agree extraordinarily well with theory (assuming an interface roughness of 4.5 Angstrom), while the agreement for the gold film is less, The overall performance of the supermirror is superior to that of gold, extending the band of reflection at least a factor of 2.8 beyond...... that of the gold, Various other design options are discussed, and we conclude that continued interest in the X-ray supermirror for broad-band hard X-ray applications is warranted....

  8. Indirect measurements of X-ray spectra

    International Nuclear Information System (INIS)

    Mainardi, R.T.

    2006-01-01

    To the effects of measuring the spectral distribution of the radiation emitted by the x-ray tubes and electron accelerators, numerous procedures that are grouped in two big categories exist at the present time: direct and indirect methods. The first ones use high resolution detectors that should be positioned, together with the appropriate collimator, in the direction of the x ray beam. The user should be an expert in the use and correction of the obtained data by the different effects that affect the detector operation such as efficiency and resolution in terms of the energy of the detected radiation. The indirect procedures, although its are more simple to use, its also require a considerable space along the beam to position the ionization chamber and the necessary absorbents to construct by this way the denominated attenuation curve. We will analyze the operation principle of the indirect methods and a new proposal in which such important novelties are introduced as the beam dispersion to avoid to measure along the main beam and that of determination of the attenuation curve in simultaneous form. By this way, with a single shot of the tube, the attenuation curve is measured, being necessary at most a shot of additional calibration to know the relative response of the detectors used in the experimental array. The physical processes involved in the obtaining of an attenuation curve are very well well-known and this it finishes it can be theoretically calculated if the analytic form of the spectrum is supposed well-known. Finally, we will see a spectra reconstruction example with the Kramers parametric form and comparisons with numeric simulations carried out with broadly validated programs as well as the possibility of the use of solid state dosemeters in the obtention of the attenuation curve. (Author)

  9. The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous X-ray Sources in the Galaxy IC 342

    DEFF Research Database (Denmark)

    Rana, Vikram; Harrison, Fiona A.; Bachetti, Matteo

    2015-01-01

    We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by ∼7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3-30 keV luminosities being $1.04+0.0...

  10. A broadband x-ray study of the Geminga pulsar with NuSTAR and XMM-Newton

    DEFF Research Database (Denmark)

    Mori, Kaya; Gotthelf, Eric V.; Dufour, Francois

    2014-01-01

    We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) observatory. The double-peaked pulse profile of non-thermal emission seen in the soft X-ray band persists at higher energies. Broadband......V. The spectral hardening in non-thermal X-ray emission as well as spectral flattening between the optical and X-ray bands argue against the conjecture that a single power law may account for multi-wavelength non-thermal spectra of middle-aged pulsars....

  11. Chemical effects in x-ray emission spectra

    International Nuclear Information System (INIS)

    Fernandes, N.G.

    1982-01-01

    The chemical bond influence in X-ray emission spectra of hafnium, iodine, iron, sulphur, aluminium and magnesium is detected. The position of one X-ray emission line is determined by three methods: parabolic profile; Gaussian distribution and extra-heavy maximum. (author)

  12. Theory of X-ray absorption and emission spectra

    International Nuclear Information System (INIS)

    Mukoyama, Takeshi

    2004-01-01

    Theoretical studies on X-ray absorption and emission spectroscopy are discussed. Simple expressions for X-ray emission rate and X-ray absorption cross section are presented in the dipole approximation. Various atomic models to obtain realistic wave functions and theoretical calculations for X-ray absorption cross sections and X-ray emission rates are described. In the case of molecules and solids, molecular orbital methods for electronic structures and molecular wave functions are discussed. The emphasis is on the procedures to obtain the excited-state and continuum wave functions for molecules and to calculate the multi-center dipole matrix elements. The examples of the calculated X-ray absorption and emission spectra are shown and compared with the experimental results

  13. X ray spectra of X Per. [oso-8 observations

    Science.gov (United States)

    Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

  14. Diversity of soft X-ray spectra in quasars

    International Nuclear Information System (INIS)

    Elvis, M.; Wilkes, B.J.; Tananbaum, H.

    1985-01-01

    Soft X-ray spectra for three quasars obtained with the Einstein Imaging Proportional Counter covering the 0.1-4.0 keV band are reported. Power-law fits to these spectra have best-fit energy indices of 1.2 +0.6 or -0.2, for the quasar NAB 0205 + 024, 0.6 +0.3 or -0.2 for the quasar B2 1028 + 313, and 2.2 + or -0.4 for the quasar PG 1211 + 143. None of the quasars shows any evidence for a column density of cold matter in excess of the galactic values. The derived spectra demonstrate that there is no single universal power law slope for quasar X-ray spectra. The implications of these results for the X-ray background, X-ray continuum emission mechanisms, and the production of the optical/UV emission lines are briefly discussed. 46 references

  15. X-ray spectra of PG quasars. I. The continuum from X-rays to infrared

    International Nuclear Information System (INIS)

    Elvis, M.; Green, R.F.; Bechtold, J.; Schmidt, M.; Neugebauer, G.; Kitt Peak National Observatory, Tucson, AZ; Steward Observatory, Tucson, AZ; Palomar Observatory, Pasadena, CA)

    1986-01-01

    Einstein IPC X-ray spectra for a sample of eight optically selected quasars from the Palomar Bright Quasar survey are presented. The quasars have a mean power law energy slope which in five individual cases is inconsistent with the value found in hard X-ray selection criterion rather than luminosity, redshift, or U-B color. New IUE and optical continuum spectra and infrared photometry are presented for these quasars. The data are combined into log vf(v) and log v distributions which support the decomposition of the overall quasar spectrum into a power law plus a superposed optical-UV big bump which may be due to an accretion disk. At least six of the quasars have vf(v)s which are roughly constant between their infrared and X-ray power laws, suggesting a strong link between the two regions. 104 references

  16. Monte Carlo simulation of x-ray spectra in mammography

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.P. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China). E-mail: benngkp at netvigator.com; Kwok, C.S.; Ng, K.P.; Tang, F.H. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2000-05-01

    A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The {chi}{sup 2} test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the {chi}{sup 2} test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

  17. Monte Carlo simulation of x-ray spectra in mammography

    International Nuclear Information System (INIS)

    Ng, K.P.

    2000-01-01

    A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The χ 2 test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the χ 2 test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

  18. X-ray Spectra of Distant Clusters

    Science.gov (United States)

    Ellingson, E.

    1998-01-01

    The masses of galaxy clusters are dominated by dark matter, and a robust determination of their temperatures and masses has the potential of indicating how much dark matter exists on large scales in the universe, and the cosmological parameter Omega. X-ray observations of galaxy clusters provide a direct measure of both the gas mass in the intra-cluster medium, and also the total gravitating mass of the cluster. We used new and archival ASCA and ROSAT observations to measure these quantities for a sample of intermediate redshift clusters which have also been subject to intensive dynamical studies, in order to compare the mass estimates from different methods. We used data from 12 of the CNOC cluster sample at 0.18 less than z less than 0.55 for this study. A direct comparison of dynamical mass estimates from Carlberg, Yee & Ellingson (1997) yielded surprisingly good results. The X-ray/dynamical mass ratios have a mean of 0.96+/- 0.10, indicating that for this sample, both methods are probably yielding very robust mass estimates. Comparison with mass estimates from gravitational lensing studies from the literature showed a small systematic with weak lensing estimates, and large discrepancies with strong lensing estimates. This latter is not surprising, given that these measurements are made close to the central core, where optical and Xray estimates are less certain, and where substructure and the effects of individual galaxies will be more pronounced. These results are presented in Lewis, Ellingson, Morris \\& Carlberg, 1998, submitted to the Astrophysical Journal.

  19. Compton spectra of atoms at high x-ray intensity

    Science.gov (United States)

    Son, Sang-Kil; Geffert, Otfried; Santra, Robin

    2017-03-01

    Compton scattering is the nonresonant inelastic scattering of an x-ray photon by an electron and has been used to probe the electron momentum distribution in gas-phase and condensed-matter samples. In the low x-ray intensity regime, Compton scattering from atoms dominantly comes from bound electrons in neutral atoms, neglecting contributions from bound electrons in ions and free (ionized) electrons. In contrast, in the high x-ray intensity regime, the sample experiences severe ionization via x-ray multiphoton multiple ionization dynamics. Thus, it becomes necessary to take into account all the contributions to the Compton scattering signal when atoms are exposed to high-intensity x-ray pulses provided by x-ray free-electron lasers (XFELs). In this paper, we investigate the Compton spectra of atoms at high x-ray intensity, using an extension of the integrated x-ray atomic physics toolkit, xatom. As the x-ray fluence increases, there is a significant contribution from ionized electrons to the Compton spectra, which gives rise to strong deviations from the Compton spectra of neutral atoms. The present study provides not only understanding of the fundamental XFEL-matter interaction but also crucial information for single-particle imaging experiments, where Compton scattering is no longer negligible. , which features invited work from the best early-career researchers working within the scope of J. Phys. B. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Sang-Kil Son was selected by the Editorial Board of J. Phys. B as an Emerging Leader.

  20. Analysis of X-Ray (L) spectra of heavy elements

    International Nuclear Information System (INIS)

    Souza Coelho, L.F. de.

    1976-08-01

    The general problem of obtaining and analysing spectra is presented, with emphasis in the comparison of methods for the analysis of gamma rays and X rays. The method proposed to obtain a standard and later the intensities of lines of an X-ray (L) spectrum is discussed. The good eesults obtained by the program RAIOXL, when simulated spectra are used, and by the program RAIXL1, when doublets are decomposed, are shown. In annex A, the listings of the programs used are presented, and in annex B a review is made of the analytical formulae used for adjustment of the pulses. (I.C.R.) [pt

  1. LINE FORMATION IN SPECTRA OF X-RAY NOVAE

    OpenAIRE

    Suleimanov, V. F.; Shimansky, V. V.

    2017-01-01

    Results of X-ray Novae (XN) optical spectra computation are presented. The continuum and Balmer line are calculated. The model of XN as a self-irradiated accretion disk is used. Local (for given radius) disk atmospheres as model stellar atmospheres, heated due to external X-ray radiation are treated. Changes of spectra shape and equivalent widths of the Balmer lines depending from the luminosity and some others accretion disk parameters are investigated. The comparison of GRO JO422+32 observe...

  2. Soft x-ray absorption spectra of ilmenite family.

    Science.gov (United States)

    Agui, A; Mizumaki, M; Saitoh, Y; Matsushita, T; Nakatani, T; Fukaya, A; Torikai, E

    2001-03-01

    We have carried out soft x-ray absorption spectroscopy to study the electronic structure of ilmenite family, such as MnTiO3, FeTiO3, and CoTiO3 at the soft x-ray beamline, BL23SU, at the SPring-8. The Ti and M L2,3 absorption spectra of MTiO3 (M=Mn, Fe, and Co) show spectra of Ti4+ and M2+ electron configurations, respectively. Except the Fe L2,3 spectrum, those spectra were understood within the O(h) symmetry around the transition metal ions. The Fe L3-edge spectrum clearly shows a doublet peak at the L3 edge, which is attributed to Fe2+ state, moreover the very high-resolution the L-edge spectra of transition metals show fine structures. The spectra of those ilmenites are compared.

  3. Model independent method to deconvolve hard X-ray spectra

    Energy Technology Data Exchange (ETDEWEB)

    Polcaro, V.F.; Bazzano, A.; Ubertini, P.; La Padula, C. (Consiglio Nazionale delle Ricerche, Frascati (Italy). Lab. di Astrofisica Spaziale); Manchanda, R.K. (Tata Inst. of Fundamental Research, Bombay (India))

    1984-07-01

    A general purpose method to deconvolve the energy spectra detected by means of the use of a hard X-ray telescope is described. The procedure does not assume any form of input spectrum and the observed energy loss spectrum is directly deconvolved into the incident photon spectrum, the form of which can be determined independently of physical interpretation of the data. Deconvolution of the hard X-ray spectrum of Her X-1, detected during the HXR 81M experiment, by the method independent method is presented.

  4. High-resolution x-ray photoemission spectra of silver

    DEFF Research Database (Denmark)

    Barrie, A.; Christensen, N. E.

    1976-01-01

    An electron spectrometer fitted with an x-ray monochromator for Al Kα1,2 radiation (1486.6 eV) has been used to record high-resolution x-ray photoelectron spectra for the 4d valence band as well as the 3d spin doublet in silver. The core-level spectrum has a line shape that can be described...... successfully in terms of the many-body theory of Mahan, Nozières, and De Dominicis. The 4d spectrum agrees well with predictions based on a relativistic-augmented-plane-wave band-structure calculation....

  5. Tetrahedral hydrocarbon nanoparticles in space: X-ray spectra

    Science.gov (United States)

    Bilalbegović, G.; Maksimović, A.; Valencic, L. A.

    2018-06-01

    It has been proposed, or confirmed, that diamond nanoparticles exist in various environments in space: close to active galactic nuclei, in the vicinity of supernovae and pulsars, in the interior of several planets in the Solar system, in carbon planets, and other exoplanets, carbon-rich stars, meteorites, in X-ray active Herbig Ae/Be stars, and in the interstellar medium. Using density functional theory methods, we calculate the carbon K-edge X-ray absorption spectrum of two large tetrahedral nanodiamonds: C26H32 and C51H52. We also study and test our methods on the astrophysical molecule CH4, the smallest C-H tetrahedral structure. A possible detection of nanodiamonds from X-ray spectra by future telescopes, such as the project Arcus, is proposed. Simulated spectra of the diffuse interstellar medium using Cyg X-2 as a source show that nanodiamonds studied in this work can be detected by Arcus, a high-resolution X-ray spectrometer mission selected by NASA for a Phase A concept study.

  6. On hard X-ray spectra of accreting neutron stars

    International Nuclear Information System (INIS)

    Zheleznyakov, V.V.

    1982-01-01

    Formation of the spectra of X-ray pulsars and gamma bursters is investigated. Interpretation of a hard X-ray spectrum of pulsars containing cyclotron lines is feasible on the basis of an isothermal model of a polar spot heated due to acccretion to a neutron star. It has been ascertained that in the regions responsible for the formation of continuum radiation and lines the mode polarization is determined by a magnetized vacuum rather than by a plasma. Bearing this in mind, the influence of the magnetic field of a star on the wide wings of the cyclotron line and on its depth is discussed. The part played by the accreting column in the case of strong accretion (approx. equal to 10 19 el cm -3 ) needed for long sustaining of the high level of X-rays from a neutron star-pulsar is studied. There occur the gaps in spectrum at frequencies close to the electron gyro-frequency and its harmonics due to the screening of the hot spot by the opaque gyro-resonant layer located within the accreting column. These gaps ensure the formation of cyclotron lines in absorption irrespective of the presence of such lines in the X-ray spectrum of a polar hot spot. (orig./WL)

  7. X-ray absorption spectra and emission spectra of plasmas

    International Nuclear Information System (INIS)

    Peng Yonglun; Yang Li; Wang Minsheng; Li Jiaming

    2002-01-01

    The author reports a theoretical method to calculate the resolved absorption spectra and emission spectra (optically thin) of hot dense plasmas. Due to its fully relativistic treatment incorporated with the quantum defect theory, it calculates the absorption spectra and emission spectra for single element or multi-element plasmas with little computational efforts. The calculated absorption spectra of LTE gold plasmas agree well with the experimental ones. It also calculates the optical thin emission spectra of LTE gold plasmas, which is helpful to diagnose the plasmas of relevant ICF plasmas. It can also provide the relevant parameters such as population density of various ionic stages, precise radiative properties for ICF studies

  8. X-ray scattering in X-ray fluorescence spectra with X-ray tube excitation - Modelling, experiment, and Monte-Carlo simulation

    International Nuclear Information System (INIS)

    Hodoroaba, V.-D.; Radtke, M.; Vincze, L.; Rackwitz, V.; Reuter, D.

    2010-01-01

    X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The knowledge of the X-ray spectrometer efficiency, but also of the spectrometer response functions makes it possible to define a physical spectral background of XRF spectra. Background subtraction relying on purely mathematical procedures is state-of-the-art. The results produced by the analytical model are at least as reliable as those obtained by Monte-Carlo simulations, even without considering the very challenging contribution of multiple scattering. Special attention has been paid to Compton broadening. Relevant applications of the implementation of the analytical model presented in this paper are the prediction of the limits of detection for particular cases or the determination of the transmission of X-ray polycapillary lenses.

  9. Broadband interference lithography at extreme ultraviolet and soft x-ray wavelengths.

    Science.gov (United States)

    Mojarad, Nassir; Fan, Daniel; Gobrecht, Jens; Ekinci, Yasin

    2014-04-15

    Manufacturing efficient and broadband optics is of high technological importance for various applications in all wavelength regimes. Particularly in the extreme ultraviolet and soft x-ray spectra, this becomes challenging due to the involved atomic absorption edges that rapidly change the optical constants in these ranges. Here we demonstrate a new interference lithography grating mask that can be used for nanopatterning in this spectral range. We demonstrate photolithography with cutting-edge resolution at 6.5 and 13.5 nm wavelengths, relevant to the semiconductor industry, as well as using 2.5 and 4.5 nm wavelength for patterning thick photoresists and fabricating high-aspect-ratio metal nanostructures for plasmonics and sensing applications.

  10. Spatially resolved X-ray spectra of coronal active regions

    International Nuclear Information System (INIS)

    Catura, R.C.; Acton, L.W.; Joki, E.G.; Rapley, C.G.; Culhane, J.L.

    1975-01-01

    X-ray spectra from a number of coronal active regions were obtained during ATM support rocket flights carried out by the Lockheed group on June 11 and December 19, 1973. Multi-grid collimators were used to provide fields of view of 40ins. diameter and 90ins. diameter for a number of scanning crystal spectrometers and a bent crystal spectrometer which employed a position sensitive proportional counter to register the diffracted spectrum. A solar image was produced on film and on a TV camera on board the rocket with the aid of a 1 A Hα filter. A small part of the X-ray collimator was used to generate a multiple spot diffraction pattern which was superimposed on the Hα image and the composite picture was transmitted to the ground. Pre-launch calibrations allowed the spot corresponding to the X-ray collimator axis to be identified and so the collimator pointing direction on the solar disc was controlled from the ground by means of commands sent to the rocket. (Auth.)

  11. Indirect measure of X-rays spectra using TLDs

    International Nuclear Information System (INIS)

    Bonzi, E. V.; Mainardi, R. T.

    2011-10-01

    A methodology of indirect measure of X-rays spectra, emitted by conventional tubes, was developed recently and its feasibility verified in the first place by Monte Carlo simulations. For that case is intended to measure, by means of plastic scintillators, attenuation curves of dispersed beams previously. In this work were carried out measurements of attenuation curves with thermoluminescent dosimeters (TLD) to verify the kindness of the indirect measure method. The attenuation curve was also measured using an ionization chamber brand Capintec (model 192) with the purpose of making a comparison. The results of the attenuation curve measured with both dosimeters present a good resolution inside the statistical fluctuations and the spectral reconstruction using diverse parametric functions is carried out in a quick and simple way with excellent resolutions in the functional form. For this reconstruction method are of fundamental importance the following properties of the used dosimeter: in the first place the repetition of the measures, property that could check; in second place the precision of the measured data and lastly the dosimeter response, this is, the increase of the thermoluminescent signal before an increase of the photons flow of X-rays. This parameter is the gradient of the curve thermoluminescent signal versus the dose imparted to the dosimeter. The measures were realized with a generator of X-rays brand Kevex provided of a conventional tube with tungsten anti cathode that polarizes with high tension to a maximum value of 50 kV and current of 0.5 ma. (Author)

  12. The high energy X-ray spectra of supernova remnants

    Science.gov (United States)

    Pravdo, S. H.; Nugent, J. J.

    The results of fitting an ionization-nonequilibrium (INE) model to the high-energy (above 5-keV) X-ray spectra of the young supernova remnants Cas A and Tycho are presented. As an additional constraint, the models must simultaneously fit lower-energy, higher-resolution data. For Cas A, a single INE component cannot adequately reproduce the features for the entire X-ray spectrum because the ionization structure of iron ions responsible for the K emission is inconsistent with that of the ions responsible for the lower-energy lines, and the flux of the highest-energy X-rays is underestimated. The iron K line and the high-energy continuum could arise from the same INE component, but the identification of this component with either the blast wave or the ejecta in the standard model is difficult. In Tycho, the high-energy data rule out a class of models for the lower-energy data which have too large a continuum contribution.

  13. Quantum chemistry interpretation of x-ray spectra

    International Nuclear Information System (INIS)

    Bocharov, D.; Kuzmin, A.

    2005-01-01

    Full text: In this study, we present the results of ab initio computer simulations on X-ray absorption spectra of some perovskite-type tungsten oxides. For our calculations, we combine a periodic bulk model with Hartree-Fock method including a posteriori electron correlation corrections, as implemented in CRYSTAL98 computer code [1]. First, we describe the results of calculations performed on some bulk properties of the tungsten oxides (lattice constant and bulk modulus), in order to achieve the necessary level of agreement with available experimental and theoretical data. Our calculations on the densities of oneelectron energy states (DOS) for models of tungsten oxides are verified by experimental X-ray absorption spectra, which allow us to make correct qualitative interpretation of the latter. The main difficulties appearing during our first principles simulations will be discussed. [1] V.R. Saunders, R. Dovesi, C. Roetti, M. Causi, N.M. Harrison, R. Orlando, and C.M. Zicovich-Wilson, CRYSTAL-98 User Manual, University of Turin, 1999

  14. Optimization and energy spectra of x-ray to be used for imaging

    International Nuclear Information System (INIS)

    Nakamori, Nobuyuki; Kanamori, Hitoshi

    1979-01-01

    The relations of the spectra of X-ray used for diagnosis to the absorbed dose of patients and X-ray information are now being investigated by a number of investigators. Here the problems and the trends of the investigations at present are described. Advent of semiconductor detectors has improved the accuracy of measuring X-ray spectra very rapidly. However, since the semiconductor detectors themselves utilize X-ray photon absorption, calibration curves must be prepared for obtaining the true X-ray spectra. Though there are methods of theoretically determining X-ray spectra, no definite theoretical formula is found. Thus, the derivation of an empirical equation based on measured data would be the most fundamental problem. Interactions in an object and the change of X-ray spectra are described on the case of monochromatic and continuous X-ray irradiation. As mentioned above, beam hardening occurs when X-ray enters a matter deep, because the interactions between X-ray and the matter depend upon the photon energy. There are a few methods for correcting the variation of CT (computed tomography) number due to beam hardening. However, prior to this, there are two methods of representing continuous X-ray with single energy, and the unification of the methods or a new way of defining X-ray quality is needed. It has been and is always desirable that monochromatic X-ray source becomes to be useable, and various methods are proposed. (Wakatsuki, Y.)

  15. New Observations of Soft X-ray (0.5-5 keV) Solar Spectra

    Science.gov (United States)

    Caspi, A.; Woods, T. N.; Mason, J. P.; Jones, A. R.; Warren, H. P.

    2013-12-01

    The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable on many time scales. However, the actual solar soft X-ray (SXR) (0.5-5 keV) spectrum is not well known, particularly during solar quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include high-resolution but very narrow-band spectra from crystal spectrometers (e.g., Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g., GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with moderate energy resolution (~0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and SAX on MESSENGER, although they did not extend to energies below ~1 keV. We present observations of solar SXR emission obtained using new instrumentation flown on recent SDO/EVE calibration rocket underflights. The photon-counting spectrometer, a commercial Amptek X123 with a silicon drift detector and an 8 μm Be window, measures the solar disk-integrated SXR emission from ~0.5 to >10 keV with ~0.15 keV FWHM resolution and 1 s cadence. A novel imager, a pinhole X-ray camera using a cooled frame-transfer CCD (15 μm pixel pitch), Ti/Al/C filter, and 5000 line/mm Au transmission grating, images the full Sun in multiple spectral orders from ~0.1 to ~5 nm with ~10 arcsec/pixel and ~0.01 nm/pixel spatial and spectral detector scales, respectively, and 10 s cadence. These instruments are prototypes for future CubeSat missions currently being developed. We present new results of solar observations on 04 October 2013 (NASA sounding rocket 36.290). We compare with previous results from 23 June 2012 (NASA sounding rocket 36.286), during which solar activity was low and no signal was observed above ~4 keV. We compare our spectral and imaging measurements with spectra and broadband irradiances from other instruments, including SDO/EVE, GOES/XRS, TIMED

  16. A model of tungsten anode x-ray spectra

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, G.; Fernández, F., E-mail: fdz@usal.es [Física Fundamental, Universidad de Salamanca, Salamanca 37008 (Spain)

    2016-08-15

    Purpose: A semiempirical model for x-ray production in tungsten thick-targets was evaluated using a new characterization of electron fluence. Methods: Electron fluence is modeled taking into account both the energy and angular distributions, each of them adjusted to Monte Carlo simulated data. Distances were scaled by the CSDA range to reduce the energy dependence. Bremsstrahlung production was found by integrating the cross section with the fluence in a 1D penetration model. Characteristic radiation was added using a semiempirical law whose validity was checked. The results were compared the experimental results of Bhat et al., with the SpekCalc numerical tool, and with MCNPX simulation results from the work of Hernandez and Boone. Results: The model described shows better agreement with the experimental results than the SpekCalc predictions in the sense of area between the spectra. A general improvement of the predictions of half-value layers is also found. The results are also in good agreement with the simulation results in the 50–640 keV energy range. Conclusions: A complete model for x-ray production in thick bremsstrahlung targets has been developed, improving the results of previous works and extending the energy range covered to the 50–640 keV interval.

  17. Comparison of hard X-ray spectra obtained by spectrometers on Hinotori and SMM and detection of 'superhot' component

    Science.gov (United States)

    Nitta, Nariaki

    1988-01-01

    Hard X-ray spectra in solar flares obtained by the broadband spectrometers aboard Hinotori and SMM are compared. Within the uncertainty brought about by assuming the typical energy of the background X-rays, spectra by the Hinotori spectrometer are usually consistent with those by the SMM spectrometer for flares in 1981. On the contrary, flares in 1982 persistently show 20-50-percent higher flux by Hinotori than by SMM. If this discrepancy is entirely attributable to errors in the calibration of energy ranges, the errors would be about 10 percent. Despite such a discrepancy in absolute flux, in the the decay phase of one flare, spectra revealed a hard X-ray component (probably a 'superhot' component) that could be explained neither by emission from a plasma at about 2 x 10 to the 7th K nor by a nonthermal power-law component. Imaging observations during this period show hard X-ray emission nearly cospatial with soft X-ray emission, in contrast with earlier times at which hard and soft X-rays come from different places.

  18. X-ray spectra of clusters of galaxies

    Science.gov (United States)

    Sarazin, Craig L.

    1990-01-01

    X-ray line observations of clusters of galaxies have shown that the X-ray emission in clusters is mainly thermal emission from hot diffuse gas, and that much of this gas has come out of stars, probably having been ejected from galaxies in the cluster. Future high resolution observations should allow us to determine the physical state of the gas. X-ray line measurements and abundance determinations can lead to strong constraints on the origin of the intracluster gas, and on the chemical evolution and history of galaxies. Some of the stronger resonant X-ray lines may be observable as absorption lines against a background quasar. Such X-ray absorption line measurement can be used to directly derive distances to clusters, using a technique similar to (and possibly complementary to) that the well-known method using the Zel'dovich-Syunyaev effect.

  19. THE XMM-NEWTON X-RAY SPECTRA OF THE MOST X-RAY LUMINOUS RADIO-QUIET ROSAT BRIGHT SURVEY-QSOs: A REFERENCE SAMPLE FOR THE INTERPRETATION OF HIGH-REDSHIFT QSO SPECTRA

    International Nuclear Information System (INIS)

    Krumpe, M.; Markowitz, A.; Lamer, G.; Corral, A.

    2010-01-01

    We present the broadband X-ray properties of four of the most X-ray luminous (L X ≥ 10 45 erg s -1 in the 0.5-2 keV band) radio-quiet QSOs found in the ROSAT Bright Survey. This uniform sample class, which explores the extreme end of the QSO luminosity function, exhibits surprisingly homogenous X-ray spectral properties: a soft excess with an extremely smooth shape containing no obvious discrete features, a hard power law above 2 keV, and a weak narrow/barely resolved Fe Kα fluorescence line for the three high signal-to-noise ratio (S/N) spectra. The soft excess can be well fitted with only a soft power law. No signatures of warm or cold intrinsic absorbers are found. The Fe Kα centroids and the line widths indicate emission from neutral Fe (E = 6.4 keV) originating from cold material from distances of only a few light days or further out. The well-constrained equivalent widths (EW) of the neutral Fe lines are higher than expected from the X-ray Baldwin effect which has been only poorly constrained at very high luminosities. Taking into account our individual EW measurements, we show that the X-ray Baldwin effect flattens above L X ∼ 10 44 erg s -1 (2-10 keV band) where an almost constant (EW) of ∼100 eV is found. We confirm the assumption of having very similar X-ray active galactic nucleus properties when interpreting stacked X-ray spectra. Our stacked spectrum serves as a superb reference for the interpretation of low S/N spectra of radio-quiet QSOs with similar luminosities at higher redshifts routinely detected by XMM-Newton and Chandra surveys.

  20. The Soft X-Ray Spectra of Sulfur Compounds.

    Science.gov (United States)

    Zhou, Ling

    1995-01-01

    The sulfur compounds including CdS, ZnS, rm MoS_2, WS_2, NiS, FeS, GaS, SnS, MgS and Alloy rm ZnS_{x }Se_{1-x} were investigated by using photon/e-beam excited soft x-ray spectroscopy through SXA, SXE, SXF and inelastic Resonant Raman scattering and resonant elastic scattering processes. For valence bands, the PDOS of S L_{2,3}, Zn M_{2,3}, Se M _{4,5}, bands locations, band gaps Eg, core level spin splitting, the lifetime broadening of valence band t_{1/2}, branching ratio of rm L_2/L_3 and shallow d level and exciton state were measured in some of these materials respectively. The excitation mechanism or threshold effects were studied for CdS, ZnS, MoS_2, WS_2, FeS, NiS, and alloy. In photon excited S L_ {2,3}^ectra, local core levels with spin splitting were found to charge threshold effects. The threshold effects are also found to be influenced by resonant elastic and inelastic scattering process. A simple model and the second order perturbation theory are used to explain the observed inelastic Raman scattering of Zn M _{2,3} spectra near d threshold. The d participation in the chemical bonding and interactions was studied. Atomiclike d bands were found in FeS and NiS from strong d-d and d-p couplings. Two groups of d bands were observed in Transitional Metal Sulfides (TMS) and the no-bonding group with a few d bands was found to across whole valence bands in TMS. The direct connection between valence bands and conduction bands is built and some conduction bands were studied. A study of alloy was included briefly. These experiments provide a rich information about TMS, and prove that Soft X-ray Spectroscopy is a powerful, precise and reliable tool in the study of fine electronic band structure in solids.

  1. The Swift Burst Alert Telescope Detected Seyfert 1 Galaxies: X-Ray Broadband Properties and Warm Absorbers

    Science.gov (United States)

    Winter, Lisa M.; Veilleux, Sylvain; McKernan, Barry; Kallman, T.

    2012-01-01

    We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy properties. Our detailed and uniform model fits to Suzaku/BAT and XMM-Newton/BAT spectra include the neutral absorption, direct power-law, reflected emission, soft excess, warm absorption, and narrow Fe I K[alpha] emission properties for the entire sample. We significantly detect O VII and O VIII edges in 52% of our sample. The strength of these detections is strongly correlated with the neutral column density measured in the spectrum. Among the strongest detections, X-ray grating and UV observations, where available, indicate outflowing material. The ionized column densities of sources with O VII and O VIII detections are clustered in a narrow range with Nwarm [approx] 1021 cm-2, while sources without strong detections have column densities of ionized gas an order of magnitude lower. Therefore, we note that sources without strong detections likely have warm ionized outflows present but at low column densities that are not easily probed with current X-ray observations. Sources with strong complex absorption have a strong soft excess, which may or may not be due to difficulties in modeling the complex spectra of these sources. Still, the detection of a flat [Gamma] [approx] 1 and a strong soft excess may allow us to infer the presence of strong absorption in low signal-to-noise active galactic nucleus spectra. Additionally, we include a useful correction from the Swift BAT luminosity to bolometric luminosity, based on a comparison of our spectral fitting results with published spectral energy distribution fits from 33 of our sources.

  2. Quasar X-Ray Spectra At z=1.5

    Science.gov (United States)

    Siemiginowska, Aneta

    2001-01-01

    The predicted counts for ASCA observation was much higher than actually observed counts in the quasar. However, there are three weak hard x-ray sources in the GIS field. We are adding them to the source counts in modeling of hard x-ray background. The work is in progress. We have published a paper in Ap.J. on the luminosity function and the quasar evolution. Based on the theory described in this paper we are predicting a number of sources and their contribution to the x-ray background at different redshifts. These model predictions will be compared to the observed data in the final paper.

  3. Time-resolved x-ray spectra of laser irradiated high-Z targets

    International Nuclear Information System (INIS)

    Lee, P.H.Y.; Attwood, D.T.; Boyle, M.J.; Campbell, E.M.; Coleman, L.C.; Kornblum, H.N.

    1977-01-01

    Recent results obtained by using the Livermore 15 psec x-ray streak camera to record x-ray emission from laser-irradiated high-z targets in the 1-20 keV range are reported. Nine to eleven K-edge filter channels were used for the measurements. In the lower energy channels, a dynamic range of x-ray emission intensity of better than three orders of magnitude have been recorded. Data will be presented which describe temporally and spectrally resolved x-ray spectra of gold disk targets irradiated by laser pulses from the Argus facility, including the temporal evolution of the superthermal x-ray tail

  4. X-ray measurements on wood - spectra measurements

    DEFF Research Database (Denmark)

    Jensen, Signe Kamp; Thygesen, Lisbeth Garbrecht; Gerward, Leif

    The report concerns simultaneous non-destructive measurements of water content and density of wood. Theoretically, this should be possible using a x-ray equipment newly build at BKM, and this work is an attempt to use the equipment for assessing water content and density of wood samples under...... laboratory conditions. A number of wood samples with different densities are placed at different relative humidities from 0.5 to 97 %RH. When equilibrium is obtained the samples are measured with the x-ray equipment such that 10 points are measured in the sample followed by measurements outside the sample...... (free-scanning). In this way 100 points are measured for each wood sample. This produces information about moisture content and density of the samples as water and wood attenuations of the x-rays are different for the different energy levels contained in the x-rays. The "real" density and moisture...

  5. Measurement of spectra for intra-oral X-ray beams using biological materials as attenuator

    International Nuclear Information System (INIS)

    Zenóbio, Madelon A.F.; Nogueira-Tavares, Maria S.; Zenóbio, Elton G.; Squair, Peterson Lima; Santos, Marcus A.P.; Silva, Teógenes A. da

    2011-01-01

    In diagnostic radiology, the radiation interaction probability in matter is a strong function of the X-ray energy. The knowledge of the X-ray energy spectral distribution allows optimizing the radiographic imaging system in order to obtain high quality images with as low as reasonably achievable patient doses. In this study, transmitted X-ray spectra through dentin and enamel that are existing materials in intra-oral radiology were experimentally determined in an X-ray equipment with 40–70 kV variable range. Dentin and enamel samples with 0.4–3.8 and 0.6–2.6 mm thick were used as attenuators. X-ray transmitted spectra were measured with XR-100T model CdTe detector and half-value layers (HVL) were determined. Characteristics of both dentin and enamel transmitted spectra showed that they have differences in the penetration power in matter and in the spectrum distribution. The results will be useful for phantom developments based on dentin and enamel for image quality control in dental radiology. - Highlights: ► The X-ray energy spectral distribution, optimize the radiographic imaging system. Transmitted X-ray spectra through dentin and enamel were experimentally determined. X-ray transmitted spectra were measured (XR-100T model CdTe detector). The transmitted spectra showed differences in the penetration power and spectrum distribution. Dentin and enamel transmitted spectra will be useful for phantom developments.

  6. Copper L X-ray spectra measured by a high resolution ion-induced X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ryohei; Hamaguchi, Dai; Kageyama, Hiroyoshi [Kyoto Inst. of Tech. (Japan); and others

    1997-03-01

    High resolution L X-ray emission spectra of Cu have been measured by 0.75 MeV/u H, He, and F, 0.73 MeV/u Ar, 0.64 MeV/u Si, and 0.073 MeV/u Si ion impacts with a crystal spectrometer. The X-ray transition energies in the Cu target for L{iota}, L{eta}, L{alpha}{sub 1,2}, L{beta}{sub 1}, and L{beta}{sub 3,4} diagram lines induced by light ion impacts are determined, which are in good agreement with those given in the reference. The difference in L X-ray emission spectra produced by H, He, F, Si, and Ar ions are considered and the L{alpha}{sub 1,2} and L{beta}{sub 1} emission spectra are compared with the calculated ones based on the multiconfiguration Dirac-Fock method. (author)

  7. An optimal ross filter system for soft X-ray spectra measurement

    International Nuclear Information System (INIS)

    Huang Tianxuan; Zheng Zhijian; Sun Kexu; Jiang Shaoen

    2000-01-01

    A broadband Ross filter spectrometer is described for measuring soft X-ray radiation (0.1∼1.5 keV) emitted from laser plasma. It consists of a number of channels, each representing a Ross filter pair in conjunction with Al cathode X-ray diodes. An optimal channel has flat response within the sensitivity band, and minimal response outside it. The effect of some uncertainties on the accuracy of measurements is calculated

  8. BROADBAND X-RAY PROPERTIES OF THE GAMMA-RAY BINARY 1FGL J1018.6–5856

    International Nuclear Information System (INIS)

    An, Hongjun; Bellm, Eric; Fuerst, Felix; Harrison, Fiona A.; Bhalerao, Varun; Boggs, Steven E.; Craig, William W.; Tomsick, John A.; Christensen, Finn E.; Hailey, Charles J.; Kaspi, Victoria M.; Natalucci, Lorenzo; Stern, Daniel; Zhang, William W.

    2015-01-01

    We report on NuSTAR, XMM-Newton, and Swift observations of the gamma-ray binary 1FGL J1018.6–5856. We measure the orbital period to be 16.544 ± 0.008 days using Swift data spanning 1900 days. The orbital period is different from the 2011 gamma-ray measurement which was used in the previous X-ray study of An et al. using ∼400 days of Swift data, but is consistent with a new gamma-ray solution reported in 2014. The light curve folded on the new period is qualitatively similar to that reported previously, having a spike at phase 0 and broad sinusoidal modulation. The X-ray flux enhancement at phase 0 occurs more regularly in time than was previously suggested. A spiky structure at this phase seems to be a persistent feature, although there is some variability. Furthermore, we find that the source flux clearly correlates with the spectral hardness throughout all orbital phases, and that the broadband X-ray spectra measured with NuSTAR, XMM-Newton, and Swift are well fit with an unbroken power-law model. This spectrum suggests that the system may not be accretion-powered

  9. Broadband X-Ray Spectral Analysis of the Double-nucleus Luminous Infrared Galaxy Mrk 463

    Science.gov (United States)

    Yamada, Satoshi; Ueda, Yoshihiro; Oda, Saeko; Tanimoto, Atsushi; Imanishi, Masatoshi; Terashima, Yuichi; Ricci, Claudio

    2018-05-01

    We present a broadband (0.4–70 keV) X-ray spectral analysis of the luminous infrared galaxy (LIRG) system Mrk 463 observed with Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton, which contains double active galactic nuclei (AGNs; Mrk 463E and Mrk 463W) with a separation of ∼3.8 kpc. Detecting their transmitted hard X-ray >10 keV continua with NuSTAR, we confirm that Mrk 463E and Mrk 463W have AGNs with intrinsic luminosities of (1.6–2.2) × 1043 and (0.5–0.6) × 1043 erg s‑1 (2–10 keV) obscured by hydrogen column densities of 8 × 1023 and 3 × 1023 cm‑2, respectively. Both nuclei show strong reflection components from cold matter. The luminosity ratio between X-ray (2–10 keV) and [O IV] 25.89 μm of Mrk 463E is ∼5 times smaller than those of normal Seyfert galaxies, suggesting that the intrinsic SED is X-ray weak relative to the UV luminosity. In fact, the bolometric AGN luminosity of Mrk 463E estimated from L‧-band (3.8 μm), [O IV] 25.89 μm, and [Ne V] 14.32 μm lines indicate a large bolometric-to-X-ray luminosity ratio, κ 2–10 keV ≈ 110–410, and a high Eddington ratio, λ Edd ∼ 0.4–0.8. We suggest that the merger triggered a rapid growth of the black hole in Mrk 463E, which is not yet deeply “buried” by circumnuclear dust. By contrast, the L‧-band luminosity of Mrk 463W is unusually small relative to the X-ray luminosity, suggesting that the Eddington ratio is low (activity.

  10. INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission

    Science.gov (United States)

    Türler, M.; Chernyakova, M.; Courvoisier, T. J.-L.; Lubiński, P.; Neronov, A.; Produit, N.; Walter, R.

    2010-03-01

    Aims: We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations in early 2006. Methods: We analyze the modulation of the IBIS/ISGRI detector counts induced by the passage of the Earth through the field of view of the instrument. Unlike previous studies, we do not fix the spectral shape of the various contributions, but model instead their spatial distribution and derive for each of them the expected modulation of the detector counts. The spectra of the diffuse emission components are obtained by fitting the normalizations of the model lightcurves to the observed modulation in different energy bins. Because of degeneracy, we guide the fits with a realistic choice of the input parameters and a constraint for spectral smoothness. Results: The obtained CXB spectrum is consistent with the historic HEAO-1 results and falls slightly below the spectrum derived with Swift/BAT. A 10% higher normalization of the CXB cannot be completely excluded, but it would imply an unrealistically high albedo of the Earth. The derived spectrum of the GRXE confirms the presence of a minimum around 80 keV with improved statistics and yields an estimate of ~0.6 M⊙ for the average mass of white dwarfs in the Galaxy. The analysis also provides updated normalizations for the spectra of the Earth's albedo and the cosmic-ray induced atmospheric emission. Conclusions: This study demonstrates the potential of INTEGRAL Earth-occultation observations to derive the hard X-ray spectra of three fundamental components: the CXB, the GRXE and the Earth emission. Further observations would be extremely valuable to confirm our results with improved statistics.

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

    Science.gov (United States)

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

    2017-11-01

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

  12. Singularities in x-ray spectra of metals

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1987-08-01

    The x-ray spectroscopies discussed are absorption, emission, and photoemission. The singularities show up in each of them in a different manner. In absorption and emission they show up as power law singularities at the thresholds frequencies. This review will emphasize two themes. First a simple model is proposed to describe this phenomena, which is now called the MND model after MAHAN-NOZIERES-DeDOMINICIS. Exact analytical solutions are now available for this model for the three spectroscopies discussed above. These analytical models can be evaluated numerically in a simple way. The second theme of this review is that great care must be used when comparing the theory to experiment. A number of factors influence the edge shapes in x-ray spectroscopy. The edge singularities play an important role, and are observed in many matals. Quantitative fits of the theory to experiment require the consideration of other factors. 51 refs

  13. Ab initio theory and calculations of X-ray spectra

    International Nuclear Information System (INIS)

    Rehr, J.J.; Kas, J.J.; Prange, M.P.; Sorini, A.P.; Takimoto, Y.; Vila, F.

    2009-01-01

    There has been dramatic progress in recent years both in the calculation and interpretation of various x-ray spectroscopies. However, current theoretical calculations often use a number of simplified models to account for many-body effects, in lieu of first principles calculations. In an effort to overcome these limitations we describe in this article a number of recent advances in theory and in theoretical codes which offer the prospect of parameter free calculations that include the dominant many-body effects. These advances are based on ab initio calculations of the dielectric and vibrational response of a system. Calculations of the dielectric function over a broad spectrum yield system dependent self-energies and mean-free paths, as well as intrinsic losses due to multielectron excitations. Calculations of the dynamical matrix yield vibrational damping in terms of multiple-scattering Debye-Waller factors. Our ab initio methods for determining these many-body effects have led to new, improved, and broadly applicable x-ray and electron spectroscopy codes. (authors)

  14. Development of multilayer optics for X-ray broadband spectrometry of plasma emission

    International Nuclear Information System (INIS)

    Emprin, Benoit

    2014-01-01

    Within the framework of the research on inertial confinement fusion, the 'Commissariat a l'energie atomique et aux energies alternatives' has studied and implemented an absolute calibrated time-Resolved broadband soft x-Ray spectrometer, called 'Diagnostic de Mesure du rayonnement X'. This diagnostic, composed of 20 measurement channels, measures the emitted radiant power from a laser created plasma in the range from 50 eV to 20 keV. We have developed additional measurement channels to obtain redundancy and an improvement in measurement accuracy. The principle of these new channels is based on an original concept to obtain spectral bounded flat-Responses. Two channels have been developed for the 2 - 4 keV and 4 - 6 keV spectral ranges, using aperiodic multilayer mirrors made at the 'Laboratoire Charles Fabry' with Cr/Sc and Ni/W/SiC/W layers respectively. These mirrors were characterized at synchrotron radiation facilities and integrated into the spectrometer. The two new channels were used during laser-Plasma experimental campaigns at the OMEGA laser facility in Rochester (USA). This allowed us to determine directly the radiant power with only one measurement within a certain spectral band, and with a better precision when compared with using standard channels. The results, in good agreement with the standard measurement channels, allowed us to validate the use of aperiodic multilayer mirrors for X-Ray broadband spectrometry. (author) [fr

  15. X-ray photoelectron spectra of γ-irradiated perfluorobenzene

    International Nuclear Information System (INIS)

    Sunder, S.; Sagert, N.H.; Wood, D.D.; Miller, N.H.

    1990-01-01

    The effect of γ-radiolysis on perfluorobenzene (PFB) was investigated using low-temperature X-ray photoelectron spectroscopy (XPS). PFB was irradiated in fluorine-passivated nickel cells using Co 60 γ-rays in an Atomic Energy of Canada Limited Gammacell at a dose rate of about 2.6 Gy·s -1 and for a total dose of about 50 kGy. The γ-radiolysis of PFB not only results in cross-linkage but also in the formation of saturated carbon centers in the PFB, as indicated by the presence of CF 2 and CF 3 groups. The relative abundance of CF, CF 2 and CF 3 groups, in the irradiated PFB, was estimated to be about 86, 9 and 5%, respectively

  16. First Principles Calculations for X-ray Resonant Spectra and Elastic Properties

    International Nuclear Information System (INIS)

    Yongbin Lee

    2006-01-01

    In this thesis, we discuss applications of first principles methods to x-ray resonant spectra and elastic properties calculation. We start with brief reviews about theoretical background of first principles methods, such as density functional theory, local density approximation (LDA), LDA+U, and the linear augmented plane wave (LAPW) method to solve Kohn-Sham equations. After that we discuss x-ray resonant scattering (XRMS), x-ray magnetic circular dichroism (XMCD) and the branching problem in the heavy rare earths Ledges. In the last chapter we discuss the elastic properties of the second hardest material AlMgB 14

  17. Modeling of X-ray images and energy spectra produced by stepping lightning leaders

    OpenAIRE

    Xu , Wei; Marshall , Robert A.; Celestin , Sébastien; Pasko , Victor P.

    2017-01-01

    International audience; Recent ground-based measurements at the International Center for Lightning Research and Testing (ICLRT) have greatly improved our knowledge of the energetics, fluence, and evolution of X-ray emissions during natural cloud-to-ground (CG) and rocket-triggered lightning flashes. In this paper, using Monte Carlo simulations and the response matrix of unshielded detectors in the Thunderstorm Energetic Radiation Array (TERA), we calculate the energy spectra of X-rays as woul...

  18. High-energy X-ray spectra of Cygnus XR-1 observed from OSO 8

    Science.gov (United States)

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

    1979-01-01

    X-ray spectra of Cygnus XR-1 were measured with the scintillation spectrometer aboard the OSO 8 satellite during a period of one-and-one-half to three weeks in each of the years from 1975 to 1977. Typical spectra of the source between 15 and 250 keV are presented and the spectra are found to be well represented by a single power-law expression whose photon number spectral index is different for the two intensity states that were considered. The observed pivoting effect is consistent with two-temperature accretion disk models of the X-ray emitting region.

  19. The X-ray electronic spectra of TiC-NbC solid solution

    International Nuclear Information System (INIS)

    Cherkashenko, V.M.; Ezhov, A.V.; Nazarova, S.Z.; Kurmaev, Eh.Z.; Nojmann, M.

    2001-01-01

    X-ray photoelectronic spectra of inner levels and valency lands in TiC-NbC solid solutions were studied. Results of combining TiL α -, NbL β2.15 -, CK α - X-ray emission spectra and photoelectronic spectra of valency bands in one energy scale in reference to the Fermi level were analyzed. It is shown that a change in crystal lattice parameters, as well as charge redistribution between titanium and niobium atoms, produce a strong effect on electronic structure formation in the mixed carbides mentioned [ru

  20. OTELO SURVEY: DEEP BVRI BROADBAND PHOTOMETRY OF THE GROTH STRIP. II. OPTICAL PROPERTIES OF X-RAY EMITTERS

    International Nuclear Information System (INIS)

    Povic, M.; Perez GarcIa, A. M.; Bongiovanni, A.; Castaneda, H.; Lorenzo, M. Fernandez; Lara-Lopez, M. A.; Sanchez-Portal, M.; Cepa, J.; Alfaro, E.; Gallego, J.; Gonzalez-Serrano, J. I.; Gonzalez, J. J.

    2009-01-01

    The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820 nm and 920 nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200 ks are analyzed and combined with optical broadband data of the Groth field, in order to study a set of optical structural parameters of the X-ray emitters and its relation with X-ray properties. To this aim, we processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations, and determined and analyzed different structural parameters, in order to produce a morphological classification of X-ray sources. We present the morphology of 340 X-ray emitters with optical counterpart detected. Objects have been classified by X-ray type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio. We did not find any clear correlation between X-ray and morphological types. We analyzed the angular clustering of X-ray sources with optical counterpart using two-point correlation functions. A significant positive angular clustering was obtained from a preliminary analysis of four subsamples of the X-ray sources catalog. The clustering signal of the optically extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in active galactic nuclei phenomena. Finally, we combined optical structural parameters with other X-ray and optical properties, and we confirmed an anticorrelation between the X/O ratio and the Abraham concentration index, which might suggest that early-type galaxies have lower Eddington rates than those of late-type galaxies.

  1. SU-F-I-76: Fluoroscopic X-Ray Beam Profiles for Spectra Incorporating Copper Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Wunderle, K [Cleveland Clinic Foundation, Cleveland, OH (United States); Wayne State University School of Medicine, Detroit, MI (United States); Godley, A; Shen, Z; Dong, F [Cleveland Clinic Foundation, Cleveland, OH (United States); Rakowski, J [Wayne State University School of Medicine, Detroit, MI (United States)

    2016-06-15

    Purpose: The purpose of this investigation is to characterize and quantify X-ray beam profiles for fluoroscopic x-ray beam spectra incorporating spectral (copper) filtration. Methods: A PTW (Freiburg, Germany) type 60016 silicon diode detector and PTW MP3 water tank were used to measure X-ray beam profiles for 60, 80, 100 and 120 kVp x-ray beams at five different copper filtration thicknesses ranging from 0–0.9 mm at 22 and 42 cm fields of view and depths of 1, 5, and 10 cm in both the anode-cathode axis (inplane) and cross-plane directions. All measurements were acquired on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope inverted from the typical orientation providing an x-ray beam originating from above the water surface with the water level set at 60 cm from the focal spot. Results: X-ray beam profiles for beam spectra without copper filtration compared well to previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)]. Our data collection benefited from the geometric orientation of the fluoroscope, providing a beam perpendicular to the tank water surface, rather than through a thin side wall as did the previously mentioned study. Profiles for beams with copper filtration were obtained which have not been previously investigated and published. Beam profiles in the anode-cathode axis near the surface and at lower x-ray energy exhibited substantial heel effect, which became less pronounced at greater depth. At higher energy with copper filtration in the beam, the dose falloff out-of-field became less pronounced, as would be anticipated given higher scatter photon energy. Conclusion: The x-ray beam profile data for the fluoroscopic x-ray beams incorporating copper filtration are intended for use as reference data for estimating doses to organs or soft tissue, including fetal dose, involving similar beam qualities or for comparison with mathematical models.

  2. A broadband X-ray study of the Geminga pulsar with NuSTAR And XMM-Newton

    International Nuclear Information System (INIS)

    Mori, Kaya; Gotthelf, Eric V.; Halpern, Jules P.; Beloborodov, Andrei M.; Hailey, Charles J.; Dufour, Francois; Kaspi, Victoria M.; An, Hongjun; Bachetti, Matteo; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Harrison, Fiona A.; Kouveliotou, Chryssa; Pivovaroff, Michael J.; Stern, Daniel; Zhang, William W.

    2014-01-01

    We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) observatory. The double-peaked pulse profile of non-thermal emission seen in the soft X-ray band persists at higher energies. Broadband phase-integrated spectra over the 0.2-20 keV band with NuSTAR and archival XMM-Newton data do not fit to a conventional two-component model of a blackbody plus power law, but instead exhibit spectral hardening above ∼5 keV. We find that two spectral models fit the data well: (1) a blackbody (kT 1 ∼ 42 eV) with a broken power law (Γ 1 ∼ 2.0, Γ 2 ∼ 1.4 and E break ∼ 3.4 keV) and (2) two blackbody components (kT 1 ∼ 44 eV and kT 2 ∼ 195 eV) with a power-law component (Γ ∼ 1.7). In both cases, the extrapolation of the Rayleigh-Jeans tail of the thermal component is consistent with the UV data, while the non-thermal component overpredicts the near-infrared data, requiring a spectral flattening at E ∼ 0.05-0.5 keV. While strong phase variation of the power-law index is present below ∼5 keV, our phase-resolved spectroscopy with NuSTAR indicates that another hard non-thermal component with Γ ∼ 1.3 emerges above ∼5 keV. The spectral hardening in non-thermal X-ray emission as well as spectral flattening between the optical and X-ray bands argue against the conjecture that a single power law may account for multi-wavelength non-thermal spectra of middle-aged pulsars.

  3. Invisible structures in the X-ray absorption spectra of actinides

    NARCIS (Netherlands)

    Kvashnina, Kristina O.; De Groot, Frank M F

    The X-ray absorption spectra of actinides are discussed with an emphasis on the fundamental effects that influence their spectral shape, including atomic multiplet theory, charge transfer theory and crystal field theory. Many actinide spectra consist of a single peak and it is shown that the use of

  4. Modeling of X-ray Images and Energy Spectra Produced by Stepping Lightning Leaders

    Science.gov (United States)

    Xu, Wei; Marshall, Robert A.; Celestin, Sebastien; Pasko, Victor P.

    2017-11-01

    Recent ground-based measurements at the International Center for Lightning Research and Testing (ICLRT) have greatly improved our knowledge of the energetics, fluence, and evolution of X-ray emissions during natural cloud-to-ground (CG) and rocket-triggered lightning flashes. In this paper, using Monte Carlo simulations and the response matrix of unshielded detectors in the Thunderstorm Energetic Radiation Array (TERA), we calculate the energy spectra of X-rays as would be detected by TERA and directly compare with the observational data during event MSE 10-01. The good agreement obtained between TERA measurements and theoretical calculations supports the mechanism of X-ray production by thermal runaway electrons during the negative corona flash stage of stepping lightning leaders. Modeling results also suggest that measurements of X-ray bursts can be used to estimate the approximate range of potential drop of lightning leaders. Moreover, the X-ray images produced during the leader stepping process in natural negative CG discharges, including both the evolution and morphological features, are theoretically quantified. We show that the compact emission pattern as recently observed in X-ray images is likely produced by X-rays originating from the source region, and the diffuse emission pattern can be explained by the Compton scattering effects.

  5. Diagnostic x-ray spectra measurements using a silicon surface barrier detector

    International Nuclear Information System (INIS)

    Pani, R.; Laitano, R.F.

    1987-01-01

    A silicon surface barrier detector having a low efficiency for x-ray is used to analyse diagnostic x-ray spectra. This characteristic is advantageous in overcoming experimental problems caused by high fluence rates typical of diagnostic x-ray beams. The pulse height distribution obtained with silicon surface barrier detectors is very different from the true photon spectra because of the presence of escaped Compton photons and the fact that detection efficiency falls abruptly when photon energy increases. A detailed analysis of the spurious effects involved in detection is made by a Monte Carlo method. A stripping procedure is described for implementation on a personal computer. The validity of this method is tested by comparison with experimental results obtained with a Ge detector. The spectra obtained with the Si detector are in fairly good agreement with the analogous spectra measured with a Ge detector. The advantages of using Si as opposed to Ge detectors in x-ray spectrometry are: its simplicity of use, its greater economy for use in routine diagnostic x-ray spectroscopy and the possibility that the stripping procedure can be implemented on a personal computer. (author)

  6. Broadband transmission masks, gratings and filters for extreme ultraviolet and soft X-ray lithography

    International Nuclear Information System (INIS)

    Brose, S.; Danylyuk, S.; Juschkin, L.; Dittberner, C.; Bergmann, K.; Moers, J.; Panaitov, G.; Trellenkamp, St.; Loosen, P.; Grützmacher, D.

    2012-01-01

    Lithography and patterning on a nanometre scale with extreme ultraviolet (EUV) and soft X-ray radiation allow creation of high resolution, high density patterns independent of a substrate type. To realize the full potential of this method, especially for EUV proximity printing and interference lithography, a reliable technology for manufacturing of the transmission masks and gratings should be available. In this paper we present a development of broadband amplitude transmission masks and gratings for extreme ultraviolet and soft X-ray lithography based on free-standing niobium membranes. In comparison with a standard silicon nitride based technology the transmission masks demonstrate high contrast not only for in-band EUV (13.5 nm) radiation but also for wavelengths below Si L-absorption edge (12.4 nm). The masks and filters with free standing areas up to 1000 × 1000 μm 2 and 100 nm to 300 nm membrane thicknesses are shown. Electron beam structuring of an absorber layer with dense line and dot patterns with sub-50 nm structures is demonstrated. Diffractive and filtering properties of obtained structures are examined with EUV radiation from a gas discharge plasma source. - Highlights: ► Broadband transmission masks for EUV proximity and interference lithography. ► Technology for free standing niobium membranes with areas up to 1 mm 2 . ► High density patterns with periods of 100 nm and structure sizes below 40 nm. ► Measured diffraction efficiency at 11 nm is in agreement with the theory. ► Produced masks can be effectively used with wavelengths between 6 nm and 17 nm.

  7. Effects of phonon broadening on x-ray near-edge spectra in molecular crystals

    Science.gov (United States)

    Vinson, John; Jach, Terrence; Elam, Tim; Denlinger, Jonathon

    2014-03-01

    Calculations of near-edge x-ray spectra are often carried out using the average atomic coordinates from x-ray or neutron scattering experiments or from density functional theory (DFT) energy minimization. This neglects disorder from thermal and zero-point vibrations. Here we look at the nitrogen K-edge of ammonium chloride and ammonium nitrate, comparing Bethe-Salpeter calculations of absorption and fluorescence to experiment. We find that intra-molecular vibrational effects lead to significant, non-uniform broadening of the spectra, and that for some features zero-point motion is the primary source of the observed shape.

  8. Lifetime-vibrational interference effects in resonantly excited x-ray emission spectra of CO

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, P.; Glans, P.; Gunnelin, K. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    The parity selection rule for resonant X-ray emission as demonstrated for O{sub 2} and N{sub 2} can be seen as an effect of interference between coherently excited degenerate localized core states. One system where the core state degeneracy is not exact but somewhat lifted was previously studied at ALS, namely the resonant X-ray emission of amino-substituted benzene (aniline). It was shown that the X-ray fluorescence spectrum resulting from excitation of the C1s at the site of the {open_quotes}aminocarbon{close_quotes} could be described in a picture separating the excitation and the emission processes, whereas the spectrum corresponding to the quasi-degenerate carbons could not. Thus, in this case it was necessary to take interference effects between the quasi-degenerate intermediate core excited states into account in order to obtain agreement between calculations and experiment. The different vibrational levels of core excited states in molecules have energy splittings which are of the same order of magnitude as the natural lifetime broadening of core excitations in the soft X-ray range. Therefore, lifetime-vibrational interference effects are likely to appear and influence the band shapes in resonant X-ray emission spectra. Lifetime-vibrational interference has been studied in non-resonant X-ray emission, and in Auger spectra. In this report the authors discuss results of selectively excited soft X-ray fluorescence spectra of molecules, where they focus on lifetime-interference effects appearing in the band shapes.

  9. Many-body effects on the x-ray spectra of metals

    International Nuclear Information System (INIS)

    Satpathy, S.S.

    1982-01-01

    The effects of band structure, of a solid surface, of temperature, and of disorder on the many-electron x-ray spectra of metals are evaluated in a change-of-mean-field approximation using a one-dimensional nearest-neighbor tight-binding model of a metal. The x-ray spectral shapes are determined by both the band structure and the final-state interactions. The effect of the band being non-free-electron-like is not felt at the x-ray threshold, but away from it such effects are noticeable. When the core hole is created at the surface, the spectra at the edge exhibit a Nozieres-de Dominicis-type singularity with the appropriate surface phase-shifts. At energies away from the edge, the one-particle effects are prominent with the x-ray emission and absorption spectra closely reflecting the local one-electron density of states. The recoil spectrum of a Fermi sea at a non-zero temperature has less asymmetry than the zero-temperature case. It was found that at ordinary temperatures the reduction of the asymmetry due to the thermal distribution of one-electron states is not very significant. Finally, using a one-dimensional Anderson model, the effect of lattice disorder on the x-ray absorption spectra is studied for the first time. There are two effects: (1) the strong infrared divergence peak is gradually quenched as disorder is increased, and (2) the threshold is broadened because the threshold energies for absorption at different sites in the crystal depend on the varying local lattice environment. It is proposed that the x-ray spectra may be useful as a tool for studying the degree of electron localization in disordered many-electron systems

  10. Sensitivity Analysis of X-ray Spectra from Scanning Electron Microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Patton, Bruce W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Weber, Charles F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bekar, Kursat B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-10-01

    The primary goal of this project is to evaluate x-ray spectra generated within a scanning electron microscope (SEM) to determine elemental composition of small samples. This will be accomplished by performing Monte Carlo simulations of the electron and photon interactions in the sample and in the x-ray detector. The elemental inventories will be determined by an inverse process that progressively reduces the difference between the measured and simulated x-ray spectra by iteratively adjusting composition and geometric variables in the computational model. The intended benefit of this work will be to develop a method to perform quantitative analysis on substandard samples (heterogeneous phases, rough surfaces, small sizes, etc.) without involving standard elemental samples or empirical matrix corrections (i.e., true standardless quantitative analysis).

  11. Time-resolved soft x-ray spectra from laser-produced Cu plasma

    International Nuclear Information System (INIS)

    Cone, K.V.; Dunn, J.; Baldis, H.A.; May, M.J.; Purvis, M.A.; Scott, H.A.; Schneider, M.B.

    2012-01-01

    The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated from a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) laser. A variable spaced grating spectrometer coupled to an x-ray streak camera measured soft x-ray emission (800-1550 eV) from the back of the copper target to characterize the bulk heating of the target. Radiation hydrodynamic simulations were modeled in 2-dimensions using the HYDRA code. The target conditions calculated by HYDRA were post-processed with the atomic kinetics code CRETIN to generate synthetic emission spectra. A comparison between the experimental and simulated spectra indicates the presence of specific ionization states of copper and the corresponding electron temperatures and ion densities throughout the laser-heated copper target.

  12. Broadband x-ray imaging and spectroscopy of the crab nebula and pulsar with NuSTAR

    DEFF Research Database (Denmark)

    Madsen, Kristin K.; Reynolds, Stephen; Harrison, Fiona

    2015-01-01

    We present broadband (3-78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar. We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power law in this energy band, spatially resolved spectroscopy of the nebula finds a break at ~9 ke...

  13. Quantitative x-ray absorption imaging with a broadband source: application to high-intensity discharge lamps

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J J [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)], E-mail: jjcurry@nist.gov

    2008-07-21

    The case of x-ray absorption imaging in which the x-ray source is broadband and the detector does not provide spectral resolution is analysed. The specific motivation is observation of the Hg vapour distribution in high-intensity discharge (HID) lamps. When absorption by the vapour is small, the problem can be couched accurately in terms of a mean absorption cross section averaged over the x-ray spectral distribution, weighted by the energy-dependent response of the detector. The method is tested against a Au foil standard and then applied to Hg. The mean absorption cross section for Hg is calculated for a Ag-anode x-ray tube at accelerating voltages of 25, 30 and 35 kV, and for HIDs in fused silica or polycrystalline alumina arc tubes.

  14. Probing symmetry and symmetry breaking in resonant soft-x-ray fluorescence spectra of molecules

    Energy Technology Data Exchange (ETDEWEB)

    Glans, P.; Gunnelin, K.; Guo, J. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Conventional non-resonant soft X-ray emission brings about information about electronic structure through its symmetry and polarization selectivity, the character of which is governed by simple dipole rules. For centro-symmetric molecules with the emitting atom at the inversion center these rules lead to selective emission through the required parity change. For the more common classes of molecules which have lower symmetry or for systems with degenerate core orbitals (delocalized over identical sites), it is merely the local symmetry selectivity that provides a probe of the local atomic orbital contribution to the molecular orbital. For instance, in X-ray spectra of first row species the intensities essentially map the p-density at each particular atomic site, and, in a molecular orbital picture, the contribution of the local p-type atomic orbitals in the LCAO description of the molecular orbitals. The situation is different for resonant X-ray fluorescence spectra. Here strict parity and symmetry selectivity gives rise to a strong frequency dependence for all molecules with an element of symmetry. In addition to symmetry selectivity the strong frequency dependence of resonant X-ray emission is caused by the interplay between the shape of a narrow X-ray excitation energy function and the lifetime and vibrational broadenings of the resonantly excited core states. This interplay leads to various observable effects, such as linear dispersion, resonance narrowing and emission line (Stokes) doubling. Also from the point of view of polarization selectivity, the resonantly excited X-ray spectra are much more informative than the corresponding non-resonant spectra. Examples are presented for nitrogen, oxygen, and carbon dioxide molecules.

  15. OSO 8 X-ray spectra of clusters of galaxies. II - Discussion

    Science.gov (United States)

    Smith, B. W.; Mushotzky, R. F.; Serlemitsos, P. J.

    1979-01-01

    An observational description of X-ray clusters of galaxies is given based on OSO 8 X-ray results for spatially integrated spectra of 20 such clusters and various correlations obtained from these results. It is found from a correlation between temperature and velocity dispersion that the X-ray core radius should be less than the galaxy core radius or, alternatively, that the polytropic index is about 1.1 for most of the 20 clusters. Analysis of a correlation between temperature and emission integral yields evidence that more massive clusters accumulate a larger fraction of their mass as intracluster gas. Galaxy densities and optical morphology, as they correlate with X-ray properties, are reexamined for indications as to how mass injection by galaxies affects the density structure of the gas. The physical arguments used to derive iron abundances from observed equivalent widths of iron line features in X-ray spectra are critically evaluated, and the associated uncertainties in abundances derived in this manner are estimated to be quite large.

  16. The X-ray spectra of clusters of galaxies and their relationship to other cluster properties

    International Nuclear Information System (INIS)

    Mitchell, R.J.; Dickens, R.J.; Burnell, S.J.B.; Culhane, J.L.

    1979-01-01

    New observations with the MSSL proportional counter spectrometer on the Ariel V satellite of the X-ray spectra of 20 candidate clusters of galaxies are reported. The data are compared with the results from the OSO-8 satellite and the combined sample of some 30 cluster X-ray spectra are analysed. The present study finds generally larger values of Lsub(X) than do Uhuru or the SSI, which, because of the larger field of view, may indicate significant amounts of hot gas away from the cluster centres. The validity of all X-ray cluster identifications has been examined, and sources have been classified according to certainty of identification. The incidence of X-ray line emission from the clusters has been investigated and temperatures, kTsub(X), have been derived on the basis of an isothermal model. Relationships between X-ray, optical and radio properties of the clusters have been studied. The more massive, centrally condensed clusters generally contain higher temperature gas and have a greater luminosity than the less massive, more irregular clusters. (author)

  17. Transmission properties of barite mortar using X-ray spectra measured with Cd Te detector

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J. C.; Mariano, L.; Costa, P. R. [Universidade de Sao Paulo, Instituto de Fisica, Rua do Matao Travessa R. 187, Cidade Universitaria, 05508-090 Sao Paulo (Brazil); Tomal, A., E-mail: josilene@usp.br [Universidade Federal de Goias, Instituto de Fisica, Campus Samambaia, 74001-970 Goiania (Brazil)

    2014-08-15

    Current methods for calculating X-ray shielding barriers do not take into account spectral distribution of the beam transmitted by the protective material. This consideration is important in dose estimations for radiation workers and general public in diagnostic radiology facilities. The aim of the present study was to estimate barite mortar attenuation curves using X-ray spectra weighted by a workload distribution. These curves were described in units of ambient dose equivalent (H (10)), since it is the radiation quantity adopted by IAEA for dose assessment in medical environment. Attenuation curves were determined using the optimized model for shielding evaluation presented by Costa and Caldas (2002). Workload distribution presented by Simpkin (1996), measured primary spectra and mass attenuation coefficients of barite mortar were used as input data in this model. X-ray beams in diagnostic energy range were generated by an industrial X-ray tube with 3 mm of aluminum additional filtration. Primary experimental spectra were measured by a Cd Te detector and corrected by the response function of detector by means of a stripping procedure. Air kerma measurements were performed using an ionization chamber for normalization purpose of the spectra. The corrected spectra presented good agreement with spectra generated by a semi-empirical model. The variation of the ambient dose equivalent as a function of barite mortar thickness was calculated. Using these data, it was estimated the optimized thickness of protective barrier needed for shielding a particular area in an X-ray imaging facility. The results obtained for primary protective barriers exhibit qualitative agreement with those presented in literature. (Author)

  18. Measurement of X-ray spectra by PIN photodiode: comparative study

    International Nuclear Information System (INIS)

    Costa, Paulo R.; Furquim, Tania A.C.; Herdade, Silvio B.

    1996-01-01

    Two different approaches for the evaluation of diagnostic X-ray spectra are presented : one based on a semiempirical model and other based on measurements using a silicon PIN photodiode. Measured and calculated values using typical kVp and filter combinations are compared

  19. Vibrational spectra, powder X-ray diffractions and physical properties of cyanide complexes with 1-ethylimidazole

    Science.gov (United States)

    Kürkçüoğlu, Güneş Süheyla; Kiraz, Fulya Çetinkaya; Sayın, Elvan

    2015-10-01

    The heteronuclear tetracyanonickelate(II) complexes of the type [M(etim)Ni(CN)4]n (hereafter, abbreviated as M-Ni-etim, M = Mn(II), Fe(II) or Co(II); etim = 1-ethylimidazole, C5H8N2) were prepared in powder form and characterized by FT-IR and Raman spectroscopy, powder X-ray diffraction (PXRD), thermal (TG; DTG and DTA), and elemental analysis techniques. The structures of these complexes were elucidated using vibrational spectra and powder X-ray diffraction patterns with the peak assignment to provide a better understanding of the structures. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from powder X-ray diffraction measurements. Vibrational spectra of the complexes were presented and discussed with respect to the internal modes of both the etim and the cyanide ligands. The C, H and N analyses were carried out for all the complexes. Thermal behaviors of these complexes were followed using TG, DTG and DTA curves in the temperature range 30-700 °C in the static air atmosphere. The FT-IR, Raman spectra, thermal and powder X-ray analyses revealed no significant differences between the single crystal and powder forms. Additionally, electrical and magnetic properties of the complexes were investigated. The FT-IR and Raman spectroscopy, PXRD, thermal and elemental analyses results propose that these complexes are similar in structure to the Hofmann-type complexes.

  20. X-ray satellite spectra of Ti, V, Cr and Mn induced by photons

    Indian Academy of Sciences (India)

    K X-ray emission spectra of Ti, V, Cr and Mn generated by photon excitation have been studied with a crystal spectrometer. The measured energy shifts of K satellite relative to the diagram line are compared with values obtained by electron excitation and with different theoretical estimates. The present experimental ...

  1. X-ray spectra from the Cornell Electron-Beam Ion Source (CEBIS I)

    International Nuclear Information System (INIS)

    Johnson, B.M.; Jones, K.W.; Kostroun, V.O.; Ghanbari, E.; Janson, S.W.

    1985-01-01

    Radiation emitted from the Cornell electron beam ion source (CEBIS I) has been surveyed with a Si(Li) x-ray detector. These spectra can be used to estimate backgrounds from electron bremsstrahlung and to evaluate the feasibility of atomic physics experiments using the CEBIS I source in this configuration. 1 ref., 2 figs

  2. Core-hole effects in the x-ray-absorption spectra of transition-metal silicides

    NARCIS (Netherlands)

    WEIJS, PJW; CZYZYK, MT; VANACKER, JF; SPEIER, W; GOEDKOOP, JB; VANLEUKEN, H; HENDRIX, HJM; DEGROOT, RA; VANDERLAAN, G; BUSCHOW, KHJ; WIECH, G; FUGGLE, JC

    1990-01-01

    We report systematic differences between the shape of the Si K x-ray-absorption spectra of transition-metal silicides and broadened partial densities of Si p states. We use a variety of calculations to show that the origin of these discrepancies is the core-hole potential appropriate to the final

  3. Envelope method for background elimination from X-ray fluorescence spectra

    International Nuclear Information System (INIS)

    Monakhov, V.V.; Naumenko, P.A.; Chashinskaya, O.A.

    2006-01-01

    The influence of the background noise caused by Bremsstrahlung on the accuracy of the envelope method at x-ray fluorescence spectra processing is studied. This is carried out by the example of model spectra at different forms of Bremsstrahlung noise as well as at the presence of background noise in spectra. The interpolation by parabolic splines is used for the estimation of the error of the envelope method for the elimination of continuos background noise. It is found out that the error of the proposed method constitutes decimal parts of percent. It is shown that the envelope method is the effective technique for the elimination of the continuous Bremsstrahlung from x-ray fluorescence spectra of the first order [ru

  4. Quasar energy distributions. I. Soft X-ray spectra of quasars

    International Nuclear Information System (INIS)

    Wilkes, B.J.; Elvis, M.

    1987-01-01

    As the initial stage of a study of quasar energy distributions (QEDs), Einstein IPC spectra of 24 quasars are presented. These are combined with previously reported IPC spectra to form a sample of 33 quasars with well-determined soft X-ray slopes. A correlation analysis shows that radio loudness, rather than redshift or luminosity, is fundamentally related to the X-ray slope. This correlation is not followed by higher energy spectra of active galaxies. Two components are required to explain both sets of results. The best-fit column densities are systematically smaller than the Galactic values. The same effect is not present in a sample of BL Lac objects, implying that the effect is intrinsic to the quasars and is caused by a low-energy turnup in the quasar spectra. 74 references

  5. An analysis of the MO X-ray spectra in U92+-Pb collisions

    International Nuclear Information System (INIS)

    Schulze, K.; Anton, J.; Sepp, W.-D.; Fricke, B.

    1999-01-01

    The investigation of quasimolecular X-rays from superheavy collision systems with bare or H-like projectiles seems to be a promising approach to get information about the behaviour of inner shell electrons with energy eigenvalues in the vicinity of the negative continuum. We present calculations of the MO X-ray spectra for the system U 92+ -Pb for varying impact energies. Furthermore we analyse the contributions due to electrons in higher lying states. The results are discussed with respect to the experimental determination of the transition energies in the superheavy quasimolecule. (orig.)

  6. A color display device recording X ray spectra, especially intended for medical radiography

    International Nuclear Information System (INIS)

    Boulch, J.-M.

    1975-01-01

    Said invention relates to a color display recording device for X ray spectra intended for medical radiography. The video signal of the X ray camera receiving the radiation having passed through the patient is amplified and transformed into a color coding according to the energy spectrum received by the camera. In a first version, the energy spectrum from the camera gives directly an image on the color tube. In a second version the energy spectrum, after having been transformed into digital signals, is first sent into a memory, then into a computer used as a spectrum analyzer, and finally into the color display device [fr

  7. Spectra transmitted by mortar barite in X-Ray qualities applied in diagnostic radiology as shielding

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Airton T., E-mail: airton.almeida@fundacentro.gov.br [Fundacaoo Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Belo Horizonte, MG (Brazil); Araujo, F.G.S. [Universidade Federal de Ouro Preto (REDEMAT/UFOP), MG (Brazil); Nogueira, M.S., E-mail: mnogue@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Santos, M.A.P. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    Concrete which contains water, cement and aggregate, is widely used in building construction such as medical hospitals. The CdZnTe spectrometry system was used to acquire the transmitted spectra in the RQR qualities and the stripping procedure was performed by taking into account both the contributions of efficiency and x-ray escape fraction, experimentally determined. The samples were prepared in rectangular plate format with dimensions of (5 x 5) cm with thicknesses varying from 0.2cm to 2cm and exposed to x-ray beams generated. The HVL and the mean energy in this energy range was determined. (author)

  8. Coronal temperature diagnostics from high-resolution soft X-ray spectra

    Science.gov (United States)

    Strong, K. T.; Claflin, E. S.; Lemen, J. R.; Linford, G. A.

    1988-01-01

    The problem of deriving the temperature of the coronal plasma from soft X-ray spectra is discussed. Spectral atlas scans of the soft X-ray spectrum from the Flat Crystal Spectrometer on the Solar Maximum Mission are compared with theoretical predictions of the relative intensities of some of the brighter lines to determine which line intensity ratios give the most reliable temperature diagnostics. The techniques considered include line widths, He-like G ratios, intensity ratios, and ratios of lines formed by different elements. It is found that the best temperature diagnostics come from the ratios of lines formed by successive ionization stages of the same element.

  9. A model independent method to deconvolve hard X-ray spectra

    International Nuclear Information System (INIS)

    Polcaro, V.F.; Bazzano, A.; Ubertini, P.; La Padula, C.

    1984-01-01

    A general purpose method to deconvolve the energy spectra detected by means of the use of a hard X-ray telescope is described. The procedure does not assume any form of input spectrum and the observed energy loss spectrum is directly deconvolved into the incident photon spectrum, the form of which can be determined independently of physical interpretation of the data. Deconvolution of the hard X-ray spectrum of Her X-1, detected during the HXR 81M experiment, by the method independent method is presented. (orig.)

  10. Influence of smoothing of X-ray spectra on parameters of calibration model

    International Nuclear Information System (INIS)

    Antoniak, W.; Urbanski, P.; Kowalska, E.

    1998-01-01

    Parameters of the calibration model before and after smoothing of X-ray spectra have been investigated. The calibration model was calculated using multivariate procedure - namely the partial least square regression (PLS). Investigations have been performed on an example of six sets of various standards used for calibration of some instruments based on X-ray fluorescence principle. The smoothing methods were compared: regression splines, Savitzky-Golay and Discrete Fourier Transform. The calculations were performed using a software package MATLAB and some home-made programs. (author)

  11. Analysis of neon soft x-ray spectra from short-pulse laser-produced plasmas

    International Nuclear Information System (INIS)

    Abare, A.C.; Keane, C.J.; Crane, J.K.; DaSilva, L.B.; Lee, R.W.; Perry, M.D.; Falcone, R.W.

    1993-04-01

    We report preliminary results from the analysis of streaked soft x-ray neon spectra a gas jet target. In obtained from the interaction of a picosecond Nd:glass laser with these experiments streaked spectra show prompt harmonic emission followed by longer time duration soft x-ray line emission. The majority of the line emission observed was found to originate from Li- and Be-like Ne and the major transitions in the observed spectra have been identified. Li-like emission lines were observed to decay faster in time than Be-like transitions, suggesting that recombination is taking place. Line ratios of n=4-2 and n=3-2 transitions supported the view that these lines were optically thin and thick, respectively. The time history of Li-like Ne 2p-4d and 2p-3d lines is in good agreement with a simple adiabatic expansion model coupled to a time dependent collisional-radiative code. Further x-ray spectroscopic analysis is underway which is aimed at diagnosing plasma conditions and assessing the potential of this recombining neon plasma as a quasi-steady-state recombination x-ray laser medium

  12. Super-Eddington accretion on to the neutron star NGC 7793 P13: Broad-band X-ray spectroscopy and ultraluminous X-ray sources

    Science.gov (United States)

    Walton, D. J.; Fürst, F.; Harrison, F. A.; Stern, D.; Bachetti, M.; Barret, D.; Brightman, M.; Fabian, A. C.; Middleton, M. J.; Ptak, A.; Tao, L.

    2018-02-01

    We present a detailed, broad-band X-ray spectral analysis of the ultraluminous X-ray source (ULX) pulsar NGC 7793 P13, a known super-Eddington source, utilizing data from the XMM-Newton, NuSTAR and Chandra observatories. The broad-band XMM-Newton+NuSTAR spectrum of P13 is qualitatively similar to the rest of the ULX sample with broad-band coverage, suggesting that additional ULXs in the known population may host neutron star accretors. Through time-averaged, phase-resolved and multi-epoch studies, we find that two non-pulsed thermal blackbody components with temperatures ∼0.5 and 1.5 keV are required to fit the data below 10 keV, in addition to a third continuum component which extends to higher energies and is associated with the pulsed emission from the accretion column. The characteristic radii of the thermal components appear to be comparable, and are too large to be associated with the neutron star itself, so the need for two components likely indicates the accretion flow outside the magnetosphere is complex. We suggest a scenario in which the thick inner disc expected for super-Eddington accretion begins to form, but is terminated by the neutron star's magnetic field soon after its onset, implying a limit of B ≲ 6 × 1012 G for the dipolar component of the central neutron star's magnetic field. Evidence of similar termination of the disc in other sources may offer a further means of identifying additional neutron star ULXs. Finally, we examine the spectrum exhibited by P13 during one of its unusual 'off' states. These data require both a hard power-law component, suggesting residual accretion on to the neutron star, and emission from a thermal plasma, which we argue is likely associated with the P13 system.

  13. Determination of x-ray spectra incident on and transmitted through whole excised breast for improved mammographic exposing technique

    International Nuclear Information System (INIS)

    Haus, A.G.; Metz, C.E.; Doi, K.; Bernstein, J.

    1976-01-01

    Measurements were made of x-ray spectra incident on and transmitted through whole excised fresh breast tissue. The spectra and corresponding radiographs show that hardening of the x-ray beam from a molybdenum anode x-ray tube by a 0.5 mm Al filter instead of the conventional 0.03 mm Mo filter allows shorter exposure times and reduces patient radiation exposure. With the Al filter, acceptable image contrast is preserved in mammography of thick or dense breasts

  14. Galactic and extragalactic hydrogen in the X-ray spectra of Gamma Ray Bursts

    Science.gov (United States)

    Rácz, I. I.; Bagoly, Z.; Tóth, L. V.; Balázs, L. G.; Horváth, I.; Pintér, S.

    2017-07-01

    Two types of emission can be observed from gamma-ray bursts (GRBs): the prompt emission from the central engine which can be observed in gamma or X-ray (as a low energy tail) and the afterglow from the environment in X-ray and at shorter frequencies. We examined the Swift XRT spectra with the XSPEC software. The correct estimation of the galactic interstellar medium is very important because we observe the host emission together with the galactic hydrogen absorption. We found that the estimated intrinsic hydrogen column density and the X-ray flux depend heavily on the redshift and the galactic foreground hydrogen. We also found that the initial parameters of the iteration and the cosmological parameters did not have much effect on the fitting result.

  15. High resolution krypton M/sub 4,5/ x-ray emission spectra

    International Nuclear Information System (INIS)

    Perera, R.C.C.; Hettrick, M.C.; Lindle, D.W.

    1987-10-01

    High resolution M/sub 4,5/ (3d → 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/ΔE, is about 300 in this energy range (∼80 eV). Three dipole-allowed 3d → 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr 2+ , and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab

  16. Theoretical modeling of Comptonized X-ray spectra of super-Eddington accretion flow: Origin of hard excess in ultraluminous X-ray sources

    Science.gov (United States)

    Kitaki, Takaaki; Mineshige, Shin; Ohsuga, Ken; Kawashima, Tomohisa

    2017-12-01

    X-ray continuum spectra of super-Eddington accretion flow are studied by means of Monte Carlo radiative transfer simulations based on the radiation hydrodynamic simulation data, in which both thermal- and bulk-Compton scatterings are taken into account. We compare the calculated spectra of accretion flow around black holes with masses of MBH = 10, 102, 103, and 104 M⊙ for a fixed mass injection rate (from the computational boundary at 103 rs) of 103 LEdd/c2 (with rs, LEdd, and c being the Schwarzschild radius, the Eddington luminosity, and the speed of light, respectively). The soft X-ray spectra exhibit mass dependence in accordance with the standard-disk relation; the maximum surface temperature is scaled as T ∝ M_{ BH}^{ -1/4}. The spectra in the hard X-ray band, by contrast with soft X-ray, look to be quite similar among different models, if we normalize the radiation luminosity by MBH. This reflects that the hard component is created by thermal- and bulk-Compton scatterings of soft photons originating from an accretion flow in the overheated and/or funnel regions, the temperatures of which have no dependence on mass. The hard X-ray spectra can be reproduced by a Wien spectrum with the temperature of T ˜ 3 keV accompanied by a hard excess at photon energy above several keV. The excess spectrum can be fitted well with a power law with a photon index of Γ ˜ 3. This feature is in good agreement with that of the recent NuSTAR observations of ULXs (ultra-luminous X-ray sources).

  17. Dynamical and Radiative Properties of X-Ray Pulsar Accretion Columns: Phase-averaged Spectra

    Energy Technology Data Exchange (ETDEWEB)

    West, Brent F. [Department of Electrical and Computer Engineering, United States Naval Academy, Annapolis, MD (United States); Wolfram, Kenneth D. [Naval Research Laboratory (retired), Washington, DC (United States); Becker, Peter A., E-mail: bwest@usna.edu, E-mail: kswolfram@gmail.com, E-mail: pbecker@gmu.edu [Department of Physics and Astronomy, George Mason University, Fairfax, VA (United States)

    2017-02-01

    The availability of the unprecedented spectral resolution provided by modern X-ray observatories is opening up new areas for study involving the coupled formation of the continuum emission and the cyclotron absorption features in accretion-powered X-ray pulsar spectra. Previous research focusing on the dynamics and the associated formation of the observed spectra has largely been confined to the single-fluid model, in which the super-Eddington luminosity inside the column decelerates the flow to rest at the stellar surface, while the dynamical effect of gas pressure is ignored. In a companion paper, we have presented a detailed analysis of the hydrodynamic and thermodynamic structure of the accretion column obtained using a new self-consistent model that includes the effects of both gas and radiation pressures. In this paper, we explore the formation of the associated X-ray spectra using a rigorous photon transport equation that is consistent with the hydrodynamic and thermodynamic structure of the column. We use the new model to obtain phase-averaged spectra and partially occulted spectra for Her X-1, Cen X-3, and LMC X-4. We also use the new model to constrain the emission geometry, and compare the resulting parameters with those obtained using previously published models. Our model sheds new light on the structure of the column, the relationship between the ionized gas and the photons, the competition between diffusive and advective transport, and the magnitude of the energy-averaged cyclotron scattering cross-section.

  18. Extensive Broadband X-Ray Monitoring During the Formation of a Giant Radio Jet Base in Cyg X-3 with AstroSat

    Science.gov (United States)

    Pahari, Mayukh; Yadav, J. S.; Verdhan Chauhan, Jai; Rawat, Divya; Misra, Ranjeev; Agrawal, P. C.; Chandra, Sunil; Bagri, Kalyani; Jain, Pankaj; Manchanda, R. K.; Chitnis, Varsha; Bhattacharyya, Sudip

    2018-01-01

    We present X-ray spectral and timing behavior of Cyg X-3 as observed by AstroSat during the onset of a giant radio flare on 2017 April 1–2. Within a timescale of a few hours, the source shows a transition from the hypersoft state (HPS) to a more luminous state (we termed as the very high state), which coincides with the time of the steep rise in radio flux density by an order of magnitude. Modeling the Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counter (LAXPC) spectra jointly in 0.5–70.0 keV, we found that the first few hours of the observation is dominated by the HPS with no significant counts above 17 keV. Later, an additional flat power-law component suddenly appeared in the spectra that extends to very high energies with the power-law photon index of {1.49}-0.03+0.04. Such a flat power-law component has never been reported from Cyg X-3. Interestingly the fitted power-law model in 25–70 keV, when extrapolated to the radio frequency, predicts the radio flux density to be consistent with the trend measured from the RATAN-600 telescope at 11.2 GHz. This provides direct evidence of the synchrotron origin of flat X-ray power-law component and the most extensive monitoring of the broadband X-ray behavior at the moment of decoupling the giant radio jet base from the compact object in Cyg X-3. Using SXT and LAXPC observations, we determine the giant flare ejection time as MJD 57845.34 ± 0.08 when 11.2 GHz radio flux density increases from ∼100 to ∼478 mJy.

  19. Modeling X-ray Spectra of Astrophysical Plasmas: Current Status and Future Needs

    Science.gov (United States)

    Smith, Randall

    Existing high-resolution astrophysical X-ray spectra has exposed the need for high-quality atomic data of all stripes: wavelengths, collisional and absorption cross sections, and radiative rates. The Astro-H soft X-ray spectrometer (2015 launch) will vastly increase the number and type of high-resolution X-ray spectra available and likely expose a number of shortcomings in our models. I will describe recent advances in theoretical calculations and laboratory measurements, as well as a number of existing needs in the field. These include accurate soft X-ray wavelengths for L-shell ions, diagnostic emission line ratios with estimated error bars, and high-resolution absorption cross sections for abundant ions and molecules. Finally, new models of emission from non-equilibrium ionization plasmas and astrophysical charge exchange will be discussed. This latter emission arises due to the interaction of highly charged ions with neutral atoms, forming a diffuse background in the case of solar wind ions and possibly also arising in more distant environments.

  20. X ray spectra and qualities for use in diagnostic radiology and equipment calibration

    International Nuclear Information System (INIS)

    Souza, Karla Cristina de

    1996-12-01

    The goal of this work was the standardization of radiation qualities of diagnostic X ray equipment of the Assay Laboratory of the Institute for Radiation Protection and Dosimetry (IRD) of the National Commission of Nuclear Energy, Brazil. X ray spectra were determined from pulse height distribution measured directly on the primary beam using a high pure planar Ge detector. A program was developed to convert pulse height distribution into radiation spectra in the range from 20 to 150 keV. X ray qualities based on those used by the 'Physikalish-Technish Bundesantalt' (PTB) primary laboratory were implanted in three radiological equipment of the Assay Laboratory. These qualities simulate radiation beams on patients submitted to typical radiological examinations. Besides the spectrometric system, a reference measurement system based on an ionization chamber calibrated in air kerma was used to establish parameters such as kilovoltage, first and second half-value layer, mean energy, effective energy and inherent filtration. Our data have shown that the implantation of these radiation qualities in the Assay Laboratory results on a metrological basis for calibration of dose measurement assemblies and kV-meters, like those used by IRD to evaluate the parameters of X ray equipment around the country. A catalogue of spectral data resulting from this work is a data bank that allows various applications like dose calculation using Monte Carlo simulation techniques. (author)

  1. Automated generation and ensemble-learned matching of X-ray absorption spectra

    Science.gov (United States)

    Zheng, Chen; Mathew, Kiran; Chen, Chi; Chen, Yiming; Tang, Hanmei; Dozier, Alan; Kas, Joshua J.; Vila, Fernando D.; Rehr, John J.; Piper, Louis F. J.; Persson, Kristin A.; Ong, Shyue Ping

    2018-03-01

    X-ray absorption spectroscopy (XAS) is a widely used materials characterization technique to determine oxidation states, coordination environment, and other local atomic structure information. Analysis of XAS relies on comparison of measured spectra to reliable reference spectra. However, existing databases of XAS spectra are highly limited both in terms of the number of reference spectra available as well as the breadth of chemistry coverage. In this work, we report the development of XASdb, a large database of computed reference XAS, and an Ensemble-Learned Spectra IdEntification (ELSIE) algorithm for the matching of spectra. XASdb currently hosts more than 800,000 K-edge X-ray absorption near-edge spectra (XANES) for over 40,000 materials from the open-science Materials Project database. We discuss a high-throughput automation framework for FEFF calculations, built on robust, rigorously benchmarked parameters. FEFF is a computer program uses a real-space Green's function approach to calculate X-ray absorption spectra. We will demonstrate that the ELSIE algorithm, which combines 33 weak "learners" comprising a set of preprocessing steps and a similarity metric, can achieve up to 84.2% accuracy in identifying the correct oxidation state and coordination environment of a test set of 19 K-edge XANES spectra encompassing a diverse range of chemistries and crystal structures. The XASdb with the ELSIE algorithm has been integrated into a web application in the Materials Project, providing an important new public resource for the analysis of XAS to all materials researchers. Finally, the ELSIE algorithm itself has been made available as part of veidt, an open source machine-learning library for materials science.

  2. A method to unfold the efficiency of gaseous detectors exposed to broad X-ray spectra

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Souza, Maria Ines S. de; Lopes, Ricardo T.

    2000-01-01

    A method to obtain the efficiency of a gaseous detector exposed to broad energy X-ray spectra was developed. It consists in the de-convolution of the integrated detector response using the shapes of those spectra as a tool to unfold the aimed detector efficiency curve. For this purpose, the spectra emitted by a X-ray tube under several anode voltages, were properly characterized through measurements with a NaI(Tl) spectrometer. A Lorentz function was then fitted to each of the spectra, and their parameters expressed as a function of the anode voltage, by using polynomial and gaussian fittings. The integral of the product of each Lorentz function, by another unknown Lorentz function, expressing the detector efficiency curve, represents the response of the detector for each anode tension, e.g., each X-ray spectrum. The symbolical integration of that product, produces a general function containing the unknown parameters of the unknown efficiency curve. A non-linear fitting of this general function, to the detector response points, as experimentally obtained, generates the aimed parameters for the efficiency curve. The final detector efficiency curve is obtained after normalization procedures. (author)

  3. Changes of soft X-ray emission spectra of oxygen and copper in high Tc superconductors

    International Nuclear Information System (INIS)

    Fukushima, Sei; Gohshi, Yohichi; Kohiki, Shigemi; Saitoh, Naoki

    1989-01-01

    X-ray induced soft X-ray emission spectroscopy is one of the bulk analysis methods used to characterize high-Tc superconductor. In this report, some observations on the changes in O Kα and Cu L spectra of thin layer LnBa 2 Cu 3 O 7-δ (Ln=Er,Gd) samples are presented. From the measurement of O Kα, no discernible difference was found between those of Gd compounds which were composed single phase or not. It may be said that the electronic structure of p state localized on the O is not sensitive to the change of Tc or zero-resistance temperature. From the measurement of Cu L spectra, it was found that Cu Lα of only Gd containing compounds has a low energy shoulder

  4. An iterative method for unfolding time-resolved soft x-ray spectra of laser plasmas

    International Nuclear Information System (INIS)

    Tang Yongjian; Shen Kexi; Xu Hepin

    1991-01-01

    Dante-recorded temporal waveforms have been unfolded by using Fast Fourier transformation (FFT) and the inverted convolution theorem of Fourier analysis. The conversion of the signals to time-dependent soft x-ray spectra is accomplished on the IBM-PC/XT-286 microcomputer system with the code DTSP including SAND II reported by W.N.Mcelory et al.. An amplitude-limited iterative and periodic smoothing technique has been developed in the code DTSP. Time-resolved soft x-ray spectra with sixteen time-cell, and time-dependent radiation, [T R (t)], have been obtained for hohlraum targets irradiated with laser beams (λ = 1.06 μm) on LF-12 in 1989

  5. Optimization of tungsten x-ray spectra for digital mammography: a comparison of model to experiment

    Science.gov (United States)

    Andre, Michael P.; Spivey, Brett A.

    1997-05-01

    Tungsten (W) target x-rays tubes are being studied for use in digital mammography to improve x-ray flux, reduce noise and increase tube heat capacity. A parametric model was developed for digital mammography to evaluate optimization of x-ray spectra for a particular sensor. The model computes spectra and mean glandular doses (MGD) for combinations of W target, beam filters, kVp, breast type and thickness. Two figures of merit were defined: (signal/noise)2/MGD and spectral quantum efficiency; these were computed as a means to approach optimization of object contrast. The model is derived from a combination of classic equations, XCOM from NBS, and published data. X-ray spectra were calculated and measured for filters of Al, Sn, Rh, Mo and Ag on a Eureka tube. (Signal/noise)2/MGD was measured for a filtered W target tube and a digital camera employing CsI scintillator optically coupled to a CCD for which the detective quantum efficiency (DQE) was known. A 3-mm thick acrylic disk was imaged on thickness of 3-8 cm of acrylic and the results were compared to the predictions of the model. The relative error between predicted and measured spectra was +/- 2 percent from 24 to 34 kVp. Calculated MGD as a function of breast thickness, half-value layer and beam filter compares very well to published data. Best performance was found for the following combinations: Mo filter with 30 mm breast, Ag filter with 45 mm, Sn filter for 60 mm, and Al filter for 75 mm thick breast. The parametric model agrees well with measurement and provides a means to explore optimum combinations of kVp and beam filter. For a particular detector, this data may be used with the DQE to estimate total system signal-to-noise ratio for a particular imaging task.

  6. Electron-electron correlation, resonant photoemission and X-ray emission spectra

    International Nuclear Information System (INIS)

    Parlebas, J.C.; Kotani, Akio; Tanaka, Satoshi.

    1991-01-01

    In this short review paper we essentially focus on the high energy spectroscopies which involve second order quantum processes, i.e., resonance photoemission, Auger and X-ray emission spectroscopies, denoted respectively by RXPS, AES and XES. First, we summarize the main 3p-RXPS and AES results obtained in Cu and Ni metals; especially we recall that the satellite near the 3p-threshold in the spectra, which arises from a d-hole pair bound state, needs a careful treatment of the electron-electron correlation. Then we analyze the RXPS spectra in a few Ce compounds (CeO 2 , Ce 2 O 3 and CeF 3 ) involving 3d or 4d core levels and we interpret the spectra consistently with the other spectroscopies, such as core XPS and XAS which are first order quantum processes. Finally within the same one-impurity model and basically with the same sets of parameters, we review a theory for the Ce 5p→3d XES, as well as for the corresponding RXES, where (1) the incident X-ray is tuned to resonate with the 3d→4f transition and (2) the X-ray emission due to the 5p→3d transition is actually observed. The paper ends with a general discussion. (author) 77 refs

  7. Experimental and Monte Carlo simulated spectra of a liquid-metal-jet x-ray source

    International Nuclear Information System (INIS)

    Marziani, M.; Gambaccini, M.; Di Domenico, G.; Taibi, A.; Cardarelli, P.

    2014-01-01

    A prototype x-ray system based on a liquid-metal-jet anode was evaluated within the framework of the LABSYNC project. The generated spectrum was measured using a CZT-based spectrometer and was compared with spectra simulated by three Monte Carlo codes: MCNPX, PENELOPE and EGS5. Notable differences in the simulated spectra were found. These are mainly attributable to differences in the models adopted for the electron-impact ionization cross section. The simulation that more closely reproduces the experimentally measured spectrum was provided by PENELOPE. - Highlights: • The x-ray spectrum of a liquid-jet x-ray anode was measured with a CZT spectrometer. • Results were compared with Monte Carlo simulations using MCNPX, PENELOPE, EGS5. • Notable differences were found among the Monte Carlo simulated spectra. • The key role was played by the electron-impact ionization cross-section model used. • The experimentally measured spectrum was closely reproduced by the PENELOPE code

  8. Absorption spectra response of XRQA radiochromic film to x-ray radiation

    International Nuclear Information System (INIS)

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

    2010-01-01

    Gafchromic XRQA, radiochromic film is a high sensitivity auto developing x-ray analysis films designed and available for kilovoltage x-ray, dose and QA assessment applications. The film is designed for reflective analysis with a yellow transparent top filter and white opaque backing materials. This allows the film to be visually inspected for colour changes with a higher level of contrast than clear coated radiochromic films such as Gafchromic EBT version 1. The spectral absorption properties in the visible wavelengths have been investigated and results show two main peaks in absorption located at 636 nm and 585 nm. These peaks are located in the same position as EBT Gafchromic film highlighting a similar chemical monomer/polymer for radiation sensitivity. A much higher sensitivity however is found at kilovoltage energies with an average 1.55 OD units per 20 cGy irradiation variation measured at 636 nm using 150 kVp x-rays. This is compared to approximately 0.12 OD units per 20 cGy measured at 636 nm for EBT film at 6 MV x-ray energy. That is, the XRQA film is more than 10 times more sensitive than EBT1 film. The visual colour change is enhanced by the yellow polyester coating. However this does not affect the absorption spectra properties in the red region of analysis which is the main area for use using desktop scanners in reflection mode.

  9. SpekCalc: a program to calculate photon spectra from tungsten anode x-ray tubes

    International Nuclear Information System (INIS)

    Poludniowski, G; Evans, P M; Landry, G; DeBlois, F; Verhaegen, F

    2009-01-01

    A software program, SpekCalc, is presented for the calculation of x-ray spectra from tungsten anode x-ray tubes. SpekCalc was designed primarily for use in a medical physics context, for both research and education purposes, but may also be of interest to those working with x-ray tubes in industry. Noteworthy is the particularly wide range of tube potentials (40-300 kVp) and anode angles (recommended: 6-30 deg.) that can be modelled: the program is therefore potentially of use to those working in superficial/orthovoltage radiotherapy, as well as diagnostic radiology. The utility is free to download and is based on a deterministic model of x-ray spectrum generation (Poludniowski 2007 Med. Phys. 34 2175). Filtration can be applied for seven materials (air, water, Be, Al, Cu, Sn and W). In this note SpekCalc is described and illustrative examples are shown. Predictions are compared to those of a state-of-the-art Monte Carlo code (BEAMnrc) and, where possible, to an alternative, widely-used, spectrum calculation program (IPEM78). (note)

  10. Study of soft X-ray energy spectra from gas-puff Z-pinch plasma

    International Nuclear Information System (INIS)

    Zou Xiaobing; Wang Xinxin; Zhang Guixin; Han Min; Luo Chengmu

    2006-01-01

    A ROSS-FILTER-PIN spectrometer in the spectral range of 0.28 keV-1.56 keV was developed to study the soft X-ray radiation emitted from gas-puff Z-pinch plasma. It is composed of five channels covering the energy interval of interest without gaps. Soft X-ray spectral energy cuts were determined by the L absorption edges of selected filter elements (K absorption edges being used for light filter elements), and the optimum thickness of filter material was designed using computer code. To minimize the residual sensitivity outside the sensitivity range of each channel, element of the first filter was added into the second filter of all the Ross pair. To diminish the area of each filter, PIN detector with small sensitive area of 1 mm 2 was adopted for the spectrometer. A filter with small area is easy to fabricate and would be helpful to withstand the Z-pinch discharge shock wave. With this ROSS-FILTER-PIN spectrometer, the energy spectra of soft X-ray from a small gas-puff Z-pinch were investigated, and the correlation between the soft X-ray yield and the plasma implosion state was also studied. (authors)

  11. Identifying Broadband Rotational Spectra with Neural Networks

    Science.gov (United States)

    Zaleski, Daniel P.; Prozument, Kirill

    2017-06-01

    A typical broadband rotational spectrum may contain several thousand observable transitions, spanning many species. Identifying the individual spectra, particularly when the dynamic range reaches 1,000:1 or even 10,000:1, can be challenging. One approach is to apply automated fitting routines. In this approach, combinations of 3 transitions can be created to form a "triple", which allows fitting of the A, B, and C rotational constants in a Watson-type Hamiltonian. On a standard desktop computer, with a target molecule of interest, a typical AUTOFIT routine takes 2-12 hours depending on the spectral density. A new approach is to utilize machine learning to train a computer to recognize the patterns (frequency spacing and relative intensities) inherit in rotational spectra and to identify the individual spectra in a raw broadband rotational spectrum. Here, recurrent neural networks have been trained to identify different types of rotational spectra and classify them accordingly. Furthermore, early results in applying convolutional neural networks for spectral object recognition in broadband rotational spectra appear promising. Perez et al. "Broadband Fourier transform rotational spectroscopy for structure determination: The water heptamer." Chem. Phys. Lett., 2013, 571, 1-15. Seifert et al. "AUTOFIT, an Automated Fitting Tool for Broadband Rotational Spectra, and Applications to 1-Hexanal." J. Mol. Spectrosc., 2015, 312, 13-21. Bishop. "Neural networks for pattern recognition." Oxford university press, 1995.

  12. Theory of pump–probe ultrafast photoemission and X-ray absorption spectra

    Energy Technology Data Exchange (ETDEWEB)

    Fujikawa, Takashi, E-mail: tfujikawa@faculty.chiba-u.jp; Niki, Kaori

    2016-01-15

    Highlights: • Pump–probe ultrafast XAFS and XPS spectra are theoretically studied. • Keldysh Green's function theory is applied. • Important many-body effects are explicitly included. - Abstract: Keldysh Green's function approach is extensively used in order to derive practical formulas to analyze pump–probe ultrafast photoemission and X-ray absorption spectra. Here the pump pulse is strong enough whereas the probe X-ray pulse can be treated by use of a perturbation theory. We expand full Green's function in terms of renormalized Green's function without the interaction between electrons and probe pulse. The present theoretical formulas allow us to handle the intrinsic and extrinsic losses, and furthermore resonant effects in X-ray Absorption Fine Structures (XAFS). To understand the radiation field screening in XPS spectra, we have to use more sophisticated theoretical approach. In the ultrafast XPS and XAFS analyses the intrinsic and extrinsic loss effects can interfere as well. In the XAFS studies careful analyses are necessary to handle extrinsic losses in terms of damped photoelectron propagation. The nonequilibrium dynamics after the pump pulse irradiation is well described by use of the time-dependent Dyson orbitals. Well above the edge threshold, ultrafast photoelectron diffraction and extended X-ray absorption fine structure (EXAFS) provide us with transient structural change after the laser pump excitations. In addition to these slow processes, the rapid oscillation in time plays an important role related to pump electronic excitations. Near threshold detailed information could be obtained for the combined electronic and structural dynamics. In particular high-energy photoemission and EXAFS are not so influenced by the details of excited states by pump pulse. Random-Phase Approximation (RPA)-boson approach is introduced to derive some practical formulas for time-dependent intrinsic amplitudes.

  13. HIGHER ORDER SPECIATION EFFECTS ON PLUTONIUM L3 X-RAY ABSORPTION NEAR EDGE SPECTRA.

    Energy Technology Data Exchange (ETDEWEB)

    Conradson, Steven D.; Abney, Kent D.; Begg, Bruce D.; Brady, Erik D.; Clark, David L.; den Auwer, Christophe; Ding, Mei; Dorhout, Peter K.; Espinosa-Faller, Francisco J.; Gordon, Pamela L.; Hess, Nancy J.; Hess, Ryan F.; Keogh, D. Webster; Lander, Gerard H.; Lupinetti, Anthony J.; Neu, Mary P.; Palmer, Phillip D.; Paviet-Hartmann, Patricia; Reilly, Sean D.; Runde, Wolfgang H.; Tait, C. Drew; Veirs, D. Kirk

    2003-06-09

    Pu L{sub 3} X-ray Near Edge Absorption Spectra for Pu(0-VII) are reported for more than 50 chalcogenides, chlorides, hydrates, hydroxides, nitrates, carbonates, oxy-hydroxides, and other compounds both as solids and in solution, and substituted in zirconlite, perovksite, and borosilicate glass. This large data base extends the known correlations between the energy and shape of these spectra from the usual association of the XANES with valence and site symmetry to higher order chemical effects. Because of the large number of compounds of these different types a number of novel and unexpected behaviors are observed.

  14. High-Resolution X-Ray Spectra of the Symbiotic Star SS73 17

    Science.gov (United States)

    Eze, R. N. C.; Luna, G. J. M.; Smith, R. K.

    2010-01-01

    SS73 17 was an innocuous Mira-type symbiotic star until the International Gamma-Ray Astrophysics Laboratory and Swift discovered its bright hard X-ray emission, adding it to the small class of "hard X-ray emitting symbiotics." Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2.0 keV bandpass. We present here follow-up observations with the Chandra High Energy Transmission Grating and Suzaku that confirm the earlier detection of strong emission lines of Fe K(alpha) fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high-resolution spectrum also shows emission lines of other highly ionized ions as Si xiv and possibly S XVI. In addition, a re-analysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe xxv lines shows that these lines are thermal, not photoionized, in origin.With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling-flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.

  15. HIGH-RESOLUTION X-RAY SPECTRA OF THE SYMBIOTIC STAR SS73 17

    International Nuclear Information System (INIS)

    Eze, R. N. C.; Luna, G. J. M.; Smith, R. K.

    2010-01-01

    SS73 17 was an innocuous Mira-type symbiotic star until the International Gamma-Ray Astrophysics Laboratory and Swift discovered its bright hard X-ray emission, adding it to the small class of 'hard X-ray emitting symbiotics'. Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2.0 keV bandpass. We present here follow-up observations with the Chandra High Energy Transmission Grating and Suzaku that confirm the earlier detection of strong emission lines of Fe Kα fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high-resolution spectrum also shows emission lines of other highly ionized ions as Si XIV and possibly S XVI. In addition, a re-analysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe XXV lines shows that these lines are thermal, not photoionized, in origin. With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling-flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.

  16. X-ray spectra of PG quasars. II - the X-ray-ultraviolet excess of PG 1211 + 143

    International Nuclear Information System (INIS)

    Bechtold, J.; Czerny, B.; Elvis, M.; Fabbiano, G.; Green, R.F.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA; Kitt Peak National Observatory, Tucson, AZ)

    1987-01-01

    Observations of the quasar PG 1211 + 143 are presented and its continuum is modelled in terms of an accretion disk and an underlying power law. The X-ray spectrum in the Einstein imaging proportional counter band is well described by a power law with the very steep spectral index 2.2 + or - 0.4. The overall continuum spectral energy distribution can be described as a power law with alpha roughly 1.2 from the infrared to about 1 keV, with the optical, ultraviolet, and soft X-rays forming a large excess above this power law. If the soft X-ray excess is attributed to emission from a physically thin, optically thick accretion disk, then the implied accretion rate is super-Eddington, from which it is concluded that the application of this simple model is not valid. The observed broad-line ratios in PG 1211 + 143 imply broad-line cloud densities that are somewhat higher than those usually derived for quasars. 82 references

  17. Spatial power-spectra from Yohkoh soft X-ray images

    Science.gov (United States)

    Martens, Petrus C. H.; Gomez, Daniel O.

    1992-01-01

    We analyze three sequences of images from active regions, and a full disk image obtained by Yohkoh's Soft X-ray Telescope. Two sequences are from a region at center disk observed through different filters, and one sequence is from the limb. After Fourier-transforming the X-ray intensity of the images we find nearly isotropic power-spectra with an azimuthally integrated slope of -2.1 for the center disk, and -2.8 for the limb images. The full-disk picture yields a spectrum of -2.4. These results are different from the active region spectra obtained with the Normal Incidence X-ray Telescope which have a slope of the order of -3.0, and we ascribe this to the difference in temperature response between the instruments. However, both the SXT and NIXT results are consistent with coronal heating as the end result of a downward quasistatic cascade (in lengthscales) of free magnetic energy in the corona, driven by footpoint motions in the photosphere.

  18. Calculations of magnetic x-ray dichroism in the 3d absorption spectra of rare-earth compounds

    NARCIS (Netherlands)

    GOEDKOOP, JB; THOLE, BT; VANDERLAAN, G; SAWATZKY, GA; DEGROOT, FMF; FUGGLE, JC; de Groot, Frank|info:eu-repo/dai/nl/08747610X

    1988-01-01

    We present atomic calculations for the recently discovered magnetic x-ray dichroism (MXD) displayed by the 3d x-ray-absorption spectra of rare-earth compounds. The spectral shapes expected at T=0 K for linear polarization parallel and normal to the local magnetic field is given, together with the

  19. Krypton K-shell X-ray spectra recorded by the HENEX spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Seely, J.F. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)]. E-mail: john.seely@nrl.navy.mil; Back, C.A. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Constantin, C. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Hudson, L.T. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Szabo, C.I. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Henins, A. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Holland, G.E. [SFA Inc., 9315 Largo Drive West Suite 200, Largo MD 20774 (United States); Atkin, R. [Tiger Innovations, L.L.C., 3610 Vacation Lane, Arlington VA 22207 (United States); Marlin, L. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)

    2006-05-15

    High-resolution X-ray spectra were recorded by the High-Energy Electronic X-ray (HENEX) spectrometer from a variety of targets irradiated by the Omega laser at the Laboratory for Laser Energetics. The HENEX spectrometer utilizes four reflection crystals covering the 1-20keV energy range and one quartz(10-11) transmission crystal (Laue geometry) covering the 11-40keV range. The time-integrated spectral images were recorded on five CMOS X-ray detectors. In the spectra recorded from krypton-filled gasbag and hohlraum targets, the helium-like K-shell transitions n=1-2, 1-3, and 1-4 appeared in the 13-17keV energy range. A number of additional spectral features were observed at energies lower than the helium-like n=1-3 and n=1-4 transitions. Based on computational simulations of the spectra using the FLYCHK/FLYSPEC codes, which included opacity effects, these additional features are identified to be inner-shell transitions from the Li-like through N-like krypton charge states. The comparisons of the calculated and observed spectra indicate that these transitions are characteristic of the plasma conditions immediately after the laser pulse when the krypton density is 2x10{sup 18}cm{sup -3} and the electron temperature is in the range 2.8-3.2keV. These spectral features represent a new diagnostic for the charge state distribution, the density and electron temperature, and the plasma opacity. Laboratory experiments indicate that it is feasible to record K-shell spectra from gold and higher Z targets in the >60keV energy range using a Ge(220) transmission crystal.

  20. Studies of the X-ray absorption spectra of some methylcyano esters

    International Nuclear Information System (INIS)

    Takahashi, Osamu; Saito, Ko; Mitani, Masaki; Yoshida, Hiroaki; Tahara, Fumitaka; Sunami, Tetsuji; Waki, Keiichiro; Senba, Yasunori; Hiraya, Atsunari; Pettersson, Lars G.M.

    2005-01-01

    Density functional theory (DFT) has been applied to simulate core-excited photoabsorption spectra for some methylcyano esters within a transition potential (TP) framework. Our calculations for methylcyano formate at the N and O K-edges are consistent with previous experimental spectra. For methylcyano acetate the photoabsorption spectra at the N and O K-edges were reinvestigated experimentally. Contrary to the previous experiment, only one main peak was observed at the N K-edge and this peak was assigned to N(1s) ->π* excitation. This result was supported by our theoretical calculations. The general trends in the X-ray absorption spectra and the site-specific bond scission of methylcyano esters at the N and O K-edges are also discussed

  1. Monte Carlo simulation of x-ray spectra in diagnostic radiology and mammography using MCNP4C

    Energy Technology Data Exchange (ETDEWEB)

    Ay, M R [Department of Physics and Nuclear Sciences, AmirKabir University of Technology, Tehran (Iran, Islamic Republic of); Shahriari, M [Department of Nuclear Engineering, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Sarkar, S [Department of Medical Physics, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Adib, M [TPP Co., GE Medical Systems, Iran Authorized Distributor, Tehran (Iran, Islamic Republic of); Zaidi, H [Division of Nuclear Medicine, Geneva University Hospital, 1211 Geneva (Switzerland)

    2004-11-07

    The general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) was used for the simulation of x-ray spectra in diagnostic radiology and mammography. The electrons were transported until they slow down and stop in the target. Both bremsstrahlung and characteristic x-ray production were considered in this work. We focus on the simulation of various target/filter combinations to investigate the effect of tube voltage, target material and filter thickness on x-ray spectra in the diagnostic radiology and mammography energy ranges. The simulated x-ray spectra were compared with experimental measurements and spectra calculated by IPEM report number 78. In addition, the anode heel effect and off-axis x-ray spectra were assessed for different anode angles and target materials and the results were compared with EGS4-based Monte Carlo simulations and measured data. Quantitative evaluation of the differences between our Monte Carlo simulated and comparison spectra was performed using student's t-test statistical analysis. Generally, there is a good agreement between the simulated x-ray and comparison spectra, although there are systematic differences between the simulated and reference spectra especially in the K-characteristic x-rays intensity. Nevertheless, no statistically significant differences have been observed between IPEM spectra and the simulated spectra. It has been shown that the difference between MCNP simulated spectra and IPEM spectra in the low energy range is the result of the overestimation of characteristic photons following the normalization procedure. The transmission curves produced by MCNP4C have good agreement with the IPEM report especially for tube voltages of 50 kV and 80 kV. The systematic discrepancy for higher tube voltages is the result of systematic differences between the corresponding spectra.

  2. Monte Carlo simulation of x-ray spectra in diagnostic radiology and mammography using MCNP4C

    Science.gov (United States)

    Ay, M. R.; Shahriari, M.; Sarkar, S.; Adib, M.; Zaidi, H.

    2004-11-01

    The general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) was used for the simulation of x-ray spectra in diagnostic radiology and mammography. The electrons were transported until they slow down and stop in the target. Both bremsstrahlung and characteristic x-ray production were considered in this work. We focus on the simulation of various target/filter combinations to investigate the effect of tube voltage, target material and filter thickness on x-ray spectra in the diagnostic radiology and mammography energy ranges. The simulated x-ray spectra were compared with experimental measurements and spectra calculated by IPEM report number 78. In addition, the anode heel effect and off-axis x-ray spectra were assessed for different anode angles and target materials and the results were compared with EGS4-based Monte Carlo simulations and measured data. Quantitative evaluation of the differences between our Monte Carlo simulated and comparison spectra was performed using student's t-test statistical analysis. Generally, there is a good agreement between the simulated x-ray and comparison spectra, although there are systematic differences between the simulated and reference spectra especially in the K-characteristic x-rays intensity. Nevertheless, no statistically significant differences have been observed between IPEM spectra and the simulated spectra. It has been shown that the difference between MCNP simulated spectra and IPEM spectra in the low energy range is the result of the overestimation of characteristic photons following the normalization procedure. The transmission curves produced by MCNP4C have good agreement with the IPEM report especially for tube voltages of 50 kV and 80 kV. The systematic discrepancy for higher tube voltages is the result of systematic differences between the corresponding spectra.

  3. The influence of magnetic field geometry on magnetars X-ray spectra

    International Nuclear Information System (INIS)

    Viganò, D; Pons, J A; Miralles, J A; Parkins, N; Zane, S; Turolla, R

    2012-01-01

    Nowadays, the analysis of the X-ray spectra of magnetically powered neutron stars or magnetars is one of the most valuable tools to gain insight into the physical processes occurring in their interiors and magnetospheres. In particular, the magnetospheric plasma leaves a strong imprint on the observed X-ray spectrum by means of Compton up-scattering of the thermal radiation coming from the star surface. Motivated by the increased quality of the observational data, much theoretical work has been devoted to develop Monte Carlo (MC) codes that incorporate the effects of resonant Compton scattering (RCS) in the modeling of radiative transfer of photons through the magnetosphere. The two key ingredients in this simulations are the kinetic plasma properties and the magnetic field (MF) configuration. The MF geometry is expected to be complex, but up to now only mathematically simple solutions (self-similar solutions) have been employed. In this work, we discuss the effects of new, more realistic, MF geometries on synthetic spectra. We use new force-free solutions [14] in a previously developed MC code [9] to assess the influence of MF geometry on the emerging spectra. Our main result is that the shape of the final spectrum is mostly sensitive to uncertain parameters of the magnetospheric plasma, but the MF geometry plays an important role on the angle-dependence of the spectra.

  4. Changes in X-ray photoelectron spectra of yttria-tetragonal zirconia polycrystal by ion sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Eiko; Yoshinari, Masao [Tokyo Dental College, Oral Health Science Center, Tokyo, Chiyoda-ku (Japan)

    2016-04-15

    This paper reports changes in X-ray photoelectron spectroscopy spectra of yttria-tetragonal zirconia polycrystal (Y-TZP) brought about by Ar ion sputtering. The changes in the core-level spectra of Y-TZP suggest that preferential sputtering of oxygen occurred. A new peak was observed near 0 eV binding energy accompanied with changes in the core-level spectra by the sputtering. After 18 h in a high vacuum following the sputtering, the spectra changed by the sputtering were returned to their original shapes. In contrast, the color of Y-TZP was changed from white to pale brown by X-ray irradiation and was changed from pale brown to dark gray by ion sputtering. However, when the new peak near 0 eV decreased after 18 h, no color change was observed. Therefore, it is thought that the new peak was mainly derived from electrons trapped in various kinds of oxygen vacancies created by the sputtering in other than color centers. (orig.)

  5. Laboratory Studies of X-ray Spectra Formed by Charge Exchange

    Science.gov (United States)

    Beiersdorfer, Peter; Ali, R.; Brown, G. V.; Koutroumpa, D.; Kelley, R. L.; Kilbourne, C.; Leutenegger, M. A.; Porter, F.

    2013-04-01

    Charge exchange between ions and neutral atoms or molecules has been accepted at an important soft producing process in our solar system. By extension, charge exchange may contribute to the X-ray emission of circumstellar material. It may also produce X-ray emission at the boundaries of supernova ejecta and star burst galaxies, or whenever hot plasma collides with neutral matter. X-ray spectra of K-shell and L-shell ions formed by charge exchange have now been studied in a variety of laboratory settings. These experiments have shown several characteristic features of line formation by charge exchange when compared to the X-ray emission produced by electron-impact excitation, e.g., enhancement emission of forbidden lines and of lines from levels with high principal quantum number. They have also shown a dependence on the interaction gas and on the energy of the ion-neutral collision. Moreover, the transfer of multiple electrons is typically preferred, provided the donor molecules or atoms have multiple valence-shell electrons. The laboratory measurements are in qualitative agreement with theory. However, the details of the observed X-ray spectra, especially those recorded with high spectral resolution, can differ substantially from predictions, especially for spectra produced at collision velocities equal to or lower than those found in thermal plasmas or produced with neutral gases other than atomic hydrogen. Puzzling discrepancies can be noted, such as enhanced emission from an upper level with the 'wrong' principal quantum number. Even more puzzling is a recent experiment in which two, co-mixed bare ion species of similar atomic number produce very different Lyman series emission upon charge exchange with a given neutral gas, defying both theoretical predictions and empirical scaling. Laboratory measurements have also shown that some of the characteristic features of charge exchange can be reproduced by radiative electron capture, i.e., by capture of a continuum

  6. Phase-dependent absorption features in X-ray spectra of X-ray Dim Isolated Neutron Stars

    Science.gov (United States)

    Borghese, A.; Rea, N.; Coti Zelati, F.; Turolla, R.; Tiengo, A.; Zane, S.

    2017-12-01

    A detailed phase-resolved spectroscopy of archival XMM-Newton observations of X-ray Dim Isolated Neutron Stars (XDINSs) led to the discovery of narrow and strongly phase-dependent absorption features in two of these sources. The first was discovered in the X-ray spectrum of RX J0720.4-3125, followed by a new possible candidate in RX J1308.6+2127. Both spectral lines have similar properties: they are detected for only ˜ 20% of the rotational cycle and appear to be stable over the timespan covered by the observations. We performed Monte Carlo simulations to test the significance of these phase-variable features and in both cases the outcome has confirmed the detection with a confidence level > 4.6σ. Because of the narrow width and the strong dependence on the pulsar rotational phase, the most likely interpretation for these spectral features is in terms of resonant proton cyclotron absorption scattering in a confined high-B structure close to the stellar surface. Within the framework of this interpretation, our results provide evidence for deviations from a pure dipole magnetic field on small scales for highly magnetized neutron stars and support the proposed scenario of XDINSs being aged magnetars, with a strong non-dipolar crustal B-field component.

  7. X-ray spectra and time variability of active galactic nuclei

    International Nuclear Information System (INIS)

    Mushotzky, R.F.

    1984-02-01

    The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha .68 + or - .15. There is, as yet, no strong evidence for time variability of this slope in a given object. The constraints that this places on simple models of the central energy source are discussed. BL Lac objects have quite different X-ray spectral properties and show pronounced X-ray spectral variability. On time scales longer than 12 hours most radio quiet AGN do not show strong, delta I/I .5, variability. The probability of variability of these AGN seems to be inversely related to their luminosity. However characteristics timescales for variability have not been measured for many objects. This general lack of variability may imply that most AGN are well below the Eddington limit. Radio bright AGN tend to be more variable than radio quiet AGN on long, tau approx 6 month, timescales

  8. Monte Carlo Simulation of Complete X-Ray Spectra for Use in Scanning Electron Microscopy Analysis

    International Nuclear Information System (INIS)

    Roet, David; Van Espen, Piet

    2003-01-01

    Full Text: The interactions of keV electrons and photons with matter can be simulated accurately with the aid of the Monte Carlo (MC) technique. In scanning electron microscopy x-ray analysis (SEM-EDX) such simulations can be used to perform quantitative analysis using a Reverse Monte Carlo method even if the samples have irregular geometry. Alternatively the MC technique can generate spectra of standards for use in quantization with partial least squares regression. The feasibility of these alternatives to the more classical ZAF or phi-rho-Z quantification methods has been proven already. In order to be applicable for these purposes the MC-code needs to generate accurately only the characteristic K and L x-ray lines, but also the Bremsstrahlung continuum, i.e. the complete x-ray spectrum need to be simulated. Currently two types of MC simulation codes are available. Programs like Electron Flight Simulator and CASINO simulate characteristic x-rays due to electron interaction in a fast and efficient way but lack provision for the simulation of the continuum. On the other hand, programs like EGS4, MCNP4 and PENELOPE, originally developed for high energy (MeV- GeV) applications, are more complete but difficult to use and still slow, even on todays fastest computers. We therefore started the development of a dedicated MC simulation code for use in quantitative SEM-EDX work. The selection of the most appropriate cross section for the different interactions will be discussed and the results obtained will be compared with those obtained with existing MC programs. Examples of the application of MC simulations for quantitative analysis of samples with various composition will be given

  9. Reconstruction of X-rays spectra of clinical linear accelerators using the generalized simulated annealing method

    International Nuclear Information System (INIS)

    Manrique, John Peter O.; Costa, Alessandro M.

    2016-01-01

    The spectral distribution of megavoltage X-rays used in radiotherapy departments is a fundamental quantity from which, in principle, all relevant information required for radiotherapy treatments can be determined. To calculate the dose delivered to the patient who make radiation therapy, are used treatment planning systems (TPS), which make use of convolution and superposition algorithms and which requires prior knowledge of the photon fluence spectrum to perform the calculation of three-dimensional doses and thus ensure better accuracy in the tumor control probabilities preserving the normal tissue complication probabilities low. In this work we have obtained the photon fluence spectrum of X-ray of the SIEMENS ONCOR linear accelerator of 6 MV, using an character-inverse method to the reconstruction of the spectra of photons from transmission curves measured for different thicknesses of aluminum; the method used for reconstruction of the spectra is a stochastic technique known as generalized simulated annealing (GSA), based on the work of quasi-equilibrium statistic of Tsallis. For the validation of the reconstructed spectra we calculated the curve of percentage depth dose (PDD) for energy of 6 MV, using Monte Carlo simulation with Penelope code, and from the PDD then calculate the beam quality index TPR_2_0_/_1_0. (author)

  10. On the origin of X-ray spectra in luminous blazars

    International Nuclear Information System (INIS)

    Sikora, Marek; Janiak, Mateusz; Moderski, Rafał; Nalewajko, Krzysztof; Madejski, Greg M.

    2013-01-01

    Gamma-ray luminosities of some quasar-associated blazars imply jet powers reaching values comparable to the accretion power even if assuming very strong Doppler boosting and very high efficiency of gamma-ray production. With much lower radiative efficiencies of protons than of electrons, and the recent reports of very strong coupling of electrons with shock-heated protons indicated by particle-in-cell simulations, the leptonic models seem to be strongly favored over the hadronic ones. However, the electron-proton coupling combined with the external-radiation-Compton (ERC) models of gamma-ray production in leptonic models predict extremely hard X-ray spectra, with energy indices α x ∼ 0. This is inconsistent with the observed 2-10 keV slopes of blazars, which cluster around α x ∼ 0.6. This problem can be resolved by assuming that electrons can be efficiently cooled down radiatively to non-relativistic energies, or that blazar spectra are entirely dominated by the synchrotron self-Compton (SSC) component up to at least 10 keV. Here, we show that the required cooling can be sufficiently efficient only at distances r < 0.03 pc. SSC spectra, on the other hand, can be produced roughly co-spatially with the observed synchrotron and ERC components, which are most likely located roughly at a parsec scale. We show that the dominant SSC component can also be produced much further than the dominant synchrotron and ERC components, at distances of ≳ 10 pc. Hence, depending on the spatial distribution of the energy dissipation along the jet, one may expect to see γ-ray/optical events with either correlated or uncorrelated X-rays. In all cases the number of e + e – pairs per proton is predicted to be very low. The direct verification of the proposed SSC scenario, and particularly the question of the co-spatiality of the SSC component with other spectral components, requires sensitive observations in the hard X-ray band. This is now possible with the deployment of the Nu

  11. Determining misorientation of graphite grains from the angular dependence of X-ray emission spectra

    International Nuclear Information System (INIS)

    Belavin, V. V.; Okotrub, A. V.; Bulusheva, L. G.; Kotosonov, A. S.; Vyalykh, D. V.; Molodtsov, S. L.

    2006-01-01

    Angular-resolved X-ray absorption spectra were measured for pyrolytic graphite samples of various quality. A new approach to determining the misorientation of graphite grains in polycrystalline samples is proposed, which is based on calculations of the angular dependence of the relative intensity of a peak corresponding to the π* state for a normal distribution of grains. The experimental values are used to construct theoretical angular dependences using partial densities of the π* and σ* states determined from the nonempirical calculations for graphite

  12. Application of direct peak analysis to energy dispersive x-ray fluorescence spectra

    International Nuclear Information System (INIS)

    Nielson, K.K.

    1977-07-01

    A modified Covell method for direct peak analysis has been applied to energy dispersive x-ray fluorescence spectra. The method is background independent and is well-suited to computerized data reduction. It provides acceptable precision, minimizes errors from instrumental gain shift, and permits peak overlap correction. Peak overlap errors exhibit both positive and negative nodes as a function of peak separation distance, and are corrected using concentration ratios determined from thin, single-element standards. Peak precisions and overlaps are evaluated as a function of window width to aid in width selection. Least-square polynomial smoothing prior to peak analysis significantly improves peak area precisions without significantly affecting their accuracies

  13. Calculation of x-ray spectra emerging from an x-ray tube. Part I. Electron penetration characteristics in x-ray targets

    International Nuclear Information System (INIS)

    Poludniowski, Gavin G.; Evans, Philip M.

    2007-01-01

    The penetration characteristics of electron beams into x-ray targets are investigated for incident electron kinetic energies in the range 50-150 keV. The frequency densities of electrons penetrating to a depth x in a target, with a fraction of initial kinetic energy, u, are calculated using Monte Carlo methods for beam energies of 50, 80, 100, 120 and 150 keV in a tungsten target. The frequency densities for 100 keV electrons in Al, Mo and Re targets are also calculated. A mixture of simple modeling with equations and interpolation from data is used to generalize the calculations in tungsten. Where possible, parameters derived from the Monte Carlo data are compared to experimental measurements. Previous electron transport approximations in the semiempirical models of other authors are discussed and related to this work. In particular, the crudity of the use of the Thomson-Whiddington law to describe electron penetration and energy loss is highlighted. The results presented here may be used towards calculating the target self-attenuation correction for bremsstrahlung photons emitted within a tungsten target

  14. Strength of shock-loaded single-crystal tantalum [100] determined using in situ broadband x-ray Laue diffraction.

    Science.gov (United States)

    Comley, A J; Maddox, B R; Rudd, R E; Prisbrey, S T; Hawreliak, J A; Orlikowski, D A; Peterson, S C; Satcher, J H; Elsholz, A J; Park, H-S; Remington, B A; Bazin, N; Foster, J M; Graham, P; Park, N; Rosen, P A; Rothman, S R; Higginbotham, A; Suggit, M; Wark, J S

    2013-03-15

    The strength of shock-loaded single crystal tantalum [100] has been experimentally determined using in situ broadband x-ray Laue diffraction to measure the strain state of the compressed crystal, and elastic constants calculated from first principles. The inferred strength reaches 35 GPa at a shock pressure of 181 GPa and is in excellent agreement with a multiscale strength model [N. R. Barton et al., J. Appl. Phys. 109, 073501 (2011)], which employs a hierarchy of simulation methods over a range of length scales to calculate strength from first principles.

  15. X-Ray Spectra from MHD Simulations of Accreting Black Holes

    Science.gov (United States)

    Schnittman, Jeremy D.; Krolik, Julian H.; Noble, Scott C.

    2012-01-01

    We present the results of a new global radiation transport code coupled to a general relativistic magneto-hydrodynamic simulation of an accreting, nonrotating black hole. For the first time, we are able to explain from first principles in a self-consistent way the X-ray spectra observed from stellar-mass black holes, including a thermal peak, Compton reflection hump, power-law tail, and broad iron line. Varying only the mass accretion rate, we are able to reproduce the low/hard, steep power-law, and thermal-dominant states seen in most galactic black hole sources. The temperature in the corona is T(sub e) 10 keV in a boundary layer near the disk and rises smoothly to T(sub e) greater than or approximately 100 keV in low-density regions far above the disk. Even as the disk's reflection edge varies from the horizon out to approximately equal to 6M as the accretion rate decreases, we find that the shape of the Fe Ka line is remarkably constant. This is because photons emitted from the plunging region are strongly beamed into the horizon and never reach the observer. We have also carried out a basic timing analysis of the spectra and find that the fractional variability increases with photon energy and viewer inclination angle, consistent with the coronal hot spot model for X-ray fluctuations.

  16. EMISSION LINES BETWEEN 1 AND 2 keV IN COMETARY X-RAY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Ian; Christian, Damian J. [Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dennerl, Konrad [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching Germany (Germany); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 (United States); Wolk, Scott J., E-mail: ian.ewing.794@my.csun.edu, E-mail: daman.christian@csun.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-01-20

    We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

  17. Construction of a catalog of X-ray spectra for mammography simulations

    International Nuclear Information System (INIS)

    Santos, L.C.S.; Vieira, J.W.

    2017-01-01

    Computational Exposure Models (MCEs) allow the simulation of the interaction of radiation with matter by means of Monte Carlo (MC) techniques. Generally, MCEs are composed of phantom, simulator algorithms of radioactive sources and an MC code to simulate the transport, interaction of the radiation with matter and to evaluate the energy deposited in regions of interest. To compose an MCE for simulations in mammography, the construction of a catalog of X-ray spectra was started, based on the catalog model constructed and using until then in MCEs by the Group of Research in Numerical Dosimetry and by the Group of Research in Computational Dosimetry & Embedded Systems (both referenced in this work as GDN). Potential of 25 kV and 35 kV and used target / filter were applied to the tube: Mo / Mo. The file containing the spectra was read correctly by EGSnrc

  18. Studies of cluster X-ray sources. Energy spectra for the Perseus, Virgo, and Coma clusters

    International Nuclear Information System (INIS)

    Kellogg, E.; Baldwin, J.R.; Koch, D.

    1975-01-01

    We present the final Uhuru X-ray differential-energy spectra for the Perseus, Virgo, and Coma clusters of galaxies. The power-law and isothermal bremsstrahlung model forms, both with a low-energy cutoff, are given. For bremsstrahlung, the energy-dependent Gaunt factor is calculated by an improved method. The spectra, best fits to the Uhuru 2-10 keV data, are also compared with other observations of these sources in the energy range 0.1-100 keV. For Perseus, the data above 20 keV favor the bremsstrahlung fit marginally. For Virgo, the data of Catura et al. between 0.25 and 1.0 keV clearly favor the bremsstrahlung curve. For Coma, the weakest of the three sources, the data are less precise, but there is some evidence for a low-energy turnover or cutoff. The implications of such a cutoff are discussed briefly

  19. Equivalent half-value thickness and mean energies of filtered X-ray bremsstrahlung spectra

    International Nuclear Information System (INIS)

    Seelentag, W.W.; Panzer, W.

    1980-01-01

    X-ray beam qualities are often conveniently described by half-value thicknesses (in connection with tube voltage and filtration). Aluminium and copper are commonly used as half-value thickness materials, and either material may be used in a large intermediate energy range. Data comparisons frequently require conversions from values in Al to values in Cu. Equivalent half-value thicknesses for polychromatic radiations depend on the shapes of the spectra, but spectrometry is too expensive for routine application. Half-value thicknesses in both Al and Cu have been determined for some 250 spectra (tube potentials 10 to 300 kV). The results are tabulated, and these results together with a nomogram enable conversion with an accuracy of better than +- 5% in most cases. (UK)

  20. The supersoft X-ray source in V5116 Sagittarii. I. The high resolution spectra

    Science.gov (United States)

    Sala, G.; Ness, J. U.; Hernanz, M.; Greiner, J.

    2017-05-01

    Context. Classical nova explosions occur on the surface of an accreting white dwarf in a binary system. After ejection of a fraction of the envelope and when the expanding shell becomes optically thin to X-rays, a bright source of supersoft X-rays arises, powered by residual H burning on the surface of the white dwarf. While the general picture of the nova event is well established, the details and balance of accretion and ejection processes in classical novae are still full of unknowns. The long-term balance of accreted matter is of special interest for massive accreting white dwarfs, which may be promising supernova Ia progenitor candidates. Nova V5116 Sgr 2005b was observed as a bright and variable supersoft X-ray source by XMM-Newton in March 2007, 610 days after outburst. The light curve showed a periodicity consistent with the orbital period. During one third of the orbit the luminosity was a factor of seven brighter than during the other two thirds of the orbital period. Aims: In the present work we aim to disentangle the X-ray spectral components of V5116 Sgr and their variability. Methods: We present the high resolution spectra obtained with XMM-Newton RGS and Chandra LETGS/HRC-S in March and August 2007. Results: The grating spectrum during the periods of high-flux shows a typical hot white dwarf atmosphere dominated by absorption lines of N VI and N VII. During the low-flux periods, the spectrum is dominated by an atmosphere with the same temperature as during the high-flux period, but with several emission features superimposed. Some of the emission lines are well modeled with an optically thin plasma in collisional equilibrium, rich in C and N, which also explains some excess in the spectra of the high-flux period. No velocity shifts are observed in the absorption lines, with an upper limit set by the spectral resolution of 500 km s-1, consistent with the expectation of a non-expanding atmosphere so late in the evolution of the post-nova. Based on

  1. Lα1 satellites in X-ray emission spectra of higher - Z elements

    International Nuclear Information System (INIS)

    Poonia, S.

    2004-01-01

    Full text: The X-ray satellite spectra arising due to 2p 3/2 -1 3x -1 - 3x -1 3d -1 (x ≡ s, p, d) transition array, in elements with Z 74 to 92, have been calculated. While the energies of various transitions of the array have been determined by using available Hartree-Fock-Slater data on 1s -1 - 2p -1 3x -1 and 2p 3/2 -1 - 3x -1 , 3x' -1 Auger transition energies and their relative intensities have been estimated by considering cross - sections of singly ionized 2x -1 (x ≡ s, p) states and then of subsequent Coster-Kronig and shake off processes. The calculated spectra have been compared with the measured satellite energies in Lα1 spectra. Their intense peaks have been identified as the observed satellite lines. The one to one correspondence between the peaks in calculated spectra and the satellites in measured spectra has been established on the basis of the agreement between the separations in the peak energies and those in the measured satellite energies. It has been established that three satellites observed in the Lα 1 region of the X-ray spectra of various elements and named α', α ix and α x in order of increasing energy are mainly emitted by 2p 3/2 -1 3d -1 - 3d -2 transitions. It is observed that the satellite α' in all these spectra can be assigned to the superposition of 3 F 4 - 3 F 4 transition and that this must be most intense one out of all these satellites, contributing in order of decreasing intensity. The line α ix , has been assigned to mainly the 1 F 3 - 1 G 4 , 1 P 1 - 1 D 2 and 1 F 3 - 1 D 2 transitions. Finally, the satellite α x , reported in the spectra of elements with Z = 74-92, has been associated with the transition 3 D 3 - 3 F 4 . The possible contributions of other transitions of the 2p 3/2 -1 3x -1 - 3x -1 3d -1 (x ≡ s, p, d) array having appreciable intensities, have also been discussed

  2. Finite temperature effects on the X-ray absorption spectra of energy related materials

    Science.gov (United States)

    Pascal, Tod; Prendergast, David

    2014-03-01

    We elucidate the role of room-temperature-induced instantaneous structural distortions in the Li K-edge X-ray absorption spectra (XAS) of crystalline LiF, Li2SO4, Li2O, Li3N and Li2CO3 using high resolution X-ray Raman spectroscopy (XRS) measurements and first-principles density functional theory calculations within the eXcited electron and Core Hole (XCH) approach. Based on thermodynamic sampling via ab-initio molecular dynamics (MD) simulations, we find calculated XAS in much better agreement with experiment than those computed using the rigid crystal structure alone. We show that local instantaneous distortion of the atomic lattice perturbs the symmetry of the Li 1 s core-excited-state electronic structure, broadening spectral line-shapes and, in some cases, producing additional spectral features. This work was conducted within the Batteries for Advanced Transportation Technologies (BATT) Program, supported by the U.S. Department of Energy Vehicle Technologies Program under Contract No. DE-AC02-05CH11231.

  3. On the origin of cyclotron lines in the spectra of X-ray pulsars

    Directory of Open Access Journals (Sweden)

    Mushtukov A. A.

    2014-01-01

    Full Text Available Cyclotron resonance scattering features are observed in the spectra of some X-ray pulsars and show significant changes in the line energy with the pulsar luminosity. In a case of bright sources, the line centroid energy is anti-correlated with the luminosity. Such a behaviour is often associated with the onset and growth of the accretion column, which is believed to be the origin of the observed emission and the cyclotron lines. However, this scenario inevitably implies large gradient of the magnetic field strength within the line-forming region, and it makes the formation of the observed line-like features problematic. Moreover, the observed variation of the cyclotron line energy is much smaller than could be anticipated for the corresponding luminosity changes. We argue that a more physically realistic situation is that the cyclotron line forms when the radiation emitted by the accretion column is reflected from the neutron star surface. The idea is based on the facts that a substantial part of column luminosity is intercepted by the neutron star surface and the reflected radiation should contain absorption features. The reflection model is developed and applied to explain the observed variations of the cyclotron line energy in a bright X-ray pulsar V 0332+53 over a wide range of luminosities.

  4. Interpretation of magnetic circular dichroism of X-ray emission spectra

    International Nuclear Information System (INIS)

    Takayama, Yasuhiro; Yoshida, Tetsuo; Nakamura, Satoshi; Sasaki, Naoya; Ishii, Hiroyoshi; Miyahara, Tsuneaki

    2006-01-01

    We have measured the dependence of the magnetic circular dichroism (MCD) of the X-ray emission spectra (XES) on the temperature and incident angle for a Gd thin film. The energy of the incident photon for the XES was 138.25eV, which corresponded to the resonant excitation to the 8 D 9/2 intermediate state. The dependence of the observed MCD on the temperature and incident angle was quite different from that of the magnetic moment estimated with a SQUID magnetometer. By considering the reflection, saturation effect, self-absorption effect and magnetic anisotropy of the thin film, the agreement of the two behaviors was considerably improved. This result shows that the revisions of the MCD of the XES are extremely important for the quantitative estimation of the magnetic moment from the MCD of the XES. (author)

  5. Electronic Structures of Purple Bronze KMo6O17 Studied by X-Ray Photoemission Spectra

    Science.gov (United States)

    Qin, Xiaokui; Wei, Junyin; Shi, Jing; Tian, Mingliang; Chen, Hong; Tian, Decheng

    X-ray photoemission spectroscopy study has been performed for the purple bronze KMo6O17. The structures of conduction band and valence band are analogous to the results of ultraviolet photoemission spectra and are also consistent with the model of Travaglini et al., but the gap between conduction and valence band is insignificant. The shape of asymmetric and broadening line of O-1s is due to unresolved contributions from the many inequivalent oxygen sites in this crystal structure. Mo 3d core-level spectrum reveals that there are two kinds of valence states of Molybdenum (Mo+5 and Mo+6). The calculated average valence state is about +5.6, which is consistent with the expectation value from the composition of this material. The tail of Mo-3d spectrum toward higher binding energy is the consequence of the excitation of electron-hole pairs with singularity index of 0.21.

  6. Fundamental quantification procedure for total reflection X-ray fluorescence spectra analysis and elements determination

    International Nuclear Information System (INIS)

    Wegrzynek, D.; Holynska, B.

    1997-01-01

    A method for the determination of the concentrations of elements in particulate-like samples measured in total reflection geometry is proposed. In the proposed method the fundamental parameters are utilized for calculating the sensitivities of elements and an internal standard is used to account for the unknown mass per unit area of a sample and geometrical constant of the spectrometer. The modification of the primary excitation spectrum on its way to a sample has been taken into consideration. The concentrations of the elements to be determined are calculated simultaneously with the spectra deconvolution procedure. In the process of quantitative analysis the intensities of all X-ray peaks corresponding to K and L-series lines present in the analyzed spectrum are taken into account. (Author)

  7. X-ray photoelectron spectra structure and chemical bonding in AmO2

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2015-01-01

    Full Text Available Quantitative analysis was done of the X-ray photoelectron spectra structure in the binding energy range of 0 eV to ~35 eV for americium dioxide (AmO2 valence electrons. The binding energies and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the Am63O216 and AmO8 (D4h cluster reflecting Am close environment in AmO2 were taken into account. The experimental data show that the many-body effects and the multiplet splitting contribute to the spectral structure much less than the effects of formation of the outer (0-~15 eV binding energy and the inner (~15 eV-~35 eV binding energy valence molecular orbitals. The filled Am 5f electronic states were shown to form in the AmO2 valence band. The Am 6p electrons participate in formation of both the inner and the outer valence molecular orbitals (bands. The filled Am 6p3/2 and the O 2s electronic shells were found to make the largest contributions to the formation of the inner valence molecular orbitals. Contributions of electrons from different molecular orbitals to the chemical bond in the AmO8 cluster were evaluated. Composition and sequence order of molecular orbitals in the binding energy range 0-~35 eV in AmO2 were established. The experimental and theoretical data allowed a quantitative scheme of molecular orbitals for AmO2, which is fundamental for both understanding the chemical bond nature in americium dioxide and the interpretation of other X-ray spectra of AmO2.

  8. OSO 8 X-ray spectra of clusters of galaxies. I - Observations of twenty clusters: Physical correlations

    Science.gov (United States)

    Mushotzky, R. F.; Serlemitsos, P. J.; Boldt, E. A.; Holt, S. S.; Smith, B. W.

    1978-01-01

    OSO 8 X-ray spectra from 2 to 20 keV have been analyzed for 26 clusters of galaxies. For 20 clusters temperatures, emission integrals, iron abundances, and low-energy absorption measurements are presented. The data give, in general, better fits to thermal bremsstrahlung than to power-law models. Eight clusters have positive iron emission-line detections at the 90% confidence level, and all 20 cluster spectra are consistent with Fe/H = 0.000014 by number with the possible exception of Virgo. Thus it is confirmed that X-ray emission in this energy band is predominantly thermal radiation from hot intracluster gas rather than inverse Compton radiation. Physical correlations between X-ray spectral parameters and other cluster properties are examined. It is found that (1) the X-ray temperature is approximately proportional to the square of the velocity dispersion of the galaxies; (2) the emission integral is a strong function of the X-ray temperature; (3) the X-ray temperature and emission integral are better correlated with cluster central-galaxy density than with richness; and (4) the fraction of galaxies which are spirals is correlated with the observed ram pressure in the cluster core.

  9. New solar broad-band hard X-ray spectrometer: first results

    Czech Academy of Sciences Publication Activity Database

    Fárník, František; Garcia, H.; Karlický, Marian

    2001-01-01

    Roč. 201, č. 2 (2001), s. 357-372 ISSN 0038-0938 R&D Projects: GA ČR GA205/00/1726; GA AV ČR IAA3003003; GA AV ČR IBS1003006; GA AV ČR KSK2043105; GA AV ČR IAA303108 Institutional research plan: CEZ:AV0Z1003909 Keywords : X-ray * spectrometer * solar flare * radio emission Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.103, year: 2001

  10. Anatomy of the AGN in NGC 5548. IX. Photoionized emission features in the soft X-ray spectra

    Science.gov (United States)

    Mao, Junjie; Kaastra, J. S.; Mehdipour, M.; Gu, Liyi; Costantini, E.; Kriss, G. A.; Bianchi, S.; Branduardi-Raymont, G.; Behar, E.; Di Gesu, L.; Ponti, G.; Petrucci, P.-O.; Ebrero, J.

    2018-04-01

    The X-ray narrow emission line region (NELR) of the archetypal Seyfert 1 galaxy NGC 5548 has been interpreted as a single-phase photoionized plasma that is absorbed by some of the warm absorber components. This scenario requires those overlaying warm absorber components to have larger distance (to the central engine) than the X-ray NELR, which is not fully consistent with the distance estimates found in the literature. Therefore, we reanalyze the high-resolution spectra obtained in 2013-2014 with the Reflection Grating Spectrometer (RGS) aboard XMM-Newton to provide an alternative interpretation of the X-ray narrow emission features. We find that the X-ray narrow emission features in NGC 5548 can be described by a two-phase photoionized plasma with different ionization parameters (logξ = 1.3 and 0.1) and kinematics (vout = -50 and -400 km s-1), and no further absorption by the warm absorber components. The X-ray and optical NELR might be the same multi-phase photoionized plasma. Both X-ray and optical NELR have comparable distances, asymmetric line profiles, and the underlying photoionized plasma is turbulent and compact in size. The X-ray NELR is not the counterpart of the UV/X-ray absorber outside the line of sight because their distances and kinematics are not consistent. In addition, X-ray broad emission features that we find in the spectrum can be accounted for by a third photoionized emission component. The RGS spectrum obtained in 2016 is analyzed as well, where the luminosity of most prominent emission lines (the O VII forbidden line and O VIII Lyα line) are the same (at a 1σ confidence level) as in 2013-2014.

  11. Parallel of semi-empirical results simulated by MCNP of X-ray spectra with a semiconductor

    International Nuclear Information System (INIS)

    Santos, L.R.; Vivolo, V.; Potiens, M.P.A.; Navarro, M.V.T.; Santos, W.S.

    2016-01-01

    The aim of this study was to use the MCNPX radiation transport code to simulate X-ray spectra generated by a constant voltage system in a CdTe semiconductor detector. As part of the validation process, we obtained a series of experimental spectra. Comparatively, in all cases there is a good correlation between the two spectra. There were no statistically significant differences between the experimental results with the simulated. (author)

  12. Examination of X-ray spectra from the antiprotonic helium isotopes 3He and 4He

    International Nuclear Information System (INIS)

    Schneider, M.

    1987-05-01

    Using the high intensity antiprotonic LEAR beam at CERN (Geneva), several measurements were done to investigate the X-ray spectra of the antiprotonic Helium isotopes 3 He and 4 He. For the first time antiprotons were stopped in gases at low pressures (600, 375, 72 and 36 mbar), which permitted observations on nearly isolated atoms. A newly developed method for stopping the antiprotons in gases by means of a focusing cyclotron field surrounding the target gas was used. The field was supplied by a superconducting magnet ('cyclotron trap'). The antiprotons were tangentially injected into the cyclotron field, where they slowed down by ionising the target gas. The inhomogeneous magnetic field guided the antiprotons in spiral orbits to the magnetic center. Thus, even at low pressures a very small stopping volume could be achieved. To detect the X-rays different Si(Li)- and Ge-semiconductor detectors were used, some of which were furnished with 'guard-rings'. They were used to investigate the effects of the strong interaction between the antiproton and the nucleus in the (3d → 2p) transition in both isotopes. The analyzis of this transition permitted directly the determination of the shift and width of the 2p-level. The width of the 3d-level could be determined only indirectly using an intensity balance. The utilization of gases with different pressures permitted investigations of the pressure dependence of the antiprotonic deexcitation process. The results for the widths and shifts were compared with earlier measurements and theoretical predictions. The theory agrees only partly with the measurements. The evaluation of a complex scattering length using an optical model contradicts some of the results of calculations. (orig.) [de

  13. Indirect measurements of X-ray spectra; Mediciones indirectas de espectros de rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, R.T. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, X5000HUA Cordoba (Argentina)

    2006-07-01

    To the effects of measuring the spectral distribution of the radiation emitted by the x-ray tubes and electron accelerators, numerous procedures that are grouped in two big categories exist at the present time: direct and indirect methods. The first ones use high resolution detectors that should be positioned, together with the appropriate collimator, in the direction of the x ray beam. The user should be an expert in the use and correction of the obtained data by the different effects that affect the detector operation such as efficiency and resolution in terms of the energy of the detected radiation. The indirect procedures, although its are more simple to use, its also require a considerable space along the beam to position the ionization chamber and the necessary absorbents to construct by this way the denominated attenuation curve. We will analyze the operation principle of the indirect methods and a new proposal in which such important novelties are introduced as the beam dispersion to avoid to measure along the main beam and that of determination of the attenuation curve in simultaneous form. By this way, with a single shot of the tube, the attenuation curve is measured, being necessary at most a shot of additional calibration to know the relative response of the detectors used in the experimental array. The physical processes involved in the obtaining of an attenuation curve are very well well-known and this it finishes it can be theoretically calculated if the analytic form of the spectrum is supposed well-known. Finally, we will see a spectra reconstruction example with the Kramers parametric form and comparisons with numeric simulations carried out with broadly validated programs as well as the possibility of the use of solid state dosemeters in the obtention of the attenuation curve. (Author)

  14. Origins of extreme broadening mechanisms in near-edge x-ray spectra of nitrogen compounds

    Science.gov (United States)

    Vinson, John; Jach, Terrence; Elam, W. T.; Denlinger, J. D.

    2014-11-01

    We demonstrate the observation of many-body lifetime effects in valence-band x-ray emission. A comparison of the N K α emission of crystalline ammonium nitrate to molecular-orbital calculations revealed an unexpected, extreme broadening of the NO σ recombination—so extensively as to virtually disappear. GW calculations establish that this disappearance is due to a large imaginary component of the self-energy associated with the NO σ orbitals. Building upon density-functional theory, we have calculated radiative transitions from the nitrogen 1 s level of ammonium nitrate and ammonium chloride using a Bethe-Salpeter method to include electron-hole interactions. The absorption and emission spectra of both crystals evince large, orbital-dependent sensitivity to molecular dynamics. We demonstrate that many-body effects as well as thermal and zero-point motion are vital for understanding observed spectra. A computational approach using average atomic positions and uniform broadening to account for lifetime and phonon effects is unsatisfactory.

  15. Analysis of fine structure of X-ray spectra from laser-irradiated gold dot

    International Nuclear Information System (INIS)

    Yang Guohong; Zhang Jiyan; Zhang Baohan; Zhou Yuqing; Li Jun

    2000-01-01

    The X-ray emission spectra from highly stripped plasma of gold has been observed by focusing a Nd-glass frequency tripled laser beam onto the surface of the gold dot at the XINGGUANG II laser facilities. The spectra of gold ions in the range of 0.0003 nm-0.0004 nm was recorded using the plate PET (2d = 0.8742 nm) crystal spectrometer. The code of average energy of relativistic sub-arrays was built on the basis of the code MCDF (Multi-Configuration-Dirac-Fock). Using the spin-orbit-split-arrays (SOSA) formalism, mean wavelengths and full widths at half height of isolated peaks of sub-arrays of lower charged gold ions, isoelectronic with Cu, Zn, Ga and Ge, was calculated. Twenty-six lines are interpreted, they pertain mainly to transitions of 3d-nf (n = 5,6,7) of gold ions from Ni-like to As-like. These results of experiment and calculation have important application in plasma diagnostics and examination of high Z elemental atomic structure calculation

  16. Temperature effect on X-ray photoelectron spectra of 3d transition metal ions

    International Nuclear Information System (INIS)

    Kochur, A.G.; Kozakov, A.T.; Yavna, V.A.; Daniel, Ph.

    2014-01-01

    Highlights: • 2p XPS of 3d metal ions are calculated in an isolated ion approximation. • 2p XPS of Ti, V, Cr, Mn, Fe ions are temperature dependent even at room temperature. • Temperature effect on 3p XPS is slight. • No temperature effect on 3s XPS is discovered. - Abstract: Temperature effect on 2p- 3s- and 3p X-ray photoelectron spectra (XPS) of various ions of Ti, V, Cr, Mn and Fe is studied theoretically within an isolated ion approximation. It is shown that the 2p XPS of those ions are temperature dependent even at room temperature due to a very slight energy splitting between the ground-state-term total-momentum J-components which can be thermally populated. Most significant temperature effect is expected in the 2p-spectra of Ti 2+ (3d 2 ), V 2+ (3d 3 ), Cr 2+ (3d 4 ), Mn 3+ (3d 4 ), and Mn 3+ (3d 4 ) ions. The temperature effect on 3p XPS is slight. No temperature effect on 3s XPS is expected

  17. X-Ray Absorption Spectra of Amorphous Ices from GW Quasiparticle Calculation

    Science.gov (United States)

    Kong, Lingzhu; Car, Roberto

    2013-03-01

    We use a GW approach[2] to compute the x-ray absorption spectra of model low- and high-density amorphous ice structures(LDA and HDA)[3]. We include the structural effects of quantum zero point motion using colored-noise Langevin molecular dynamics[4]. The calculated spectra differences in the main and post edge region between LDA and HDA agree well with experimental observations. We attribute these differences to the presence of interstitial molecules within the first coordination shell range in HDA. This assignment is further supported by a calculation of the spectrum of ice VIII, a high-pressure structure that maximizes the number of interstitial molecules and, accordingly, shows a much weaker post-edge feature. We further rationalize the spectral similarity between HDA and liquid water, and between LDA and ice Ih in terms of the respective similarities in the H-bond network topology and bond angle distributions. Supported by grants DOE-DE-SC0005180, DOE DE-SC0008626 and NSF-CHE-0956500.

  18. Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

    International Nuclear Information System (INIS)

    Singh, K.P.; Garmire, G.P.; Nousek, J.

    1985-01-01

    The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption. 34 references

  19. An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV.

    Science.gov (United States)

    Boone, J M; Seibert, J A

    1997-11-01

    A tungsten anode spectral model using interpolating polynomials (TASMIP) was used to compute x-ray spectra at 1 keV intervals over the range from 30 kV to 140 kV. The TASMIP is not semi-empirical and uses no physical assumptions regarding x-ray production, but rather interpolates measured constant potential x-ray spectra published by Fewell et al. [Handbook of Computed Tomography X-ray Spectra (U.S. Government Printing Office, Washington, D.C., 1981)]. X-ray output measurements (mR/mAs measured at 1 m) were made on a calibrated constant potential generator in our laboratory from 50 kV to 124 kV, and with 0-5 mm added aluminum filtration. The Fewell spectra were slightly modified (numerically hardened) and normalized based on the attenuation and output characteristics of a constant potential generator and metal-insert x-ray tube in our laboratory. Then, using the modified Fewell spectra of different kVs, the photon fluence phi at each 1 keV energy bin (E) over energies from 10 keV to 140 keV was characterized using polynomial functions of the form phi (E) = a0[E] + a1[E] kV + a2[E] kV2 + ... + a(n)[E] kVn. A total of 131 polynomial functions were used to calculate accurate x-ray spectra, each function requiring between two and four terms. The resulting TASMIP algorithm produced x-ray spectra that match both the quality and quantity characteristics of the x-ray system in our laboratory. For photon fluences above 10% of the peak fluence in the spectrum, the average percent difference (and standard deviation) between the modified Fewell spectra and the TASMIP photon fluence was -1.43% (3.8%) for the 50 kV spectrum, -0.89% (1.37%) for the 70 kV spectrum, and for the 80, 90, 100, 110, 120, 130 and 140 kV spectra, the mean differences between spectra were all less than 0.20% and the standard deviations were less than approximately 1.1%. The model was also extended to include the effects of generator-induced kV ripple. Finally, the x-ray photon fluence in the units of

  20. Determination of half value layer and applied voltage from emitted spectra by an X-ray tube

    International Nuclear Information System (INIS)

    Santos, Josilene C.; Gonzales, Alejandro H.L.; Terini, Ricardo A.; Costa, Paulo R.

    2016-01-01

    This work describes a method for assessment of half value layer (HVL) and peak tube voltage (kVp) applied in an X-ray tube by means of experimental X-ray spectra measured using a CdTe detector. It was assessed some parameters that can affect the evaluation of these quantities such as dead time, count rate and tube current (mA). For this study, two sets of X-ray spectra were measured: Set A), spectra measurements using Cu filters with different thicknesses (1.8 - 5.4 mm) and fixed tube current; Set B), spectra measurements keeping a fixed Cu filtration and varying tube current (0.5 - 3.0 mA). The experimental setup for the Set A spectra measurements allowed the assessment of the HVL and kVp for different count rates and dead time in the detection system, while the Set B setup allowed to assess the dependence of these quantities with the tube current. The spectrometer was energy calibrated using standard X/γ rays radioactive sources. The tube voltage values were estimated by means of experimental measured X-ray spectra, using linear regression in order to search the end point of each spectrum. The spectra correction was performed using the stripping procedure developed for the Matlab® software and the HVL values were derived from these corrected spectra. For comparison, HVL was also determined using a 30 cm"3 ion chamber and high purity Al filters. The results show that it is possible to determine the kVp with accuracy and reproducibility using spectra with dead time of up to 10%. In spite of this, the values obtained showed a deviation of up to 7 kV, for spectra measured using the same nominal tube voltage different tube current values, indicating dependence between these two parameters. (author)

  1. Simulation of pulse height analysis soft X-ray spectra expected from W7-X

    Science.gov (United States)

    Jabłoński, S.; Czarnecka, A.; Kubkowska, M.; Ryć, L.; Weller, A.; Biedermann, C.; König, R.; W7-X Team

    2015-10-01

    A computer code named RayX has been developed for checking the performance of a spectroscopy system and optimizing individual parts, like detectors and filters for the pulse height analysis (PHA) diagnostic system designed for the stellarator W7-X. Using the code, the intensity and shape of the X-ray spectra are simulated for different plasma scenarios characterized by varying the temperature and density profiles as well as the electron cyclotron resonance heating (ECRH) power over a wide range. In the simulations of the recorded spectra, the influence of geometrical configuration changes of the diagnostic system (pinhole size, detector size, location of each diagnostic component), of the timing of data collection, as well as of the type and thickness of filters are being investigated. The atomic processes of free-free (bremsstrahlung), free-bound (recombination radiation), and bound-bound emission (line radiation) are considered. For the impurities fractional abundancies of 3% carbon (C), 0.5% oxygen (O) and 0.002% iron (Fe) are taken into account. Information about the number of photons which reach the detector and the current generated inside the detector is given. It is shown that the distance between pinhole and detector has a larger impact on the registered spectra (intensity and total number of photons) than the distance between plasma and pinhole. Based on the results of the simulations, the expected optimal positions of the individual components (pinholes, detectors) were defined for the PHA W7-X diagnostic system. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  2. The Zone of Avoidance as an X-ray absorber - the role of the galactic foreground modelling Swift XRT spectra

    Science.gov (United States)

    Racz, I. I.; Bagoly, Z.; Tóth, L. V.; Balázs, L. G.; Horvath, I.; Zahorecz, S.

    2018-05-01

    Gamma-ray bursts (GRBs) are the most powerful explosive events in the Universe. The prompt gamma emission is followed by an X-ray afterglow that is also detected for over nine hundred GRBs by the Swift BAT and XRT detectors. The X-ray afterglow spectrum bears essential information about the burst, and the surrounding interstellar medium (ISM). Since the radiation travels through the line of sight intergalactic medium and the ISM in the Milky Way, the observed emission is influenced by extragalactic and galactic components. The column density of the Galactic foreground ranges several orders of magnitudes, due to both the large scale distribution of ISM and its small scale structures. We examined the effect of local HI column density on the penetrating X-ray emission, as the first step towards a precise modeling of the measured X-ray spectra. We fitted the X-ray spectra using the Xspec software, and checked how the shape of the initially power low spectrum changes with varying input Galactic HI column density. The total absorbing HI column is a sum of the intrinsic and Galactic component. We also investigated the model results for the intrinsic component varying the Galactic foreground. We found that such variations may alter the intrinsic hydrogen column density up to twenty-five percent. We will briefly discuss its consequences.

  3. Steep Hard-X-ray Spectra Indicate Extremely High Accretion Rates in Weak Emission-Line Quasars

    Science.gov (United States)

    Marlar, Andrea; Shemmer, Ohad; Anderson, Scott F.; Brandt, W. Niel; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Luo, Bin; Plotkin, Richard; Richards, Gordon T.; Schneider, Donald P.; Wu, Jianfeng

    2018-06-01

    We present XMM-Newton imaging spectroscopy of ten weak emission-line quasars (WLQs) at 0.928 ≤ z ≤ 3.767, six of which are radio quiet and four which are radio intermediate. The new X-ray data enabled us to measure the hard-X-ray power-law photon index (Γ) in each source with relatively high accuracy. These measurements allowed us to confirm previous reports that WLQs have steeper X-ray spectra, therefore indicating higher accretion rates with respect to "typical" quasars. A comparison between the Γ values of our radio-quiet WLQs and those of a carefully-selected, uniform sample of 84 quasars shows that the first are significantly higher, at the ≥ 3σ level. Collectively, the four radio-intermediate WLQs have lower Γ values with respect to the six radio-quiet WLQs, as may be expected if the spectra of the first group are contaminated by X-ray emission from a jet. These results suggest that, in the absence of significant jet emission along our line of sight, WLQs constitute the extreme high end of the accretion rate distribution in quasars. We detect soft excess emission in our lowest-redshift radio-quiet WLQ, in agreement with previous findings suggesting that the prominence of this feature is associated with a high accretion rate. We have not detected signatures of Compton reflection, Fe Kα lines, or strong variability between two X-ray epochs in any of our WLQs.

  4. CHARGE-TRANSFER SATELLITES AND MULTIPLET SPLITTING IN X-RAY PHOTOEMISSION SPECTRA OF LATE TRANSITION-METAL HALIDES

    NARCIS (Netherlands)

    OKADA, K; KOTANI, A; THOLE, BT

    1992-01-01

    Core-level X-ray photoemission spectra (XPS) are calculated for Ni and Co dihalides with an MX6 cluster model (M = Ni, Co; X = F, Cl, Br), where intra-atomic multiplet coupling as well as covalency mixing is taken into account. The effects of the intra-atomic configuration interaction between

  5. Determination of semi-reducing layer and applied stress through spectra emitted by an X-ray tube

    International Nuclear Information System (INIS)

    Santos, Josilene C.; Gonzalez, Alejandro H.L.; Terini, Ricardo A.; Costa, Paulo R.

    2016-01-01

    This work describes a method for assessment of half value layer (HVL) and peak tube voltage (kVp) by means of experimental x-ray spectra measured using a CdTe detector. The work also evaluated spectrometry parameters such as dead time and count rate, and x-ray tube characteristics that can affect the assessment of these quantities. Two sets of x-ray spectra were measured: A) using Cu filters with different thicknesses and fixed tube current, and B) keeping a fixed Cu filtration and different tube current and, so, ranging the count rates. The spectrometer was energy calibrated using standard radioactive sources. kVp value was estimated by means of experimental measured x-ray spectra, using linear regression in order to search the end point of each spectrum. HVL was estimated after the correction of the measured spectra, using an analytical method implemented using Matlab® software. For comparison, HVL was also determined using a 30 cm"3 ion chamber and high purity Al filters. (author)

  6. ULX spectra revisited: Accreting, highly magnetized neutron stars as the engines of ultraluminous X-ray sources

    Science.gov (United States)

    Koliopanos, Filippos; Vasilopoulos, Georgios; Godet, Olivier; Bachetti, Matteo; Webb, Natalie A.; Barret, Didier

    2017-12-01

    Aims: In light of recent discoveries of pulsating ultraluminous X-ray sources (ULXs) and recently introduced theoretical schemes that propose neutron stars (NSs) as the central engines of ULXs, we revisit the spectra of eighteen well known ULXs, in search of indications that favour this newly emerging hypothesis. Methods: We examine the spectra from high-quality XMM-Newton and NuSTAR observations. We use a combination of elementary black body and multicolour disk black body (MCD) models, to diagnose the predictions of classic and novel theoretical models of accretion onto NSs. We re-interpret the well established spectral characteristics of ULXs in terms of accretion onto lowly or highly magnetised NSs, and explore the resulting parameter space for consistency. Results: We confirm the previously noted presence of the low-energy (≲6 keV) spectral rollover and argue that it could be interpreted as due to thermal emission. The spectra are well described by a double thermal model consisting of a "hot" (≳1 keV) and a "cool" (≲0.7 keV) multicolour black body (MCB). Under the assumption that the "cool" MCD emission originates in a disk truncated at the neutron star magnetosphere, we find that all ULXs in our sample are consistent with accretion onto a highly magnetised (B ≳ 1012 G) neutron star. We note a strong correlation between the strength of the magnetic field, the temperature of the "hot" thermal component and the total unabsorbed luminosity. Examination of the NuSTAR data supports this interpretation and also confirms the presence of a weak, high-energy (≳15 keV) tail, most likely the result of modification of the MCB emission by inverse Compton scattering. We also note that the apparent high-energy tail, may simply be the result of mismodelling of MCB emission with an atypical temperature (T) versus radius (r) gradient, using a standard MCD model with a fixed gradient of T r-0.75. Conclusions: We have offered a new and robust physical interpretation for

  7. Quantifying the effect of anode surface roughness on diagnostic x-ray spectra using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mehranian, A.; Ay, M. R.; Alam, N. Riyahi; Zaidi, H. [Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of) and Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of) and Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland) and Geneva Neuroscience Center, Geneva University, CH-1205 Geneva (Switzerland)

    2010-02-15

    Purpose: The accurate prediction of x-ray spectra under typical conditions encountered in clinical x-ray examination procedures and the assessment of factors influencing them has been a long-standing goal of the diagnostic radiology and medical physics communities. In this work, the influence of anode surface roughness on diagnostic x-ray spectra is evaluated using MCNP4C-based Monte Carlo simulations. Methods: An image-based modeling method was used to create realistic models from surface-cracked anodes. An in-house computer program was written to model the geometric pattern of cracks and irregularities from digital images of focal track surface in order to define the modeled anodes into MCNP input file. To consider average roughness and mean crack depth into the models, the surface of anodes was characterized by scanning electron microscopy and surface profilometry. It was found that the average roughness (R{sub a}) in the most aged tube studied is about 50 {mu}m. The correctness of MCNP4C in simulating diagnostic x-ray spectra was thoroughly verified by calling its Gaussian energy broadening card and comparing the simulated spectra with experimentally measured ones. The assessment of anode roughness involved the comparison of simulated spectra in deteriorated anodes with those simulated in perfectly plain anodes considered as reference. From these comparisons, the variations in output intensity, half value layer (HVL), heel effect, and patient dose were studied. Results: An intensity loss of 4.5% and 16.8% was predicted for anodes aged by 5 and 50 {mu}m deep cracks (50 kVp, 6 deg. target angle, and 2.5 mm Al total filtration). The variations in HVL were not significant as the spectra were not hardened by more than 2.5%; however, the trend for this variation was to increase with roughness. By deploying several point detector tallies along the anode-cathode direction and averaging exposure over them, it was found that for a 6 deg. anode, roughened by 50 {mu}m deep

  8. Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography*

    Science.gov (United States)

    Paixão, Lucas; Oliveira, Bruno Beraldo; Viloria, Carolina; de Oliveira, Marcio Alves; Teixeira, Maria Helena Araújo; Nogueira, Maria do Socorro

    2015-01-01

    Objective Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations. Materials and Methods Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL) of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode. Results Calculated HVL values showed good agreement as compared with those obtained experimentally. The greatest relative difference between the Monte Carlo calculated HVL values and experimental HVL values was 4%. Conclusion The results show that the filtered tungsten anode X-ray spectra and the EGSnrc Monte Carlo code can be used for mean glandular dose determination in mammography. PMID:26811553

  9. Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography

    Directory of Open Access Journals (Sweden)

    Lucas Paixão

    2015-12-01

    Full Text Available Abstract Objective: Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations. Materials and Methods: Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode. Results: Calculated HVL values showed good agreement as compared with those obtained experimentally. The greatest relative difference between the Monte Carlo calculated HVL values and experimental HVL values was 4%. Conclusion: The results show that the filtered tungsten anode X-ray spectra and the EGSnrc Monte Carlo code can be used for mean glandular dose determination in mammography.

  10. Simulation of X-ray absorption spectra with orthogonality constrained density functional theory.

    Science.gov (United States)

    Derricotte, Wallace D; Evangelista, Francesco A

    2015-06-14

    Orthogonality constrained density functional theory (OCDFT) [F. A. Evangelista, P. Shushkov and J. C. Tully, J. Phys. Chem. A, 2013, 117, 7378] is a variational time-independent approach for the computation of electronic excited states. In this work we extend OCDFT to compute core-excited states and generalize the original formalism to determine multiple excited states. Benchmark computations on a set of 13 small molecules and 40 excited states show that unshifted OCDFT/B3LYP excitation energies have a mean absolute error of 1.0 eV. Contrary to time-dependent DFT, OCDFT excitation energies for first- and second-row elements are computed with near-uniform accuracy. OCDFT core excitation energies are insensitive to the choice of the functional and the amount of Hartree-Fock exchange. We show that OCDFT is a powerful tool for the assignment of X-ray absorption spectra of large molecules by simulating the gas-phase near-edge spectrum of adenine and thymine.

  11. ROSAT Energy Spectra of Low-Mass X-Ray Binaries

    Science.gov (United States)

    Schulz, N. S.

    1999-01-01

    The 0.1-2.4 keV bandpass of the ROSAT Position Sensitive Proportional Counter (PSPC) offers an opportunity to study the very soft X-ray continuum of bright low-mass X-ray binaries (LMXBs). In 46 pointed observations, 23 LMXBs were observed with count rates between 0.4 and 165.4 counts s-1. The survey identified a total of 29 different luminosity levels, which are compared with observations and identified spectral states from other missions. The atoll source 4U 1705-44 was observed near Eddington luminosities in an unusually high intensity state. Spectral analysis provided a measure of the interstellar column density for all 49 observations. The sensitivity of spectral fits depends strongly on column density. Fits to highly absorbed spectra are merely insensitive toward any particular spectral model. Sources with column densities well below 1022 cm-2 are best fitted by power laws, while the blackbody model gives clearly worse fits to the data. Most single-component fits from sources with low column densities, however, are not acceptable at all. The inclusion of a blackbody component in eight sources can improve the fits significantly. The obtained emission radii of less than 5 km suggest emission from the neutron star surface. In 10 sources acceptable fits can only be achieved by including soft-line components. With a spectral resolution of the PSPC of 320-450 eV, between 0.6 and 1.2 keV unresolved broad-line features were detected around 0.65, 0.85, and 1.0 keV. The line fluxes range within 10-11 and 10-12 ergs cm-2 s-1, with equivalent widths between 24 and 210 eV. In LMC X-2, 2S 0918-549, and 4U 1254-690, line emission is indicated for the first time. The soft emission observed in 4U 0614+091 compares with recent ASCA results, with a new feature indicated at 1.31 keV. The deduced line fluxes in 4U 1820-30 and Cyg X-2 showed variability of a factor of 2 within timescales of 1-2 days. Average fluxes of line components in 4U 1820-30 varied by the same factor over a

  12. Dose and absorption spectra response of EBT2 Gafchromic film to high energy X-rays

    International Nuclear Information System (INIS)

    Butson, M.J.; Cheung, T.; Yu, P.K.N.; Alnawaf, H.

    2009-01-01

    Full text: With new advancements in radiochromic film designs and sensitivity to suit different niche applications, EBT2 is the latest offering for the megavoltage radiotherapy market. New construction specifications including different physical construction and the use of a yellow coloured dye has provided the next generation radiochromic film for therapy applications. The film utilises the same active chemical for radiation measurement as its predecessor, EBT Gafchromic. Measurements have been performed using photo spectrometers to analyse the absorption spectra properties of this new EBT2 Gafchromic, radiochromic film. Results have shown that whilst the physical coloration or absorption spectra of the film, which turns yellow to green as compared to EBT film, (clear to blue) is significantly different due to the added yellow dye, the net change in absorption spectra properties for EBT2 are similar to the original EBT film. Absorption peaks are still located at 636 n m and 585 n m positions. A net optical density change of 0.590 ± 0.020 (2SD) for a 1 Gy radiation absorbed dose using 6 MV x-rays when measured at the 636 n m absorption peak was found. This is compared to 0.602 ± 0.025 (2SD) for the original EBT film (2005 Batch) and 0.557 ± 0.027 (2009 Batch) at the same absorption peak. The yellow dye and the new coating material produce a significantly different visible absorption spectra results for the EBT2 film compared to EBT at wavelengths especially below approximately 550 n m. At wavelengths above 550 n m differences in absolute OD are seen however, when dose analysis is performed at wavelengths above 550 n m using net optical density changes, no significant variations are seen. If comparing results of the late production EBT to new production EBT2 film, net optical density variations of approximately 10 % to 15 % are seen. As all new film batches should be calibrated for sensitivity upon arrival this should not be of concern.

  13. Broadband time-resolved elliptical crystal spectrometer for X-ray spectroscopic measurements in laser-produced plasmas

    International Nuclear Information System (INIS)

    Wang Rui-Rong; Jia Guo; Fang Zhi-Heng; Wang Wei; Meng Xiang-Fu; Xie Zhi-Yong; Zhang Fan

    2014-01-01

    The X-ray spectrometer used in high-energy-density plasma experiments generally requires both broad X-ray energy coverage and high temporal, spatial, and spectral resolutions for overcoming the difficulties imposed by the X-ray background, debris, and mechanical shocks. By using an elliptical crystal together with a streak camera, we resolve this issue at the SG-II laser facility. The carefully designed elliptical crystal has a broad spectral coverage with high resolution, strong rejection of the diffuse and/or fluorescent background radiation, and negligible source broadening for extended sources. The spectra that are Bragg reflected (23° < θ < 38°) from the crystal are focused onto a streak camera slit 18 mm long and about 80 μm wide, to obtain a time-resolved spectrum. With experimental measurements, we demonstrate that the quartz(1011) elliptical analyzer at the SG-II laser facility has a single-shot spectral range of (4.64–6.45) keV, a typical spectral resolution of E/ΔE = 560, and an enhanced focusing power in the spectral dimension. For titanium (Ti) data, the lines of interest show a distribution as a function of time and the temporal variations of the He-α and Li-like Ti satellite lines and their spatial profiles show intensity peak red shifts. The spectrometer sensitivity is illustrated with a temporal resolution of better than 25 ps, which satisfies the near-term requirements of high-energy-density physics experiments. (atomic and molecular physics)

  14. Dynamics of hot spots in the DPF-78 plasma focus from x-ray spectra and REB emission

    International Nuclear Information System (INIS)

    Schmidt, H.; Wang, X.X.

    1995-01-01

    The X-ray emission from hot spots in the plasma focus DPF-78 was investigated with the help of two X-ray quartz crystal spectrometers of the Johann type and a 4 fold magnifying X-ray pinhole camera. In the experiments the working gas was chosen to be 300 Pa deuterium with 20 Pa argon admixture. X-ray spectra in the wavelength range from 3.55 angstrom to 4.0 angstrom, including H-like and He-like Argon lines, were recorded on Kodak DEF-2 film. From the spatially resolved spectra recorded side-on, a relative spectral shift between different hot spots of the same shot was often observed. The shift could be attributed to the Doppler shift. From spectral characteristics such as intensities and FWHM of Ar resonant and intercombination lines electron densities of up to 3 x 10 27 m -3 were determined. Radial dimensions of the hot spots ranging from about 140 microm to 300 microm were found from pinhole pictures applying the penumbra method. Usually two pulses of relativistic electron beams were observed using Cherenkov detectors in a magnetic spectrometer. The energy of the first pulse, which was emitted at the time of maximum compression, was higher than that of the second pulse. The measured FWHM of the REB pulses ranges from 3 ns to about 10 ns. The characteristics of the time-integrated X-ray spectra and the time resolved REB spectra and their dependence on the composition of the filling gas are discussed

  15. Correcting X-ray spectra obtained from the AXAF VETA-I mirror calibration for pileup, continuum, background and deadtime

    Science.gov (United States)

    Chartas, G.; Flanagan, K.; Hughes, J. P.; Kellogg, E. M.; Nguyen, D.; Zombek, M.; Joy, M.; Kolodziejezak, J.

    1993-01-01

    The VETA-I mirror was calibrated with the use of a collimated soft X-ray source produced by electron bombardment of various anode materials. The FWHM, effective area and encircled energy were measured with the use of proportional counters that were scanned with a set of circular apertures. The pulsers from the proportional counters were sent through a multichannel analyzer that produced a pulse height spectrum. In order to characterize the properties of the mirror at different discrete photon energies one desires to extract from the pulse height distribution only those photons that originated from the characteristic line emission of the X-ray target source. We have developed a code that fits a modeled spectrum to the observed X-ray data, extracts the counts that originated from the line emission, and estimates the error in these counts. The function that is fitted to the X-ray spectra includes a Prescott function for the resolution of the detector a second Prescott function for a pileup peak and a X-ray continuum function. The continuum component is determined by calculating the absorption of the target Bremsstrahlung through various filters, correcting for the reflectivity of the mirror and convolving with the detector response.

  16. Theoretically predicted soft x-ray emission and absorption spectra of graphitic-structured BC2N

    Science.gov (United States)

    Muramatsu, Yasuji

    Theoretical B K, C K and N K x-ray emission/absorption spectra of three possible graphitic-structured BC2N clusters are predicted based on the B2p-, C2p-, and N2p- density-of-states (DOS) calculated by discrete variational (DV)-X[alpha] molecular orbital calculations. Several prominent differences in DOS spectral features among BC2Ns, h-BN, and graphite are confirmed from comparison of calculated B2p-, C2p-, and N2p-DOS spectra. These variations in the spectra allow BC2N structures to be positively identified by high-resolution x-ray emission/absorption spectroscopy in the B K, C K, and N K regions.

  17. PROBING WOLF–RAYET WINDS: CHANDRA/HETG X-RAY SPECTRA OF WR 6

    Energy Technology Data Exchange (ETDEWEB)

    Huenemoerder, David P.; Schulz, N. S. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Hamann, W.-R.; Oskinova, L.; Shenar, T. [Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States); Nichols, J. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 34, Cambridge, MA 02138 (United States); Pollock, A. M. T., E-mail: dph@space.mit.edu, E-mail: ken.gayley@gmail.com, E-mail: wrh@astro.physik.uni-potsdam.de, E-mail: lida@astro.physik.uni-potsdam.de, E-mail: shtomer@astro.physik.uni-potsdam.de, E-mail: ignace@mail.etsu.edu, E-mail: jnichols@cfa.harvard.edu [European Space Agency, ESAC, Apartado 78, E-28691 Villanueva de la Cañada (Spain)

    2015-12-10

    With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. Variability was present in X-rays and simultaneous optical photometry, but neither were correlated with the known period of the system or with each other. An enhanced abundance of sodium revealed nuclear-processed material, a quantity related to the evolutionary state of the star. The characterization of the extent and nature of the hot plasma in WR 6 will help to pave the way to a more fundamental theoretical understanding of the winds and evolution of massive stars.

  18. Sub-keV, subnanosecond measurements of x-ray spectra from laser-produced plasmas

    International Nuclear Information System (INIS)

    Kornblum, H.N.; Koppel, L.N.; Slivinsky, V.W.; Glaros, S.S.; Ahlstrom, H.G.; Larsen, J.T.

    1977-01-01

    As part of the effort to extend our x-ray diagnostic capabilities, we have made x-ray spectral measurements of laser-produced plasmas for photon energies down to 100 eV with a time response of 0.5 nsec. Fast, windowless x-ray diodes were used in conjunction with critical angle reflecting mirrors and thin filters for energy definition for two channels, 300 to 600 eV and 800 to 1300 eV. A third channel, using only an x-ray diode and filter, provided spectral information in the 100 to 300 eV region. Results from exploding pusher targets will be presented and compared with those of other diagnostic techniques and Lasnex calculations. Future expansion and modifications of the present system will be discussed

  19. The Intrinsically X-Ray-weak Quasar PHL 1811. II. Optical and UV Spectra and Analysis

    Science.gov (United States)

    Leighly, Karen M.; Halpern, Jules P.; Jenkins, Edward B.; Casebeer, Darrin

    2007-11-01

    This is the second of two papers reporting observations and analysis of the unusually bright (mb=14.4), luminous (MB=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray-weak and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong Fe II and Fe III, and unusual low-ionization lines such as Na I D and Ca II H and K are observed. High-ionization lines are very weak; C IV has an equivalent width of 6.6 Å, a factor of ~5 smaller than measured from quasar composite spectra. An unusual feature near 1200 Å can be deblended in terms of Lyα, N V, Si II, and C III* using the blueshifted C IV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys may be biased against finding similar objects. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with proposal 9181. Based on observations obtained at Kitt Peak National Observatory, a division of the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.

  20. Radiative electron rearrangement and polarization in target K x-ray spectra

    International Nuclear Information System (INIS)

    Jamison, K.A.

    1978-01-01

    Two topics in the atomic physics of ion-atom collisions are studied. The first is an investigation of a free-atom decay process that is shown to be a two-electron one-photon decay. This two-electron decay requires an initial state with multiple inner-shell vacancies that has a high probability of creation in ion-atom collisions. Because this decay promotes one electron to a higher shell while allowing the other to fall to a lower shell, it is referred to as radiative electron rearrangement (RER). The investigation of this process includes the experimental study of the x-ray spectra region approx. 150 eV below the characteristic Kα 1 2 target radiation in third period elements when bombarded by various ion beams in the energy range 1 to 2 MeV/amu. Theoretical calculations of the transition energies, line strengths, and line widths are performed to verify the origin of the RER lines. The second topic of consideration is the study of the polarization of Kα satellite radiation from targets of Al and Si. It is shown that the polarization, which is observed experimentally with a curved-crystal polarimeter, is due to the nonstatistical population of the magnetic substates created in specific ion-atom collisions. Further, the polarization of the RER lines is studied. The connection between the polarization of the normal Kα satellite radiation and the polarization of the RER lines adds final proof to their origin as two-electron one-photon transitions

  1. Optimization of x-ray spectra in digital mammography through Monte Carlo simulations.

    Science.gov (United States)

    Cunha, D M; Tomal, A; Poletti, M E

    2012-04-07

    In this work, a Monte Carlo code was used to investigate the performance of different x-ray spectra in digital mammography, through a figure of merit (FOM), defined as FOM = CNR²/(¯)D(g), with CNR being the contrast-to-noise ratio in image and [Formula: see text] being the average glandular dose. The FOM was studied for breasts with different thicknesses t (2 cm ≤ t ≤ 8 cm) and glandular contents (25%, 50% and 75% glandularity). The anode/filter combinations evaluated were those traditionally employed in mammography (Mo/Mo, Mo/Rh, Rh/Rh), and a W anode combined with Al or K-edge filters (Zr, Mo, Rh, Pd, Ag, Cd, Sn), for tube potentials between 22 and 34 kVp. Results show that the W anode combined with K-edge filters provides higher values of FOM for all breast thicknesses investigated. Nevertheless, the most suitable filter and tube potential depend on the breast thickness, and for t ≥ 6 cm, they also depend on breast glandularity. Particularly for thick and dense breasts, a W anode combined with K-edge filters can greatly improve the digital technique, with the values of FOM up to 200% greater than that obtained with the anode/filter combinations and tube potentials traditionally employed in mammography. For breasts with t < 4 cm, a general good performance was obtained with the W anode combined with 60 μm of the Mo filter at 24-25 kVp, while 60 μm of the Pd filter provided a general good performance at 24-26 kVp for t = 4 cm, and at 28-30 and 29-31 kVp for t = 6 and 8 cm, respectively.

  2. Restricted active space calculations of L-edge X-ray absorption spectra: from molecular orbitals to multiplet states.

    Science.gov (United States)

    Pinjari, Rahul V; Delcey, Mickaël G; Guo, Meiyuan; Odelius, Michael; Lundberg, Marcus

    2014-09-28

    The metal L-edge (2p → 3d) X-ray absorption spectra are affected by a number of different interactions: electron-electron repulsion, spin-orbit coupling, and charge transfer between metal and ligands, which makes the simulation of spectra challenging. The core restricted active space (RAS) method is an accurate and flexible approach that can be used to calculate X-ray spectra of a wide range of medium-sized systems without any symmetry constraints. Here, the applicability of the method is tested in detail by simulating three ferric (3d(5)) model systems with well-known electronic structure, viz., atomic Fe(3+), high-spin [FeCl6](3-) with ligand donor bonding, and low-spin [Fe(CN)6](3-) that also has metal backbonding. For these systems, the performance of the core RAS method, which does not require any system-dependent parameters, is comparable to that of the commonly used semi-empirical charge-transfer multiplet model. It handles orbitally degenerate ground states, accurately describes metal-ligand interactions, and includes both single and multiple excitations. The results are sensitive to the choice of orbitals in the active space and this sensitivity can be used to assign spectral features. A method has also been developed to analyze the calculated X-ray spectra using a chemically intuitive molecular orbital picture.

  3. Soft X-ray absorption spectra of aqueous salt solutions with highly charged cations in liquid microjets

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; Drisdell, Walter S.; Smith, Jared D.; Saykally, Richard J.

    2010-03-11

    X-ray absorption spectra of 1M aqueous solutions of indium (III) chloride, yttrium (III) bromide, lanthanum (III) chloride, tin (IV) chloride and chromium (III) chloride have been measured at the oxygen K-edge. Relatively minor changes are observed in the spectra compared to that of pure water. SnCl{sub 4} and CrCl{sub 3} exhibit a new onset feature which is attributed to formation of hydroxide or other complex molecules in the solution. At higher energy, only relatively minor, but salt-specific changes in the spectra occur. The small magnitude of the observed spectral changes is ascribed to offsetting perturbations by the cations and anions.

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

    NARCIS (Netherlands)

    de Groot, F.M.F.

    2016-01-01

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

  5. BROADBAND X-RAY IMAGING AND SPECTROSCOPY OF THE CRAB NEBULA AND PULSAR WITH NuSTAR

    International Nuclear Information System (INIS)

    Madsen, Kristin K.; Harrison, Fiona; Grefenstette, Brian W.; Reynolds, Stephen; An, Hongjun; Boggs, Steven; Craig, William W.; Zoglauer, Andreas; Christensen, Finn E.; Fryer, Chris L.; Hailey, Charles J.; Nynka, Melania; Markwardt, Craig; Zhang, William; Stern, Daniel

    2015-01-01

    We present broadband (3-78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar. We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power law in this energy band, spatially resolved spectroscopy of the nebula finds a break at ∼9 keV in the spectral photon index of the torus structure with a steepening characterized by ΔΓ ∼ 0.25. We also confirm a previously reported steepening in the pulsed spectrum, and quantify it with a broken power law with break energy at ∼12 keV and ΔΓ ∼ 0.27. We present spectral maps of the inner 100'' of the remnant and measure the size of the nebula as a function of energy in seven bands. These results find that the rate of shrinkage with energy of the torus size can be fitted by a power law with an index of γ = 0.094 ± 0.018, consistent with the predictions of Kennel and Coroniti. The change in size is more rapid in the NW direction, coinciding with the counter-jet where we find the index to be a factor of two larger. NuSTAR observed the Crab during the latter part of a γ-ray flare, but found no increase in flux in the 3-78 keV energy band

  6. Analysis of kiwi fruit (Accented deliciosa) by energy dispersive X-ray fluorescence spectra

    International Nuclear Information System (INIS)

    Oliveira, Ana Claudia S.; Oliveira, Marcia L. de; Silva, Lucia C.A.S.; Arthur, Valter; Almeida, Eduardo

    2011-01-01

    The search for a healthy life has led consumers to eat fruits and vegetables in place of manufactured products, however, the demand for minimally processed products has evolved rapidly. The kiwi has at least eight nutrients beneficial to health: calcium, magnesium, manganese, phosphorus, iron, potassium, sodium and has also high vitamin C, which has wide acceptance in consumer markets. Energy dispersive spectroscopy X-ray (EDX) is the analytical technique used for elemental analysis or chemical characterization of a sample. It is a variant of fluorescence spectroscopy X-ray based on the sample through an investigation of interactions between electromagnetic radiation and matter, analyzing X-rays emitted by matter in response to being struck by charged particles. The aim of this study were to determine potassium, calcium, iron and bromine (K, Ca, Fe and Br, respectively) present in kiwifruit using the technique of fluorescence X-ray energy dispersive (EDXRF). Kiwifruit were peeled, washed and cut into slices and freeze-dried. After drying the sample was held digestion and subsequent reading of the same equipment in the X-ray fluorescence energy dispersive (EDXRF). The results indicated that the contents of potassium, calcium, iron and bromine are present in kiwifruit as expected when compared to Brazilian Table of Food Composition. (author)

  7. A deep X-ray view of the bare AGN Ark 120. IV. XMM-Newton and NuSTAR spectra dominated by two temperature (warm, hot) Comptonization processes

    Science.gov (United States)

    Porquet, D.; Reeves, J. N.; Matt, G.; Marinucci, A.; Nardini, E.; Braito, V.; Lobban, A.; Ballantyne, D. R.; Boggs, S. E.; Christensen, F. E.; Dauser, T.; Farrah, D.; Garcia, J.; Hailey, C. J.; Harrison, F.; Stern, D.; Tortosa, A.; Ursini, F.; Zhang, W. W.

    2018-01-01

    Context. The physical characteristics of the material closest to supermassive black holes (SMBHs) are primarily studied through X-ray observations. However, the origins of the main X-ray components such as the soft X-ray excess, the Fe Kα line complex, and the hard X-ray excess are still hotly debated. This is particularly problematic for active galactic nuclei (AGN) showing a significant intrinsic absorption, either warm or neutral, which can severely distort the observed continuum. Therefore, AGN with no (or very weak) intrinsic absorption along the line of sight, so-called "bare AGN", are the best targets to directly probe matter very close to the SMBH. Aims: We perform an X-ray spectral analysis of the brightest and cleanest bare AGN known so far, Ark 120, in order to determine the process(es) at work in the vicinity of the SMBH. Methods: We present spectral analyses of data from an extensive campaign observing Ark 120 in X-rays with XMM-Newton (4 × 120 ks, 2014 March 18-24), and NuSTAR (65.5 ks, 2014 March 22). Results: During this very deep X-ray campaign, the source was caught in a high-flux state similar to the earlier 2003 XMM-Newton observation, and about twice as bright as the lower-flux observation in 2013. The spectral analysis confirms the "softer when brighter" behavior of Ark 120. The four XMM-Newton/pn spectra are characterized by the presence of a prominent soft X-ray excess and a significant Fe Kα complex. The continuum is very similar above about 3 keV, while significant variability is present for the soft X-ray excess. We find that relativistic reflection from a constant-density, flat accretion disk cannot simultaneously produce the soft excess, broad Fe Kα complex, and hard X-ray excess. Instead, Comptonization reproduces the broadband (0.3-79 keV) continuum well, together with a contribution from a mildly relativistic disk reflection spectrum. Conclusions: During this 2014 observational campaign, the soft X-ray spectrum of Ark 120 below 0

  8. Extracting ion emission lines from femtosecond-laser plasma x-ray spectra heavily contaminated by spikes

    International Nuclear Information System (INIS)

    Gasilov, S. V.; Faenov, A. Ya.; Pikuz, T. A.; Villoresi, P.; Poletto, L.; Stagira, S.; Calegari, F.; Vozzi, C.; Nisoli, M.

    2007-01-01

    Nowadays charged-coupled device (CCD) detectors are widely used for the registration of multicharged ions x-ray spectra. These spectra are generated in a plasma during interaction of ultrashort, ultraintense laser pulses with solid targets. Strong parasitic radiation from the plasma affects CCD detectors and contaminates resulting spectra, so that spectral features can be completely covered by noise even during measurements with a very short accumulation time. In this work we propose a ''mean to median'' (M2M) algorithm for noise suppression in femtosecond laser plasma x-ray spectra. Series of spectra is necessary for the identification of corrupted data points by the developed method. The algorithm was tested with model spectra which reflect main features of experimental data. In practice we used it for extracting information about spectral lines of Ne-like Fe ions and He-like Al ions which allowed us to calculate plasma parameters. It is demonstrated that M2M method is able to clean spectra with more than 10% of corrupted pixels. Fluctuations in intensity of spectral lines induced by laser instability do not affect validity of the proposed method

  9. Peculiar time dependence of unexpected lines in delayed beam-foil X-ray spectra of V, Fe and Ni

    International Nuclear Information System (INIS)

    Ahmad, Nissar; Karn, Ranjeet K.; Marketos, Pan; Nandi, T.

    2005-01-01

    Delayed beam-foil X-ray spectra of highly charged ions of V, Fe and Ni show a few lines at energies higher than the H-like Lyman α-line of the respective projectile ions. These can only be attributed to heavier ions. Further the time dependence of such unexpected lines display a peculiar behavior. This work presents the experimental observations systematically

  10. Jupiter's X-ray Auroral Pulsations and Spectra During Juno Perijove 7

    Science.gov (United States)

    Dunn, W.; Branduardi-Raymont, G.; Ray, L. C.; Jackman, C. M.; Kraft, R.; Gladstone, R.; Yao, Z.; Rae, J.; Gray, R.; Elsner, R.; Grodent, D. C.; Nichols, J. D.; Ford, P. G.; Ness, J. U.; Kammer, J.; Rodriguez, P.

    2017-12-01

    Jupiter's X-ray aurora is concentrated into a bright and dynamic hot spot that is produced by precipitating 10 MeV ions [Gladstone et al. 2002; Elsner et al. 2005; Branduardi-Raymont et al. 2007]. These highly energetic emissions exhibit pulsations over timescales of 10s of minutes and change morphology, intensity and precipitating particle populations from observation to observation and pole to pole [e.g. Dunn et al. 2016; in-press]. The acceleration process/es that allow Jupiter to produce these high-energy ion charge exchange emissions are not well understood, but are concentrated in the most poleward regions of the aurora, where field lines map to the outer magnetosphere and possibly beyond [Vogt et al. 2015; Kimura et al. 2016]. On July 11th 2017, NASA's Juno spacecraft conducted its 7th perijove flyby of Jupiter and is predicted to have flown directly through field lines that map to the Northern and Southern X-ray hot spots. During this unique flight, the XMM-Newton observatory conducted 40 hours of continuous time-tagged X-ray observations. We present the results from these X-ray observations, showing that Jupiter's X-ray aurora varies significantly from one planetary rotation to the next and that the spectral signatures, indicative of the precipitating ion and electron populations producing the emission, also vary. We measure the Doppler broadening of the spectral lines to calculate the ion energies at the point when they impact the ionosphere, in order that these might be compared with in-situ data to constrain Jovian auroral acceleration processes. Finally, we compare X-ray signatures from the last decade of observations with UV polar emissions at similar times to further enrich multi-wavelength connections and deepen our understanding of how Jupiter is able to generate its highly energetic polar auroral precipitations.

  11. Influence of changes in the valence electronic configuration on the structure of L-X-ray spectra of molybdenum

    International Nuclear Information System (INIS)

    Polasik, M; Koziol, K; Slabkowska, K; Czarnota, M; Pajek, M

    2009-01-01

    Extensive multiconfiguration Dirac-Fock (MCDF) calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on molybdenum to explain the dependence of the structure of Lα 1,2 and Lβ 1 lines on the changes in configurations of the valence electrons belonging to two different configuration types: three open-shell 4d 6-r 5s r (r = 2,1,0) configurations and one closed-shell 4d 4 3/2 5s 2 configuration. It has been found that the MCDF predictions for open-shell valence configurations (4d 4 5s 2 , 4d 5 5s 1 , 4d 6 5s 0 ) much better reproduce observed structure of Lα 1,2 lines in X-ray spectra of molybdenum than closed-shell 4d 4 3/2 5s 2 valence configuration. The influence of changes in the valence electronic configuration on the structure of L-X-ray spectra of molybdenum is noticeable. Moreover, the observation of the shapes of L-X-ray spectra seems to be very good method to investigate the changes of the valence electronic configuration caused by the chemical environment.

  12. Studies of momentum transfer and X-ray spectra in a laser-produced plasma

    International Nuclear Information System (INIS)

    Leroy, Pierre

    Studies of momentum transfer from a ballistic pendulum appear to give satisfactory results for absorbed laser energies in excess of 200 mJ i.e. for fluxes in the 3.10 10 to 3.10 12 W.cm -2 range. A hard X-ray component attributed to fast electrons was revealed by an X-ray spectrometer with a PM system of greater sensitivity than PIN diodes. The laser energy is however too weak to enable studies to be conducted as a function of laser flux or measurements to be performed on targets of low Z [fr

  13. Fast spectral fitting of hard X-ray bremsstrahlung from truncated power-law electron spectra

    Czech Academy of Sciences Publication Activity Database

    Brown, J. C.; Kašparová, Jana; Massone, A.M.; Piana, M.

    2008-01-01

    Roč. 486, č. 3 (2008), s. 1023-1029 ISSN 0004-6361 R&D Projects: GA ČR GP205/06/P135 Institutional research plan: CEZ:AV0Z10030501 Keywords : sun flares * X-rays * gamma rays Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

  14. Multiplet splitting of x-ray photoemission spectra core levels in magnetic metals

    International Nuclear Information System (INIS)

    Kowalczyk, S.P.; McFeely, F.R.; Ley, L.; Shirley, D.A.

    1975-01-01

    The results of high resolution x-ray photoemission studies of the multiplet splitting of the 3s core levels in the 3d transition metals and the 4s, 5s and 4d core levels in the lanthanide metals are reported

  15. NEWFIT, a computer program for the analysis of alpha, X-ray and gamma-ray spectra

    International Nuclear Information System (INIS)

    Welch, R.B.; Gyger, F.; Jost, D.T.; Gunten, H.R. von; Kraehenbuehl, U.

    1988-01-01

    The computer program NEWFIT has been developed for analysis of gamma-ray, X-ray and alpha spectra. The general shape used for the analysis of activity peaks is a Gaussian function. An exponential tail can be added for use in alpha spectra analysis. The algorithms to analyze the peak shapes and the program operation are presented. Special features include the ability to create realistic peak shapes based on the systematic deviations of the real peaks from the theoretical Gaussian shape, as well as the option to constrain the calculated areas of peaks from a given emitting nuclide to their relative branching ratios. The program is available from the authors. (orig.)

  16. Analysis of the X-ray emission spectra of copper, germanium and rubidium plasmas produced at the Phelix laser facility

    Science.gov (United States)

    Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.; Denis-Petit, D.; Méot, V.; Gosselin, G.; Morel, P.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.

    2017-03-01

    We present the analysis of X-ray emission spectra of copper, germanium and rubidium plasmas measured at the Phelix laser facility. The laser intensity was around 6×1014 W.cm-2. The analysis is based on the hypothesis of an homogeneous plasma in local thermodynamic equilibrium using an effective temperature. This temperature is deduced from hydrodynamic simulations and collisional-radiative computations. Spectra are then calculated using the LTE opacity codes OPAMCDF and SCO-RCG and compared to experimental data.

  17. X-ray photoelectron spectra structure of actinide compounds stipulated by electrons of the inner valence molecular orbitals (IVMO)

    International Nuclear Information System (INIS)

    Teterin, Yu. A.; Ivanov, K. E.

    1997-01-01

    Development of precise X-ray photoelectron spectroscopy using X-ray radiation hν< 1.5 KeV allowed to carry out immediate investigations of fine spectra structure of both weakly bond and deep electrons. Based on the experiments and the obtained results it may be concluded: 1. Under favourable conditions the inner valence molecular orbitals (IVMO) may form in all actinide compounds. 2. The XPS spectra fine structure stipulated by IVMO electrons allows to judge upon the degree of participation of the filled AO electrons in the chemical bond, on the structure o considered atom close environment and the bond lengths in compounds. For amorphous compounds the obtaining of such data based on X-ray structure analysis is restricted. 3. The summary contribution of IVMO electrons to the absolute value of the chemical bonding is comparable with the corresponding value of OMO electrons contribution to the atomic bonding. This fact is very important and new in chemistry. (author)

  18. Comparative Analysis and Variability of the Jovian X-Ray Spectra Detected by the Chandra and XMM-Newton Observatories

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Yawei [ORNL; Schultz, David Robert [ORNL; Kharchenko, Vasili A [ORNL; Bhardwaj, Anil [Vikram Sarabhai Space Center, Trivandrum, India; Branduardi-Raymont, Graziella [University College, London; Stancil, Phillip C. [University of Georgia, Athens, GA; Cravens, Thomas E. E. [University of Kansas; Lisse, Carey M. [Johns Hopkins University; Dalgarno, A. [Harvard-Smithsonian Center for Astrophysics

    2010-01-01

    Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X-ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM-Newton by systematically varying the initial precipitating ion parameters to obtain the best fit model for the observed spectra. In addition to the oxygen and sulfur ions considered previously, carbon is included to discriminate between solar wind and Jovian magnetospheric ion origins, enabled by the use of extensive databases of both atomic collision cross sections and radiative transitions. On the basis of fits to all the Chandra observations, we find that carbon contributes negligibly to the observed polar X-ray emission suggesting that the highly accelerated precipitating ions are of magnetospheric origin. Most of the XMM-Newton fits also favor this conclusion with one exception that implies a possible carbon contribution. Comparison among all the spectra from these two observatories in light of the inferred initial energies and relative abundances of precipitating ions from the modeling show that they are significantly variable in time (observation date) and space (north and south polar X-ray auroras).

  19. Determination of Al concentration in Al doped ZnO using Auger spectra excited by Mo X-rays

    International Nuclear Information System (INIS)

    Toth, J.; Koever, L.; Cserny, I.; Varga, D.

    2006-01-01

    Complete text of publication follows. A good conductor with excellent transparency is of crucial importance for the window layer of CIGS solar cells. Al doped ZnO is a good candidate for this purpose, its conductivity depends on the concentration and chemical state of the Al dopant atoms. It was demonstrated that the non-conventional XPS using Mo X-rays for excitation is a very sensitive tool for the detection of Al, P, Si [1, 2, 3]. The present paper compares the experimental ratios for Zn/Al photoinduced peak intensity ratios obtained using both Al and Mo X-ray excitations. The Mo excited Zn/Al intensity ratios can be determined with higher selectivity and sensitivity than the Zn/Al intensity ratios excited by Al X-rays. The experiments were performed with a hemispherical deflector electron spectrometer [4]. The chemical state of the Al was identified to be close to that in Al 2 O 3 . The atomic concentrations were determined using a calibration curve based on ZnO/Al samples with known composition of Al. The energy dependent efficiency of the electron spectrometer was determined comparing REELS spectra of Cu specimen to standard spectra measured by K. Goto (Nagoya Institute of Technology, Japan). For evaluation of the Al atomic concentrations from the measured photoelectron intensities the photoionisation cross-sections of Band et al [5] and the IMFP data of S. Tanuma et al [6] and C.J. Powell and A. Jablonski [7] were used. (author)

  20. Analysis of X-ray Spectra of High-Z Elements obtained on Nike with high spectral and spatial resolution

    Science.gov (United States)

    Aglitskiy, Yefim; Weaver, J. L.; Karasik, M.; Serlin, V.; Obenschain, S. P.; Ralchenko, Yu.

    2014-10-01

    The spectra of multi-charged ions of Hf, Ta, W, Pt, Au and Bi have been studied on Nike krypton-fluoride laser facility with the help of two kinds of X-ray spectrometers. First, survey instrument covering a spectral range from 0.5 to 19.5 angstroms which allows simultaneous observation of both M- and N- spectra of above mentioned elements with high spectral resolution. Second, an imaging spectrometer with interchangeable spherically bent Quartz crystals that added higher efficiency, higher spectral resolution and high spatial resolution to the qualities of the former one. Multiple spectral lines with X-ray energies as high as 4 keV that belong to the isoelectronic sequences of Fe, Co, Ni, Cu and Zn were identified with the help of NOMAD package developed by Dr. Yu. Ralchenko and colleagues. In our continuous effort to support DOE-NNSA's inertial fusion program, this campaign covered a wide range of plasma conditions that result in production of relatively energetic X-rays. Work supported by the US DOE/NNSA.

  1. Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Paixao, L.; Oliveira, B. B.; Nogueira, M. do S. [Centro de Desenvolvimento da Tecnologia Nuclear, Post-graduation in Science and Technology of Radiations, Minerals and Materials, Pte. Antonio Carlos 6.627, Pampulha, 31270-901 Belo Horizonte (Brazil); Viloria, C. [UFMG, Departamento de Engenharia Nuclear, Post-graduation in Nuclear Sciences and Techniques, Pte. Antonio Carlos 6.627, Pampulha, 31270-901 Belo Horizonte (Brazil); Alves de O, M. [UFMG, Department of Anatomy and Imaging, Prof. Alfredo Balena 190, 30130-100 Belo Horizonte (Brazil); Araujo T, M. H., E-mail: lpr@cdtn.br [Dr Maria Helena Araujo Teixeira Clinic, Guajajaras 40, 30180-100 Belo Horizonte (Brazil)

    2014-08-15

    It is widely accepted that the mean glandular dose (D{sub G}) for the glandular tissue is the more useful magnitude for characterizing the breast cancer risk. The procedure to estimate the D{sub G}, for being difficult to measure it directly in the breast, it is to make the use of conversion factors that relate incident air kerma (K{sub i}) at this dose. Generally, the conversion factors vary with the x-ray spectrum half-value layer and the breast composition and thickness. Several authors through computer simulations have calculated such factors by the Monte Carlo (Mc) method. Many spectral models for D{sub G} computer simulations purposes are available in the diagnostic range. One of the models available generates unfiltered spectra. In this work, the Monte Carlo EGSnrc code package with the C++ class library (eg spp) was employed to derive filtered tungsten x-ray spectra used in digital mammography systems. Filtered spectra for rhodium and aluminium filters were obtained for tube potentials between 26 and 32 kV. The half-value layer of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F and Mam Detector Platinum and 8201023-C Xi Base unit Platinum Plus w m As in a Hologic Selenia Dimensions system using a Direct Radiography mode. Calculated half-value layer values showed good agreement compared to those obtained experimentally. These results show that the filtered tungsten anode x-ray spectra and the EGSnrc Mc code can be used for D{sub G} determination in mammography. (Author)

  2. Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography

    International Nuclear Information System (INIS)

    Paixao, L.; Oliveira, B. B.; Nogueira, M. do S.; Viloria, C.; Alves de O, M.; Araujo T, M. H.

    2014-08-01

    It is widely accepted that the mean glandular dose (D G ) for the glandular tissue is the more useful magnitude for characterizing the breast cancer risk. The procedure to estimate the D G , for being difficult to measure it directly in the breast, it is to make the use of conversion factors that relate incident air kerma (K i ) at this dose. Generally, the conversion factors vary with the x-ray spectrum half-value layer and the breast composition and thickness. Several authors through computer simulations have calculated such factors by the Monte Carlo (Mc) method. Many spectral models for D G computer simulations purposes are available in the diagnostic range. One of the models available generates unfiltered spectra. In this work, the Monte Carlo EGSnrc code package with the C++ class library (eg spp) was employed to derive filtered tungsten x-ray spectra used in digital mammography systems. Filtered spectra for rhodium and aluminium filters were obtained for tube potentials between 26 and 32 kV. The half-value layer of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F and Mam Detector Platinum and 8201023-C Xi Base unit Platinum Plus w m As in a Hologic Selenia Dimensions system using a Direct Radiography mode. Calculated half-value layer values showed good agreement compared to those obtained experimentally. These results show that the filtered tungsten anode x-ray spectra and the EGSnrc Mc code can be used for D G determination in mammography. (Author)

  3. Implications for gravitational lensing and the dark matter content in clusters of galaxies from spatially resolved x-ray spectra

    Science.gov (United States)

    Loewenstein, M.

    1994-01-01

    A simple method for deriving well-behaved temperature solutions to the equation of hydrostatic equilibrium for intracluster media with X-ray imaging observations is presented and applied to a series of generalized models as well as to observations of the Perseus cluster and Abell 2256. In these applications the allowed range in the ratio of nonbaryons to baryons as a function of radius is derived, taking into account the uncertainties and crude spatial resolution of the X-ray spectra and considering a range of physically reasonable mass models with various scale heights. Particular attention is paid to the central regions of the cluster, and it is found that the dark matter can be sufficiently concentrated to be consistent with the high central mass surface densities for moderate-redshift clusters from their gravitational lensing properties.

  4. Simultaneous acquisition of X-ray spectra using a multi-wire, position-sensitive gas flow detector

    International Nuclear Information System (INIS)

    Beaven, Peter A.; Marmotti, Mauro; Kampmann, Reinhard; Knoth, Joachim; Schwenke, Heinrich

    2003-01-01

    A multi-wire, gas-filled position-sensitive detector has been developed for the simultaneous recording of wavelength-dispersed X-ray signals that enables X-ray fluorescence spectrometry with a limited multi-element capability in the low Z element range. Details of the modular construction of the detector are given. The detector performance was characterized using Al-Kα radiation and a variable slit system. The detector has been applied in a laboratory spectrometer equipped with an electron source and a double multilayer mirror device as the wavelength-dispersing element. Spectra from Al and Si obtained in the simultaneous acquisition mode show good agreement with calculations performed using a ray-tracing model

  5. X-ray spectra and electronic structure of the Ca3Ga2Ge3О12 compound

    Science.gov (United States)

    Shcherba, I. D.; Kostyk, L. V.; Noga, H.; Bekenov, L. V.; Uskokovich, D.; Jatsyk, B. M.

    2017-09-01

    The band structure of Ca3Ga2Ge3О12 with the garnet structure has been determined for the first time by X-ray emission and photoelectron spectroscopy. It has been established that the bottom of the valence band is formed by Ge d states, which are not dominant in the chemical bonding. Strong hybridization of oxygen 2s states with 4p states of Ga and Ge revealed by the presence of an extra structure in the X-ray emission spectra has been found. The middle of the valence band has been demonstrated to be occupied by d states of Ga, while Ga and Ge 4рstates with a considerable admixture of oxygen 2p states form the top of the valence band.

  6. Quantum many-body effects in x-ray spectra efficiently computed using a basic graph algorithm

    Science.gov (United States)

    Liang, Yufeng; Prendergast, David

    2018-05-01

    The growing interest in using x-ray spectroscopy for refined materials characterization calls for an accurate electronic-structure theory to interpret the x-ray near-edge fine structure. In this work, we propose an efficient and unified framework to describe all the many-electron processes in a Fermi liquid after a sudden perturbation (such as a core hole). This problem has been visited by the Mahan-Noziéres-De Dominicis (MND) theory, but it is intractable to implement various Feynman diagrams within first-principles calculations. Here, we adopt a nondiagrammatic approach and treat all the many-electron processes in the MND theory on an equal footing. Starting from a recently introduced determinant formalism [Phys. Rev. Lett. 118, 096402 (2017), 10.1103/PhysRevLett.118.096402], we exploit the linear dependence of determinants describing different final states involved in the spectral calculations. An elementary graph algorithm, breadth-first search, can be used to quickly identify the important determinants for shaping the spectrum, which avoids the need to evaluate a great number of vanishingly small terms. This search algorithm is performed over the tree-structure of the many-body expansion, which mimics a path-finding process. We demonstrate that the determinantal approach is computationally inexpensive even for obtaining x-ray spectra of extended systems. Using Kohn-Sham orbitals from two self-consistent fields (ground and core-excited state) as input for constructing the determinants, the calculated x-ray spectra for a number of transition metal oxides are in good agreement with experiments. Many-electron aspects beyond the Bethe-Salpeter equation, as captured by this approach, are also discussed, such as shakeup excitations and many-body wave function overlap considered in Anderson's orthogonality catastrophe.

  7. ERX: a software for editing files containing X-ray spectra to be used in exposure computational models

    International Nuclear Information System (INIS)

    Cabral, Manuela O.M.; Vieira, Jose W.; Silva, Alysson G.; Leal Neto, Viriato; Oliveira, Alex C.H.; Lima, Fernando R.A.

    2011-01-01

    Exposure Computational Models (ECMs) are utilities that simulate situations in which occurs irradiation in a given environment. An ECM is composed primarily by an anthropomorphic model (phantom), and a Monte Carlo code (MC). This paper presents a tutorial of the software Espectro de Raios-X (ERX). This software performs reading and numerical and graphical analysis of text files containing diagnostic X-ray spectra for use in algorithms of radioactive sources in the ECMs of a Grupo de Dosimetria Numerica. The ERX allows the user to select one among several X-ray spectrums in the energy range Diagnostic radiology X-Ray most commonly used in radiology clinics. In the current version of the ERX there are two types of input files: the contained in mspectra.dat file and the resulting of MC simulations in Geant4. The software allows the construction of charts of the Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of a selected spectrum as well as the table with the values of these functions and the spectrum. In addition, the ERX allows the user to make comparative analysis between the PDF graphics of the two catalogs of spectra available, besides being can perform dosimetric evaluations with the selected spectrum. A software of this kind is an important computational tool for researchers in numerical dosimetry because of the diversity of Diagnostic radiology X-Ray machines, which implies in a mass of input data highly diverse. And because of this, the ERX provides independence to the group related to the data origin that is contained in the catalogs created, not being necessary to resort to others. (author)

  8. X-RAY REFLECTED SPECTRA FROM ACCRETION DISK MODELS. I. CONSTANT DENSITY ATMOSPHERES

    International Nuclear Information System (INIS)

    Garcia, J.; Kallman, T. R.

    2010-01-01

    We present new models for illuminated accretion disks, their structure, and reprocessed emission. We consider the effects of incident X-rays on the surface of an accretion disk by simultaneously solving the equations of radiative transfer, energy balance, and ionization equilibrium over a large range of column densities. We assume plane-parallel geometry and azimuthal symmetry, such that each calculation corresponds to a ring at a given distance from the central object. Our models include recent and complete atomic data for K-shell processes of the iron and oxygen isonuclear sequences. We examine the effect on the spectrum of fluorescent Kα line emission and absorption in the emitted spectrum. We also explore the dependence of the spectrum on the strength of the incident X-rays and other input parameters, and discuss the importance of Comptonization on the emitted spectrum.

  9. Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M [Osaka Univ., Suita (Japan). Medical School; Kanamori, H; Toragaito, T; Taniguchi, A

    1996-07-01

    We modified the formula of stripping procedure presented by E. Di. Castor et al. We added the Compton scattering and separated K{sub {alpha}} radiation of Cd and Te (23 and 27keV, respectively). Using the new stripping procedure diagnostic x-ray spectra (object 4mm-Al) of tube voltage 50kV to 100kV for CdTe and CdZnTe detectors are corrected with comparison of those spectra for the Ge detector. The corrected spectra for CdTe and CdZnTe detectors coincide with those for Ge detector at lower tube voltage than 70kV. But the corrected spectra at higher tube voltage than 70kV do not coincide with those for Ge detector. The reason is incomplete correction for full energy peak efficiencies of real CdTe and CdZnTe detectors. (J.P.N.)

  10. High-resolution X-ray spectra from low-temperature, highly charged ions

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1996-09-01

    The electron beam ion traps (EBIT) at Livermore were designed for studying the x-ray emission of highly charged ions produced and excited by a monoenergetic electron beam. The precision with which the x-ray emission can be analyzed has recently been increased markedly when it became possible to decouple the temperature of the ions from the energy of the electron beam by several orders of magnitude. By adjusting the trap parameters, ion temperatures as low as 15.8±4.4 eV for Ti 20+ and 59.4±9.9 eV for Cs 45+ were achieved. These temperatures were more than two orders of magnitude lower than the energy of the multi-keV electron beam used for the production and excitation of the ions. A discussion of the techniques used to produce and study low-temperature highly charged ions is presented in this progress report. The low ion temperatures enabled measurements heretofore impossible. As an example, a direct observation of the natural line width of fast electric dipole allowed x-ray transitions is described. From the observed natural line width and b making use of the time-energy relations of the uncertainty principle we were able to determine a radiative transition rate of 1.65 fs for the 2p-3d resonance transition in neonlike Cs 45+ . A brief discussion of other high-precision measurements enabled by our new technique is also given

  11. Specdata: Automated Analysis Software for Broadband Spectra

    Science.gov (United States)

    Oliveira, Jasmine N.; Martin-Drumel, Marie-Aline; McCarthy, Michael C.

    2017-06-01

    With the advancement of chirped-pulse techniques, broadband rotational spectra with a few tens to several hundred GHz of spectral coverage are now routinely recorded. When studying multi-component mixtures that might result, for example, with the use of an electrical discharge, lines of new chemical species are often obscured by those of known compounds, and analysis can be laborious. To address this issue, we have developed SPECdata, an open source, interactive tool which is designed to simplify and greatly accelerate the spectral analysis and discovery. Our software tool combines both automated and manual components that free the user from computation, while giving him/her considerable flexibility to assign, manipulate, interpret and export their analysis. The automated - and key - component of the new software is a database query system that rapidly assigns transitions of known species in an experimental spectrum. For each experiment, the software identifies spectral features, and subsequently assigns them to known molecules within an in-house database (Pickett .cat files, list of frequencies...), or those catalogued in Splatalogue (using automatic on-line queries). With suggested assignments, the control is then handed over to the user who can choose to accept, decline or add additional species. Data visualization, statistical information, and interactive widgets assist the user in making decisions about their data. SPECdata has several other useful features intended to improve the user experience. Exporting a full report of the analysis, or a peak file in which assigned lines are removed are among several options. A user may also save their progress to continue at another time. Additional features of SPECdata help the user to maintain and expand their database for future use. A user-friendly interface allows one to search, upload, edit or update catalog or experiment entries.

  12. Indirect measure of X-rays spectra using TLDs; Medicion indirecta de espectros de rayos X utilizando TLDs

    Energy Technology Data Exchange (ETDEWEB)

    Bonzi, E. V.; Mainardi, R. T. [Universidad Nacional de Cordoba, Facultad de Matematica, Astronomia y Fisica, Av. Haya de la Torre y Av. Medina Allende s/n, Ciudad Universitaria, X5016LEA Cordoba (Argentina)

    2011-10-15

    A methodology of indirect measure of X-rays spectra, emitted by conventional tubes, was developed recently and its feasibility verified in the first place by Monte Carlo simulations. For that case is intended to measure, by means of plastic scintillators, attenuation curves of dispersed beams previously. In this work were carried out measurements of attenuation curves with thermoluminescent dosimeters (TLD) to verify the kindness of the indirect measure method. The attenuation curve was also measured using an ionization chamber brand Capintec (model 192) with the purpose of making a comparison. The results of the attenuation curve measured with both dosimeters present a good resolution inside the statistical fluctuations and the spectral reconstruction using diverse parametric functions is carried out in a quick and simple way with excellent resolutions in the functional form. For this reconstruction method are of fundamental importance the following properties of the used dosimeter: in the first place the repetition of the measures, property that could check; in second place the precision of the measured data and lastly the dosimeter response, this is, the increase of the thermoluminescent signal before an increase of the photons flow of X-rays. This parameter is the gradient of the curve thermoluminescent signal versus the dose imparted to the dosimeter. The measures were realized with a generator of X-rays brand Kevex provided of a conventional tube with tungsten anti cathode that polarizes with high tension to a maximum value of 50 kV and current of 0.5 ma. (Author)

  13. Processing and quantification of x-ray energy dispersive spectra in the Analytical Electron Microscope

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1988-08-01

    Spectral processing in x-ray energy dispersive spectroscopy deals with the extraction of characteristic signals from experimental data. In this text, the four basic procedures for this methodology are reviewed and their limitations outlined. Quantification, on the other hand, deals with the interpretation of the information obtained from spectral processing. Here the limitations are for the most part instrumental in nature. The prospects of higher voltage operation does not, in theory, present any new problems and may in fact prove to be more desirable assuming that electron damage effects do not preclude analysis. 28 refs., 6 figs

  14. X-Ray Absorption Spectra of Water from First Principles Calculations

    International Nuclear Information System (INIS)

    Prendergast, David; Galli, Giulia

    2006-01-01

    We present a series of ab initio calculations of the x-ray absorption cross section (XAS) of ice and liquid water at ambient conditions. Our results show that all available experimental data and theoretical results are consistent with the standard model of the liquid as comprising molecules with approximately four hydrogen bonds. Our simulations of ice XAS including the lowest lying excitonic state are in excellent agreement with experiment and those of a quasitetrahedral model of water are in reasonable agreement with recent measurements. Hence we propose that the standard, quasitetrahedral model of water, although approximate, represents a reasonably accurate description of the local structure of the liquid

  15. The effect of SNR structure on non-equilibrium X-ray spectra

    International Nuclear Information System (INIS)

    Hamilton, A.J.S.; Sarazin, C.L.

    1983-01-01

    A technique is presented for characterizing the ionization structure and consequent thermal X-ray emission of a SNR when non-equilibrium ionization effects are important. The technique allows different theoretical SNR models to be compared and contrasted rapidly in advance of detailed numerical computations. In particular it is shown that the spectrum of a Sedov remnant can probably be applied satisfactorily in a variety of SNR structures, including the reverse shock model advocated by Chevalier (1982) for Type I SN, the isothermal similarity solution of Solinger, Rappaport and Buff (1975), and various inhomogenous or 'messy' structures. (Auth.)

  16. Pulsator-like Spectra from Ultraluminous X-Ray Sources and the Search for More Ultraluminous Pulsars

    International Nuclear Information System (INIS)

    Pintore, F.; Mereghetti, S.; Zampieri, L.; Stella, L.; Israel, G. L.; Wolter, A.

    2017-01-01

    Ultraluminous X-ray sources (ULXs) are a population of extragalactic objects whose luminosity exceeds the Eddington limit for a 10 M ⊙ black hole (BH). Their properties have been widely interpreted in terms of accreting stellar-mass or intermediate-mass BHs. However at least three neutron stars (NSs) have been recently identified in ULXs through the discovery of periodic pulsations. Motivated by these findings we studied the spectral properties of a sample of bright ULXs using a simple continuum model which was extensively used to fit the X-ray spectra of accreting magnetic NSs in the Galaxy. We found that such a model, consisting of a power-law with a high-energy exponential cut-off, fits most of the ULX spectra analyzed here very well, at a level comparable to that of models involving an accreting BH. On these grounds alone we suggest that other non-pulsating ULXs may host NSs. We also found that above 2 keV the spectrum of known pulsating ULXs is harder than that of the majority of the other ULXs of the sample, with only IC 342 X-1 and Ho IX X-1 displaying spectra of comparable hardness. We thus suggest that these two ULXs may host an accreting NS and encourage searches for periodic pulsations in the flux.

  17. Pulsator-like Spectra from Ultraluminous X-Ray Sources and the Search for More Ultraluminous Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Pintore, F.; Mereghetti, S. [INAF-IASF Milano, via E. Bassini 15, I-20133 Milano (Italy); Zampieri, L. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Stella, L.; Israel, G. L. [INAF—Osservatorio astronomico di Roma, Via Frascati 44, I-00078, Monteporzio Catone (Italy); Wolter, A. [INAF, Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano (Italy)

    2017-02-10

    Ultraluminous X-ray sources (ULXs) are a population of extragalactic objects whose luminosity exceeds the Eddington limit for a 10 M {sub ⊙} black hole (BH). Their properties have been widely interpreted in terms of accreting stellar-mass or intermediate-mass BHs. However at least three neutron stars (NSs) have been recently identified in ULXs through the discovery of periodic pulsations. Motivated by these findings we studied the spectral properties of a sample of bright ULXs using a simple continuum model which was extensively used to fit the X-ray spectra of accreting magnetic NSs in the Galaxy. We found that such a model, consisting of a power-law with a high-energy exponential cut-off, fits most of the ULX spectra analyzed here very well, at a level comparable to that of models involving an accreting BH. On these grounds alone we suggest that other non-pulsating ULXs may host NSs. We also found that above 2 keV the spectrum of known pulsating ULXs is harder than that of the majority of the other ULXs of the sample, with only IC 342 X-1 and Ho IX X-1 displaying spectra of comparable hardness. We thus suggest that these two ULXs may host an accreting NS and encourage searches for periodic pulsations in the flux.

  18. Structure of the X-ray photoelectron spectra of fluorides and oxides of lanthanides connected with the dynamic effect

    International Nuclear Information System (INIS)

    Teterin, Yu.A.; Teterin, A.Yu.; Lebedev, A.M.; Utkin, I.O.; Nikitin, A.S.

    1998-01-01

    Impact of dynamic effect on the fine structure of the X-ray electron spectra of the lanthanide oxides and fluorides is considered. Significant complication of the Ln4p-electrons occurs due to interaction of configurations of the basic single-hole and additional two-hole finite states of the 4p 5 4d 10 4f n ↔ 4p 6 4d 8 4f n+1 type. Impact of the atoms nature of the nearest surrounding of the lanthanides ions on the parameters of such fine structure is evaluated [ru

  19. X-ray electron spectra of chalcogenide glasses and polycrystalline alloys of Ge-Te and As-Te systems

    International Nuclear Information System (INIS)

    Panus, V.R.

    1990-01-01

    Comparative investigation into structures of crystals and glasses in Ge-Te and As-Te two-component systems was conducted. Analysis of x-ray electron spectra of Ge-Te and As-Te systems indicates, that processes of dissociation-association resulting in formation of new structure units occur in telluride melts at synthesis temperatures. Structural chemical composition of binary glass-like alloys of Ge-Te and As-Te systems differs essentially from the one that corresponds to fusibility equilibrium curve. Oxygen doping into tellurium-base glasses results mainly in occurence of structures forecasted due to thermochemical calculation

  20. The rotation of accretion-disks and the power spectra of X-rays 'flickering'

    International Nuclear Information System (INIS)

    Zhang Xiaohe; Bao Gang

    1990-07-01

    The X-ray producing, inner region of the accretion disk in Active Galactic Nuclei (AGN) is likely to be non-stationary and non-axisymmetric. This non-stationarity and non-axisymmetry in disk surface brightness may be modeled by considering the pre-sense of many 'hot spots' on a steady, axisymmetric disk. As long as a 'spot' can survive for a few orbital periods, its orbital frequency can be introduced into the light curve either by relativistic orbital motion or by eclipsing of the spot by the disk. These rotational effects vary with the local properties of the spot population. Depending on the radial variation of spot brightness, lifetime and number density, the observed variability power spectrum may differ from that due to the intrinsic variability of spots alone, within the orbital frequency range in which these spots occur. In this paper, we explore the relation between properties assumed for the spot population and the resulting predictions for the observed variability. The implications of our results for the 'flickering' of X-ray sources powered by accretion disks (both AGN and galactic sources) are also discussed. (author). 24 refs, 6 figs

  1. Revisiting the total ion yield x-ray absorption spectra of liquid water microjets

    International Nuclear Information System (INIS)

    Saykally, Richard J; Cappa, Chris D.; Smith, Jared D.; Wilson, Kevin R.; Saykally, Richard J.

    2008-01-01

    Measurements of the total ion yield (TIY) x-ray absorption spectrum (XAS) of liquid water by Wilson et al. (2002 J. Phys.: Condens. Matter 14 L221 and 2001 J. Phys. Chem. B 105 3346) have been revisited in light of new experimental and theoretical efforts by our group. Previously, the TIY spectrum was interpreted as a distinct measure of the electronic structure of the liquid water surface. However, our new results indicate that the previously obtained spectrum may have suffered from as yet unidentified experimental artifacts. Although computational results indicate that the liquid water surface should exhibit a TIY-XAS that is fundamentally distinguishable from the bulk liquid XAS, the new experimental results suggest that the observable TIY-XAS is actually nearly identical in appearance to the total electron yield (TEY-)XAS, which is a bulk probe. This surprising similarity between the observed TIY-XAS and TEY-XAS likely results from large contributions from x-ray induced electron stimulated desorption of ions, and does not necessarily indicate that the electronic structure of the bulk liquid and liquid surface are identical

  2. Compton scattering artifacts in electron excited X-ray spectra measured with a silicon drift detector.

    Science.gov (United States)

    Ritchie, Nicholas W M; Newbury, Dale E; Lindstrom, Abigail P

    2011-12-01

    Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive X-ray spectrometry. Peaks that result from nonideal behavior in the detector or sample can fool even an experienced microanalyst into believing that they have trace amounts of an element that is not present. Many artifacts, such as the Si escape peak, absorption edges, and coincidence peaks, can be traced to the detector. Others, such as secondary fluorescence peaks and scatter peaks, can be traced to the sample. We have identified a new sample-dependent artifact that we attribute to Compton scattering of energetic X-rays generated in a small feature and subsequently scattered from a low atomic number matrix. It seems likely that this artifact has not previously been reported because it only occurs under specific conditions and represents a relatively small signal. However, with the advent of silicon drift detectors and their utility for trace element analysis, we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to mistakenly identify the Compton scatter artifact as approximately 1% of an element that is not present.

  3. Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra.

    Science.gov (United States)

    Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2016-07-01

    Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1-20 cm), and a CdTe X-ray spectrometer assuming one pixel of the X-ray imaging detector. Then, with the following two experimental settings, corresponding X-ray spectra were measured with 40-120 kVp and 0.5-1000 mAs at a source-to-detector distance of 100 cm: (1) X-rays penetrating a soft-tissue-equivalent phantom with the OSL dosimeter attached directly on the phantom, and (2) X-rays penetrating only the soft-tissue-equivalent phantom. Next, the energy fluence and errors in the fluence were calculated from the spectra. When the energy fluence with errors concerning these two experimental conditions was estimated to be indistinctive, we defined the condition as the OSL dosimeter not being identified on the X-ray image. Based on our analysis, we determined the identification limit of the dosimeter. We then compared our results with those for the general irradiation conditions used in clinics. We found that the OSL dosimeter could not be identified under the irradiation conditions of abdominal and chest radiography, namely, one can apply the OSL dosimeter to measurement of the exposure dose in the irradiation field of X-rays without disturbing medical images.

  4. Soft x-ray absorption and emission spectra and the electronic structure of some exotic materials

    International Nuclear Information System (INIS)

    Ederer, D.L.; Canfield, L.R.; Callcott, T.A.; Tsang, K.L.; Zhang, C.H.; Arakawa, E.T.

    1988-01-01

    The technique of soft x-ray fluorescence spectroscopy (SXE) is complimentary to that of photoemission spectroscopy (PES). SXE probes the local partial density of states (PDOS), selects dipole allowed symmetries, and is not necessarily surface sensitive. PES on the other hand, averages over the DOS and can be used to measure the dispersion of the energy bands. PES is also very surface sensitive. We present measurements on the high T/sub c/ superconductors, the quasicrystalline phase of AlMn, and the LiAl intermetallic alloy. These measurements provide insight for theoretical modeling. In the case of the high T/sub c/ compound and the intermetallic compound the measurements are in good agreement with the theory. However, for the quasicrystals the measurements provide new insights to challenge theory. 13 refs., 3 figs

  5. A hydrodynamical model of Kepler's supernova remnant constrained by x-ray spectra

    International Nuclear Information System (INIS)

    Ballet, J.; Arnaud, M.; Rothinfluo, R.; Chieze, J.P.; Magne, B.

    1988-01-01

    The remnant of the historical supernova observed by Kepler in 1604 was recently observed in x-rays by the EXOSAT satellite up to 10 keV. A strong Fe K emission line around 6.5 keV is readily apparent in the spectrum. From an analysis of the light curve of the SN, reconstructed from historical descriptions, a previous study proposed to classify it as type I. Standard models of SN I based on carbon deflagration of white dwarf predict the synthesis of about 0.5 M circle of iron in the ejecta. Observing the iron line is a crucial check for such models. It has been argued that the light curve of Sn II-L is very similar to that of SN I and that the original observations are compatible with either type. In view of this uncertainty the authors have run a hydrodynamics-ionization code for both SN II and SN I remnants

  6. The Effect of Broadband Soft X-Rays in SO2-Containing Ices: Implications on the Photochemistry of Ices toward Young Stellar Objects

    Science.gov (United States)

    Pilling, S.; Bergantini, A.

    2015-10-01

    We investigate the effects produced mainly by broadband soft X-rays up to 2 keV (plus fast (˜keV) photoelectrons and low-energy (˜eV) induced secondary electrons) in the ice mixtures containing H2O:CO2:NH3:SO2 (10:1:1:1) at two different temperatures (50 and 90 K). The experiments are an attempt to simulate the photochemical processes induced by energetic photons in SO2-containing ices present in cold environments in the ices surrounding young stellar objects (YSO) and in molecular clouds in the vicinity of star-forming regions, which are largely illuminated by soft X-rays. The measurements were performed using a high-vacuum portable chamber from the Laboratório de Astroquímica e Astrobiologia (LASA/UNIVAP) coupled to the spherical grating monochromator beamline at the Brazilian Synchrotron Light Source (LNLS) in Campinas, Brazil. In situ analyses were performed by a Fourier transform infrared spectrometer. Sample processing revealed the formation of several organic molecules, including nitriles, acids, and other compounds such as H2O2, H3O+, SO3, CO, and OCN-. The dissociation cross section of parental species was on the order of (2-7) × 10-18 cm2. The ice temperature does not seem to affect the stability of SO2 in the presence of X-rays. Formation cross sections of new species produced were also determined. Molecular half-lives at ices toward YSOs due to the presence of incoming soft X-rays were estimated. The low values obtained employing two different models of the radiation field of YSOs (TW Hydra and typical T-Tauri star) reinforce that soft X-rays are indeed a very efficient source of molecular dissociation in such environments.

  7. THE EFFECT OF BROADBAND SOFT X-RAYS IN SO2-CONTAINING ICES: IMPLICATIONS ON THE PHOTOCHEMISTRY OF ICES TOWARD YOUNG STELLAR OBJECTS

    International Nuclear Information System (INIS)

    Pilling, S.; Bergantini, A.

    2015-01-01

    We investigate the effects produced mainly by broadband soft X-rays up to 2 keV (plus fast (∼keV) photoelectrons and low-energy (∼eV) induced secondary electrons) in the ice mixtures containing H 2 O:CO 2 :NH 3 :SO 2 (10:1:1:1) at two different temperatures (50 and 90 K). The experiments are an attempt to simulate the photochemical processes induced by energetic photons in SO 2 -containing ices present in cold environments in the ices surrounding young stellar objects (YSO) and in molecular clouds in the vicinity of star-forming regions, which are largely illuminated by soft X-rays. The measurements were performed using a high-vacuum portable chamber from the Laboratório de Astroquímica e Astrobiologia (LASA/UNIVAP) coupled to the spherical grating monochromator beamline at the Brazilian Synchrotron Light Source (LNLS) in Campinas, Brazil. In situ analyses were performed by a Fourier transform infrared spectrometer. Sample processing revealed the formation of several organic molecules, including nitriles, acids, and other compounds such as H 2 O 2 , H 3 O + , SO 3 , CO, and OCN − . The dissociation cross section of parental species was on the order of (2–7) × 10 −18 cm 2 . The ice temperature does not seem to affect the stability of SO 2 in the presence of X-rays. Formation cross sections of new species  produced were also determined. Molecular half-lives at ices toward YSOs due to the presence of incoming soft X-rays were estimated. The low values obtained employing two different models of the radiation field of YSOs (TW Hydra and typical T-Tauri star) reinforce that soft X-rays are indeed a very efficient source of molecular dissociation in such environments

  8. Correlations between variations in solar EUV and soft X-ray irradiance and photoelectron energy spectra observed on Mars and Earth

    Science.gov (United States)

    Peterson, W. K.; Brain, D. A.; Mitchell, D. L.; Bailey, S. M.; Chamberlin, P. C.

    2013-11-01

    extreme ultraviolet (EUV; 10-120 nm) and soft X-ray (XUV; 0-10 nm) radiation are major heat sources for the Mars thermosphere as well as the primary source of ionization that creates the ionosphere. In investigations of Mars thermospheric chemistry and dynamics, solar irradiance models are used to account for variations in this radiation. Because of limited proxies, irradiance models do a poor job of tracking the significant variations in irradiance intensity in the EUV and XUV ranges over solar rotation time scales when the Mars-Sun-Earth angle is large. Recent results from Earth observations show that variations in photoelectron energy spectra are useful monitors of EUV and XUV irradiance variability. Here we investigate photoelectron energy spectra observed by the Mars Global Surveyor (MGS) Electron Reflectometer (ER) and the FAST satellite during the interval in 2005 when Earth, Mars, and the Sun were aligned. The Earth photoelectron data in selected bands correlate well with calculations based on 1 nm resolution observations above 27 nm supplemented by broadband observations and a solar model in the 0-27 nm range. At Mars, we find that instrumental and orbital limitations to the identifications of photoelectron energy spectra in MGS/ER data preclude their use as a monitor of solar EUV and XUV variability. However, observations with higher temporal and energy resolution obtained at lower altitudes on Mars might allow the separation of the solar wind and ionospheric components of electron energy spectra so that they could be used as reliable monitors of variations in solar EUV and XUV irradiance than the time shifted, Earth-based, F10.7 index currently used.

  9. Correlations Between Variations in Solar EUV and Soft X-Ray Irradiance and Photoelectron Energy Spectra Observed on Mars and Earth

    Science.gov (United States)

    Peterson, W. K.; Brain, D. A.; Mitchell, D. L.; Bailey, S. M.; Chamberlin, P. C.

    2013-01-01

    Solar extreme ultraviolet (EUV; 10-120 nm) and soft X-ray (XUV; 0-10 nm) radiation are major heat sources for the Mars thermosphere as well as the primary source of ionization that creates the ionosphere. In investigations of Mars thermospheric chemistry and dynamics, solar irradiance models are used to account for variations in this radiation. Because of limited proxies, irradiance models do a poor job of tracking the significant variations in irradiance intensity in the EUV and XUV ranges over solar rotation time scales when the Mars-Sun-Earth angle is large. Recent results from Earth observations show that variations in photoelectron energy spectra are useful monitors of EUV and XUV irradiance variability. Here we investigate photoelectron energy spectra observed by the Mars Global Surveyor (MGS) Electron Reflectometer (ER) and the FAST satellite during the interval in 2005 when Earth, Mars, and the Sun were aligned. The Earth photoelectron data in selected bands correlate well with calculations based on 1 nm resolution observations above 27 nm supplemented by broadband observations and a solar model in the 0-27 nm range. At Mars, we find that instrumental and orbital limitations to the identifications of photoelectron energy spectra in MGS/ER data preclude their use as a monitor of solar EUV and XUV variability. However, observations with higher temporal and energy resolution obtained at lower altitudes on Mars might allow the separation of the solar wind and ionospheric components of electron energy spectra so that they could be used as reliable monitors of variations in solar EUV and XUV irradiance than the time shifted, Earth-based, F(10.7) index currently used.

  10. Local moments and electronic correlations in Fe-based Heusler alloys: Kα x-ray emission spectra measurements

    International Nuclear Information System (INIS)

    Svyazhin, Artem; Kurmaev, Ernst; Shreder, Elena; Shamin, Sergey; Sahle, Christoph J.

    2016-01-01

    Heusler alloys are a property-rich class of materials, intensively investigated today from both theoretical and real-world application points of view. In this paper, we attempt to shed light on the role of electronic correlations in the Fe_2MeAl group (where Me represents all 3d elements from Ti to Ni) of Heusler alloys. For this purpose, we have investigated the local moments of iron by means of the x-ray emission spectroscopy technique. To obtain numerical values of local moments, the Kα-FWHM method has been employed for the first time. In every compound of the group, the presence of a local moment on the Fe atom was detected. As has been revealed, the values of these moments are temperature-independent, pointing to an insufficiency of a pure itinerant approach to magnetism in these alloys. We also comprehensively compare the usage of Kβ main lines and Kα spectra as tools for the probing of local moments and point out the significant advantages of the latter. - Highlights: • Local spin moments of iron in Fe_2MeAl (Me = Ti … Ni) Heusler alloys were investigated by means of x-ray emission spectroscopy. • Independence of the local moments from temperature confirms their localized nature. • A local moment value of iron in Fe_2MeAl raises with the atomic number of element Me. • The applicability of the Kα x-ray emission line for extracting local moment values of 3d elements was established.

  11. Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra

    OpenAIRE

    Takegami, Kazuki ; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi ; Maehata, Itsumi ; Kanazawa, Yuki ; Okazaki, Tohru ; Hashizume, Takuya ; Kobayashi, Ikuo 

    2016-01-01

    Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1–20 cm), and a CdTe X...

  12. Spatially resolved x-ray laser spectra and demonstration of gain in nickel-like systems

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, D.A.; Keane, C.J.; MacGowan, B.J.; Matthews, D.L.; Trebes, J.E.; Eckart, M.J.

    1987-09-25

    A recent series of experiments have provided spatially resolved near field images of several candidate x-ray lasing transition in neon-like, nickel-like, and hydrogen-like ions from laser-produced plasmas. From these time-gated, spatially, and spectrally resolved measurements the source size for the J = 0 - 1 and the J = 2 - 1 transitions in Ne-like selenium have been determined. Source regions as small as 50 ..mu..m have been observed on transitions with gain-length products >9. In addition, we have obtained the first experimental evidence for the amplification of spontaneous emission in the nickel-like ions of europium and ytterbium. Gains of order 1 cm/sup -1/ and gain-length products of up to 3.8 are observed on the J = 0 - 1, 4d-4p transitions in Eu + 35 at 65.26 and 71.00 A. Analogous transitions in Yb = +42 have been identified and some evidence for ASE has been observed. 7 refs., 11 figs.

  13. Spatially resolved X-ray laser spectra and demonstration of gain in nickel-like systems

    International Nuclear Information System (INIS)

    Whelan, D.A.; Keane, C.J.; MacGowan, B.J.; Matthews, D.L.; Trebes, J.E.; Eckart, M.J.

    1987-01-01

    A recent series of experiments have provided spatially resolved near field images of several candidate x-ray lasing transition in neon-like, nickel-like, and hydrogen-like ions from laser-produced plasmas. From these time-gated, spatially, and spectrally resolved measurements the source size for the J=0-1 and the J=2-1 transitions in Ne-like selenium have been determined. Source regions as small as 50 μm have been observed on transitions with gain-length products >9. In addition, the authors have obtained the first experimental evidence for the amplification of spontaneous emission in the nickel-like ions of europium and ytterbium. Gains of order 1 cm/sup -1/ and gain-length products of up to 3.8 are observed on the J=0-1,4d-4p transitions in Eu/sup +35/ at 65.83 and 71.00A. Analogous transitions in Yb/sup +42/ have been identified and some evidence for ASE has been observed

  14. XMM-Newton Survey of Local O VII Absorption Lines in the Spectra of Galactic X-Ray Sources

    Science.gov (United States)

    Luo, Yang; Fang, Taotao; Ma, Renyi

    2018-04-01

    The detection of highly ionized metal absorption lines in the X-ray spectra of the Galactic X-ray binaries (XRBs) implies the distribution of hot gas along the sightline toward the background sources. However, the origin of this hot gas is still unclear: it can arise in the hot interstellar medium (ISM), or is intrinsic to the XRBs. In this paper, we present an XMM-Newton survey of the O VII absorption lines in the spectra of Galactic XRBs. A total of 33 XRBs were selected, with 29 low-mass XRBs and 4 high-mass XRBs. At a more than 3σ threshold, O VII absorption line was detected in 16 targets, among which 4 were newly discovered in this work. The average line equivalent width is centered around ∼20 mÅ. Additionally, we do not find strong correlations between the O VII EWs and the Galactic neutral absorption N H, the Galactic coordinates, or the distance of background targets. Such non-correlation may suggest contamination of the circumstellar material, or a lack of constraints on the line Doppler-b parameter. We also find that regardless of the direction of the XRBs, the O VII absorption lines are always detected when the flux of the background XRBs reaches a certain level, suggesting a uniform distribution of this hot gas. We estimate a ratio of 0.004–0.4 between the hot and neutral phases of the ISM. This is the second paper in the series following Fang et al. (2015), in which we focused on the local O VII absorption lines detected in the background AGN spectra. Detailed modeling of the hot ISM distribution will be investigated in a future paper.

  15. X-ray Reflected Spectra from Accretion Disk Models. III. A Complete Grid of Ionized Reflection Calculations

    Science.gov (United States)

    Garcia, J.; Dauser, T.; Reynolds, C. S.; Kallman, T. R.; McClintock, J. E.; Wilms, J.; Ekmann, W.

    2013-01-01

    We present a new and complete library of synthetic spectra for modeling the component of emission that is reflected from an illuminated accretion disk. The spectra were computed using an updated version of our code xillver that incorporates new routines and a richer atomic data base. We offer in the form of a table model an extensive grid of reflection models that cover a wide range of parameters. Each individual model is characterized by the photon index Gamma of the illuminating radiation, the ionization parameter zeta at the surface of the disk (i.e., the ratio of the X-ray flux to the gas density), and the iron abundance A(sub Fe) relative to the solar value. The ranges of the parameters covered are: 1.2 <= Gamma <= 3.4, 1 <= zeta <= 104, and 0.5 <= A(sub Fe) <= 10. These ranges capture the physical conditions typically inferred from observations of active galactic nuclei, and also stellar-mass black holes in the hard state. This library is intended for use when the thermal disk flux is faint compared to the incident power-law flux. The models are expected to provide an accurate description of the Fe K emission line, which is the crucial spectral feature used to measure black hole spin. A total of 720 reflection spectra are provided in a single FITS file suitable for the analysis of X-ray observations via the atable model in xspec. Detailed comparisons with previous reflection models illustrate the improvements incorporated in this version of xillver.

  16. The spectra of the standard x-ray qualities used in STUK's Radiation Metrology Laboratory

    International Nuclear Information System (INIS)

    Tapiovaara, T.; Tapiovaara, M.; Siiskonen, T.; Hakanen, A.

    2008-02-01

    This report presents the fluence spectra of the standard x-radiation qualities used in the Radiation Dosimetry Laboratory of Radiation and Nuclear Safety Authority (STUK). The spectra were measured in August 2007. The radiation qualities characterised in the report are the ISO Narrow spectrum series (ISO N10-N200, ISO 4037-1:1996) and both of the RQR-spectrum series specified by the IEC (IEC 1267:1994 and IEC 61267:2005). The measurements were made using a high purity Ge-detector and the measured pulse height spectra were corrected to fluence spectra. Spectral characteristics were computed from the spectral data and compared to the requirements in the standards and to the values given in the quality manual of the laboratory. (orig.)

  17. X-ray, MP2 and DFT studies of the structure and vibrational spectra of trigonellinium chloride

    International Nuclear Information System (INIS)

    Szafran, M.; Koput, J.; Dega-Szafran, Z.; Katrusiak, A.; Pankowski, M.; Stobiecka, K.

    2003-01-01

    The effects of hydrogen bonding, inter- and intramolecular electrostatic interactions on the conformation of trigonellinium chloride, TRGH...Cl, in the crystal and on that of a single molecule have been studied by X-ray diffraction, FT-IR, Raman, 1 H and 13 C NMR spectroscopies, and by MP2 and DFT calculations. In the crystal, the Cl - anion is connected with protonated trigonelline via hydrogen bond, O-H...Cl - =2.915(3) Angst, and three N + ...Cl - intermolecular electrostatic interactions. In a single molecule, the Cl - anion is also engaged in a slightly longer hydrogen bond, O-H...Cl - =2.948-3.019 Angst, but only in one type of intramolecular electrostatic interaction. The optimized bond lengths and bond angles at the MP2 and B3LYP levels of theory are in good agreement with the X-ray data, except conformation of the COOH group, which is cis (syn) in the crystal and trans (anti) in the single molecule. The probable assignments for the experimental solid state vibrational spectra of TRGH.Cl and TRGD.Cl based on the calculated MP2/cc-pVDZ frequencies and intensities were made. The effect of quaternization of nicotinic acid, its salt and amide on chemical shifts of the ring protons and carbons is analyzed

  18. Calculation of Absorbed Glandular Dose using a FORTRAN Program Based on Monte Carlo X-ray Spectra in Mammography

    Directory of Open Access Journals (Sweden)

    Ali Asghar Mowlavi

    2011-03-01

    Full Text Available Introduction: Average glandular dose calculation in mammography with Mo-Rh target-filter and dose calculation for different situations is accurate and fast. Material and Methods: In this research, first of all, x-ray spectra of a Mo target bombarded by a 28 keV electron beam with and without a Rh filter were calculated using the MCNP code. Then, we used the Sobol-Wu parameters to write a FORTRAN code to calculate average glandular dose. Results: Average glandular dose variation was calculated against the voltage of the mammographic x-ray tube for d = 5 cm, HVL= 0.35 mm Al, and different value of g. Also, the results related to average glandular absorbed dose variation per unit roentgen radiation against the glandular fraction of breast tissue for kV = 28 and HVL = 0.400 mmAl and different values of d are presented. Finally, average glandular dose against d for g = 60% and three values of kV (23, 27, 35 kV with corresponding HVLs have been calculated. Discussion and Conclusion: The absorbed dose computational program is accurate, complete, fast and user friendly. This program can be used for optimization of exposure dose in mammography. Also, the results of this research are in good agreement with the computational results of others.

  19. Broadband x-ray properties of the gamma-ray binary 1FGL J1018.6-5856

    DEFF Research Database (Denmark)

    An, Hongjun; Bellm, Eric; Bhalerao, Varun

    2015-01-01

    -ray study of An et al. using ~400 days of Swift data, but is consistent with a new gamma-ray solution reported in 2014. The light curve folded on the new period is qualitatively similar to that reported previously, having a spike at phase 0 and broad sinusoidal modulation. The X-ray flux enhancement...

  20. Accurate quasiparticle calculation of x-ray photoelectron spectra of solids.

    Science.gov (United States)

    Aoki, Tsubasa; Ohno, Kaoru

    2018-05-31

    It has been highly desired to provide an accurate and reliable method to calculate core electron binding energies (CEBEs) of crystals and to understand the final state screening effect on a core hole in high resolution x-ray photoelectron spectroscopy (XPS), because the ΔSCF method cannot be simply used for bulk systems. We propose to use the quasiparticle calculation based on many-body perturbation theory for this problem. In this study, CEBEs of band-gapped crystals, silicon, diamond, β-SiC, BN, and AlP, are investigated by means of the GW approximation (GWA) using the full ω integration and compared with the preexisting XPS data. The screening effect on a deep core hole is also investigated in detail by evaluating the relaxation energy (RE) from the core and valence contributions separately. Calculated results show that not only the valence electrons but also the core electrons have an important contribution to the RE, and the GWA have a tendency to underestimate CEBEs due to the excess RE. This underestimation can be improved by introducing the self-screening correction to the GWA. The resulting C1s, B1s, N1s, Si2p, and Al2p CEBEs are in excellent agreement with the experiments within 1 eV absolute error range. The present self-screening corrected GW approach has the capability to achieve the highly accurate prediction of CEBEs without any empirical parameter for band-gapped crystals, and provide a more reliable theoretical approach than the conventional ΔSCF-DFT method.

  1. Accurate quasiparticle calculation of x-ray photoelectron spectra of solids

    Science.gov (United States)

    Aoki, Tsubasa; Ohno, Kaoru

    2018-05-01

    It has been highly desired to provide an accurate and reliable method to calculate core electron binding energies (CEBEs) of crystals and to understand the final state screening effect on a core hole in high resolution x-ray photoelectron spectroscopy (XPS), because the ΔSCF method cannot be simply used for bulk systems. We propose to use the quasiparticle calculation based on many-body perturbation theory for this problem. In this study, CEBEs of band-gapped crystals, silicon, diamond, β-SiC, BN, and AlP, are investigated by means of the GW approximation (GWA) using the full ω integration and compared with the preexisting XPS data. The screening effect on a deep core hole is also investigated in detail by evaluating the relaxation energy (RE) from the core and valence contributions separately. Calculated results show that not only the valence electrons but also the core electrons have an important contribution to the RE, and the GWA have a tendency to underestimate CEBEs due to the excess RE. This underestimation can be improved by introducing the self-screening correction to the GWA. The resulting C1s, B1s, N1s, Si2p, and Al2p CEBEs are in excellent agreement with the experiments within 1 eV absolute error range. The present self-screening corrected GW approach has the capability to achieve the highly accurate prediction of CEBEs without any empirical parameter for band-gapped crystals, and provide a more reliable theoretical approach than the conventional ΔSCF-DFT method.

  2. Dynamical correlation effects in a weakly correlated material: Inelastic x-ray scattering and photoemission spectra of beryllium

    Science.gov (United States)

    Seidu, Azimatu; Marini, Andrea; Gatti, Matteo

    2018-03-01

    Beryllium is a weakly correlated simple metal. Still we find that dynamical correlation effects, beyond the independent-particle picture, are necessary to successfully interpret the electronic spectra measured by inelastic x-ray scattering (IXS) and photoemission spectroscopies (PES). By combining ab initio time-dependent density-functional theory (TDDFT) and many-body Green's function theory in the G W approximation (G W A ), we calculate the dynamic structure factor, the quasiparticle (QP) properties and PES spectra of bulk Be. We show that band-structure effects (i.e., due to interaction with the crystal potential) and QP lifetimes (LT) are both needed in order to explain the origin of the measured double-peak features in the IXS spectra. A quantitative agreement with experiment is obtained only when LT are supplemented to the adiabatic local-density approximation (ALDA) of TDDFT. Besides the valence band, PES spectra display a satellite, a signature of dynamical correlation due to the coupling of QPs and plasmons, which we are able to reproduce thanks to the combination of the G W A for the self-energy with the cumulant expansion of the Green's function.

  3. A Monte Carlo study of the energy spectra and transmission characteristics of scattered radiation from x-ray computed tomography.

    Science.gov (United States)

    Platten, David John

    2014-06-01

    Existing data used to calculate the barrier transmission of scattered radiation from computed tomography (CT) are based on primary beam CT energy spectra. This study uses the EGSnrc Monte Carlo system and Epp user code to determine the energy spectra of CT scatter from four different primary CT beams passing through an ICRP 110 male reference phantom. Each scatter spectrum was used as a broad-beam x-ray source in transmission simulations through seventeen thicknesses of lead (0.00-3.50 mm). A fit of transmission data to lead thickness was performed to obtain α, β and γ parameters for each spectrum. The mean energy of the scatter spectra were up to 12.3 keV lower than that of the primary spectrum. For 120 kVp scatter beams the transmission through lead was at least 50% less than predicted by existing data for thicknesses of 1.5 mm and greater; at least 30% less transmission was seen for 140 kVp scatter beams. This work has shown that the mean energy and half-value layer of CT scatter spectra are lower than those of the corresponding primary beam. The transmission of CT scatter radiation through lead is lower than that calculated with currently available data. Using the data from this work will result in less lead shielding being required for CT scanner installations.

  4. Cost and sensitivity of restricted active-space calculations of metal L-edge X-ray absorption spectra.

    Science.gov (United States)

    Pinjari, Rahul V; Delcey, Mickaël G; Guo, Meiyuan; Odelius, Michael; Lundberg, Marcus

    2016-02-15

    The restricted active-space (RAS) approach can accurately simulate metal L-edge X-ray absorption spectra of first-row transition metal complexes without the use of any fitting parameters. These characteristics provide a unique capability to identify unknown chemical species and to analyze their electronic structure. To find the best balance between cost and accuracy, the sensitivity of the simulated spectra with respect to the method variables has been tested for two models, [FeCl6 ](3-) and [Fe(CN)6 ](3-) . For these systems, the reference calculations give deviations, when compared with experiment, of ≤1 eV in peak positions, ≤30% for the relative intensity of major peaks, and ≤50% for minor peaks. When compared with these deviations, the simulated spectra are sensitive to the number of final states, the inclusion of dynamical correlation, and the ionization potential electron affinity shift, in addition to the selection of the active space. The spectra are less sensitive to the quality of the basis set and even a double-ζ basis gives reasonable results. The inclusion of dynamical correlation through second-order perturbation theory can be done efficiently using the state-specific formalism without correlating the core orbitals. Although these observations are not directly transferable to other systems, they can, together with a cost analysis, aid in the design of RAS models and help to extend the use of this powerful approach to a wider range of transition metal systems. © 2015 Wiley Periodicals, Inc.

  5. Understanding reliability and some limitations of the images and spectra reconstructed from a multi-monochromatic x-ray imager

    Science.gov (United States)

    Nagayama, T.; Mancini, R. C.; Mayes, D.; Tommasini, R.; Florido, R.

    2015-11-01

    Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multi-monochromatic x-ray imager (MMI) is an attractive diagnostic for this purpose. The MMI records the spectral signature from an ICF implosion core with time resolution, 2-D space resolution, and spectral resolution. While narrow-band images and 2-D space-resolved spectra from the MMI data constrain temperature and density spatial structure of the core, the accuracy of the images and spectra depends not only on the quality of the MMI data but also on the reliability of the post-processing tools. Here, we synthetically quantify the accuracy of images and spectra reconstructed from MMI data. Errors in the reconstructed images are less than a few percent when the space-resolution effect is applied to the modeled images. The errors in the reconstructed 2-D space-resolved spectra are also less than a few percent except those for the peripheral regions. Spectra reconstructed for the peripheral regions have slightly but systematically lower intensities by ˜6% due to the instrumental spatial-resolution effects. However, this does not alter the relative line ratios and widths and thus does not affect the temperature and density diagnostics. We also investigate the impact of the pinhole size variation on the extracted images and spectra. A 10% pinhole size variation could introduce spatial bias to the images and spectra of ˜10%. A correction algorithm is developed, and it successfully reduces the errors to a few percent. It is desirable to perform similar synthetic investigations to fully understand the reliability and limitations of each MMI application.

  6. Understanding reliability and some limitations of the images and spectra reconstructed from a multi-monochromatic x-ray imager

    International Nuclear Information System (INIS)

    Nagayama, T.; Mancini, R. C.; Mayes, D.; Tommasini, R.; Florido, R.

    2015-01-01

    Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multi-monochromatic x-ray imager (MMI) is an attractive diagnostic for this purpose. The MMI records the spectral signature from an ICF implosion core with time resolution, 2-D space resolution, and spectral resolution. While narrow-band images and 2-D space-resolved spectra from the MMI data constrain temperature and density spatial structure of the core, the accuracy of the images and spectra depends not only on the quality of the MMI data but also on the reliability of the post-processing tools. Here, we synthetically quantify the accuracy of images and spectra reconstructed from MMI data. Errors in the reconstructed images are less than a few percent when the space-resolution effect is applied to the modeled images. The errors in the reconstructed 2-D space-resolved spectra are also less than a few percent except those for the peripheral regions. Spectra reconstructed for the peripheral regions have slightly but systematically lower intensities by ∼6% due to the instrumental spatial-resolution effects. However, this does not alter the relative line ratios and widths and thus does not affect the temperature and density diagnostics. We also investigate the impact of the pinhole size variation on the extracted images and spectra. A 10% pinhole size variation could introduce spatial bias to the images and spectra of ∼10%. A correction algorithm is developed, and it successfully reduces the errors to a few percent. It is desirable to perform similar synthetic investigations to fully understand the reliability and limitations of each MMI application

  7. Understanding reliability and some limitations of the images and spectra reconstructed from a multi-monochromatic x-ray imager.

    Science.gov (United States)

    Nagayama, T; Mancini, R C; Mayes, D; Tommasini, R; Florido, R

    2015-11-01

    Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multi-monochromatic x-ray imager (MMI) is an attractive diagnostic for this purpose. The MMI records the spectral signature from an ICF implosion core with time resolution, 2-D space resolution, and spectral resolution. While narrow-band images and 2-D space-resolved spectra from the MMI data constrain temperature and density spatial structure of the core, the accuracy of the images and spectra depends not only on the quality of the MMI data but also on the reliability of the post-processing tools. Here, we synthetically quantify the accuracy of images and spectra reconstructed from MMI data. Errors in the reconstructed images are less than a few percent when the space-resolution effect is applied to the modeled images. The errors in the reconstructed 2-D space-resolved spectra are also less than a few percent except those for the peripheral regions. Spectra reconstructed for the peripheral regions have slightly but systematically lower intensities by ∼6% due to the instrumental spatial-resolution effects. However, this does not alter the relative line ratios and widths and thus does not affect the temperature and density diagnostics. We also investigate the impact of the pinhole size variation on the extracted images and spectra. A 10% pinhole size variation could introduce spatial bias to the images and spectra of ∼10%. A correction algorithm is developed, and it successfully reduces the errors to a few percent. It is desirable to perform similar synthetic investigations to fully understand the reliability and limitations of each MMI application.

  8. DMSO-Water Clustering in Solution Observed in Soft X-ray Spectra.

    Science.gov (United States)

    Engel, Nicholas; Atak, Kaan; Lange, Kathrin M; Gotz, Malte; Soldatov, Mikhail; Golnak, Ronny; Suljoti, Edlira; Rubensson, Jan-Erik; Aziz, Emad F

    2012-12-20

    The significant deviation from the ideality of dimethyl sulfoxide (DMSO)/water mixtures can be addressed based on the change of the local molecular orbitals of each solvent upon mixing. Oxygen K-edge absorption and emission spectra of DMSO/water solutions were measured using the liquid microjet technique. The spectra demonstrate that the hydrogen bond network in liquid water is already influenced at small DMSO concentrations, and at the molar fraction xDMSO = 0.43 we find strong evidence of DMSO-water clustering reflected by the influence on the occupied molecular orbitals.

  9. On the Weak-Wind Problem in Massive Stars: X-Ray Spectra Reveal a Massive Hot Wind in mu Columbae

    Science.gov (United States)

    Huenemoerder, David P.; Oskinova, Lidia M.; Ignace, Richard; Waldron, Wayne L.; Todt, Helge; Hamaguchi, Kenji; Kitamoto, Shunji

    2012-01-01

    Mu Columbae is a prototypical weak-wind O star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS instrument and a low-resolution spectrum with Suzaku. This allows us, for the first time, to investigate the role of X-rays on the wind structure in a bona fide weak-wind system and to determine whether there actually is a massive hot wind. The X-ray emission measure indicates that the outflow is an order of magnitude greater than that derived from UV lines and is commensurate with the nominal wind-luminosity relationship for O stars. Therefore, the "weak-wind problem"--identified from cool wind UV/optical spectra--is largely resolved by accounting for the hot wind seen in X-rays. From X-ray line profiles, Doppler shifts, and relative strengths, we find that this weak-wind star is typical of other late O dwarfs. The X-ray spectra do not suggest a magnetically confined plasma-the spectrum is soft and lines are broadened; Suzaku spectra confirm the lack of emission above 2 keV. Nor do the relative line shifts and widths suggest any wind decoupling by ions. The He-like triplets indicate that the bulk of the X-ray emission is formed rather close to the star, within five stellar radii. Our results challenge the idea that some OB stars are "weak-wind" stars that deviate from the standard wind-luminosity relationship. The wind is not weak, but it is hot and its bulk is only detectable in X-rays.

  10. The x-ray emission spectra of multicharged xenon ions in a gas puff laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Skobelev, I.Yu.; Dyakin, V.M.; Faenov, A.Ya. [Multicharged Ion Spectra Data Center, VNIIFTRI, Mendeleevo (Russian Federation); Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Warsaw (Poland); Biemont, E. [Institut de Physique Nucleaire Experimentale, Universite de Liege, Liege (Belgium); Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Quinet, P. [Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Nilsen, J. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Behar, E.; Doron, R.; Mandelbaum, P.; Schwob, J.L. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem (Israel)

    1999-01-14

    Emission spectra of multicharged xenon ions produced by a laser gas puff are observed with high spectral resolution in the 8.5-9.5 and 17-19 A wavelength ranges. Three different theoretical methods are employed to obtain 3l-n'l'(n' = 4 to 10) wavelengths and Einstein coefficients for Ni-like Xe{sup 26+}. For the 3d-4p transitions, very good agreement is found between the experimental wavelengths and the various theoretical wavelengths. These accurate energy level measurements can be useful for studying the Ni-like xenon x-ray laser scheme. On the other hand, several intense spectral lines could not be identified as 3l-n'l' lines of Ni-like xenon, despite the very good agreement between the wavelengths and Einstein coefficients calculated for these transitions using the three different methods. (author)

  11. Investigation of the antiprotonic X-ray spectra of the isotopes 6Li, 7Li and 40Ca

    International Nuclear Information System (INIS)

    Barth, H.

    1987-04-01

    With the commissioning of the Low-Energy Antiproton Ring (LEAR) at CERN in Geneva a high intensity, high purity antiproton beam became available, enabling precision measurements of antiprotonic X-ray spectra to be carried out. Besides informations about properties of the elementary particle antiproton itself, as for example its mass and its magnetic moment, such measurements provide informations about the strong-interaction potential between antiproton and nucleus at very low energies, which, in turn, can be derived from the elementary antinucleon-nucleon interaction by using microscopic models. This work investigates the antiprotonic X-ray spectra of the isotopes 6 Li, 7 Li and 40 Ca. The data were taken during the experiment PS176 at LEAR. The strong interaction between antiproton and nucleus leads to an energy shift ε and an absorption width Γ of the lower level of the last observable transition and also to intensity reductions, which can be converted to an absorption width for the upper level. For the isotopes 6 Li, 7 Li and 40 Ca the following results were obtained: 6 Li: ε(2p)=(-215±25) eV, Γ(2p)=(660±170) eV and Γ(3d)=(135±16) meV, 7 Li ε(2p)=(-265±20) eV, Γ(2p)=(690±170) eV and Γ(3d)=(129±13) meV, 40 Ca: ε(4f)=(-1060±130) eV, Γ(4f)=(3670±600) eV and Γ(5g)=(34.9±3.3) eV. The results are in fair agreement with theoretical calculations, at the same time showing up the limits of present understanding of antiproton-nucleus interaction. Particularly the spin-orbit part of the strong interaction seems to play a nonnegligible role. (orig.) [de

  12. Soft X-Ray Spectra from High Current Nitrogen Z-Pinch Discharge

    Czech Academy of Sciences Publication Activity Database

    Vrba, Pavel; Vrbová, M.; Nevrkla, M.; Jančárek, A.

    2016-01-01

    Roč. 3, č. 1 (2016), s. 48 ISSN 2336-2626. [SPPT 2016 - 27th Symposium on Plasma Physics and Technology/27./. Prague, 20.06.2016-23.06.2016] Institutional support: RVO:61389021 Keywords : Capillary discharge * recombination pumping * pinch dynamics * evolution of spectra emission * computer modelling Subject RIV: BH - Optics, Masers, Lasers www.plasmaconference.cz

  13. The 5 Hour Pulse Period and Broadband Spectrum of the Symbiotic X-Ray Binary 3A 1954+319

    Science.gov (United States)

    Marcu, Diana M.; Fuerst, Felix; Pottschmidt, Katja; Grinberg, Victoria; Miller, Sebstian; Wilms, Joern; Postnov, Konstantin A.; Corbet, Robin H. D.; Markwardt, Craig B.; Cadolle Bel, Marion

    2011-01-01

    We present an analysis of the highly variable accreting X-ray pulsar 3A 1954+319 using 2005-2009 monitoring data obtained with INTEGRAL and Swift. This considerably extends the pulse period history and covers flaring episodes in 2005 and 2008. In 2006 the source was identified as one of only a few known symbiotic X-ray binaries, Le" systems composed of a neutron star accreting from the inhomogeneous medium around an M-giant star. The extremely long pulse period of approximately 5.3 h is directly visible in the 2008 INTEGRAL-ISGRI outburst light curve. The pulse profile is double peaked and not significantly energy dependent. During the outburst a strong spin-up of -1.8 x 10(exp -4) h h(exp -1) occurred. Between 2005 and 2008 a long term spin-down trend of 2.1 x 10(exp -5) h h(exp -1) was observed for the first time for this source. The 3-80 keV pulse peak spectrum of 3A 1954+319 during the 2008 flare could be well described by a thermal Comptonization model. We interpret the results within the framework of a recently developed quasi-spherical accretion model for symbiotic X-ray binaries.

  14. Conformation and orientation effects in the x-ray photoelectron spectra of organic polymers

    International Nuclear Information System (INIS)

    Beamson, G.

    2001-01-01

    Conformation and orientation effects in the XPS spectra of organic polymers are small but can be observed with modem high performance equipment. This paper discusses some of the experimental factors that should be considered when attempting to detect such effects, and describes several recent studies which illustrate the subtle phenomena that can now be observed. Conformation effects, revealed by melting semicrystalline polymer samples in the analysis chamber of an XPS spectrometer, are reported for the valence band and C 1s spectra of nylon 12 and poly(ethylene adipate), and for the valence band spectrum of poly(ethylene succinate). For nylon 12 the changes in the C 2s region of the valence band spectrum are interpreted in terms of disordering of the planar zig-zag conformation of the (CH 2 ) 11 segments of the polymer chain. Pendant group surface orientation effects, detected by angle resolved XPS (with emission angles as low as 5 deg. relative to the sample surface), are reported for poly(2-chloroethyl methacrylate) (PCEMA), poly(lauryl methacrylate) (PLMA) and poly(2-hydroxyethyl methacrylate) (PHEMA). For PCEMA and PLMA the uppermost surfaces are enriched with -CH 2 CH 2 Cl and -(CH 2 ) 11 CH 3 pendant groups respectively, whereas for PHEMA the data suggest relatively few -CH 2 CH 2 OH pendant groups at the surface. The C 1s and Cl 2p spectra of PCEMA reveal surface core level binding energy shifts of - +0.2 eV, and the Cl L 23 M 23 M 23 spectrum a surface Auger kinetic energy shift of ∼ -0.6. The C 1s spectra of PLMA and PHEMA also reveal surface core level shifts and for PLMA this is interpreted in terms of a disordered and open arrangement of the -(CH 2 ) 11 CH 3 pendant groups at the polymer surface. (author)

  15. Evaluation of transmitted spectra of megavoltage X rays through concrete using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Cordeiro, Thaiana de Paula Vieira; Silva, Ademir Xavier da

    2010-01-01

    With the improvement of technology in radiotherapic centers, medical linear accelerators are largely replacing Cobalt-60 teletherapy units. In most of the cases, the same room that, before, was used to place a 60 Co teletherapy unit is reused to install, in replacement, a linear accelerator. When the room physical space can not be changed, high - density concrete is employed to provide shielding against the primary, scatter and leakage radiation. This work presents a study based on Monte Carlo simulations of transmission of some clinical photon spectra (of 10, 15 and 25 MV accelerators) through concrete of two different densities. Concrete walls of thickness 1.0, 1.5 and 2.0 m were irradiated with 30 cm x 30 cm primary beam spectra. The results show that the thickness of the barrier decreases up to approximately 35%, when barite (high - density concrete) is used instead of ordinary concrete. The average energies of primary and transmitted beam spectra were also calculated. (author)

  16. Evaluation of transmitted spectra of megavoltage X rays through concrete using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Cordeiro, Thaiana de Paula Vieira; Silva, Ademir Xavier da, E-mail: tcordeiro@con.ufrj.b, E-mail: Ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear

    2010-07-01

    With the improvement of technology in radiotherapic centers, medical linear accelerators are largely replacing Cobalt-60 teletherapy units. In most of the cases, the same room that, before, was used to place a {sup 60}Co teletherapy unit is reused to install, in replacement, a linear accelerator. When the room physical space can not be changed, high - density concrete is employed to provide shielding against the primary, scatter and leakage radiation. This work presents a study based on Monte Carlo simulations of transmission of some clinical photon spectra (of 10, 15 and 25 MV accelerators) through concrete of two different densities. Concrete walls of thickness 1.0, 1.5 and 2.0 m were irradiated with 30 cm x 30 cm primary beam spectra. The results show that the thickness of the barrier decreases up to approximately 35%, when barite (high - density concrete) is used instead of ordinary concrete. The average energies of primary and transmitted beam spectra were also calculated. (author)

  17. Application- and patient size-dependent optimization of x-ray spectra for CT

    International Nuclear Information System (INIS)

    Kalender, Willi A.; Deak, Paul; Kellermeier, Markus; Straten, Marcel van; Vollmar, Sabrina V.

    2009-01-01

    Although x-ray computed tomography (CT) has been in clinical use for over 3 decades, spectral optimization has not been a topic of great concern; high voltages around 120 kV have been in use since the beginning of CT. It is the purpose of this study to analyze, in a rigorous manner, the energies at which the patient dose necessary to provide a given contrast-to-noise ratio (CNR) for various diagnostic tasks can be minimized. The authors used cylindrical water phantoms and quasianthropomorphic phantoms of the thorax and the abdomen with inserts of 13 mm diameter mimicking soft tissue, bone, and iodine for simulations and measurements. To provide clearly defined contrasts, these inserts were made of solid water with a 1% difference in density (DD) to represent an energy-independent soft-tissue contrast of 10 Hounsfield units (HU), calcium hydroxyapatite (Ca) representing bone, and iodine (I) representing the typical contrast medium. To evaluate CT of the thorax, an adult thorax phantom (300x200 mm 2 ) plus extension rings up to a size of 460x300 mm 2 to mimic different patient cross sections were used. For CT of the abdomen, we used a phantom of 360x200 mm 2 and an extension ring of 460x300 mm 2 . The CT scanner that the authors used was a SOMATOM Definition (Siemens Healthcare, Forchheim, Germany) at 80, 100, 120, and 140 kV. Further voltage settings of 60, 75, 90, and 105 kV were available in an experimental mode. The authors determined contrast for the density difference, calcium, and iodine, and noise and 3D dose distributions for the available voltages by measurements. Additional voltage values and monoenergetic sources were evaluated by simulations. The dose-weighted contrast-to-noise ratio (CNRD) was used as the parameter for optimization. Simulations and measurements were in good agreement with respect to absolute values and trends regarding the dependence on energy for the parameters investigated. For soft-tissue imaging, the standard settings of 120-140 k

  18. Secondary electronic processes and the structure of X-ray photoelectron spectra of lanthanides in oxygen-containing compounds

    International Nuclear Information System (INIS)

    Teterin, Yu.A.; Teterin, A.Yu.; Lebedev, A.M.; Ivanov, K.E.

    2004-01-01

    X-ray photoelectron spectra of lanthanide compounds in the binding energy range 0-1250 eV beside the spin-orbitally split doublets exhibit fine structure. In particular, in the low-energy spectral range 0-50 eV such structure appears most likely due to the formation of the inner (IVMO) and outer (OVMO) valence molecular orbitals. The many-body perturbation shows up in the spectra of all the studied electronic shells but with different probabilities, while the multiplet splitting and dynamic effect in the spectra of just some inner shells. The present work studies the X-ray photoelectron spectral structure of lanthanide (La-Lu except for Pm) oxides and orthoniobates due to the secondary electronic processes accompanying the photoemission from the inner shells: many-body perturbation and dynamic effect. As a result, for example, the relative intensity of the line due to the many-body perturbation (shake-up process) with ΔE sat ∼4 eV for LaNbO 4 was found to decrease with decreasing of the binding energy of the inner electrons from 0.72 (E b for La 3d 5/2 =834.8 eV) to 0.28 (E b for La 4d 5/2 =102.9 eV). The full-width at half-maximum of the Ln 3d 5/2 line of lanthanide oxides and orthoniobates decreases as the atomic number Z of lanthanide grows in the range 58≤Z≤67 to the middle of the lanthanide row, and then increases. This agrees with the fact that for the beginning of the lanthanide row the Ln 3d 5/2 photoemission is accompanied by the shake-up process, while for the second half of the row--by the shake-down. It is important to note that it is connected with the Ln 4f binding energy change relative to the OVMO in compounds. The present work also confirms experimentally that the dynamic effect due to the gigantic Coster-Kronig transitions observed in the Ln 4p spectra takes place within the inner Ln 4p, 4d and outer Ln 4f shells with formation of the additional two-hole final state Ln 4p 6 4d 8 4f n+1 . The influence of the chemical environment on the Ln 4

  19. Accounting for nanometer-thick adventitious carbon contamination in X-ray absorption spectra of carbon-based materials.

    Science.gov (United States)

    Mangolini, Filippo; McClimon, J Brandon; Rose, Franck; Carpick, Robert W

    2014-12-16

    Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometer-scale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photoabsorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp(2)-hybridized carbon from 5 to 20% and reveals that the adventitious contamination can be described as a layer containing carbon and oxygen ([O]/[C] = 0.11 ± 0.02) with a thickness of 0.6 ± 0.2 nm and a fraction of sp(2)-bonded carbon of 0.19 ± 0.03. This

  20. DXRaySMCS. First user friendly interface developed for prediction of diagnostic radiology X-ray spectra produced by Monte Carlo (MCNP-4C) simulation in Iran

    International Nuclear Information System (INIS)

    Bahreyni Toossi, M.T.; Zare, H.; Moradi Faradanbe, H.

    2008-01-01

    An accurate knowledge of the output energy spectra of an x-ray tube is essential in many areas of radiological studies. It forms the basis of almost all image quality simulations and enable system designers to predict patient dose more accurately. Many radiological physics problems that can be solved by Monte Carlo simulation methods require an x-ray spectra as input data. Computer simulation of x-ray spectra is one of the most important tools for investigation of patient dose and image quality in diagnostic radiology systems. In this work the general purpose Monte Carlo N-particle radiation transport computer code (MCNP-4C) was used for the simulation of x-ray spectra in diagnostic radiology, Electron's path in the target was followed until it's energy was reduced to 10 keV. A user friendly interface named 'Diagnostic X-ray Spectra by Monte Carlo Simulation (DXRaySMCS)' was developed to facilitate the application of MCNP-4C code for diagnostic radiology spectrum prediction. The program provides a user friendly interface for modifying the MCNP input file, launching the MCNP program to simulate electron and photon transport and processing the MCNP output file to yield a summary of the results (Relative Photon Number per Energy Bin). In this article the development and characteristics of DXRaySMCS are outlined. As part of the validation process, out put spectra for 46 diagnostic radiology system settings produced by DXRaySMCS were compared with the corresponding IPEM78. Generally, there is a good agreement between the two sets of spectra. No statistically significant differences have been observed between IPEM78 reported spectra and the simulated spectra generated in this study. (author)

  1. Precise material identification method based on a photon counting technique with correction of the beam hardening effect in X-ray spectra

    International Nuclear Information System (INIS)

    Kimoto, Natsumi; Hayashi, Hiroaki; Asahara, Takashi; Mihara, Yoshiki; Kanazawa, Yuki; Yamakawa, Tsutomu; Yamamoto, Shuichiro; Yamasaki, Masashi; Okada, Masahiro

    2017-01-01

    The aim of our study is to develop a novel material identification method based on a photon counting technique, in which the incident and penetrating X-ray spectra are analyzed. Dividing a 40 kV X-ray spectra into two energy regions, the corresponding linear attenuation coefficients are derived. We can identify the materials precisely using the relationship between atomic number and linear attenuation coefficient through the correction of the beam hardening effect of the X-ray spectra. - Highlights: • We propose a precise material identification method to be used as a photon counting system. • Beam hardening correction is important, even when the analysis is applied to the short energy regions in the X-ray spectrum. • Experiments using a single probe-type CdTe detector were performed, and Monte Carlo simulation was also carried out. • We described the applicability of our method for clinical diagnostic X-ray imaging in the near future.

  2. THE EFFECT OF BROADBAND SOFT X-RAYS IN SO{sub 2}-CONTAINING ICES: IMPLICATIONS ON THE PHOTOCHEMISTRY OF ICES TOWARD YOUNG STELLAR OBJECTS

    Energy Technology Data Exchange (ETDEWEB)

    Pilling, S.; Bergantini, A., E-mail: sergiopilling@pq.cnpq.br [Universidade do Vale do Paraíba (UNIVAP), Laboratório de Astroquímica e Astrobiologia (LASA), São José dos Campos, SP (Brazil)

    2015-10-01

    We investigate the effects produced mainly by broadband soft X-rays up to 2 keV (plus fast (∼keV) photoelectrons and low-energy (∼eV) induced secondary electrons) in the ice mixtures containing H{sub 2}O:CO{sub 2}:NH{sub 3}:SO{sub 2} (10:1:1:1) at two different temperatures (50 and 90 K). The experiments are an attempt to simulate the photochemical processes induced by energetic photons in SO{sub 2}-containing ices present in cold environments in the ices surrounding young stellar objects (YSO) and in molecular clouds in the vicinity of star-forming regions, which are largely illuminated by soft X-rays. The measurements were performed using a high-vacuum portable chamber from the Laboratório de Astroquímica e Astrobiologia (LASA/UNIVAP) coupled to the spherical grating monochromator beamline at the Brazilian Synchrotron Light Source (LNLS) in Campinas, Brazil. In situ analyses were performed by a Fourier transform infrared spectrometer. Sample processing revealed the formation of several organic molecules, including nitriles, acids, and other compounds such as H{sub 2}O{sub 2}, H{sub 3}O{sup +}, SO{sub 3}, CO, and OCN{sup −}. The dissociation cross section of parental species was on the order of (2–7) × 10{sup −18} cm{sup 2}. The ice temperature does not seem to affect the stability of SO{sub 2} in the presence of X-rays. Formation cross sections of new species  produced were also determined. Molecular half-lives at ices toward YSOs due to the presence of incoming soft X-rays were estimated. The low values obtained employing two different models of the radiation field of YSOs (TW Hydra and typical T-Tauri star) reinforce that soft X-rays are indeed a very efficient source of molecular dissociation in such environments.

  3. The broad-band X-ray spectrum of IC 4329A from a joint NuSTAR/Suzaku observation

    DEFF Research Database (Denmark)

    Brenneman, L. W.; Madejski, G.; Fuerst, F.

    2014-01-01

    We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku andNuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption, and distant reflection components in the spectrum. The absorbing column is found...... also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than justNuSTAR alone: Ecut = 186±14 keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate...

  4. Natural widths and Coster-Kronig transitions of L X-ray spectra in elements between Pd and Sb

    International Nuclear Information System (INIS)

    Sakakura, Shusuke; Oohashi, Hirofumi; Ito, Yoshiaki; Tochio, Tatsunori; Vlaicu, Aurel M.; Yoshikawa, Hideki; Ikenaga, Eiji; Kobayashi, Keisuke

    2006-01-01

    The Lα and Lβ X-ray emission spectra in the elements between Pd (Z=46) and Sb (Z=51) were measured using a high-resolution double-crystal vacuum spectrometer. The relative intensities of satellite structures, which originate in L 1 L 3 M 4,5 Coster-Kronig transitions, were estimated to that of each diagram line, and compared with calculated values. According to the work of Chen et al. [1977a. Theoretical L-shell Coster-Kronig energies 11≤Z≤103. At. Data Nucl. Data Tables 19, 97-151], Salgueiro et al. [1987. J. Phys. (Paris) 48 Colloq. C9, 609] and Vlaicu et al. [1998. Investigation of the 74W L emission spectra and satellites. Phys. Rev. A 58, 3544] L 1 L 3 M 4 Coster-Kronig transition is forbidden for 50≤Z≤77, and L 1 L 3 M 5 Coster-Kronig transition is forbidden for 50≤Z≤73. The results suggest that L 1 L 3 M 4,5 Coster-Kronig transitions may be allowed even for Sn (Z=50) and Sb (Z=51)

  5. Use of X-Ray Absorption Spectra as a ``Fingerprint'' of the Local Environment in Complex Chalcogenides

    Science.gov (United States)

    Branci, C.; Womes, M.; Lippens, P. E.; Olivier-Fourcade, J.; Jumas, J. C.

    2000-03-01

    The local environment of tin, titanium, iron, and sulfur in spinel compounds Cu2FeSn3S8 and Cu2FeTi3S8 was studied by X-ray absorption spectroscopy (XAS) at the titanium, iron, sulfur K edges, and the tin LI-edge. As detailed calculations of the electronic structure of these compounds are difficult to carry out due to the large number of atoms contained in the unit cell, the XAS spectra of the spinels are compared to those of relatively simple binary sulfides like SnS2, TiS2, and FeS. Indeed, the metal environments in these binary compounds are very similar to those in the spinels, and they can be considered good model compounds allowing the interpretation of electronic transitions observed in the spectra of quaternary phases. In the latter, the bottom of the conduction band is mainly formed by Sn 5s-S 3p, Sn 5p-S 3p antibonding states for the tin-based compounds and by Ti 3dt2g-S 3p, Ti 3deg-S 3p antibonding states for the titanium-based compounds. It it shown that the local environment of iron atoms remains unchanged when substituting tin with titanium atoms, according to a topotactic substitution.

  6. Measurement of characteristic to total spectrum ratio of tungsten X-ray spectra for the validation of the modified Tbc model

    International Nuclear Information System (INIS)

    Lopez G, A. H.; Costa, P. R.; Tomal, A.

    2014-08-01

    Primary X-ray spectra were measured in the range of 80 to 150 kV in order to validate a computer program based on a semiempirical model for X-ray spectra evaluation(tbc and mod). The ratio between the characteristic lines and total spectrum was considered for comparing the simulated results and experimental data. The raw spectra measured by the Cd Te detector were corrected by the detector efficiency, Compton effects and characteristic Cd and Te X-rays escape peaks, using a software specifically developed. The software Origin 8.5.1 was used to calculate the spectra and characteristic peaks areas. The obtained result shows that the experimental spectra have higher effective energy than the simulated spectra computed with tbc and mod software. The behavior of the ratio between the characteristic lines and total spectrum for simulated data presents discrepancy with the experimental result. Computed results are in good agreement with theoretical data published by Green, for spectra obtained with 3.04 mm of additional aluminum filtration. The difference of characteristic to total spectrum ratio between experimental and simulated data increases with the tube voltage. (Author)

  7. Measurement of characteristic to total spectrum ratio of tungsten X-ray spectra for the validation of the modified Tbc model

    Energy Technology Data Exchange (ETDEWEB)

    Lopez G, A. H.; Costa, P. R. [University of Sao Paulo, Institute of Physics, Laboratory of Radiation Dosimetry and Medical Physics, Matao Street, alley R, 187, 66318 Sao Paulo (Brazil); Tomal, A., E-mail: ahlopezg@usp.br [Universidade Federal de Goias, Physics Institute, Campus Samambaia, 131 Goiania, Goias (Brazil)

    2014-08-15

    Primary X-ray spectra were measured in the range of 80 to 150 kV in order to validate a computer program based on a semiempirical model for X-ray spectra evaluation(tbc and mod). The ratio between the characteristic lines and total spectrum was considered for comparing the simulated results and experimental data. The raw spectra measured by the Cd Te detector were corrected by the detector efficiency, Compton effects and characteristic Cd and Te X-rays escape peaks, using a software specifically developed. The software Origin 8.5.1 was used to calculate the spectra and characteristic peaks areas. The obtained result shows that the experimental spectra have higher effective energy than the simulated spectra computed with tbc and mod software. The behavior of the ratio between the characteristic lines and total spectrum for simulated data presents discrepancy with the experimental result. Computed results are in good agreement with theoretical data published by Green, for spectra obtained with 3.04 mm of additional aluminum filtration. The difference of characteristic to total spectrum ratio between experimental and simulated data increases with the tube voltage. (Author)

  8. X-ray photoelectron spectra and electronic structure of quasi-one-dimensional SbSeI crystals

    Directory of Open Access Journals (Sweden)

    J.Grigas

    2007-01-01

    Full Text Available The paper presents the X-ray photoelectron spectra (XPS of the valence band (VB and of the principal core levels from the (110 and (001 crystal surfaces for the quasi-one-dimensional high permittivity SbSeI single crystal isostructural to ferroelectric SbSI. The XPS were measured with monochromatized Al Ka radiation in the energy range of 0-1400 eV at room temperature. The VB is located from 1.6 to 20 eV below the Fermi level. Experimental energies of the VB and core levels are compared with the results of theoretical ab initio calculations of the molecular model of the SbSeI crystal. The electronic structure of the VB is revealed. Shifts in the core-level binding energies of surface atoms relative to bulk ones, which show a dependency on surface crystallography, have been observed. The chemical shifts of the core levels (CL in the SbSeI crystal for the Sb, I and Se states are obtained.

  9. X-ray emission spectra of the plasma produced by an ultrashort laser pulse in cluster targets

    International Nuclear Information System (INIS)

    Stenz, C; Bagnoud, V; Blasco, F; Roche, J R; Salin, F; Faenov, A Ya; Skobelev, I Yu; Magunov, A I; Pikuz, T A

    2000-01-01

    The first observation of x-ray emission spectra of multiply charged ions in the plasma produced by a 35-fs laser pulse with an intensity up to 10 17 W cm -2 in CO 2 and Kr gas jet targets is reported. The emission in the wavelength ranges of the 1snp-1s 2 (n=3-6) transitions of O VII ions and the Ly α line of O VIII ions, as well as of the (2s 1/2 2p 6 3p 3/2 ) 1 -2s 2 2p 6 1 S 0 and (2s 1/2 2p 6 3p 1/2 ) 1 -2s 2 2p 6 1 S 0 lines of Ne-like KrXXVII ions testifies that the highly ionised plasma is formed by collision processes in clusters. Modelling the shape of the spectral lines of oxygen ions by including the principal mechanisms of broadening and absorption in optically dense plasmas reveals that the main contribution to the time-integrated intensity is made by the plasma with the parameters N e =(2-20)x10 20 cm -3 and T e =100 - 115 eV. (interaction of laser radiation with matter. laser plasma)

  10. Application of an expectation maximization method to the reconstruction of X-ray-tube spectra from transmission data

    International Nuclear Information System (INIS)

    Endrizzi, M.; Delogu, P.; Oliva, P.

    2014-01-01

    An expectation maximization method is applied to the reconstruction of X-ray tube spectra from transmission measurements in the energy range 7–40 keV. A semiconductor single-photon counting detector, ionization chambers and a scintillator-based detector are used for the experimental measurement of the transmission. The number of iterations required to reach an approximate solution is estimated on the basis of the measurement error, according to the discrepancy principle. The effectiveness of the stopping rule is studied on simulated data and validated with experiments. The quality of the reconstruction depends on the information available on the source itself and the possibility to add this knowledge to the solution process is investigated. The method can produce good approximations provided that the amount of noise in the data can be estimated. - Highlights: • An expectation maximization method was used together with the discrepancy principle. • The discrepancy principle is a suitable criterion for stopping the iteration. • The method can be applied to a variety of detectors/experimental conditions. • The minimum information required is the amount of noise that affects the data. • Improved results are achieved by inserting more information when available

  11. Understanding Breaks in Flare X-Ray Spectra: Evaluation of a Cospatial Collisional Return-current Model

    Science.gov (United States)

    Alaoui, Meriem; Holman, Gordon D.

    2017-12-01

    Hard X-ray (HXR) spectral breaks are explained in terms of a one-dimensional model with a cospatial return current. We study 19 flares observed by the Ramaty High Energy Solar Spectroscopic Imager with strong spectral breaks at energies around a few deka-keV, which cannot be explained by isotropic albedo or non-uniform ionization alone. We identify these breaks at the HXR peak time, but we obtain 8 s cadence spectra of the entire impulsive phase. Electrons with an initially power-law distribution and a sharp low-energy cutoff lose energy through return-current losses until they reach the thick target, where they lose their remaining energy through collisions. Our main results are as follows. (1) The return-current collisional thick-target model provides acceptable fits for spectra with strong breaks. (2) Limits on the plasma resistivity are derived from the fitted potential drop and deduced electron-beam flux density, assuming the return current is a drift current in the ambient plasma. These resistivities are typically 2–3 orders of magnitude higher than the Spitzer resistivity at the fitted temperature, and provide a test for the adequacy of classical resistivity and the stability of the return current. (3) Using the upper limit of the low-energy cutoff, the return current is always stable to the generation of ion-acoustic and electrostatic ion-cyclotron instabilities when the electron temperature is nine times lower than the ion temperature. (4) In most cases, the return current is most likely primarily carried by runaway electrons from the tail of the thermal distribution rather than by the bulk drifting thermal electrons. For these cases, anomalous resistivity is not required.

  12. Simulations of iron K pre-edge X-ray absorption spectra using the restricted active space method.

    Science.gov (United States)

    Guo, Meiyuan; Sørensen, Lasse Kragh; Delcey, Mickaël G; Pinjari, Rahul V; Lundberg, Marcus

    2016-01-28

    The intensities and relative energies of metal K pre-edge features are sensitive to both geometric and electronic structures. With the possibility to collect high-resolution spectral data it is important to find theoretical methods that include all important spectral effects: ligand-field splitting, multiplet structures, 3d-4p orbital hybridization, and charge-transfer excitations. Here the restricted active space (RAS) method is used for the first time to calculate metal K pre-edge spectra of open-shell systems, and its performance is tested against on six iron complexes: [FeCl6](n-), [FeCl4](n-), and [Fe(CN)6](n-) in ferrous and ferric oxidation states. The method gives good descriptions of the spectral shapes for all six systems. The mean absolute deviation for the relative energies of different peaks is only 0.1 eV. For the two systems that lack centrosymmetry [FeCl4](2-/1-), the ratios between dipole and quadrupole intensity contributions are reproduced with an error of 10%, which leads to good descriptions of the integrated pre-edge intensities. To gain further chemical insight, the origins of the pre-edge features have been analyzed with a chemically intuitive molecular orbital picture that serves as a bridge between the spectra and the electronic structures. The pre-edges contain information about both ligand-field strengths and orbital covalencies, which can be understood by analyzing the RAS wavefunction. The RAS method can thus be used to predict and rationalize the effects of changes in both the oxidation state and ligand environment in a number of hard X-ray studies of small and medium-sized molecular systems.

  13. First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen

    International Nuclear Information System (INIS)

    Li, Zi; Zhang, Shen; Kang, Wei; Wang, Cong; Zhang, Ping

    2016-01-01

    X-ray absorption spectrum is a powerful tool for atomic structure detection on warm dense matter. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations on warm dense nitrogen along a Hugoniot curve. From the molecular dynamics trajectory, the detailed atomic structures are examined for each thermodynamical condition. The K-shell X-ray absorption spectrum is calculated, and its changes with temperature and pressure along the Hugoniot curve are discussed. The warm dense nitrogen systems may contain isolated nitrogen atoms, N 2 molecules, and nitrogen clusters, which show quite different contributions to the total X-ray spectrum due to their different electron density of states. The changes of X-ray spectrum along the Hugoniot curve are caused by the different nitrogen structures induced by the temperature and the pressure. Some clear signatures on X-ray spectrum for different thermodynamical conditions are pointed out, which may provide useful data for future X-ray experiments.

  14. Formation and evaluation of convex-curved crystals of lithium fluoride for use in analyzing x-ray spectra

    International Nuclear Information System (INIS)

    Sellick, B.O.

    1976-01-01

    Lithium fluoride as received from the vendor in boule form is 38 x 38 x 13 mm thick. This block is cleaved to wafers of the desired thickness, x-ray-evaluated for ''d'' spacing and greatest intensity, bent to the required radius, and then acid-etched to remove foreign material. The diffraction and dispersion characteristics of a wafer are analyzed using well-collimated tungsten x rays that strike the crystal and are diffracted onto no-screen x-ray film. If the crystal is satisfactory, it is mounted in a spectrogoniometer and rotated through an x-ray beam while a detector is set at the optimized angle for the diffracted x rays. The average intensity across the length of the crystal is recorded by multichannel scaling. Any imperfections appear as peaks or dips compared to the average intensity. The crystal next goes to a 10-channel, filter-fluorescer x-ray unit that compares zero-order intensity to diffracted Kα and Kβ intensity. Counts for 100-s intervals are taken in groups of three and averaged. Correction factors for instrument geometry, air, pinhole diameter at zero order, Kα-Kβ, barometric pressure, temperature, etc., are added to the efficiency calculations to obtain the crystal efficiency (epsilon) vs keV data. The crystal is mounted in the spectrograph or spectrometer and calibrated to either the detector or film plane by using direct radiation with proper x-ray filters or absorbers. The crystal is then ready for use

  15. Charge exchange recombination in X-ray spectra of He-like argon measured at the tokamak TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Schlummer, Tobias

    2014-06-16

    Charge exchange recombination between ions and atomic hydrogen is an important atomic process in magnetically confined fusion plasmas. Besides radiative cooling of the plasma edge, charge exchange causes modifications of the ionization balance and the population densities of excited ion states. The central goal of this work is to investigate the influence of charge exchange on X-ray spectra measured at the tokamak TEXTOR. A new 2D X-ray spectrometer developed for future use at the stellarator W7-X was recently installed at TEXTOR. The spectrometer is optimized for measuring the K{sub α}-spectrum of He-like argon (1s2l - 1s{sup 2}) at wavelengths close to 4 Aa. K{sub α}-spectroscopy on He-like impurity ions is an established diagnostic for electron and ion temperature measurements in fusion plasmas. Still, up to now the observed intensity ratios of the K{sub α}-lines and their associated satellites are not fully understood. They show significant deviations from the predictions made by basic corona models. In the past charge exchange with the neutral particle background and radial impurity transport have been discussed as likely explanations. Yet a detailed description of the experimental spectra still has not been achieved. To reconstruct the 2D K{sub α}-spectra measured at TEXTOR the radial argon ion distribution is modeled using an impurity transport code. The model accounts for charge exchange and transport on basis of given radial profiles of the neutral particle density n{sub 0}(r) and the diffusion coefficient D {sub perpendicular} {sub to} (r). The theoretical spectrum is then constructed based on the processes relevant for line emission. Within an iterative procedure n{sub 0}(r) and D {sub perpendicular} {sub to} (r) are varied until consistency between the theoretical and the experimental spectra is achieved. It is shown that the 2D K{sub α}-spectra allow a clear distinction of charge exchange and transport effects, ensuring unique solutions for n

  16. Comparison of theoretically predicted and observed Solar Maximum Mission X-ray spectra for the 1980 April 13 and May 9 flares

    International Nuclear Information System (INIS)

    Smith, D.F.; Orwig, L.E.

    1982-01-01

    A method for predicting the hard X-ray spectrum in the 10--100 keV range for compact flares during their initial rise is developed on the basis of a thermal model. Observations of the flares of 1980 April 13, 4:05 U.T., and 1980 May 9, 7:12 U.T. are given and their combined spectra from the Hard X-ray Burst Spectrometer and Hard X-ray Imaging Spectrometer on the Solar Maximum Mission are deduced. Constraints on the cross sectional area of the supposed emitting arch are obtained from data from the Hard X-ray Imaging Spectrometer. A power-law spectrum is predicted for the rise of the flare of April 13 for initial arch densities less than 10 10 cm -3 and also for the flare of May 9 for initial arch densities less than 5.4 x 10 10 cm -3 . In both cases power-law spectra are observed. Limitations and implications of these results are discussed

  17. The broad-band X-ray spectrum of IC 4329A from a joint NuSTAR/Suzaku observation

    Energy Technology Data Exchange (ETDEWEB)

    Brenneman, L. W.; Elvis, M. [Harvard-Smithsonian CfA, 60 Garden St., MS-67, Cambridge, MA 02138 (United States); Madejski, G. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Fuerst, F.; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K.; Rivers, E.; Walton, D. J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Matt, G.; Marinucci, A. [Dipartimento di Matematica e Fisica, Università Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Boggs, S. E. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E.; Craig, W. W. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, W. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-06-10

    We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku and NuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption, and distant reflection components in the spectrum. The absorbing column is found to be modest (∼6×10{sup 21} cm{sup −2} ), and does not introduce any significant curvature in the Fe K band. We are able to place a strong constraint on the presence of a broadened Fe Kα line (E{sub rest}=6.46{sub −0.07}{sup +0.08} keV with σ=0.33{sub −0.07}{sup +0.08} keV and EW=34{sub −7}{sup +8} eV), though we are not able to constrain any of the parameters of a relativistic reflection model. These results highlight the range in broad Fe K line strengths observed in nearby, bright, active galactic nuclei (roughly an order of magnitude), and imply a corresponding range in the physical properties of the inner accretion disk in these sources. We have also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than just NuSTAR alone: E {sub cut} = 186 ± 14 keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate this parameter from the plasma's optical depth and to update our results for these parameters as well. We derive kT=50{sub −3}{sup +6} keV with τ=2.34{sub −0.11}{sup +0.16} using a spherical geometry, kT = 61 ± 1 keV with τ = 0.68 ± 0.02 for a slab geometry, with both having an equivalent goodness-of-fit.

  18. Utilization of the statistics techniques for the analysis of the XPS (X-ray photoelectron spectroscopy) and Auger electronic spectra's deconvolutions

    International Nuclear Information System (INIS)

    Puentes, M.B.

    1987-01-01

    For the analysis of the XPS (X-ray photoelectron spectroscopy) and Auger spectra, it is important to performe the peaks' separation and estimate its intensity. For this purpose, a methodology was implemented, including: a spectrum's filter; b) substraction of the base line (or inelastic background); c) deconvolution (separation of the distribution that integrates the spectrum) and d) error of calculation of the mean estimation, comprising adjustment quality tests. A software (FORTRAN IV plus) that permits to use the methodology proposed from the experimental spectra was implemented. The quality of the methodology was tested with simulated spectra. (Author) [es

  19. SU-F-I-75: Half-Value Layer Thicknesses and Homogeneity Coefficients for Fluoroscopic X-Ray Beam Spectra Incorporating Spectral Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Wunderle, K [Cleveland Clinic Foundation, Cleveland, OH (United States); Wayne State University School of Medicine, Detroit, MI (United States); Godley, A; Shen, Z; Dong, F [Cleveland Clinic Foundation, Cleveland, OH (United States); Rakowski, J [Wayne State University School of Medicine, Detroit, MI (United States)

    2016-06-15

    Purpose: The purpose of this investigation is to quantify various first half-value-layers (HVLs), second HVLs and homogeneity coefficients (HCs) for a state-of-the-art fluoroscope utilizing spectral (copper) filtration. Methods: A Radcal (Monrovia, Ca) AccuPro dosimeter with a 10×6-6 calibrated ionization chamber was used to measure air kerma for radiographic x-ray exposures made on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope operated in the service mode. The ionization chamber was centered in the x-ray beam at 72 cm from the focal spot with a source-to-image-distance of 120 cm. The collimators were introduced to limit the x-ray field to approximately 5 cm × 5 cm at the ionization chamber plane. Type-1100 aluminum filters, in 0.5 mm increments, were used to determine the HVL. Two HVL calculation methods were used, log-linear interpolation and Lambert-W interpolation as described by Mathieu [Med Phys, 38(8), 4546 (2011)]. Multiple measurements were made at 60, 80, 100, 120 kVp at spectral filtration thicknesses of 0, 0.1, 0.3, 0.6 and 0.9 mm. Results: First HVL, second HVL, and HCs are presented for the fluoroscopic x-ray beam spectra indicated above, with nearly identical results from the two interpolation methods. Accuracy of the set kVp was also determined and deviated less than 2%. First HVLs for fluoroscopic x-ray beam spectra without spectral filtration determined in our study were 7%–16% greater than previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)]. However, the FDA minimum HVL requirements changed since that publication, requiring larger HVLs as of 2006. Additionally, x-ray tube and generator architecture have substantially changed over the last 15 years providing different beam spectra. Conclusion: X-ray beam quality characteristics for state-of-the-art fluoroscopes with spectral filtration have not been published. This study provides reference data which will be useful for defining beam qualities encountered on

  20. An energy-dispersive X-ray monochromator for measurements in the soft X-ray spectra: design, construction and first measurements. Ein energiedispersiver Roentgenmonochromator mit der Moeglichkeit von Messungen im weichen Roentgenbereich: Entwurf, Aufbau und erste Messungen

    Energy Technology Data Exchange (ETDEWEB)

    Steil, S.

    1993-12-01

    An Energy-Dispersive X-ray Monochromator (EDM) for time-resolved X-ray absorption spectroscopy was built in the Synchrotron radiation laboratory at the 3.5 GeV ELectron Stretcher and Accelerator (ELSA). Bragg angles up to 70 and a specially designed vacuum system allow measurements down to an energy of 2.149 keV (P K-edge) with a Si(111)-crystal. Compared to a standard double crystal monochromator and for an EXAFS spectrum at the Cu K-edge at 8.979 keV for concentrated samples, the EDM boosts time resolution by 3 orders of magnitude. The time resolution increases by a factor of 50 for a XANES spectrum at the S K-edge at 2.472 keV for a rubber sample with 4% sulfur. The energy resolution of the EDM is limited by the Darwin width [Omega] of the Bragg crystal. The harmonics in the 'monochromatized' beam, which increase to lower energies, could be nearly eliminated by using a quartz mirror. The spherical aberration of the focus was described theoretically for a cylindrically bent crystal and compared with measurements. In a first time-resolved measurement at the S K-edge, which comprehended about 120 spectra taken in 40 minutes, the thermal ageing of a rubber sample was investigated to demonstrate the performance of the monochromator. (orig.)

  1. Self-consistent modelling of X-ray photoelectron spectra from air-exposed polycrystalline TiN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Greczynski, G., E-mail: grzgr@ifm.liu.se; Hultman, L.

    2016-11-30

    Highlights: • We present first self-consistent model of TiN core level spectra with a cross-peak qualitative and quantitative agreement. • Model is tested for a series of TiN thin films oxidized to different extent by varying the venting temperature. • Conventional deconvolution process relies on reference binding energies that typically show large spread introducing ambiguity. • By imposing requirement of quantitative cross-peak self-consistency reliability of extracted chemical information is enhanced. • We propose that the cross-peak self-consistency should be a prerequisite for reliable XPS peak modelling. - Abstract: We present first self-consistent modelling of x-ray photoelectron spectroscopy (XPS) Ti 2p, N 1s, O 1s, and C 1s core level spectra with a cross-peak quantitative agreement for a series of TiN thin films grown by dc magnetron sputtering and oxidized to different extent by varying the venting temperature T{sub v} of the vacuum chamber before removing the deposited samples. So-obtained film series constitute a model case for XPS application studies, where certain degree of atmosphere exposure during sample transfer to the XPS instrument is unavoidable. The challenge is to extract information about surface chemistry without invoking destructive pre-cleaning with noble gas ions. All TiN surfaces are thus analyzed in the as-received state by XPS using monochromatic Al Kα radiation (hν = 1486.6 eV). Details of line shapes and relative peak areas obtained from deconvolution of the reference Ti 2p and N 1 s spectra representative of a native TiN surface serve as an input to model complex core level signals from air-exposed surfaces, where contributions from oxides and oxynitrides make the task very challenging considering the influence of the whole deposition process at hand. The essential part of the presented approach is that the deconvolution process is not only guided by the comparison to the reference binding energy values that often show

  2. Spectra of molecular changes induced in DNA of Drosophila spermatozoa by 1-ethyl-1-nitrosourea and X-rays

    International Nuclear Information System (INIS)

    Batzer, M.A.; Fossett, N.G.; Lee, W.R.; Louisiana State Univ., Baton Rouge; Tedeschi, B.; Tucker, A.; Kilroy, G.; Arbour, P.

    1988-01-01

    Mutations induced in Drosophila spermatozoa at the alcohol dehydrogenase Adh locus by 1-ethyl-1-nitrosourea (ENU) were compared to X-ray-induced mutations using genetic tests for complementation, southern blotting, western blotting and northern blotting. 8 of 10 ENU-induced mutations complemented all known adjacent loci and were presumed to be intragenic. In contrast, 8 of 30 X-ray-induced mutations were intragenic. The interpretation of these results is that in spermatozoa X-rays induce primarily deletions that either produce deficiencies of the Adh locus or nonsense mutations within the locus, whereas ENU induces primarily missense mutations. This forward mutation assay based on loss of enzymatic activity efficiently recovered a broad spectrum of mutations ranging from missense to intragenic deletions and multi-locus deficiencies. Only 3 of these 40 mutations produced a polypeptide detectable as an electrophoretic variant. 37 refs.; 6 figs.; 2 tabs

  3. Absolute radiant power measurement for the Au M lines of laser-plasma using a calibrated broadband soft X-ray spectrometer with flat-spectral response.

    Science.gov (United States)

    Troussel, Ph; Villette, B; Emprin, B; Oudot, G; Tassin, V; Bridou, F; Delmotte, F; Krumrey, M

    2014-01-01

    CEA implemented an absolutely calibrated broadband soft X-ray spectrometer called DMX on the Omega laser facility at the Laboratory for Laser Energetics (LLE) in 1999 to measure radiant power and spectral distribution of the radiation of the Au plasma. The DMX spectrometer is composed of 20 channels covering the spectral range from 50 eV to 20 keV. The channels for energies below 1.5 keV combine a mirror and a filter with a coaxial photo-emissive detector. For the channels above 5 keV the photoemissive detector is replaced by a conductive detector. The intermediate energy channels (1.5 keV power measurements with the new MLM channel and with the usual channel composed of a thin titanium filter and a coaxial detector (without mirror) are compared. All elements of the channel have been calibrated in the laboratory of the Physikalisch-Technische Bundesanstalt, Germany's National Metrology Institute, at the synchrotron radiation facility BESSY II in Berlin using dedicated well established and validated methods.

  4. DXRaySMCS: a user-friendly interface developed for prediction of diagnostic radiology X-ray spectra produced by Monte Carlo (MCNP-4C) simulation.

    Science.gov (United States)

    Bahreyni Toossi, M T; Moradi, H; Zare, H

    2008-01-01

    In this work, the general purpose Monte Carlo N-particle radiation transport computer code (MCNP-4C) was used for the simulation of X-ray spectra in diagnostic radiology. The electron's path in the target was followed until its energy was reduced to 10 keV. A user-friendly interface named 'diagnostic X-ray spectra by Monte Carlo simulation (DXRaySMCS)' was developed to facilitate the application of MCNP-4C code for diagnostic radiology spectrum prediction. The program provides a user-friendly interface for: (i) modifying the MCNP input file, (ii) launching the MCNP program to simulate electron and photon transport and (iii) processing the MCNP output file to yield a summary of the results (relative photon number per energy bin). In this article, the development and characteristics of DXRaySMCS are outlined. As part of the validation process, output spectra for 46 diagnostic radiology system settings produced by DXRaySMCS were compared with the corresponding IPEM78. Generally, there is a good agreement between the two sets of spectra. No statistically significant differences have been observed between IPEM78 reported spectra and the simulated spectra generated in this study.

  5. Spectra of soft X-ray excitation potentials of titanium and vanadium compounds with carbon and nitrogen of a variable composition

    International Nuclear Information System (INIS)

    Brytov, I.A.; Bleher, B. Eh.; Neshpor, V.S.

    1979-01-01

    Lsub(3,2) spectra of excitation potentials (SEP) of a soft X-ray radiation of titanium and vanadium carbides and titanium nitrides in their homogeneity range, as well as solid solutions of nitrogen in α-titanium, are studied. The binding energies of electrons of the exciting levels relatively to the Fermi level are determined, adequacy of different quantomechanical calculations is experimentally proved. The observed changes in SEP at the variation of the metalloid concentration are explained by a quantitative transformation model of valent state energetic spectra when metalloid vacancies and connected with them local levels form

  6. Traditional x-ray imaging

    International Nuclear Information System (INIS)

    Hay, G.A.

    1982-01-01

    Methods of imaging x-rays, with particular reference to medicine, are reviewed. The history and nature of x-rays, their production and spectra, contrast, shapes and fine structure, image transducers, including fluorescent screens, radiography, fluoroscopy, and image intensifiers, image detection, perception and enhancement and clinical applications are considered. (U.K.)

  7. Self-consistent method for quantifying indium content from X-ray spectra of thick compound semiconductor specimens in a transmission electron microscope.

    Science.gov (United States)

    Walther, T; Wang, X

    2016-05-01

    Based on Monte Carlo simulations of X-ray generation by fast electrons we calculate curves of effective sensitivity factors for analytical transmission electron microscopy based energy-dispersive X-ray spectroscopy including absorption and fluorescence effects, as a function of Ga K/L ratio for different indium and gallium containing compound semiconductors. For the case of InGaN alloy thin films we show that experimental spectra can thus be quantified without the need to measure specimen thickness or density, yielding self-consistent values for quantification with Ga K and Ga L lines. The effect of uncertainties in the detector efficiency are also shown to be reduced. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  8. Reconstruction of energetic electron spectra in the upper atmosphere: balloon observations of auroral X-rays coordinated with measurements from the EISCAT radar

    International Nuclear Information System (INIS)

    Olafsson, K.J.

    1990-08-01

    Energetic electron precipitation in the auroral zone has been studied using coordinated auroral X-ray measurements from balloons, altitude profiles of the ionospheric electron density measured by the EISCAT radar above the balloons, and cosmic noise absorption data from the Scandinavian riometer network. The data were obtained during the Coordinated EISCAT and Balloon Observations (CEBO) campaign in August 1984. The energy spectral variations of both the X-ray fluxes and the primary precipitating electrons were examined for two precipitation events in the morning sector. As far as reasonably can be concluded from observations of magnetic activity in the auroral zone, and from the temporal development of the energy spectra, the two precipitation events can be interpreted in the frame of present models of energetic electron precipitation on the mordning side of the auroral zone. 96 refs., 70 figs., 11 tabs

  9. Einstein Observatory SSS and MPC observations of the complex X-ray spectra of Seyfert galaxies. [Solid State Spectrometer and Monitor Proportional Counter

    Science.gov (United States)

    Turner, T. J.; Weaver, K. A.; Mushotzky, R. F.; Holt, S. S.; Madejski, G. M.

    1991-01-01

    The X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory have been investigated. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. It is found that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for about 48 percent of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed.

  10. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  11. The influence of mammographic X-ray spectra on absorbed energy distribution in breast: Monte Carlo simulation studies

    International Nuclear Information System (INIS)

    Delis, H.; Spyrou, G.; Tzanakos, G.; Panayiotakis, G.

    2005-01-01

    A mathematical model, based on Monte Carlo simulation, is proposed for deriving absorbed energy and dose distribution in mammography utilizing a mathematical water-like phantom. The model was validated for its accuracy against experimental and published data. The main factor discriminating absorbed energy distribution characteristics among different mammographic techniques was considered the X-ray spectrum. The absorbed energy distribution inside the phantom was investigated via percentage depth dose and isodose curves. The influence of the factors affecting X-ray spectrum (tube voltage, anode material, filter material and thickness) on absorbed energy distribution was examined. The hardness of the beam, due to increase of tube voltage or filtration, was found to be the major factor affecting absorbed energy distribution inside the phantom. In general, Mo and W anode systems demonstrated superior dosimetric characteristics against those of W-Mo or Rh. The model presented can be used for estimating absolute and relative breast dose values and their spatial distributions

  12. Detailed analysis of hollow ions spectra from dense matter pumped by X-ray emission of relativistic laser plasma

    International Nuclear Information System (INIS)

    Hansen, S. B.; Colgan, J.; Abdallah, J.; Faenov, A. Ya.; Pikuz, S. A.; Skobelev, I. Yu.; Wagenaars, E.; Culfa, O.; Dance, R. J.; Tallents, G. J.; Rossall, A. K.; Woolsey, N. C.; Booth, N.; Lancaster, K. L.; Evans, R. G.; Gray, R. J.; McKenna, P.; Kaempfer, T.; Schulze, K. S.; Uschmann, I.

    2014-01-01

    X-ray emission from hollow ions offers new diagnostic opportunities for dense, strongly coupled plasma. We present extended modeling of the x-ray emission spectrum reported by Colgan et al. [Phys. Rev. Lett. 110, 125001 (2013)] based on two collisional-radiative codes: the hybrid-structure Spectroscopic Collisional-Radiative Atomic Model (SCRAM) and the mixed-unresolved transition arrays (MUTA) ATOMIC model. We show that both accuracy and completeness in the modeled energy level structure are critical for reliable diagnostics, investigate how emission changes with different treatments of ionization potential depression, and discuss two approaches to handling the extensive structure required for hollow-ion models with many multiply excited configurations

  13. Influence of electric gas discharge to x-ray spectra on composite varistor based on ZnO-polymer

    International Nuclear Information System (INIS)

    Ahadzade, Sh.M.

    2016-01-01

    In work the X-ray spectrum of the composite resistors before and after being subjected to an electric discharge is carried out. It is found that the effect of electrical discharge on the samples greatly influences on the intensity of the diffraction reflexes. It was revealed that, the intensity of the reflections increases in dependence on the percentage of filler content in the case of samples exposed to electric discharge.

  14. Electronic states in Li/sub c/Mg/sub l-c/ alloys: soft x-ray emission spectra

    International Nuclear Information System (INIS)

    Stocks, G.M.; Tagle, J.A.; Callcott, T.A.; Arakawa, E.T.

    1980-01-01

    A first principles theory is developed for Li-Mg alloy systems which avoids the use of pseudo-potentials and, more importantly, low-order perturbation theory and which can be checked quantitatively against detailed probes of the electronic structure such as soft x-ray spectroscopy. These calculations can then be used as a base against which the psuedo-potential methods can, in the future, be checked

  15. Broad-band monitoring tracing the evolution of the jet and disc in the black hole candidate X-ray binary MAXI J1659-152

    NARCIS (Netherlands)

    van der Horst, A.J.; Curran, P.A.; Miller-Jonis, J.C.A.; Linford, J.D.; Gorosabel, J.; Russell, D.M.; De Ugarte Postigo, A.; Lundgren, A.A.; Taylor, G.B.; Maitra, D.; Guziy, S.; Belloni, T.M.; Kouveliotou, C.; Jonker, P.G.; Kamble, A.; Paragi, Z.; Homan, J.; Kuulkers, E.; Granot, J.; Altamirano, D.; Buxton, M.M.; Castro-Tirado, A.; Fender, R.P.; Garret, M.A.; Gehrels, N.; Hartmann, D.H.; Kennea, J.A.; Krimm, H.A.; Mangano, V.; Ramirez-Ruiz, E.; Romano, P.; Wijers, R.A.M.J.; Wijnands, R.; Yang, Y.J.

    2013-01-01

    MAXI J1659−152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a black hole as the most likely compact object. Dips in the X-ray light curves have revealed that MAXI J1659−152 is the shortest

  16. CORE-COLLAPSE MODEL OF BROADBAND EMISSION FROM SNR RX J1713.7–3946 WITH THERMAL X-RAYS AND GAMMA RAYS FROM ESCAPING COSMIC RAYS

    International Nuclear Information System (INIS)

    Ellison, Donald C.; Slane, Patrick; Patnaude, Daniel J.; Bykov, Andrei M.

    2012-01-01

    We present a spherically symmetric, core-collapse model of SNR RX J1713.7–3946 that includes a hydrodynamic simulation of the remnant evolution coupled to the efficient production of cosmic rays (CRs) by nonlinear diffusive shock acceleration. High-energy CRs that escape from the forward shock (FS) are propagated in surrounding dense material that simulates either a swept-up, pre-supernova shell or a nearby molecular cloud. The continuum emission from trapped and escaping CRs, along with the thermal X-ray emission from the shocked heated interstellar medium behind the FS, integrated over the remnant, is compared against broadband observations. Our results show conclusively that, overall, the GeV-TeV emission is dominated by inverse-Compton from CR electrons if the supernova is isolated regardless of its type, i.e., not interacting with a >>100 M ☉ shell or cloud. If the supernova remnant is interacting with a much larger mass ∼> 10 4 M ☉ , pion decay from the escaping CRs may dominate the TeV emission, although a precise fit at high energy will depend on the still uncertain details of how the highest energy CRs are accelerated by, and escape from, the FS. Based on morphological and other constraints, we consider the 10 4 M ☉ pion-decay scenario highly unlikely for SNR RX J1713.7–3946 regardless of the details of CR escape. Importantly, even though CR electrons dominate the GeV-TeV emission, the efficient production of CR ions is an essential part of our leptonic model.

  17. Soft X-ray focusing Telescope aboard AstroSat

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  18. Skull x-ray

    Science.gov (United States)

    X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

  19. Neck x-ray

    Science.gov (United States)

    X-ray - neck; Cervical spine x-ray; Lateral neck x-ray ... There is low radiation exposure. X-rays are monitored so that the lowest amount of radiation is used to produce the image. Pregnant women and ...

  20. Structure of X-ray photoelectron spectra of low-energy and core electrons of Ln(C6H4OCH3COO-3

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2005-01-01

    Full Text Available This paper deals with the results of an X-ray photo electron spectroscopy of lanthanide ortho-metoxybenzoates Ln(C6H4OCH3COO-3, where Ln represents lanthanides La through Lu except for Pm and C6H4OCH3COO- - residuum of ortho-metoxybenzoic acid. The core and outer electron X-ray photo electron spectroscopy spectra in the binding energy range of 0-1250 eV were shown to exhibit a complex, fine structure. The said structure was established due to the outer (0-15 eV binding energy and inner (15-50 eV binding energy valence molecular orbital from the filled Ln5p and O2s atomic shells multiple splitting, many-body perturbation, dynamic effect, etc. The mechanisms of such a fine structure formation were shown to manifest different probabilities in the spectrum of a certain electronic shell. There fore, the fine X-ray photo electron spectroscopy spectral structure resulting from a certain mechanism can be interpreted and its quantitative parameters related to the physical and chemical properties of the studied com pounds (degree of delocalization and participation of Ln4f electrons in the chemical bond, electronic configuration and oxidation states, density of uncoupled electrons on paramagnetic ions, degree of participation of the low binding energy filled electronic shells of lanthanide and ligands information of the outer and in nervalence molecular orbitals, lanthanide close environment structure in amorphous materials, etc.

  1. Reconstruction of energetic electron spectra in the upper atmosphere: balloon observations of auroral X-rays coordinated with measurements from the Eiscat radar

    International Nuclear Information System (INIS)

    Olafsson, K.J.

    1990-01-01

    Energetic electron precipitation in the auroral zone has been studied using coordinated auroral X-ray measurements from balloons, altitude profiles of the ionospheric electron density measured by the EISCAT radar above the balloons, and cosmic noise absorption data from the Scandinavian riometer network. The data were obtained during the coordinated EISCAT and balloon observation campaign in August 1984. A method by which an estimate of the energy spectrum of precipitating energetic electrons can be obtained from balloon measurements of bremsstrahlung X-rays is described. The energy spectral variation of both the X-ray fluxes and the primary precipitating electrons were examined for two precipitation events in the morning sector. As far as reasonably can be concluded from observations of magnetic activity in the auroral zone, and from the temporal development of the energy spectra, the two precipitation events can be interpreted in the frame of present models of energetic electron precipitation on the morning side of the auroral zone. 96 refs

  2. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, M. J., E-mail: macdonm@umich.edu [University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Gorkhover, T. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Technische Universität, 10623 Berlin (Germany); Bachmann, B.; Hau-Riege, S. P.; Pardini, T.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bucher, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Argonne National Lab, Lemont, Illinois 60439 (United States); Carron, S. [California Lutheran University, Thousand Oaks, California 91360 (United States); Coffee, R. N.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Krzywinski, J.; O’Grady, C. P.; Osipov, T.; Swiggers, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Ferguson, K. R. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford University, Stanford, California 94305 (United States); Kraus, D. [University of California, Berkeley, California 94720 (United States); and others

    2016-11-15

    Atomic clusters can serve as ideal model systems for exploring ultrafast (∼100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

  3. Analysis of monochromatic and quasi-monochromatic X-ray sources in imaging and therapy

    Science.gov (United States)

    Westphal, Maximillian; Lim, Sara; Nahar, Sultana; Orban, Christopher; Pradhan, Anil

    2017-04-01

    We studied biomedical imaging and therapeutic applications of recently developed quasi-monochromatic and monochromatic X-ray sources. Using the Monte Carlo code GEANT4, we found that the quasi-monochromatic 65 keV Gaussian X-ray spectrum created by inverse Compton scattering with relatavistic electron beams were capable of producing better image contrast with less radiation compared to conventional 120 kV broadband CT scans. We also explored possible experimental detection of theoretically predicted K α resonance fluorescence in high-Z elements using the European Synchrotron Research Facility with a tungsten (Z = 74) target. In addition, we studied a newly developed quasi-monochromatic source generated by converting broadband X-rays to monochromatic K α and β X-rays with a zirconium target (Z = 40). We will further study how these K α and K β dominated spectra can be implemented in conjunction with nanoparticles for targeted therapy. Acknowledgement: Ohio Supercomputer Center, Columbus, OH.

  4. Mass attenuation coefficient (μ/ρ), effective atomic number (Zeff) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    International Nuclear Information System (INIS)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S.; Goncalves Z, E.

    2015-10-01

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z eff of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z eff using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  5. Hydrogen isotope effect on muonic x-ray spectra of (CH2)/sub x/ and H2O

    International Nuclear Information System (INIS)

    Mausner, L.F.; Knight, J.D.; Orth, C.J.; Schillaci, M.E.; Naumann, R.A.

    1977-01-01

    We have measured the muonic x-ray intensity patterns of C in (CH 2 )/sub x/ and (CD 2 )/sub x/ and of O in H 2 O and D 2 O. In both cases the relative intensities of the higher Lyman series members are significantly lower in the deuterium compounds, indicating that the initial angular momentum distribution of the muons captured on C and O is weighted to higher l states compared to the normal hydrogen compounds. This isotope effect has not been predicted by any model of negative-meson capture

  6. Non-linearity issues and multiple ionization satellites in the PIXE portion of spectra from the Mars alpha particle X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, John L., E-mail: icampbel@uoguelph.ca; Heirwegh, Christopher M.; Ganly, Brianna

    2016-09-15

    Spectra from the laboratory and flight versions of the Curiosity rover’s alpha particle X-ray spectrometer were fitted with an in-house version of GUPIX, revealing departures from linear behavior of the energy-channel relationships in the low X-ray energy region where alpha particle PIXE is the dominant excitation mechanism. The apparent energy shifts for the lightest elements present were attributed in part to multiple ionization satellites and in part to issues within the detector and/or the pulse processing chain. No specific issue was identified, but the second of these options was considered to be the more probable. Approximate corrections were derived and then applied within the GUAPX code which is designed specifically for quantitative evaluation of APXS spectra. The quality of fit was significantly improved. The peak areas of the light elements Na, Mg, Al and Si were changed by only a few percent in most spectra. The changes for elements with higher atomic number were generally smaller, with a few exceptions. Overall, the percentage peak area changes are much smaller than the overall uncertainties in derived concentrations, which are largely attributable to the effects of rock heterogeneity. The magnitude of the satellite contributions suggests the need to incorporate these routinely in accelerator-based PIXE using helium beams.

  7. Electronic Raman scattering with excitation between localized states observed in the zinc M{sub 2,3} soft x-ray spectra of ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, L.; Callcott, T.A.; Jia, J.J. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1997-04-01

    Zn M{sub 2,3} soft x-ray fluorescence (SXF) spectra of ZnS and ZnS{sub .5}Se{sub .5} excited near threshold show strong inelastic scattering effects that can be explained using a simple model and an inelastic scattering theory based on second order perturbation theory. This scattering is often called electronic resonance Raman scattering. Tulkki and Aberg have developed this theory in detail for atomic systems, but their treatment can be applied to solid systems by utilizing electronic states characteristic of solids rather than of atomic systems.

  8. Resonant inelastic X-ray scattering spectra at the Ir L-edge in Na{sub 2}IrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Jun-ichi, E-mail: junichi.igarashi.kiryu@vc.ibaraki.ac.jp [Faculty of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Nagao, Tatsuya, E-mail: nagao@gunma-u.ac.jp [Faculty of Engineering, Gunma University, Kiryu, Gunma 376-8515 (Japan)

    2016-10-15

    Highlights: • A theoretical framework of resonant inelastic X-ray scattering (RIXS) on the basis of the itinerant electron scheme has been developed. • The RIXS theory is applied to iridate Na{sub 2}IrO{sub 3}. • The origins of the multi-peak structure of the excitation spectra found in the RIXS experiment have been assigned to the magnetic and excitonic excitations. - Abstract: We analyze resonant X-ray scattering (RIXS) spectra in Na{sub 2}IrO{sub 3} on the basis of the itinerant electron picture. Employing a multi-orbital tight-binding model on a honeycomb lattice, we find that the zigzag magnetic order is the most stable with sizable energy gap in the one-electron band within the Hartree–Fock approximation. We derive the RIXS spectra, which are connected to the generalized density–density correlation function. We calculate the spectra as a function of excitation energy ω, within the random phase approximation. The spectra consist of the peaks with ω < 20 meV, and of the peaks with 0.4 < ω < 0.8 eV. The former peaks are composed of four bound states in the density–density correlation function, and may be identified as the magnetic excitations, while the latter peaks are composed of 16 bound states below the energy continuum of individual electron–hole pair excitations, and may be identified as the excitonic excitations. The calculated spectra agree qualitatively with the recent RIXS experiment.

  9. Vibrational, X-ray absorption, and Mössbauer spectra of sulfate minerals from the weathered massive sulfide deposit at Iron Mountain, California

    Science.gov (United States)

    Majzlan, Juraj; Alpers, Charles N.; Bender Koch, Christian; McCleskey, R. Blaine; Myneni, Satish B.C.; Neil, John M.

    2014-01-01

    The Iron Mountain Mine Superfund site in California is a prime example of an acid mine drainage (AMD) system with well developed assemblages of sulfate minerals typical for such settings. Here we present and discuss the vibrational (infrared), X-ray absorption, and Mössbauer spectra of a number of these phases, augmented by spectra of a few synthetic sulfates related to the AMD phases. The minerals and related phases studied in this work are (in order of increasing Fe2O3/FeO): szomolnokite, rozenite, siderotil, halotrichite, römerite, voltaite, copiapite, monoclinic Fe2(SO4)3, Fe2(SO4)3·5H2O, kornelite, coquimbite, Fe(SO4)(OH), jarosite and rhomboclase. Fourier transform infrared spectra in the region 750–4000 cm−1 are presented for all studied phases. Position of the FTIR bands is discussed in terms of the vibrations of sulfate ions, hydroxyl groups, and water molecules. Sulfur K-edge X-ray absorption near-edge structure (XANES) spectra were collected for selected samples. The feature of greatest interest is a series of weak pre-edge peaks whose position is determined by the number of bridging oxygen atoms between Fe3+ octahedra and sulfate tetrahedra. Mössbauer spectra of selected samples were obtained at room temperature and 80 K for ferric minerals jarosite and rhomboclase and mixed ferric–ferrous minerals römerite, voltaite, and copiapite. Values of Fe2+/[Fe2+ + Fe3+] determined by Mössbauer spectroscopy agree well with those determined by wet chemical analysis. The data presented here can be used as standards in spectroscopic work where spectra of well-characterized compounds are required to identify complex mixtures of minerals and related phases.

  10. The MIT/OSO 7 catalog of X-ray sources - Intensities, spectra, and long-term variability

    Science.gov (United States)

    Markert, T. H.; Laird, F. N.; Clark, G. W.; Hearn, D. R.; Sprott, G. F.; Li, F. K.; Bradt, H. V.; Lewin, W. H. G.; Schnopper, H. W.; Winkler, P. F.

    1979-01-01

    This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1-40-keV X-ray detectors on OSO 7 between October 1971 and May 1973. Specifically, mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3-10-keV range are computed. For those sources for which a statistically significant (greater than 20) intensity was found in the 3-10-keV band (138 sources), further intensity determinations were made in the 1-15-keV, 1-6-keV, and 15-40-keV energy bands. Graphs and other simple techniques are provided to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Long-term light curves (counting rates in one or more energy bands as a function of time) are plotted for 86 of the brighter sources.

  11. MIT/OSO 7 catalog of x-ray sources: intensities, spectra, and long-term variability

    International Nuclear Information System (INIS)

    Markert, T.H.; Winkler, P.F.; Laird, F.N.; Clark, G.W.; Hearn, D.R.; Sprott, G.F.; Li, F.K.; Bradt, H.V.; Lewin, W.H.G.; Schnopper, H.W.

    1979-01-01

    This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1--40 KeV X-ray detectors on the OSO 7 between 1971 October and 1973 May. Specifically, we have computed the mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3--10 KeV range. For those sources for which a statistically significant (>20) intensity was found in the 3--10 KeV band (138 sources), further intensity determinations were made in the 1--15 KeV, 1--6 KeV, and 15--40 KeV energy bands. We have provided graphs and other simple techniques to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Finally, we have plotted long-term light curves (counting rates in one or more energy bands as a function of time) for 86 of the brighter sources

  12. Electrokinetic detection for X-ray spectra of weakly interacting liquids: n-decane and n-nonane

    International Nuclear Information System (INIS)

    Lam, Royce K.; Smith, Jacob W.; Sheardy, Alex T.; Rizzuto, Anthony M.; Saykally, Richard J.; Shih, Orion; Prendergast, David

    2014-01-01

    The introduction of liquid microjets into soft X-ray absorption spectroscopy enabled the windowless study of liquids by this powerful atom-selective high vacuum methodology. However, weakly interacting liquids produce large vapor backgrounds that strongly perturb the liquid signal. Consequently, solvents (e.g., hydrocarbons, ethers, ketones, etc.) and solutions of central importance in chemistry and biology have been inaccessible by this technology. Here we describe a new detection method, upstream detection, which greatly reduces the vapor phase contribution to the X-ray absorption signal while retaining important advantages of liquid microjet sample introduction (e.g., minimal radiation damage). The effectiveness of the upstream detection method is demonstrated in this first study of room temperature liquid hydrocarbons: n-nonane and n-decane. Good agreement with first principles’ calculations indicates that the eXcited electron and Core Hole theory adequately describes the subtle interactions in these liquids that perturb the electronic structure of the unoccupied states probed in core-level experiments

  13. Electrokinetic detection for X-ray spectra of weakly interacting liquids: n-decane and n-nonane

    Science.gov (United States)

    Lam, Royce K.; Shih, Orion; Smith, Jacob W.; Sheardy, Alex T.; Rizzuto, Anthony M.; Prendergast, David; Saykally, Richard J.

    2014-06-01

    The introduction of liquid microjets into soft X-ray absorption spectroscopy enabled the windowless study of liquids by this powerful atom-selective high vacuum methodology. However, weakly interacting liquids produce large vapor backgrounds that strongly perturb the liquid signal. Consequently, solvents (e.g., hydrocarbons, ethers, ketones, etc.) and solutions of central importance in chemistry and biology have been inaccessible by this technology. Here we describe a new detection method, upstream detection, which greatly reduces the vapor phase contribution to the X-ray absorption signal while retaining important advantages of liquid microjet sample introduction (e.g., minimal radiation damage). The effectiveness of the upstream detection method is demonstrated in this first study of room temperature liquid hydrocarbons: n-nonane and n-decane. Good agreement with first principles' calculations indicates that the eXcited electron and Core Hole theory adequately describes the subtle interactions in these liquids that perturb the electronic structure of the unoccupied states probed in core-level experiments.

  14. Microwave imaging of a solar limb flare - Comparison of spectra and spatial geometry with hard X-rays

    Science.gov (United States)

    Schmahl, E. J.; Kundu, M. R.; Dennis, B. R.

    1985-01-01

    A solar limb flare was mapped using the Very Large Array (VLA) together with hard X-ray (HXR) spectral and spatial observations of the Solar Maximum Mission satellite. Microwave flux records from 2.8 to 19.6 GHz were instrumental in determining the burst spectrum, which has a maximum at 10 GHz. The flux spectrum and area of the burst sources were used to determine the number of electrons producing gyrosynchrotron emission, magnetic field strength, and the energy distribution of gyrosynchrotron-emitting electrons. Applying the thick target model to the HXR spectrum, the number of high energy electrons responsible for the X-ray bursts was found to be 10 to the 36th, and the electron energy distribution was approximately E exp -5, significantly different from the parameters derived from the microwave observations. The HXR imaging observations exhibit some similiarities in size and structure o the first two burst sources mapped with the VLA. However, during the initial burst, the HXR source was single and lower in the corona than the double 6 cm source. The observations are explained in terms of a single loop with an isotropic high-energy electron distribution which produced the microwaves, and a larger beamed component which produced the HXR at the feet of the loop.

  15. Different effectiveness of hyperthermia with regard to fast electrons and X-rays with different energy spectra

    International Nuclear Information System (INIS)

    Schrader-Reichhardt, U.; Markus, B.

    1981-01-01

    The synergistic enhancement of the irradiation effect by mild (40.5 0 C) and strong (43 0 C) hyperthermia (TER = temperature enhancement ratio) was examined for different sparsely ionizing radiation qualities (15 MeV electrons in two irradiation depths corresponding to a relative depth dose of 100% and 30%, 200-kV and 29-kV-X-rays). Hypotetraploid ( 4n ) and diploid (2n), asynchronous, exponentially growing CHO fibroblasts were used as experimental subjects. The survival in the colony test was used as criterion to assess the effect. The experiments carried out with 4n cells showed that, for the two temperatures, the TER decreases with increasing ionization density and, when applying fast electrons producing an extremely sparse ionization in an irradiation depth of 100%, the TER shows a maximum increase as compared to the more densely ionizing radiation qualities. Already when mild hyperthermia is employed, fast electrons show a TER of 1.25 which rises to about 2.25 at 43 0 C. In case of 29-kV-X-rays, these values amount to 1 and 1.66 respectively. As to the 2n cells, the TER reaches here the double value and seems to be similarly dependent on the ionization density. (orig.) [de

  16. Electrokinetic detection for X-ray spectra of weakly interacting liquids: n-decane and n-nonane

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Royce K.; Smith, Jacob W.; Sheardy, Alex T.; Rizzuto, Anthony M.; Saykally, Richard J., E-mail: saykally@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Shih, Orion [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Prendergast, David [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-06-21

    The introduction of liquid microjets into soft X-ray absorption spectroscopy enabled the windowless study of liquids by this powerful atom-selective high vacuum methodology. However, weakly interacting liquids produce large vapor backgrounds that strongly perturb the liquid signal. Consequently, solvents (e.g., hydrocarbons, ethers, ketones, etc.) and solutions of central importance in chemistry and biology have been inaccessible by this technology. Here we describe a new detection method, upstream detection, which greatly reduces the vapor phase contribution to the X-ray absorption signal while retaining important advantages of liquid microjet sample introduction (e.g., minimal radiation damage). The effectiveness of the upstream detection method is demonstrated in this first study of room temperature liquid hydrocarbons: n-nonane and n-decane. Good agreement with first principles’ calculations indicates that the eXcited electron and Core Hole theory adequately describes the subtle interactions in these liquids that perturb the electronic structure of the unoccupied states probed in core-level experiments.

  17. Assignment of near-edge x-ray absorption fine structure spectra of metalloporphyrins by means of time-dependent density-functional calculations

    International Nuclear Information System (INIS)

    Schmidt, Norman; Fink, Rainer; Hieringer, Wolfgang

    2010-01-01

    The C 1s and N 1s near-edge x-ray absorption fine structure (NEXAFS) spectra of three prototype tetraphenyl porphyrin (TPP) molecules are discussed in the framework of a combined experimental and theoretical study. We employ time-dependent density-functional theory (TDDFT) to compute the NEXAFS spectra of the open- and closed-shell metalloporphyrins CoTPP and ZnTPP as well as the free-base 2HTPP in realistic nonplanar conformations. Using Becke's well-known half-and-half hybrid functional, the computed core excitation spectra are mostly in good agreement with the experimental data in the low-energy region below the appropriate ionization threshold. To make these calculations feasible, we apply a new, simple scheme based on TDDFT using a modified single-particle input spectrum. This scheme is very easy to implement in standard codes and allows one to compute core excitation spectra at a similar cost as ordinary UV/vis spectra even for larger molecules. We employ these calculations for a detailed assignment of the NEXAFS spectra including subtle shifts in certain peaks of the N 1s spectra, which depend on the central coordination of the TPP ligand. We furthermore assign the observed NEXAFS resonances to the individual molecular subunits of the investigated TPP molecules.

  18. X-ray diagnostic in gas discharge

    International Nuclear Information System (INIS)

    Chen Suhe; Wang Dalun; Cui Gaoxian; Wang Mei; Fu Yibei; Zhang Xinwei; Zhang Wushou

    1995-01-01

    X rays were observed when the anomalous phenomenon in the metal loaded with deuterium studied by the gas-discharge method. Therefore the X-ray energy spectra were measured by the absorption method, the specific X-ray approach and the NaI scintillation counter, while X-ray intensity was estimated by using 7 Li thermoluminescent foils. The X-ray average energy measured by the absorption method is 27.6 +- 2.1 keV, which is fitted within the error extent to 26.0 +-2.4 keV monoenergetic X rays measured by the NaI scintillation counter

  19. Experimental time resolved measurement of fluence and energy spectra of photons emitted by a pulsed X-ray generator in the range 5-300 keV

    International Nuclear Information System (INIS)

    Vie, M.; Baboulet, J.P.

    1989-01-01

    We have developed: - A sensor to measure locally X ray fluence rate amplitude and variation versus time during X ray pulses, - A spectrometer based on ROSS method to measure absolute X ray spectrum versus time during X ray pulses. This metrology is used to characterise single shot X ray pulsed sources emitting photons in the range of 5 to 300 keV. Fluence domain is between 10 -9 and 5 10 -4 J. cm -2 with a few nanoseconds time resolution [fr

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

    Science.gov (United States)

    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.

  1. Effects of Cu stress on maize seedlings using X-ray energy spectrum and FTIR spectra methods

    International Nuclear Information System (INIS)

    Qiao Lin; Fu Zhaolin; Qiao Chuanying

    2011-01-01

    The effects of Cu 2+ stress on maize seedlings by using scanning electron microscope, X-ray energy spectrum and Fourier transform infrared attenuated total reflection (FTIR-ATR) spectrometry were investigated, and antioxidative enzymes activities such as SOD, CAT, POD, APX were measured. Results showed that, with the increasing of Cu concentration, the content of chlorophyll decreased, and antioxidative enzyme activities increased at first and then decreased at higher concentration stress. High concentration Cu 2+ treatment twisted the cells' shape and increased copper content on leaf surface, and absorption of other nutrients were also affected. The result of FTIR-ATR analysis showed that the organic content of leaf were changed by Cu 2+ stress. (authors)

  2. X-ray spectra, chemical bonding, and electron structure of ScM2Si2 (M = Fe, Co, Ni)

    International Nuclear Information System (INIS)

    Shcherba, I.D.; Kotur, B.Ya.

    1990-01-01

    In a study of the interaction of the components in the ternary systems Sc-M-Si (where M is a 3d transition metal) it was established that there are compounds of the empirical formula ScM 2 Si 2 (M = Fe, Co, Ni). They crystallize in two structural types, HfFe 2 Si 2 (the compound ScFe 2 Si 2 ) and CeGa 2 Al 2 (ScCo 2 Si 2 and ScNi 2 Si 2 ) (ref. 1), leading to different coordination environment of the atoms in the structures of the compounds. With the aim of investigating the electron structure and the type ofin these compounds, they authors made a systematic x-ray spectral investigation with simultaneous analysis of the crystal structures of ScM 2 Si 2

  3. Broadband Correlations Provide Evidence for Synchrotron Self-Compton X-rays from the Black Hole Binary GX 339-4

    International Nuclear Information System (INIS)

    Coriat, M.; Corbel, S.; Buxton, M. M.; Baylin, C. D.

    2009-01-01

    GX 339-4 has been one of the key sources for unravelling the accretion ejection coupling in accreting stellar mass black holes. After a long period of quiescence between 1999 and 2002, GX 339-4 underwent a series of 4 outbursts that have been intensively observed by many ground based observatories (radio/infrared/optical) and satellites (X-rays). Here, we present some specific results of these broad band observational campaigns, focusing on the optical-infrared/X-ray flux correlations over the four outbursts. Thanks to our extensive data-set, we found a strong OIR/X-ray correlation over four decades with the presence of a break in the correlation index. These results seem to favour a synchrotron self-Compton origin for the X-ray emission in GX 339-4 during the hard state and could also provide an indirect detection of the break frequency in the synchrotron spectrum of the compact jets.

  4. Study of X-Ray and $\\gamma$-Ray Spectra from Antiprotonic Atoms at the Slowly Extracted Antiproton Beam of LEAR

    CERN Multimedia

    2002-01-01

    This experiment will study the X-ray spectra of antiprotonic atoms and the $\\gamma$ spectra of residual nuclei after the antiproton absorption. We intend to begin with measurements on selected isotopically pure targets. Strong interaction effects, the antiproton absorption and the atomic cascade are analysed through the measurement of energies, lineshapes, relative and absolute intensities of all observable lines. The experiments are continued to determine st in resolved fine structure levels and in different isotopes of the same element. Coincidence techniques may be applied. All components of the experimental set-up are already existing from previous experiments and we could begin the measurements with any slowly extracted beam of low energy at LEAR.

  5. Simultaneous broadband observations and high-resolution X-ray spectroscopy of the transitional millisecond pulsar PSR J1023+0038

    Science.gov (United States)

    Coti Zelati, F.; Campana, S.; Braito, V.; Baglio, M. C.; D'Avanzo, P.; Rea, N.; Torres, D. F.

    2018-03-01

    We report on the first simultaneous XMM-Newton, NuSTAR, and Swift observations of the transitional millisecond pulsar PSR J1023+0038 in the X-ray active state. Our multi-wavelength campaign allowed us to investigate with unprecedented detail possible spectral variability over a broad energy range in the X-rays, as well as correlations and lags among emissions in different bands. The soft and hard X-ray emissions are significantly correlated, with no lags between the two bands. On the other hand, the X-ray emission does not correlate with the UV emission. We refine our model for the observed mode switching in terms of rapid transitions between a weak propeller regime and a rotation-powered radio pulsar state, and report on a detailed high-resolution X-ray spectroscopy using all XMM-Newton Reflection Grating Spectrometer data acquired since 2013. We discuss our results in the context of the recent discoveries on the system and of the state of the art simulations on transitional millisecond pulsars, and show how the properties of the narrow emission lines in the soft X-ray spectrum are consistent with an origin within the accretion disc.

  6. Accretion Disk Spectra of the Ultra-Luminous X-Ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, T

    2003-12-11

    Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework of the standard optically thick accretion disk in the Schwarzschild metric. On the other hand, the standard accretion disk around the Kerr black hole might explain the observed high disk temperature, as the inner radius of the Kerr disk gets smaller and the disk temperature can be consequently higher. However, we point out that the observable Kerr disk spectra becomes significantly harder than Schwarzschild disk spectra only when the disk is highly inclined. This is because the emission from the innermost part of the accretion disk is Doppler-boosted for an edge-on Kerr disk, while hardly seen for a face-on disk. The Galactic superluminal jet sources are known to be highly inclined systems, thus their energy spectra may be explained with the standard Kerr disk with known black hole masses. For ULXs, on the other hand, the standard Kerr disk model seems implausible, since it is highly unlikely that their accretion disks are preferentially inclined, and, if edge-on Kerr disk model is applied, the black hole mass becomes unreasonably large (> 300 M{sub solar}). Instead, the slim disk (advection dominated optically thick disk) model is likely to explain the observed super-Eddington luminosities, hard energy spectra, and spectral variations of ULXs. We suggest that ULXs are accreting black holes with a few tens of solar mass, which is not unexpected from the standard stellar evolution scenario, and that their X-ray emission is from the slim disk shining at super-Eddington luminosities.

  7. Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Hiroyuki; Fukao, Taishi; Minami, Hirotake; Ukai, Masatoshi [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588 (Japan); Fujii, Kentaro; Yokoya, Akinari [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Fukuda, Yoshihiro; Saitoh, Yuji [Synchrotron Radiation Research Center, Japan Atomic Energy Agency, Sayo-gun, Hyougo 679-5148 (Japan)

    2014-08-07

    The N K-edge X-ray absorption near edge structure (XANES) spectra of the purine-containing nucleotide, guanosine 5{sup ′}-monophosphate (GMP), in aqueous solution are measured under various pH conditions. The spectra show characteristic peaks, which originate from resonant excitations of N 1s electrons to π* orbitals inside the guanine moiety of GMP. The relative intensities of these peaks depend on the pH values of the solution. The pH dependence is explained by the core-level shift of N atoms at specific sites caused by protonation and deprotonation. The experimental spectra are compared with theoretical spectra calculated by using density functional theory for GMP and the other purine-containing nucleotides, adenosine 5{sup ′}-monophosphate, and adenosine 5{sup ′}-triphosphate. The N K-edge XANES spectra for all of these nucleotides are classified by the numbers of N atoms with particular chemical bonding characteristics in the purine moiety.

  8. On the Determination of the Spin of the Black Hole in Cyg X-1 from X-Ray Reflection Spectra

    Science.gov (United States)

    Fabian, A. C.; Wilkins, D.; Miller, J. M.; Reis, R. C.; Reynolds, C. S.; Cackett, E. M.; Nowak, M. A.; Pooley, G.; Pottschmidt, K.; Sanders, J. S.; hide

    2012-01-01

    The spin of Cygnus X-I is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keY. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg = GM/c(exp 2)) and a value for the dimensionless black hole spin is obtained of 0.97(sup .0.14) (sup -0.02). This agrees with recent measurements using the continuum fitting method by Gou et al. and of the broad iron line by Duro et al. The disc inclination is measured at 23.7(sup +6.7) (sup -5.4) deg. which is consistent with the recent optical measurement of the binary system inclination by Orosz et al of 27+/- 0.8 deg. We pay special attention to the emissivity profile caused by irradiation of the inner disc by the hard power-law source. 1be X-ray observations and simulations show that the index q of that profile deviates from the commonly used, Newtonian, value of 3 within 3r(sub g), steepening considerably within 2r(sub g). as expected in the strong gravity regime.

  9. ON ESTIMATING THE HIGH-ENERGY CUTOFF IN THE X-RAY SPECTRA OF BLACK HOLES VIA REFLECTION SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    García, Javier A.; Steiner, James F.; McClintock, Jeffrey E.; Keck, Mason L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Dauser, Thomas; Wilms, Jörn, E-mail: javier@head.cfa.harvard.edu, E-mail: jem@cfa.harvard.edu, E-mail: jsteiner@head.cfa.harvard.edu, E-mail: keckm@bu.edu, E-mail: thomas.dauser@sternwarte.uni-erlangen.de [Dr. Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics, Sternwartstr. 7, D-96049 Bamberg (Germany)

    2015-08-01

    The fundamental parameters describing the coronal spectrum of an accreting black hole are the slope Γ of the power-law continuum and the energy E{sub cut} at which it rolls over. Remarkably, this latter parameter can be accurately measured for values as high as 1 MeV by modeling the spectrum of X-rays reflected from a black hole accretion disk at energies below 100 keV. This is possible because the details in the reflection spectrum, rich in fluorescent lines and other atomic features, are very sensitive to the spectral shape of the hardest coronal radiation illuminating the disk. We show that by fitting simultaneous NuSTAR (3–79 keV) and low-energy (e.g., Suzaku) data with the most recent version of our reflection model relxill one can obtain reasonable constraints on E{sub cut} at energies from tens of keV up to 1 MeV, for a source as faint as 1 mCrab in a 100 ks observation.

  10. Experimental study of the X-ray spectra optimization for computed radiography mammography systems; Investigacao experimental da otimizacao do espectro de raios X em sistemas de mamografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Tomal, Alessandra, E-mail: atomal@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin; Cunha, Diego M. [Universidade Federal de Uberlandia (UFU), Uberlandia, MG (Brazil). Instituto de Fisica; Nogueira, Maria S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Gaspar, Fabio [Vigilancia Sanitaria, Campinas, SP (Brazil); Poletti, Martin E. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Departamento de Fisica

    2013-12-15

    Digital mammography is replacing screen-film mammography due to several advantages of digital receptors. The use of Computed Radiography (CR) mammography systems has been considered an alternative to achieve digital images with a low cost. Besides, the optimization of the X-ray spectrum, characterized by the anode/filter combination and tube potential, is an important step in order to improve the image quality with the lower dose to the breast. In this work, we investigated the optimal X-ray spectra using a figure of merit for two mammography equipment: Senographe DMR (General Electric Medical Systems) and Mammomat 3000 Nova (Siemens), both using an image plate Kodak EHR-M2 (Kodak DirectView). A PMMA phantom, simulating breast with thicknesses of 5 cm, was used. The anode/filter combinations evaluated were: Mo/Mo, Mo/Rh, Rh/Rh and Rh/Al for the Senographe system, and Mo/Mo, Mo/Rh, W/Rh for the Mammomat system, for all the intervals of tube potential range from 24 to 35 kVp. Results demonstrate that the higher values of FOM were achieved with the Rh/Rh at 29 kVp and Rh/Al at 26 kVp for the Senographe system, and for the W/Rh at 28 kVp in the Mammomat one. The reduction in the dose associated with the optimum spectra was 13 and 26% for the Senographe and Mammomat systems, respectively. Finally, our results suggest that anode/filter combinations of more energetic spectra than the standard Mo/Mo combination are recommended for thicker breast, in order to reduce the breast dose levels. (author)

  11. Carbon X-ray absorption spectra of fluoroethenes and acetone: a study at the coupled cluster, density functional, and static-exchange levels of theory.

    Science.gov (United States)

    Fransson, Thomas; Coriani, Sonia; Christiansen, Ove; Norman, Patrick

    2013-03-28

    Near carbon K-edge X-ray absorption fine structure spectra of a series of fluorine-substituted ethenes and acetone have been studied using coupled cluster and density functional theory (DFT) polarization propagator methods, as well as the static-exchange (STEX) approach. With the complex polarization propagator (CPP) implemented in coupled cluster theory, relaxation effects following the excitation of core electrons are accounted for in terms of electron correlation, enabling a systematic convergence of these effects with respect to electron excitations in the cluster operator. Coupled cluster results have been used as benchmarks for the assessment of propagator methods in DFT as well as the state-specific static-exchange approach. Calculations on ethene and 1,1-difluoroethene illustrate the possibility of using nonrelativistic coupled cluster singles and doubles (CCSD) with additional effects of electron correlation and relativity added as scalar shifts in energetics. It has been demonstrated that CPP spectra obtained with coupled cluster singles and approximate doubles (CC2), CCSD, and DFT (with a Coulomb attenuated exchange-correlation functional) yield excellent predictions of chemical shifts for vinylfluoride, 1,1-difluoroethene, trifluoroethene, as well as good spectral features for acetone in the case of CCSD and DFT. Following this, CPP-DFT is considered to be a viable option for the calculation of X-ray absorption spectra of larger π-conjugated systems, and CC2 is deemed applicable for chemical shifts but not for studies of fine structure features. The CCSD method as well as the more approximate CC2 method are shown to yield spectral features relating to π∗-resonances in good agreement with experiment, not only for the aforementioned molecules but also for ethene, cis-1,2-difluoroethene, and tetrafluoroethene. The STEX approach is shown to underestimate π∗-peak separations due to spectral compressions, a characteristic which is inherent to this

  12. Identification of X-ray spectra in the Na-like to O-like rubidium ions in the range of 3.8-7.3 Angstroms

    International Nuclear Information System (INIS)

    Denis-Petit, D.; Bonnet, T.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.; Comet, M.; Gosselin, G.; Meot, V.; Morel, P.; Pain, J.Ch.; Gilleron, F.; Frank, A.; Bagnoud, V.; Blazevic, A.; Dorchies, F.; Peyrusse, O.; Cayzac, W.; Roth, M.

    2014-01-01

    The X-rays emitted by a rubidium plasma source created by the PHELIX laser at an intensity of about 6*10"1"4 W/cm"2 were studied. The lines have been measured using Bragg crystals in the wavelength range between 3.8 and 7.3 Angstroms and identified by means of a numerical method developed to describe highly charged rubidium ions in LTE plasma. The experimental plasma temperature, density and charge state distributions have been estimated using non-LTE codes such as CHIVAS and AVERROES. The LTE plasma temperature and density used in the calculations are those allowing to reproduce the calculated NLTE charge state distribution. In order to optimize the use of computational resources, a criterion is established to select the configurations contributing most to the spectra among all those obtained in detailed level accounting based on the MCDF code. Seventy Rb-X-rays have been identified among which forty-nine are reported for the first time. The capabilities of our method are demonstrated by the good agreement of our identifications with previously published data when available. (authors)

  13. Pair Natural Orbital Restricted Open-Shell Configuration Interaction (PNO-ROCIS) Approach for Calculating X-ray Absorption Spectra of Large Chemical Systems.

    Science.gov (United States)

    Maganas, Dimitrios; DeBeer, Serena; Neese, Frank

    2018-02-08

    In this work, the efficiency of first-principles calculations of X-ray absorption spectra of large chemical systems is drastically improved. The approach is based on the previously developed restricted open-shell configuration interaction singles (ROCIS) method and its parametrized version, based on a density functional theory (DFT) ground-state determinant ROCIS/DFT. The combination of the ROCIS or DFT/ROCIS methods with the well-known machinery of the pair natural orbitals (PNOs) leads to the new PNO-ROCIS and PNO-ROCIS/DFT variants. The PNO-ROCIS method can deliver calculated metal K-, L-, and M-edge XAS spectra orders of magnitude faster than ROCIS while maintaining an accuracy with calculated spectral parameters better than 1% relative to the original ROCIS method (referred to as canonical ROCIS). The method is of a black box character, as it does not require any user adjustments, while it scales quadratically with the system size. It is shown that for large systems, the size of the virtual molecular orbital (MO) space is reduced by more than 90% with respect to the canonical ROCIS method. This allows one to compute the X-ray absorption spectra of a variety of large "real-life" chemical systems featuring hundreds of atoms using a first-principles wave-function-based approach. Examples chosen from the fields of bioinorganic and solid-state chemistry include the Co K-edge XAS spectrum of aquacobalamin [H 2 OCbl] + , the Fe L-edge XAS spectrum of deoxymyoglobin (DMb), the Ti L-edge XAS spectrum of rutile TiO 2 , and the Fe M-edge spectrum of α-Fe 2 O 3 hematite. In the largest calculations presented here, molecules with more than 700 atoms and cluster models with more than 50 metal centers were employed. In all the studied cases, very good to excellent agreement with experiment is obtained. It will be shown that the PNO-ROCIS method provides an unprecedented performance of wave-function-based methods in the field of computational X-ray spectroscopy.

  14. X-Ray

    Science.gov (United States)

    ... enema. What you can expect During the X-ray X-rays are performed at doctors' offices, dentists' offices, ... as those using a contrast medium. Your child's X-ray Restraints or other techniques may be used to ...

  15. Abdominal x-ray

    Science.gov (United States)

    Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

  16. Chest X-Ray

    Medline Plus

    Full Text Available ... talk with you about chest radiography also known as chest x-rays. Chest x-rays are the ... treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray ...

  17. A new Monte Carlo code for simulation of the effect of irregular surfaces on X-ray spectra

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Antonio, E-mail: brunetti@uniss.it; Golosio, Bruno

    2014-04-01

    Generally, quantitative X-ray fluorescence (XRF) analysis estimates the content of chemical elements in a sample based on the areas of the fluorescence peaks in the energy spectrum. Besides the concentration of the elements, the peak areas depend also on the geometrical conditions. In fact, the estimate of the peak areas is simple if the sample surface is smooth and if the spectrum shows a good statistic (large-area peaks). For this reason often the sample is prepared as a pellet. However, this approach is not always feasible, for instance when cultural heritage or valuable samples must be analyzed. In this case, the sample surface cannot be smoothed. In order to address this problem, several works have been reported in the literature, based on experimental measurements on a few sets of specific samples or on Monte Carlo simulations. The results obtained with the first approach are limited by the specific class of samples analyzed, while the second approach cannot be applied to arbitrarily irregular surfaces. The present work describes a more general analysis tool based on a new fast Monte Carlo algorithm, which is virtually able to simulate any kind of surface. At the best of our knowledge, it is the first Monte Carlo code with this option. A study of the influence of surface irregularities on the measured spectrum is performed and some results reported. - Highlights: • We present a fast Monte Carlo code with the possibility to simulate any irregularly rough surfaces. • We show applications to multilayer measurements. • Real time simulations are available.

  18. X-ray astronomy

    International Nuclear Information System (INIS)

    Giacconi, R.; Gursky, H.

    1974-01-01

    This text contains ten chapters and three appendices. Following an introduction, chapters two through five deal with observational techniques, mechanisms for the production of x rays in a cosmic setting, the x-ray sky and solar x-ray emission. Chapters six through ten include compact x-ray sources, supernova remnants, the interstellar medium, extragalactic x-ray sources and the cosmic x-ray background. Interactions of x rays with matter, units and conversion factors and a catalog of x-ray sources comprise the three appendices. (U.S.)

  19. X-rays as a probe of the Universe

    Indian Academy of Sciences (India)

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

  20. Inner-shell X-ray line spectra of highly ionized titanium, chromium, iron and nickel and their application to laboratory plasmas

    International Nuclear Information System (INIS)

    Lemen, J.R.; Phillips, K.J.H.; Doschek, G.A.; Cowan, R.D.

    1986-06-01

    The intensities of X-ray lines due to inner-shell 1s-2p transitions in 0 I-, N I-, and C I-like ions of Ti XV-XVII, Cr XVII-XIX, Fe XIX-XXI, and Ni XXI-XXIII, seen in tokamak plasmas are calculated. The lines are assumed to be formed by dielectronic recombination and inner-shell excitation. The dielectronic rates were calculated using a suite of computer programs developed by one of the authors. The inner-shell contribution was estimated by van Regemorter's formula. The present calculations were applied to the problem of radial ion diffusion in tokamaks. Spectra were calculated by integrating along various lines-of-sight to simulate what might be observed by an actual spectrometer viewing a tokamak plasma. A method for determining the diffusion coefficient from tokamak observations is discussed. (author)

  1. Pyrimidine and halogenated pyrimidines near edge x-ray absorption fine structure spectra at C and N K-edges: experiment and theory

    International Nuclear Information System (INIS)

    Bolognesi, P.; O'Keeffe, P.; Ovcharenko, Y.; Coreno, M.; Avaldi, L.; Feyer, V.; Plekan, O.; Prince, K. C.; Zhang, W.; Carravetta, V.

    2010-01-01

    The inner shell excitation of pyrimidine and some halogenated pyrimidines near the C and N K-edges has been investigated experimentally by near edge x-ray absorption fine structure spectroscopy and theoretically by density functional theory calculations. The selected targets, 5-Br-pyrimidine, 2-Br-pyrimidine, 2-Cl-pyrimidine, and 5-Br-2-Cl-pyrimidine, allow the effects of the functionalization of the pyrimidine ring to be studied either as a function of different halogen atoms bound to the same molecular site or as a function of the same halogen atom bound to different molecular sites. The results show that the individual characteristics of the different spectra of the substituted pyrimidines can be rationalized in terms of variations in electronic and geometrical structures of the molecule depending on the localization and the electronegativity of the substituent.

  2. Theory and optical design of x-ray echo spectrometers

    Science.gov (United States)

    Shvyd'ko, Yuri

    2017-08-01

    X-ray echo spectroscopy, a space-domain counterpart of neutron spin echo, is a recently proposed inelastic x-ray scattering (IXS) technique. X-ray echo spectroscopy relies on imaging IXS spectra and does not require x-ray monochromatization. Due to this, the echo-type IXS spectrometers are broadband, and thus have a potential to simultaneously provide dramatically increased signal strength, reduced measurement times, and higher resolution compared to the traditional narrow-band scanning-type IXS spectrometers. The theory of x-ray echo spectrometers presented earlier [Yu. Shvyd'ko, Phys. Rev. Lett. 116, 080801 (2016), 10.1103/PhysRevLett.116.080801] is developed here further with a focus on questions of practical importance, which could facilitate optical design and assessment of the feasibility and performance of the echo spectrometers. Among others, the following questions are addressed: spectral resolution, refocusing condition, echo spectrometer tolerances, refocusing condition adjustment, effective beam size on the sample, spectral window of imaging and scanning range, impact of the secondary source size on the spectral resolution, angular dispersive optics, focusing and collimating optics, and detector's spatial resolution. Examples of optical designs and characteristics of echo spectrometers with 1-meV and 0.1-meV resolutions are presented.

  3. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

    Science.gov (United States)

    Rana, Vikram; Loh, Alan; Corbel, Stephane; Tomsick, John A.; Chakrabarty, Deepto; Walton, Dominic J.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William; hide

    2016-01-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0.3-30 keV) quiescent luminosity of the source is 8.9 x 10(exp 32) erg per sec for a distance of 2.4 kpc. The source shows clear variability on short timescales (an hour to a couple of hours) in the radio, soft X-ray, and hard X-ray bands in the form of multiple flares. The broadband X-ray spectra obtained from XMM-Newton and NuSTAR can be characterized with a power-law model having a photon index of gamma = 2.12 +/- 0.07 (90% confidence errors); however, residuals at high energies indicate spectral curvature significant at a 3 sigma confidence level with the e-folding energy of the cutoff as 20(sub -7)(sup +20) keV. Such curvature can be explained using synchrotron emission from the base of a jet outflow. Radio observations using the VLA reveal that the spectral index evolves on very fast timescales (as short as 10 minutes), switching between optically thick and thin synchrotron emission, possibly due to instabilities in the compact jet or stochastic instabilities in the accretion rate. We explore different scenarios to explain this very fast variability.

  4. Increasing the applicability of density functional theory. V. X-ray absorption spectra with ionization potential corrected exchange and correlation potentials

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prakash; Bartlett, Rodney J., E-mail: bartlett@qtp.ufl.edu [Quantum Theory Project, University of Florida, Gainesville, Florida 32611 (United States)

    2016-07-21

    Core excitation energies are computed with time-dependent density functional theory (TD-DFT) using the ionization energy corrected exchange and correlation potential QTP(0,0). QTP(0,0) provides C, N, and O K-edge spectra to about an electron volt. A mean absolute error (MAE) of 0.77 and a maximum error of 2.6 eV is observed for QTP(0,0) for many small molecules. TD-DFT based on QTP (0,0) is then used to describe the core-excitation spectra of the 22 amino acids. TD-DFT with conventional functionals greatly underestimates core excitation energies, largely due to the significant error in the Kohn-Sham occupied eigenvalues. To the contrary, the ionization energy corrected potential, QTP(0,0), provides excellent approximations (MAE of 0.53 eV) for core ionization energies as eigenvalues of the Kohn-Sham equations. As a consequence, core excitation energies are accurately described with QTP(0,0), as are the core ionization energies important in X-ray photoionization spectra or electron spectroscopy for chemical analysis.

  5. Increasing the applicability of density functional theory. V. X-ray absorption spectra with ionization potential corrected exchange and correlation potentials.

    Science.gov (United States)

    Verma, Prakash; Bartlett, Rodney J

    2016-07-21

    Core excitation energies are computed with time-dependent density functional theory (TD-DFT) using the ionization energy corrected exchange and correlation potential QTP(0,0). QTP(0,0) provides C, N, and O K-edge spectra to about an electron volt. A mean absolute error (MAE) of 0.77 and a maximum error of 2.6 eV is observed for QTP(0,0) for many small molecules. TD-DFT based on QTP (0,0) is then used to describe the core-excitation spectra of the 22 amino acids. TD-DFT with conventional functionals greatly underestimates core excitation energies, largely due to the significant error in the Kohn-Sham occupied eigenvalues. To the contrary, the ionization energy corrected potential, QTP(0,0), provides excellent approximations (MAE of 0.53 eV) for core ionization energies as eigenvalues of the Kohn-Sham equations. As a consequence, core excitation energies are accurately described with QTP(0,0), as are the core ionization energies important in X-ray photoionization spectra or electron spectroscopy for chemical analysis.

  6. Analysis of x-ray spectra emitted from highly ionized atoms in the vacuum spark and laser-produced high power plasma sources

    International Nuclear Information System (INIS)

    Mandelbaum, P.

    1987-05-01

    The interest in atomic spectroscopy has greatly been reinforced in the last ten years. This gain of interest is directly related to the developments in different fields of research where hot plasmas are created. These fields include in particular controlled thermonuclear fusion research by means of inertial or magnetic confinement approaches and also the most recent efforts to achieve lasers in the XUV region. The present work is based on the specific contribution of the atomic spectroscopy group at the Hebrew University. The recent development of both theoretical and experimental tools allowed us to progress in the understanding of the highly ionized states of heavy elements. In this work the low-inductance vacuum-spark developed at the Hebrew University was used as the hot plasma source. The spectra were recorded in the 7-300 A range by means of a high-resolution extreme-grazing-incidence spectrometer developed at the Racah Institute by Profs. J.L. Schwob and B.S. Fraenkel. To the extend the spectroscopic studies to higher-Z atoms, the laser-produced plasma facility at Soreq Nuclear Center was used. In this work the spectra of the sixth row elements were recorded in the x-rays by means of a crystal spectrometer. All these experimental systems are briefly described in chapter one. Chapter two deals with the theoretical methods used in the present work for the atomic calculations. Chapter three deals with the spectra of elements of the fifth row emitted from the vacuum-spark in the 30-150 A range. These spectra as experimental data were used in order to test ab-initio computations along the NiI sequence 3d-nl transitions. The results of this work are presented in chapter four. Chapter five is devoted to the measurement and analysis of spectra emitted from the vacuum-spark by rare-earth elements. (author)

  7. Comparison of various molecular forms of bovine trypsin: Correlation of infrared spectra with X-ray crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Prestrelski, S.J. (Mount Sinai School of Medicine of the City Univ. of New York (USA)); Byler, D.M. (U.S. Department of Agriculture, Philadelphia, PA (USA)); Liebman, M.N. (AMOCO Technology Corporation, Naperville, IL (USA))

    1991-01-01

    Fourier-transform infrared spectroscopy is a valuable method for the study of protein conformation in solution primarily because of the sensitivity to conformation of the amide I band (1700-1620 cm{sup {minus}1}) which arises from the backbone C{double bond}O stretching vibration. Combined with resolution-enhancement techniques such as derivative spectroscopy and self-deconvolution, plus the application of iterative curve-fitting techniques, this method provides a wealth of information concerning protein secondary structure. Further extraction of conformational information from the amide I band is dependent upon discerning the correlations between specific conformation types and component bands in the amide I region. In this paper the authors report spectra-structure correlations derived from conformational perturbations in bovine trypsin which arise from autolytic processing, zymogen activation, and active-site inhibition. IR spectra were collected for the single-chain ({beta}-trypsin) and once-cleaved, double-chain ({alpha}-trypsin) forms as well as at various times during the course of autolysis and also for zymogen, trypsinogen, and {beta}-trypsin inhibited with diisopropyl fluorophosphate. Spectral differences among the various molecular forms were interpreted in light of previous biochemical studies of autolysis and the known three-dimensional structures of the zymogen, the active enzyme, and the DIP-inhibited form. The spectroscopic results from these proteins in D{sub 2}O imply that certain loop structures may absorb in the region of 1655 cm{sup {minus}1}. They estimate that this approach to data analysis and interpretation is sensitive to changes of 0.01 unit or less in the relative integrated intensities of component bands in spectra whose peaks are well resolved.

  8. Chest X-Ray

    Medline Plus

    Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

  9. X-ray sky

    International Nuclear Information System (INIS)

    Gruen, M.; Koubsky, P.

    1977-01-01

    The history is described of the discoveries of X-ray sources in the sky. The individual X-ray detectors are described in more detail, i.e., gas counters, scintillation detectors, semiconductor detectors, and the principles of X-ray spectrometry and of radiation collimation aimed at increased resolution are discussed. Currently, over 200 celestial X-ray sources are known. Some were identified as nebulae, in some pulsations were found or the source was identified as a binary star. X-ray bursts of novae were also observed. The X-ray radiation is briefly mentioned of spherical star clusters and of extragalactic X-ray sources. (Oy)

  10. Parallel of semi-empirical results simulated by MCNP of X-ray spectra with a semiconductor; Paralelo de resultado semi- empiricos simulados por MCNPX de espectros de raios-X com um semicondutor

    Energy Technology Data Exchange (ETDEWEB)

    Santos, L.R.; Vivolo, V.; Potiens, M.P.A., E-mail: dossantos.lucasrodrigues@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Navarro, M.V.T.; Santos, W.S. [Universidade Federal de Uberlandia (INFIS/UFU), MG (Brazil). Instituto de Fisica

    2016-07-01

    The aim of this study was to use the MCNPX radiation transport code to simulate X-ray spectra generated by a constant voltage system in a CdTe semiconductor detector. As part of the validation process, we obtained a series of experimental spectra. Comparatively, in all cases there is a good correlation between the two spectra. There were no statistically significant differences between the experimental results with the simulated. (author)

  11. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

    DEFF Research Database (Denmark)

    Rana, Vikram; Loh, Alan; Corbel, Stephane

    2016-01-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0...

  12. The ultraluminous x-ray sources ngc 1313 x-1 and x-2: a broadband study with NuSTAR and XMM-Newton

    DEFF Research Database (Denmark)

    Bachetti, Matteo; Rana, Vikram; Walton, Dominic J.

    2013-01-01

    We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources: NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites enables us to produce the first spectrum of X-1 between 0.3 and 30 keV, while X-2 is not significantly detected by NuSTAR...

  13. Experimental investigation of bright spots in broadband, gated x-ray images of ignition-scale implosions on the National Ignition Facility

    International Nuclear Information System (INIS)

    Barrios, M. A.; Suter, L. J.; Glenn, S.; Benedetti, L. R.; Bradley, D. K.; Collins, G. W.; Hammel, B. A.; Izumi, N.; Ma, T.; Scott, H.; Smalyuk, V. A.; Regan, S. P.; Epstein, R.; Kyrala, G. A.

    2013-01-01

    Bright spots in the hot spot intensity profile of gated x-ray images of ignition-scale implosions at the National Ignition Facility [G. H. Miller et al., Opt. Eng. 443, (2004)] are observed. X-ray images of cryogenically layered deuterium-tritium (DT) and tritium-hydrogen-deuterium (THD) ice capsules, and gas filled plastic shell capsules (Symcap) were recorded along the hohlraum symmetry axis. Heterogeneous mixing of ablator material and fuel into the hot spot (i.e., hot-spot mix) by hydrodynamic instabilities causes the bright spots. Hot-spot mix increases the radiative cooling of the hot spot. Fourier analysis of the x-ray images is used to quantify the evolution of bright spots in both x- and k-space. Bright spot images were azimuthally binned to characterize bright spot location relative to known isolated defects on the capsule surface. A strong correlation is observed between bright spot location and the fill tube for both Symcap and cryogenically layered DT and THD ice targets, indicating the fill tube is a significant seed for the ablation front instability causing hot-spot mix. The fill tube is the predominant seed for Symcaps, while other capsule non-uniformities are dominant seeds for the cryogenically layered DT and THD ice targets. A comparison of the bright spot power observed for Si- and Ge-doped ablator targets shows heterogeneous mix in Symcap targets is mostly material from the doped ablator layer

  14. Predicting Near Edge X-ray Absorption Spectra with the Spin-Free Exact-Two-Component Hamiltonian and Orthogonality Constrained Density Functional Theory.

    Science.gov (United States)

    Verma, Prakash; Derricotte, Wallace D; Evangelista, Francesco A

    2016-01-12

    Orthogonality constrained density functional theory (OCDFT) provides near-edge X-ray absorption (NEXAS) spectra of first-row elements within one electronvolt from experimental values. However, with increasing atomic number, scalar relativistic effects become the dominant source of error in a nonrelativistic OCDFT treatment of core-valence excitations. In this work we report a novel implementation of the spin-free exact-two-component (X2C) one-electron treatment of scalar relativistic effects and its combination with a recently developed OCDFT approach to compute a manifold of core-valence excited states. The inclusion of scalar relativistic effects in OCDFT reduces the mean absolute error of second-row elements core-valence excitations from 10.3 to 2.3 eV. For all the excitations considered, the results from X2C calculations are also found to be in excellent agreement with those from low-order spin-free Douglas-Kroll-Hess relativistic Hamiltonians. The X2C-OCDFT NEXAS spectra of three organotitanium complexes (TiCl4, TiCpCl3, TiCp2Cl2) are in very good agreement with unshifted experimental results and show a maximum absolute error of 5-6 eV. In addition, a decomposition of the total transition dipole moment into partial atomic contributions is proposed and applied to analyze the nature of the Ti pre-edge transitions in the three organotitanium complexes.

  15. Core-level spectra and binding energies of transition metal nitrides by non-destructive x-ray photoelectron spectroscopy through capping layers

    International Nuclear Information System (INIS)

    Greczynski, G.; Primetzhofer, D.; Lu, J.; Hultman, L.

    2017-01-01

    Highlights: • First non-destructive measurements of XPS core level binding energies for group IVb-VIb transition metal nitrides are presented. • All films are grown under the same conditions and analyzed in the same instrument, providing a useful reference for future XPS studies. • Extracted core level BE values are more reliable than those obtained from sputter-cleaned N-deficient surfaces. • Comparison to Ar+-etched surfaces reveals that even mild etching conditions result in the formation of a nitrogen-deficient surface layer. • The N/metal concentration ratios from capped samples are found to be 25-90% higher than those from the corresponding ion-etched surfaces. - Abstract: We present the first measurements of x-ray photoelectron spectroscopy (XPS) core level binding energies (BE:s) for the widely-applicable group IVb-VIb polycrystalline transition metal nitrides (TMN’s) TiN, VN, CrN, ZrN, NbN, MoN, HfN, TaN, and WN as well as AlN and SiN, which are common components in the TMN-based alloy systems. Nitride thin film samples were grown at 400 °C by reactive dc magnetron sputtering from elemental targets in Ar/N 2 atmosphere. For XPS measurements, layers are either (i) Ar + ion-etched to remove surface oxides resulting from the air exposure during sample transfer from the growth chamber into the XPS system, or (ii) in situ capped with a few nm thick Cr or W overlayers in the deposition system prior to air-exposure and loading into the XPS instrument. Film elemental composition and phase content is thoroughly characterized with time-of-flight elastic recoil detection analysis (ToF-E ERDA), Rutherford backscattering spectrometry (RBS), and x-ray diffraction. High energy resolution core level XPS spectra acquired with monochromatic Al Kα radiation on the ISO-calibrated instrument reveal that even mild etching conditions result in the formation of a nitrogen-deficient surface layer that substantially affects the extracted binding energy values. These

  16. Core-level spectra and binding energies of transition metal nitrides by non-destructive x-ray photoelectron spectroscopy through capping layers

    Energy Technology Data Exchange (ETDEWEB)

    Greczynski, G., E-mail: grzgr@ifm.liu.se [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-581 83 Linköping (Sweden); Primetzhofer, D. [Department of Physics and Astronomy, The Ångström Laboratory, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); Lu, J.; Hultman, L. [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-581 83 Linköping (Sweden)

    2017-02-28

    Highlights: • First non-destructive measurements of XPS core level binding energies for group IVb-VIb transition metal nitrides are presented. • All films are grown under the same conditions and analyzed in the same instrument, providing a useful reference for future XPS studies. • Extracted core level BE values are more reliable than those obtained from sputter-cleaned N-deficient surfaces. • Comparison to Ar+-etched surfaces reveals that even mild etching conditions result in the formation of a nitrogen-deficient surface layer. • The N/metal concentration ratios from capped samples are found to be 25-90% higher than those from the corresponding ion-etched surfaces. - Abstract: We present the first measurements of x-ray photoelectron spectroscopy (XPS) core level binding energies (BE:s) for the widely-applicable group IVb-VIb polycrystalline transition metal nitrides (TMN’s) TiN, VN, CrN, ZrN, NbN, MoN, HfN, TaN, and WN as well as AlN and SiN, which are common components in the TMN-based alloy systems. Nitride thin film samples were grown at 400 °C by reactive dc magnetron sputtering from elemental targets in Ar/N{sub 2} atmosphere. For XPS measurements, layers are either (i) Ar{sup +} ion-etched to remove surface oxides resulting from the air exposure during sample transfer from the growth chamber into the XPS system, or (ii) in situ capped with a few nm thick Cr or W overlayers in the deposition system prior to air-exposure and loading into the XPS instrument. Film elemental composition and phase content is thoroughly characterized with time-of-flight elastic recoil detection analysis (ToF-E ERDA), Rutherford backscattering spectrometry (RBS), and x-ray diffraction. High energy resolution core level XPS spectra acquired with monochromatic Al Kα radiation on the ISO-calibrated instrument reveal that even mild etching conditions result in the formation of a nitrogen-deficient surface layer that substantially affects the extracted binding energy

  17. A Test of Thick-Target Nonuniform Ionization as an Explanation for Breaks in Solar Flare Hard X-Ray Spectra

    Science.gov (United States)

    Holman, gordon; Dennis Brian R.; Tolbert, Anne K.; Schwartz, Richard

    2010-01-01

    Solar nonthermal hard X-ray (HXR) flare spectra often cannot be fitted by a single power law, but rather require a downward break in the photon spectrum. A possible explanation for this spectral break is nonuniform ionization in the emission region. We have developed a computer code to calculate the photon spectrum from electrons with a power-law distribution injected into a thick-target in which the ionization decreases linearly from 100% to zero. We use the bremsstrahlung cross-section from Haug (1997), which closely approximates the full relativistic Bethe-Heitler cross-section, and compare photon spectra computed from this model with those obtained by Kontar, Brown and McArthur (2002), who used a step-function ionization model and the Kramers approximation to the cross-section. We find that for HXR spectra from a target with nonuniform ionization, the difference (Delta-gamma) between the power-law indexes above and below the break has an upper limit between approx.0.2 and 0.7 that depends on the power-law index delta of the injected electron distribution. A broken power-law spectrum with a. higher value of Delta-gamma cannot result from nonuniform ionization alone. The model is applied to spectra obtained around the peak times of 20 flares observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI from 2002 to 2004 to determine whether thick-target nonuniform ionization can explain the measured spectral breaks. A Monte Carlo method is used to determine the uncertainties of the best-fit parameters, especially on Delta-gamma. We find that 15 of the 20 flare spectra require a downward spectral break and that at least 6 of these could not be explained by nonuniform ionization alone because they had values of Delta-gamma with less than a 2.5% probability of being consistent with the computed upper limits from the model. The remaining 9 flare spectra, based on this criterion, are consistent with the nonuniform ionization model.

  18. X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Vries, J.L. de.

    1976-01-01

    The seventh edition of Philips' Review of Literature on x-ray fluorescence spectrometry starts with a list of conference proceedings on the subject, organised by the Philips organisation at regular intervals in various European countries. It is followed by a list of bulletins. The bibliography is subdivided according to spectra, equipment, applications and absorption analysis

  19. The ultraluminous X-ray sources NGC 1313 X-1 and X-2: A broadband study with NuSTAR and XMM-Newton

    Energy Technology Data Exchange (ETDEWEB)

    Bachetti, Matteo; Barret, Didier; Webb, Natalie A. [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Rana, Vikram; Walton, Dominic J.; Harrison, Fiona A.; Fürst, Felix; Grefenstette, Brian W.; Madsen, Kristin K. [Cahill Center for Astronomy and Astrophysics, Caltech, Pasadena, CA 91125 (United States); Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, Andrew C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Hornschemeier, Ann; Ptak, Andrew F.; Zhang, William W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Miller, Jon M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Stern, Daniel, E-mail: matteo.bachetti@irap.omp.eu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2013-12-01

    We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources: NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites enables us to produce the first spectrum of X-1 between 0.3 and 30 keV, while X-2 is not significantly detected by NuSTAR above 10 keV. The NuSTAR data demonstrate that X-1 has a clear cutoff above 10 keV, whose presence was only marginally detectable with previous X-ray observations. This cutoff rules out the interpretation of X-1 as a black hole in a standard low/hard state, and it is deeper than predicted for the downturn of a broadened iron line in a reflection-dominated regime. The cutoff differs from the prediction of a single-temperature Comptonization model. Further, a cold disk-like blackbody component at ∼0.3 keV is required by the data, confirming previous measurements by XMM-Newton only. We observe a spectral transition in X-2, from a state with high luminosity and strong variability to a lower-luminosity state with no detectable variability, and we link this behavior to a transition from a super-Eddington to a sub-Eddington regime.

  20. How calibration and reference spectra affect the accuracy of absolute soft X-ray solar irradiance measured by the SDO/EVE/ESP during high solar activity

    Science.gov (United States)

    Didkovsky, Leonid; Wieman, Seth; Woods, Thomas

    2016-10-01

    The Extreme ultraviolet Spectrophotometer (ESP), one of the channels of SDO's Extreme ultraviolet Variability Experiment (EVE), measures solar irradiance in several EUV and soft x-ray (SXR) bands isolated using thin-film filters and a transmission diffraction grating, and includes a quad-diode detector positioned at the grating zeroth-order to observe in a wavelength band from about 0.1 to 7.0 nm. The quad diode signal also includes some contribution from shorter wavelength in the grating's first-order and the ratio of zeroth-order to first-order signal depends on both source geometry, and spectral distribution. For example, radiometric calibration of the ESP zeroth-order at the NIST SURF BL-2 with a near-parallel beam provides a different zeroth-to-first-order ratio than modeled for solar observations. The relative influence of "uncalibrated" first-order irradiance during solar observations is a function of the solar spectral irradiance and the locations of large Active Regions or solar flares. We discuss how the "uncalibrated" first-order "solar" component and the use of variable solar reference spectra affect determination of absolute SXR irradiance which currently may be significantly overestimated during high solar activity.

  1. Many-electron theory of x-ray photoelectron spectra: N-shell linewidths in the 46Pd to 92U range

    International Nuclear Information System (INIS)

    Ohno, M.; Wendin, G.

    1985-01-01

    The linewidths and energies of 4d holes (main lines in x-ray photoelectron spectra) are calculated for a number of elements in the range 70 Yb to 92 U, with use of nonrelativistic atomic many-body theory. The nonrelativistic Hartree-Fock frozen-core approximation for one-electron wave functions and Auger energies gives very good agreement with experiment. In the case of 4s and 4p holes, the Auger (in particular, super-Coster-Kronig) energies have to be calculated with inclusion of relaxation and relativistic effects. Combined with frozen-core, nonrelativistic one-electron wave functions, this gives good agreement with experimental energies and widths for 4s and 4p holes in 80 Hg. In conclusion, it is very important to include the effects of two final-state holes on the Auger electron, as well as the polarization response which screens the Auger emission matrix element. This latter effect is largely equivalent to the so-called exchange interaction between the Auger electron and the final-state holes

  2. Classification of X-ray spectra from laser produced plasmas of atoms from Tm to Pt in the range 6-9A

    International Nuclear Information System (INIS)

    Mandelbaum, P.; Klapisch, M.; Bar-Shalom, A.; Schwob, J.L.; Zigler, A.

    1983-01-01

    X-ray spectra of highly ionized tungsten and neighbouring atoms (Tm, Yb, Hf, Ta, W, Re and Pt) has been observed from laser produced plasmas in the lambda = 6-9A range. Beside the prominent lines of the Ni I-like ions, lines belonging to Co I (3d 9 -3d 8 4p), Cu I (3d 10 4s-3d 9 4s4p, 3d 10 4p-3d 9 4p 2 ) and Zn I-like ions (3d 10 4s 2 -3d 9 4s 2 4p, 3d 10 4s4p-3d 9 4s4p 2 ) have been identified. Classification was based on isoelectronic sequence analysis and on comparison with ab-initio relativistic calculations. A collisional-radiative model of the Cu I-like ions in the plasma is used to show that the contribution of the 3d 10 4d-3d 9 4p4d and 3d 10 4f-3d 9 4f4p transition arrays to the 3d-4p spectrum is small. The importance of configuration interaction is pointed out. Computations agree with measurements within experimental uncertainty. (Auth.)

  3. Chest X-Ray

    Medline Plus

    Full Text Available ... some concerns about chest x-rays. However, it’s important to consider the likelihood of benefit to your health. While a chest x-ray use a ... posted: How to Obtain and Share ...

  4. Chest X-Ray

    Medline Plus

    Full Text Available ... X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey Rubin, a radiologist ... about chest x-rays, visit Radiology Info dot org. Thank you for your time! Spotlight Recently posted: ...

  5. X-ray apparatus

    International Nuclear Information System (INIS)

    Sell, L.J.

    1981-01-01

    A diagnostic x-ray device, readily convertible between conventional radiographic and tomographic operating modes, is described. An improved drive system interconnects and drives the x-ray source and the imaging device through coordinated movements for tomography

  6. X-ray - skeleton

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this ... Degenerative bone conditions Osteomyelitis Risks There is low radiation exposure. X-rays machines are set to provide the smallest ...

  7. Chest X-Ray

    Medline Plus

    Full Text Available ... I’d like to talk with you about chest radiography also known as chest x-rays. Chest x-rays are the most ... far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! ...

  8. Chest X-Ray

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  9. Flash X-ray

    International Nuclear Information System (INIS)

    Sato, Eiichi

    2003-01-01

    Generation of quasi-monochromatic X-ray by production of weakly ionized line plasma (flash X-ray), high-speed imaging by the X-ray and high-contrast imaging by the characteristic X-ray absorption are described. The equipment for the X-ray is consisted from the high-voltage power supply and condenser, turbo molecular pump, and plasma X-ray tube. The tube has a long linear anticathode to produce the line plasma and flash X-ray at 20 kA current at maximum. X-ray spectrum is measured by the imaging plate equipped in the computed radiography system after diffracted by a LiF single crystal bender. Cu anticathode generates sharp peaks of K X-ray series. The tissue images are presented for vertebra, rabbit ear and heart, and dog heart by X-ray fluoroscopy with Ce anticathode. Generation of K-orbit characteristic X-ray with extremely low bremsstrahung is to be attempted for medical use. (N.I.)

  10. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-09

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

  11. X-ray astronomy

    International Nuclear Information System (INIS)

    Culhane, J.L.; Sanford, P.W.

    1981-01-01

    X-ray astronomy has been established as a powerful means of observing matter in its most extreme form. The energy liberated by sources discovered in our Galaxy has confirmed that collapsed stars of great density, and with intense gravitational fields, can be studied by making observations in the X-ray part of the electromagnetic spectrum. The astronomical objects which emit detectable X-rays include our own Sun and extend to quasars at the edge of the Universe. This book describes the history, techniques and results obtained in the first twenty-five years of exploration. Space rockets and satellites are essential for carrying the instruments above the Earth's atmosphere where it becomes possible to view the X-rays from stars and nebulae. The subject is covered in chapters, entitled: the birth of X-ray astronomy; the nature of X-radiation; X-rays from the Sun; solar-flare X-rays; X-rays from beyond the solar system; supernovae and their remnants; X-rays from binary stars; white dwarfs and neutron stars; black holes; X-rays from galaxies and quasars; clusters of galaxies; the observatories of the future. (author)

  12. NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. I. HARD X-RAY MORPHOLOGY AND SPECTROSCOPY OF THE DIFFUSE EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kaya; Hailey, Charles J.; Perez, Kerstin; Nynka, Melania; Zhang, Shuo; Canipe, Alicia M. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Krivonos, Roman; Tomsick, John A.; Barrière, Nicolas; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Hong, Jaesub [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Ponti, Gabriele [Max-Planck-Institut f. extraterrestrische Physik, HEG, Garching (Germany); Bauer, Franz [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Alexander, David M. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Baganoff, Frederick K. [Kavli Institute for Astrophysics and Space Research, Massachusets Institute of Technology, Cambridge, MA 02139 (United States); Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Christensen, Finn E. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Forster, Karl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Giommi, Paolo, E-mail: kaya@astro.columbia.edu [ASI Science Data Center, Via del Politecnico snc I-00133, Roma (Italy); and others

    2015-12-01

    We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). NuSTAR detects four non-thermal X-ray filaments, extending the detection of their power-law spectra with Γ ∼ 1.3–2.3 up to ∼50 keV. A morphological and spectral study of the filaments suggests that their origin may be heterogeneous, where previous studies suggested a common origin in young pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission spatially correlated with the 6.4 keV Fe Kα fluorescence line emission associated with two Sgr A molecular clouds: MC1 and the Bridge. Broadband X-ray spectral analysis with a Monte-Carlo based X-ray reflection model self-consistently determined their intrinsic column density (∼10{sup 23} cm{sup −2}), primary X-ray spectra (power-laws with Γ ∼ 2) and set a lower limit of the X-ray luminosity of Sgr A* flare illuminating the Sgr A clouds to L{sub X} ≳ 10{sup 38} erg s{sup −1}. Above ∼20 keV, hard X-ray emission in the central 10 pc region around Sgr A* consists of the candidate PWN G359.95–0.04 and the CHXE, possibly resulting from an unresolved population of massive CVs with white dwarf masses M{sub WD} ∼ 0.9 M{sub ⊙}. Spectral energy distribution analysis suggests that G359.95–0.04 is likely the hard X-ray counterpart of the ultra-high gamma-ray source HESS J1745–290, strongly favoring a leptonic origin of the GC TeV emission.

  13. X-ray holography

    International Nuclear Information System (INIS)

    Faigel, G.; Tegze, M.; Belakhovsky, M.; Marchesini, S.; Bortel, G.

    2003-01-01

    In the last decade holographic methods using hard X-rays were developed. They are able to resolve atomic distances, and can give the 3D arrangement of atoms around a selected element. Therefore, hard X-ray holography has potential applications in chemistry, biology and physics. In this article we give a general description of these methods and discuss the developments in the experimental technique. The capabilities of hard X-ray holography are demonstrated by examples

  14. Symbiotic Stars in X-rays

    Science.gov (United States)

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

    2014-01-01

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

  15. Providing x-rays

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.

    1985-01-01

    This invention provides an apparatus for providing x-rays to an object that may be in an ordinary environment such as air at approximately atmospheric pressure. The apparatus comprises: means (typically a laser beam) for directing energy onto a target to produce x-rays of a selected spectrum and intensity at the target; a fluid-tight enclosure around the target; means for maintaining the pressure in the first enclosure substantially below atmospheric pressure; a fluid-tight second enclosure adjoining the first enclosure, the common wall portion having an opening large enough to permit x-rays to pass through but small enough to allow the pressure reducing means to evacuate gas from the first enclosure at least as fast as it enters through the opening; the second enclosure filled with a gas that is highly transparent to x-rays; the wall of the second enclosure to which the x-rays travel having a portion that is highly transparent to x-rays (usually a beryllium or plastic foil), so that the object to which the x-rays are to be provided may be located outside the second enclosure and adjacent thereto and thus receive the x-rays substantially unimpeded by air or other intervening matter. The apparatus is particularly suited to obtaining EXAFS (extended x-ray fine structure spectroscopy) data on a material

  16. Contribution to time resolved X-ray fluence and differential spectra measurement method improvement in 5-200 KeV range. Application to pulsed emission sources

    International Nuclear Information System (INIS)

    Vie, M.

    1983-09-01

    Two types of sensors have been developed to measure locally the time-resolved fluence and differential energetic spectrum of pulsed X-ray in the energy range 5 to 200 keV. Rise time of these sensors is very short (10 ns) in order to permit time-resolved measurements. Fluence sensors have been developed by putting filters in front of detector in order to make sensor response independent of X-ray energy and proportional to X-ray fluence. The energetic differential spectrum was calculated by way of a method similar to the ROSS method but using filters separated within a pair defining adjacent spectral width. A detailed analysis of uncertainties affecting calculated fluence and spectrum has been done [fr

  17. THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Zabalza, V.; Paredes, J. M. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Marti i Franques 1, E08028 Barcelona (Spain); Bosch-Ramon, V., E-mail: vzabalza@am.ub.es [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

    2011-12-10

    Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

  18. Reconstruction of Spectra Using X-ray Flat Panel Detector; Reconstruccion de Espectros de Rayos X Utilizando un Detector Flat Panel

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Querol, A.; Pozuelo, F.; Juste, B.; Rodenas, J.; Verdu, G.

    2013-07-01

    In this work, we used a flat panel detector with a wedge of PMMA for absorbed dose curve for given working conditions of X-ray tube The relationship between absorbed dose curve recorded by the flat panel and primary X-ray spectrum is defined by a response function that can be obtained using the Monte Carlo method, namely the MCNP5 code. However there are some problems that affect the applicability of this method such as: flat panel characteristics and the characteristics of the physical process (ill-conditioned problem). Both aspects are discussed in this paper.

  19. X-ray interferometers

    International Nuclear Information System (INIS)

    Franks, A.

    1980-01-01

    An improved type of amplitude-division x-ray interferometer is described. The wavelength at which the interferometer can operate is variable, allowing the instrument to be used to measure x-ray wavelength, and the angle of inclination is variable for sample investigation. (U.K.)

  20. Extremity x-ray

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003461.htm Extremity x-ray To use the sharing features on this page, ... in the body Risks There is low-level radiation exposure. X-rays are monitored and regulated to provide the ...

  1. X-rays utilization

    International Nuclear Information System (INIS)

    Rebigan, F.

    1979-03-01

    The modality of X-ray utilization in different activities and economy is given. One presents firstly quantities and units used in radiation dosimetry and other fields. One gives the generation of X-rays, their properties as well as the elements of radiation protection. The utilization characteristics of these radiations in different fields are finally given. (author)

  2. Chest X-Ray

    Medline Plus

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

  3. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    L. Miaja-Avila

    2015-03-01

    Full Text Available We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  4. Resonant inelastic x-ray scattering studies of elementary excitations

    NARCIS (Netherlands)

    Ament, Lucas Johannes Peter (Luuk)

    2010-01-01

    Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

  5. A study of radiative Auger emission, satellites and hypersatellites in photon-induced K x-ray spectra of some elements in the range 20≤Z≤32

    International Nuclear Information System (INIS)

    Verma, H.R.

    2000-01-01

    Photon-induced K x-ray spectra of Ca, Ti, Fe, Zn and Ge have been investigated. The measurements have been made using a crystal spectrometer combined with a thin scintillation detector. Excited by the collimated photon beam from an Rh-anode x-ray tube, the spectra of all these elements reveal the existence of radiative Auger emission (RAE) structure and the satellite and hypersatellite lines along with the diagram lines. The energies and intensities of the Kα 2 , Kα 1 , Kβ 1,3 and Kβ 5 diagram lines and the Kα satellites and hypersatellite transitions are presented. The intensity of the RAE structure corresponding to the Kβ 1,3 x-ray transition and the energy of the RAE edge for each element is also reported. The measured results have been compared with the values from other sources such as electron/heavy-ion excitation and theoretical values. From the intensities of the satellite lines of these elements, the average L-vacancy fraction P L has been deduced in each case. (author)

  6. Application of Monte Carlo Method in the Analysis of Materials. Used in Flat Panel Detectors to Get X-ray spectra; Aplicacion del Metodo de Monte Carlo en el Analisis de Materiales Utilizados en Detectores Flat Panel para Obtener Espectros de Rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Pozuelo, F.; Querol, A.; Rodenas, J.; Verdu, G.

    2013-07-01

    They have used various methods of reconstruction for the X-ray spectrum curve knowing the dose-response function. The results demonstrate that the method modified truncated singular value decomposition (MTSVD) is appropriate to reconstruct the spectra of X-ray scintillator materials studied in this work.

  7. X-ray crystallography

    Science.gov (United States)

    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.

  8. X-ray stars observed in LAMOST spectral survey

    Science.gov (United States)

    Lu, Hong-peng; Zhang, Li-yun; Han, Xianming L.; Shi, Jianrong

    2018-05-01

    X-ray stars have been studied since the beginning of X-ray astronomy. Investigating and studying the chromospheric activity from X-ray stellar optical spectra is highly significant in providing insights into stellar magnetic activity. The big data of LAMOST survey provides an opportunity for researching stellar optical spectroscopic properties of X-ray stars. We inferred the physical properties of X-ray stellar sources from the analysis of LAMOST spectra. First, we cross-matched the X-ray stellar catalogue (12254 X-ray stars) from ARXA with LAMOST data release 3 (DR3), and obtained 984 good spectra from 713 X-ray sources. We then visually inspected and assigned spectral type to each spectrum and calculated the equivalent width (EW) of Hα line using the Hammer spectral typing facility. Based on the EW of Hα line, we found 203 spectra of 145 X-ray sources with Hα emission above the continuum. For these spectra we also measured the EWs of Hβ, Hγ, Hδ and Ca ii IRT lines of these spectra. After removing novae, planetary nebulae and OB-type stars, we found there are 127 X-ray late-type stars with Hα line emission. By using our spectra and results from the literature, we found 53 X-ray stars showing Hα variability; these objects are Classical T Tauri stars (CTTs), cataclysmic variables (CVs) or chromospheric activity stars. We also found 18 X-ray stars showing obvious emissions in the Ca ii IRT lines. Of the 18 X-ray stars, 16 are CTTs and 2 are CVs. Finally, we discussed the relationships between the EW of Hα line and X-ray flux.

  9. X-ray lasers

    CERN Document Server

    Elton, Raymond C

    2012-01-01

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

  10. X-ray apparatus

    International Nuclear Information System (INIS)

    Bernstein, S.; Stagg, L.; Lambert, T.W.; Griswa, P.J.

    1976-01-01

    A patient support system for X-ray equipment in arteriographic studies of the heart is described in detail. The support system has been designed to overcome many of the practical problems encountered in using previous types of arteriographic X-ray equipment. The support system is capable of horizontal movement and, by a series of shafts attached to the main support system, the X-ray source and image intensifier or detector may be rotated through the same angle. The system is highly flexible and details are given of several possible operational modes. (U.K.)

  11. X-ray detector

    International Nuclear Information System (INIS)

    Whetten, N.R.; Houston, J.M.

    1977-01-01

    An ionization chamber for use in determining the spatial distribution of x-ray photons in tomography systems comprises a plurality of substantially parallel, planar anodes separated by parallel, planar cathodes and enclosed in a gas of high atomic weight at a pressure from approximately 10 atmospheres to approximately 50 atmospheres. The cathode and anode structures comprise metals which are substantially opaque to x-ray radiation and thereby tend to reduce the resolution limiting effects of x-ray fluoresence in the gas. In another embodiment of the invention the anodes comprise parallel conductive bars disposed between two planar cathodes. Guard rings eliminate surface leakage currents between adjacent electrodes. 8 figures

  12. X-ray apparatus

    International Nuclear Information System (INIS)

    Grady, J.K.

    1985-01-01

    X-ray apparatus is described which has a shutter between the X-ray source and the patient. The shutter controls the level of radiation to which the patient is exposed instead of merely discontinuing the electric power supplied to the source. When the shutter is opened a radiation sensor senses the level of X-radiation. When a preset quantity of X-radiation has been measured an exposure control closes the shutter. Instead of using the radiation sensor, the integrated power supplied to the anode of the X-ray source may be measured. (author)

  13. Bone X-Ray (Radiography)

    Medline Plus

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

  14. Bone X-Ray (Radiography)

    Medline Plus

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

  15. X-ray examination apparatus

    NARCIS (Netherlands)

    2000-01-01

    The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an

  16. Bone X-Ray (Radiography)

    Medline Plus

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

  17. Bone X-Ray (Radiography)

    Science.gov (United States)

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

  18. Bone X-Ray (Radiography)

    Medline Plus

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

  19. Abdomen X-Ray (Radiography)

    Science.gov (United States)

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

  20. X-ray novae - what are they

    International Nuclear Information System (INIS)

    Wennfors, B.

    1976-01-01

    Ten of the two hundred cosmic X-ray sources exhibit characteristics in their emissions analogous to novae, i.e. after a rapid increase in luminosity, lasting about three days, follows a period of about a month with a slow decrease, and thereafter a rapid decrease to invisibility. The spectra of such sources are discussed in general terms and brief descriptions are given of the five which have been identified with optical objects. Three models for the history of X-ray novae, all based on X-ray emission from a compact object in an orbit very near a larger star, are discussed. (JIW)

  1. X-ray streak crystal spectography

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Brown, T.; Medecki, H.

    1983-01-01

    We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11 0 to 38 0 and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/δE > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given

  2. Streaked, x-ray-transmission-grating spectrometer

    International Nuclear Information System (INIS)

    Ceglio, N.M.; Roth, M.; Hawryluk, A.M.

    1981-08-01

    A free standing x-ray transmission grating has been coupled with a soft x-ray streak camera to produce a time resolved x-ray spectrometer. The instrument has a temporal resolution of approx. 20 psec, is capable of covering a broad spectral range, 2 to 120 A, has high sensitivity, and is simple to use requiring no complex alignment procedure. In recent laser fusion experiments the spectrometer successfully recorded time resolved spectra over the range 10 to 120 A with a spectral resolving power, lambda/Δlambda of 4 to 50, limited primarily by source size and collimation effects

  3. Chest X-Ray

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey ...

  4. Chest X-Ray

    Medline Plus

    Full Text Available ... also be useful to help diagnose and monitor treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  5. X-ray tubes

    International Nuclear Information System (INIS)

    Young, R.W.

    1979-01-01

    A form of x-ray tube is described which provides satisfactory focussing of the electron beam when the beam extends for several feet from gun to target. Such a tube can be used for computerised tomographic scanning. (UK)

  6. Chest X-Ray

    Medline Plus

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

  7. Chest X-Ray

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Chest X-ray ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

  8. Chest X-Ray

    Medline Plus

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

  9. Chest X-Ray

    Medline Plus

    Full Text Available ... Site Index A-Z Spotlight Recently posted: Pancreatic Cancer The Limitations of Online Dose Calculators Video: The ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  10. Chest X-Ray

    Medline Plus

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

  11. Chest X-Ray

    Medline Plus

    Full Text Available ... However, it’s important to consider the likelihood of benefit to your health. While a chest x-ray use a tiny dose of ionizing radiation, the benefit of an accurate diagnosis far outweighs any risk. ...

  12. Chest X-Ray

    Medline Plus

    Full Text Available ... June is Men's Health Month Recently posted: Pancreatic Cancer The Limitations of Online Dose Calculators Video: The ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  13. X-ray sources

    International Nuclear Information System (INIS)

    Masswig, I.

    1986-01-01

    The tkb market survey comparatively evaluates the X-ray sources and replacement tubes for stationary equipment currently available on the German market. It lists the equipment parameters of 235 commercially available X-ray sources and their replacement tubes and gives the criteria for purchase decisions. The survey has been completed with December 1985, and offers good information concerning medical and technical aspects as well as those of safety and maintenance. (orig.) [de

  14. Calibration of GafChromic XR-RV3 radiochromic film for skin dose measurement using standardized x-ray spectra and a commercial flatbed scanner

    International Nuclear Information System (INIS)

    McCabe, Bradley P.; Speidel, Michael A.; Pike, Tina L.; Van Lysel, Michael S.

    2011-01-01

    Purpose: In this study, newly formulated XR-RV3 GafChromic film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures. Methods: The film was calibrated free-in-air to air kerma levels between 15 and 1100 cGy using four moderately filtered x-ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film reflective density-to-air kerma calibration curves were constructed for each beam quality, with both the orange and white sides facing the x-ray source. A method to correct for nonuniformity in scanner response (up to 25% depending on position) was developed to enable dose measurement with large films. The response of XR-RV3 film under patient backscattering conditions was examined using on-phantom film exposures and Monte Carlo simulations. Results: The response of XR-RV3 film to a given air kerma depended on kVp and film orientation. For a 200 cGy air kerma exposure with the orange side of the film facing the source, the film response increased by 20% from 60 to 120 kVp. At 500 cGy, the increase was 12%. When 500 cGy exposures were performed with the white side facing the x-ray source, the film response increased by 4.0% (60 kVp) to 9.9% (120 kVp) compared to the orange-facing orientation. On-phantom film measurements and Monte Carlo simulations show that using a NIST-traceable free-in-air calibration curve to determine air kerma in the presence of backscatter results in an error from 2% up to 8% depending on beam quality. The combined uncertainty in the air kerma measurement from the calibration curves and scanner nonuniformity correction was ±7.1% (95% C.I.). The film showed notable stability. Calibrations of film and scanner separated by 1 yr differed by 1.0%. Conclusions: XR-RV3 radiochromic film response to a given air kerma shows dependence on beam quality and film

  15. Bone X-Ray (Radiography)

    Medline Plus

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

  16. Bone X-Ray (Radiography)

    Medline Plus

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

  17. Bone X-Ray (Radiography)

    Medline Plus

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

  18. Bone X-Ray (Radiography)

    Medline Plus

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

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? A ...

  20. Bone X-Ray (Radiography)

    Medline Plus

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

  1. Mass attenuation coefficient (μ/ρ), effective atomic number (Z{sub eff}) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil); Goncalves Z, E., E-mail: madelon@cdtn.br [Pontifice Catholic University of Minas Gerais, Av. Dom Jose Gaspar 500, Belo Horizonte 30535-901, Minas Gerais (Brazil)

    2015-10-15

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z{sub eff} of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z{sub eff} using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  2. Hybridization and bond-orbital components in site-specific X-ray photoelectron spectra of rutile TiO2

    International Nuclear Information System (INIS)

    Woicik, J.C.; Nelson, E.J.; Kronik, Leeor; Jain, Manish; Chelikowsky, James R.; Heskett, D.; Berman, L.E.; Herman, G.S.

    2002-01-01

    We have determined the Ti and O components of the rutile TiO 2 valence band using the method of site-specific x-ray photoelectron spectroscopy. Comparisons with calculations based on pseudopotentials within the local density approximation reveal the hybridization of the Ti 3d, 4s, and 4p states, and the O 2s and 2p states on each site. These chemical effects are observed due to the large differences between the angular-momentum dependent matrix elements of the photoelectron process

  3. Theoretical interpretation for 2p − nd absorption spectra of iron, nickel, and copper in X-ray range measured at the LULI2000 facility

    Directory of Open Access Journals (Sweden)

    Poirier M.

    2013-11-01

    Full Text Available The 2p − nd absorption structures in medium Z elements present a valuable benchmark for atomic models since they exhibit a complex dependence on temperature and density. For these transitions lying in the X-ray range, one observes a competition between the spin-orbit splitting and the broadening associated to the excitation of complex structures. Detailed opacity codes based on the HULLAC or FAC suites agree with the statistical code SCO; but in iron computations predict higher peak absorption than measured. An addition procedure on opacities calculated with detailed codes is proposed and successfully tested.

  4. Reconstruction of X-rays spectra of clinical linear accelerators using the generalized simulated annealing method; Reconstrucao de espectros de raios-X de aceleradores lineares clinicos usando o metodo de recozimento simulado generalizado

    Energy Technology Data Exchange (ETDEWEB)

    Manrique, John Peter O.; Costa, Alessandro M., E-mail: johnp067@usp.br, E-mail: amcosta@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil)

    2016-07-01

    The spectral distribution of megavoltage X-rays used in radiotherapy departments is a fundamental quantity from which, in principle, all relevant information required for radiotherapy treatments can be determined. To calculate the dose delivered to the patient who make radiation therapy, are used treatment planning systems (TPS), which make use of convolution and superposition algorithms and which requires prior knowledge of the photon fluence spectrum to perform the calculation of three-dimensional doses and thus ensure better accuracy in the tumor control probabilities preserving the normal tissue complication probabilities low. In this work we have obtained the photon fluence spectrum of X-ray of the SIEMENS ONCOR linear accelerator of 6 MV, using an character-inverse method to the reconstruction of the spectra of photons from transmission curves measured for different thicknesses of aluminum; the method used for reconstruction of the spectra is a stochastic technique known as generalized simulated annealing (GSA), based on the work of quasi-equilibrium statistic of Tsallis. For the validation of the reconstructed spectra we calculated the curve of percentage depth dose (PDD) for energy of 6 MV, using Monte Carlo simulation with Penelope code, and from the PDD then calculate the beam quality index TPR{sub 20/10}. (author)

  5. Classification of x-ray spectra of 2-3 transitions in the Ne-like and Na-like isoelectronic sequences of the elements from krypton to molybdenum

    International Nuclear Information System (INIS)

    Gordon, H.; Hobby, M.G.; Peacock, N.J.; Cowan, R.D.

    1979-01-01

    Plasmas produced by the laser irradiation of solid targets and in a plasma focus device have been employed as sources of x-ray spectra of the elements Kr(Z = 36)-Mo(Z = 42). The Ne-like isoelectronic sequence has been investigated by comparing observed wavelengths with ab initio atomic structure calculations and isoelectronic interpolation. Previous identifications in Ne-like ions have been extended to krypton, rubidium and strontium. The Na-like satellite structure of these elements has also been studied and a detailed classification of these satellites is presented. (author)

  6. Analysis of the X-ray spectra emitted by laser-produced plasma of highly ionized lanthanum and praseodymium in the 8. 4 to 12. 0 A wavelength range

    Energy Technology Data Exchange (ETDEWEB)

    Zigler, A [Racah Inst. of Physics, Hebrew Univ., Jerusalem (Israel); Mandelbaum, P [Racah Inst. of Physics, Hebrew Univ., Jerusalem (Israel); Schwob, J L [Racah Inst. of Physics, Hebrew Univ., Jerusalem (Israel); Mitnik, D [Racah Inst. of Physics, Hebrew Univ., Jerusalem (Israel)

    1994-06-01

    A detailed analysis of the X-ray spectra emitted by laser produced plasma of lanthanum (8.5-12.5 A) and praseodymium (8.4-11.3 A) is given, using ab-initio calculations with the HULLAC relativistic code. Resonance 3d-nf (n 4, 5, 6) and 3p-4s, 4d transitions of the La XXX and Pr XXXII Ni I-like ions and neighbouring ionization states (La XXVIII to La XXXVI, Pr XXX to Pr XXXVI) have been identified. (orig.).

  7. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    Qin Yi

    2007-12-01

    A soft X-lens was devised with waveguide X-ray optics of total external reflection (TER). The lens consists of a stack of 1 387 TER waveguides with inner diameter of 0.45 mm and outer diameter of 0.60 mm. With the help of plasma sources of soft X-ray radiation, high density of pure soft X-ray radiation (without plasma expansion fragments) with broad-band spectral range can be obtained at the focus of the lens. As laser-plasma is considered, the radiation density of 1.3 x 10 5 W/cm 2 is obtained, the transmission coefficient is 18.6%, the ratio of the density at the focus with and without the lens is 1000 and the radiation capture is 28.9 degree. The density of 0.5 TW/cm 2 can be obtained as far as Qiang-Guang I facility is considered. (authors)

  8. Time-resolved suprathermal x-rays

    International Nuclear Information System (INIS)

    Lee, P.H.Y.; Rosen, M.D.

    1978-01-01

    Temporally resolved x-ray spectra in the range of 1 to 20 keV have been obtained from gold disk targets irradiated by 1.06 μm laser pulses from the Argus facility. The x-ray streak camera used for the measurement has been calibrated for streak speed and dynamic range by using an air-gap Fabry-Perot etalon, and the instrument response has been calibrated using a multi-range monoenergetic x-ray source. The experimental results indicate that we are able to observe the ''hot'' x-ray temperature evolve in time and that the experimentally observed values can be qualitatively predicted by LASNEX code computations when the inhibited transport model is used

  9. X-ray tube

    International Nuclear Information System (INIS)

    Webley, R.S.

    1975-01-01

    The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

  10. X-ray astronomy

    International Nuclear Information System (INIS)

    Giacconi, R.; Setti, G.

    1980-01-01

    This book contains the lectures, and the most important seminars held at the NATO meeting on X-Ray astronomy in Erice, July 1979. The meeting was an opportune forum to discuss the results of the first 8-months of operation of the X-ray satellite, HEAO-2 (Einstein Observatory) which was launched at the end of 1978. Besides surveying these results, the meeting covered extragalactic astronomy, including the relevant observations obtained in other portions of the electromagnetic spectrum (ultra-violet, optical, infrared and radio). The discussion on galactic X-ray sources essentially covered classical binaries, globular clusters and bursters and its significance to extragalactic sources and to high energy astrophysics was borne in mind. (orig.)

  11. Flash x-ray

    International Nuclear Information System (INIS)

    Johnson, Q.; Pellinen, D.

    1976-01-01

    The complementary techniques of flash x-ray radiography (FXR) and flash x-ray diffraction (FXD) provide access to a unique domain in nondestructive materials testing. FXR is useful in studies of macroscopic properties during extremely short time intervals, and FXD, the newer technique, is used in studies of microscopic properties. Although these techniques are similar in many respects, there are some substantial differences. FXD generally requires low-voltage, line-radiation sources and extremely accurate timing; FXR is usually less demanding. Phenomena which can be profitably studied by FXR often can also be studied by FXD to permit a complete materials characterization

  12. X-ray astronomy

    International Nuclear Information System (INIS)

    Narayanan, M.S.

    1976-01-01

    The deployment of detectors outside the deleterious effects of the atmosphere by sending them in space vehicles, has been explained. This has thrown open the entire spectrum of the electromagnetic and particle radiation to direct observations, thus enlarging the vistas of the field of astronomy and astrophysics. The discovery of strong emitters of X-rays such as SCO X-1, NorX-2, transient sources such as Cen X-2, Cen X-4, Cen X-1, Supernova remnants Tan X-1, etc., are reported. The background of the X-ray spectrum as measured during two rocket flights over Thumba, India is presented. (K.B.)

  13. X-ray masks

    International Nuclear Information System (INIS)

    Greenwood, J.C.; Satchell, D.W.

    1984-01-01

    In semiconductor manufacture, where X-ray irradiation is used, a thin silicon membrane can be used as an X-ray mask. This membrane has areas on which are patterns to define the regions to be irradiated. These regions are of antireflection material. With the thin, in the order of 3 microns, membranes used, fragility is a problem. Hence a number of ribs of silicon are formed integral with the membrane, and which are relatively thick, 5 to 10 microns. The ribs may be formed by localised deeper boron deposition followed by a selective etch. (author)

  14. X-ray detector

    International Nuclear Information System (INIS)

    Houston, J.M.; Whetten, N.R.

    1981-01-01

    An ionization chamber for use in determining the spatial distribution of x-ray photons in tomography systems comprises a plurality of substantially parallel, planar anodes separated by parallel, planar cathodes and enclosed in a gas of high atomic weight at a pressure from approximately 10 atmospheres to approximately 50 atmospheres. The cathode and anode structures comprise metals which are substantially opaque to x-ray radiation and thereby tend to reduce the resolution limiting effects of xray fluoresence in the gas. In another embodiment of the invention the anodes comprise parallel conductive bars disposed between two planar cathodes. Guard rings eliminate surface leakage currents between adjacent electrodes

  15. Optical spectroscopy of the Be/X-ray binary V850 Centauri/GX 304-1 during faint X-ray periodical activity

    Science.gov (United States)

    Malacaria, C.; Kollatschny, W.; Whelan, E.; Santangelo, A.; Klochkov, D.; McBride, V.; Ducci, L.

    2017-07-01

    Context. Be/X-ray binaries (BeXRBs) are the most populous class of high-mass X-ray binaries. Their X-ray duty cycle is tightly related to the optical companion wind activity, which in turn can be studied through dedicated optical spectroscopic observations. Aims: We study optical spectral features of the Be circumstellar disk to test their long-term variability and their relation with the X-ray activity. Special attention has been given to the Hα emission line, one of the best tracers of the disk conditions. Methods: We obtained optical broadband medium resolution spectra from a dedicated campaign with the Anglo-Australian Telescope and the Southern African Large Telescope in 2014-2015. Data span over one entire binary orbit, and cover both X-ray quiescent and moderately active periods. We used Balmer emission lines to follow the evolution of the circumstellar disk. Results: We observe prominent spectral features, like double-peaked Hα and Hβ emission lines. The HαV/R ratio significantly changes over a timescale of about one year. Our observations are consistent with a system observed at a large inclination angle (I ≳ 60°). The derived circumstellar disk size shows that the disk evolves from a configuration that prevents accretion onto the neutron star, to one that allows only moderate accretion. This is in agreement with the contemporary observed X-ray activity. Our results are interpreted within the context of inefficient tidal truncation of the circumstellar disk, as expected for this source's binary configuration. We derived the Hβ-emitting region size, which is equal to about half of the corresponding Hα-emitting disk, and constrain the luminosity class of V850 Cen as III-V, consistent with the previously proposed class.

  16. Panoramic Dental X-Ray

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

  17. Subluminous X-ray binaries

    NARCIS (Netherlands)

    Armas Padilla, M.

    2013-01-01

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

  18. X-Ray Exam: Pelvis

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Pelvis KidsHealth / For Parents / X-Ray Exam: ... Ray Exam: Hip Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  19. X-Ray Exam: Forearm

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Forearm KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  20. X-Ray Exam: Foot

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Foot KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  1. X-Ray Exam: Wrist

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Wrist KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  2. Thoracic spine x-ray

    Science.gov (United States)

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

  3. X-Ray Exam: Finger

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Finger KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  4. Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Higley, Daniel J., E-mail: dhigley@stanford.edu; Yuan, Edwin [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Hirsch, Konstantin; Dakovski, Georgi L.; Jal, Emmanuelle; Lutman, Alberto A.; Coslovich, Giacomo; Hart, Philip; Hoffmann, Matthias C.; Mitra, Ankush; Moeller, Stefan; Ohldag, Hendrik; Seaberg, Matthew; Stöhr, Joachim; Nuhn, Heinz-Dieter; Reid, Alex H.; Dürr, Hermann A.; Schlotter, William F. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Liu, Tianmin; MacArthur, James P. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); and others

    2016-03-15

    X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L{sub 3,2}-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature.

  5. CRL X-ray tube

    International Nuclear Information System (INIS)

    Kolchevsky, N.N.; Petrov, P.V.

    2015-01-01

    A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed. (authors)

  6. X rays and condensed matter

    International Nuclear Information System (INIS)

    Daillant, J.

    1997-01-01

    After a historical review of the discovery and study of X rays, the various interaction processes between X rays and matter are described: Thomson scattering, Compton scattering, X-photon absorption through photoelectric effect, and magnetic scattering. X ray sources such as the European Synchrotron Radiation Facility (ESRF) are described. The various X-ray applications are presented: imagery such as X tomography, X microscopy, phase contrast; X-ray photoelectron spectroscopy and X-ray absorption spectroscopy; X-ray scattering and diffraction techniques

  7. X-ray binaries, part 1

    International Nuclear Information System (INIS)

    Hammerschlag-Hensberge, G.C.M.J.

    1977-01-01

    Optical observations of X-ray binaries and their interpretation are described. A number of early-type stars which are identified as companions of X-ray sources are photometrically and spectroscopically observed. The spectra were obtained with the coude spectrograph attached to the 1.5 m telescope of the European Southern Observatory, La Silla, Chile. Registrations of the spectra were made with the Faul-Coradi microphotometer of the Observatory at Utrecht. To study radial velocity variations, the positions of the spectral lines were measured with the Grant comparator of the University of Groningen

  8. Electron-ion-x-ray spectrometer system

    International Nuclear Information System (INIS)

    Southworth, S.H.; Deslattes, R.D.; MacDonald, M.A.

    1993-01-01

    The authors describe a spectrometer system developed for electron, ion, and x-ray spectroscopy of gas-phase atoms and molecules following inner-shell excitation by tunable synchrotron radiation. The spectrometer has been used on beamline X-24A at the National Synchrotron Light Source for excitation-dependent studies of Ar L-shell and K-shell photoexcitation and vacancy decay processes. The instrumentation and experimental methods are discussed, and examples are given of electron spectra and coincidence spectra between electrons and fluorescent x-rays

  9. X-ray beam qualities for dental radiology purposes

    International Nuclear Information System (INIS)

    Santos, Marcus Aurelio P. dos; Fragoso, Maria da Conceicao de F.; Lima, Ricardo de A.; Hazim, Clovis A.

    2009-01-01

    In order to establish characteristics or properties of equipment for diagnostic radiology, e.g. ion chambers and semiconductor detectors, calibration laboratories offer a set of well-defined radiation conditions, called X-ray qualities, which can be used for many Physics studies and medical purposes. The standardization of radiation qualities has been carried out in several fields of study, but little attention has been given to the area of dental radiology, mainly for medical and physical applications using single-phase units with half-wave rectification. For this reason, a single-phase dental unit with adjustable peak voltage and tube current, called 'variable potential X-ray equipment', was developed aiming to define X-ray beam qualities for test and calibrations purposes. X-ray spectra at 50, 60 and 70 kVp were determined by using a CdTe detector and compared with those obtained for ten commercial X-ray dental units. As a result of this study, a set of X-ray qualities for the variable potential X-ray equipment was determined. The X-ray qualities spectra were utilized as reference for determination of a new set of X-ray qualities characterized for a constant potential X-ray equipment. Thus, sets of X-ray qualities were standardized and implemented in two X-ray laboratories: one with the variable potential X-ray equipment and other with constant potential X-ray equipment. These reference X-ray beam qualities should be used for test and calibration purposes involving scientific studies and services. (author)

  10. X-ray beam generator

    International Nuclear Information System (INIS)

    Koller, T.J.; Randmer, J.A.

    1977-01-01

    A method of minimizing the preferential angular absorption of the divergent beam from an X-ray generator is described. The generator consists of an X-ray shielded housing with an X-ray transmissive window symmetrically placed in radial alignment with a focal spot area on a sloped target surface of an X-ray tube in the housing. The X-ray tube may be of the stationary anode type or of the rotating anode type. (U.K.)

  11. The properties of cross-correlation and spectra of the low-mass X-ray binary 4U 1608-52

    International Nuclear Information System (INIS)

    Lei, Ya-Juan; Yuan, Hai-Long; Dong, Yi-Qiao; Zhang, Hao-Tong; Zhang, Cheng-Min; Zhao, Yong-Heng; Zhang, Shu; Qu, Jin-Lu; Wang, Ya-Nan; Li, Zhi-Bing

    2014-01-01

    With RXTE data, we analyzed the cross-correlation function between the soft and hard X-rays of the transient atoll source 4U 1608-52. We found anti-correlations in three outbursts occurred in 1998, 2002, and 2010, and we found significant time lags of several hundreds of seconds in the latter two outbursts. Our results show no correlation between the soft and hard X-rays in the extreme island state and a dominated positive correlation in the lower banana state. Anti-correlations are presented at the upper banana state for the outburst of 2010 and at the island and the lower left banana states for the other two outbursts. So far for atoll sources, the cross-correlation has been studied statistically only for 4U 1735-44, where anti-correlations showed up in the upper banana state. Here our investigation on 4U 1608-52 provides a similar result in its 2010 outburst. In addition, we notice that the luminosities in the upper banana of the 1998 and 2002 outbursts are about 1.5 times that of the 2010 outburst whose luminosity in the upper banana is close to that of 4U 1735-44. The results suggest that the states in the color-color diagram of a source could be correlated with the luminosity of the source. A further spectral analysis during the 2010 outburst is also shown, which suggests that the disk can be a little truncated in the upper banana. The feature on the upper banana is similar to the previous results of the flaring branch in Z sources.

  12. Chest X-Ray

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... x-ray is used to evaluate the lungs, heart and chest wall and may be used to ...

  13. X-ray sources

    International Nuclear Information System (INIS)

    Bonse, U.

    1979-11-01

    The author describes several possibilities for the production of X-radiation. Especially he discusses the use of bremsstrahlung at electron impact on solid targets and the synchrotron radiation. He presents some equations for the calculation of X-ray intensities. Especially the X-radiation from the DORIS storage ring is discussed. (HSI)

  14. Medical x-ray

    International Nuclear Information System (INIS)

    Abd Aziz Mhd Ramli; Gui Ah Auu; Husaini Salleh; Idris Besar; Mohd Ashhar Khalid; Muhammad Jamal Md Isa; Shaharuddin Mohd; Siti Najila Mohd Janib; Mohamed Ali Abdul Khader; Mahalatchimi Dave; Mohd Fazly Abdul Rahim; Ng Chee Moon; Ram Piari; Teoh Hoon Heng; Lee Peter

    2004-01-01

    This book describes the fundamental subject about medical radiography. It is a multidisciplinary field that requires cross professional input from scientists, engineers and medical doctors. However, it is presented in simple language to suit different levels of readers from x-ray operators and radiographers to physists, general practitioners and radiology specialists.The book is written in accordance to the requirements of the standard syllabus approved by the Ministry of Health Malaysia for the training of medical x-ray operator and general practitioners. In general, the content is not only designed to provide relevant and essential subject for related professionals in medical radiological services such as x-ray operator, radiographer and radiologists, but also to address those in associated radiological services including nurses, medical technologists and physicists.The book is organized and arranged sequentially into 3 parts for easy reference: Radiation safety; X-ray equipment and associated facilities; Radiography practices. With proper grasping of all these parts, the radiological services could be provided with confident and the highest professional standard. Thus, medical imaging with highest quality that can provide useful diagnostic information at minimum doses and at cost effective could be assured

  15. Chest X-Ray

    Medline Plus

    Full Text Available ... change into a gown. You may have some concerns about chest x-rays. However, it’s important to ... You Sponsored by About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

  16. X-ray spectroscopy and X-ray crystallography of metalloenzymes at XFELs

    International Nuclear Information System (INIS)

    Yano, Junko

    2016-01-01

    The ultra-bright femtosecond X-ray pulses provided by X-ray Free Electron Lasers (XFELs) open capabilities for studying the structure and dynamics of a wide variety of biological and inorganic systems beyond what is possible at synchrotron sources. Although the structure and chemistry at the catalytic sites have been studied intensively in both biological and inorganic systems, a full understanding of the atomic-scale chemistry requires new approaches beyond the steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure at ambient conditions, while overcoming X-ray damage to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by using the intense and ultra-short femtosecond X-ray pulses from an XFEL, where sample is probed before it is damaged. We have developed methodology for simultaneously collecting crystallography data and X-ray emission spectra, using an energy dispersive spectrometer at ambient conditions. In addition, we have developed a way to collect metal L-edge data of dilute samples using soft X-rays at XFELs. The advantages and challenges of these methods will be described in this review. (author)

  17. Construction of a catalog of X-ray spectra for mammography simulations; Construção de um catálogo de espectros de raios X para simulações em mamografia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, L.C.S.; Vieira, J.W., E-mail: larissa.css@outlook.com [Instituto Federal de Pernambuco (IFPE), Recife, PE (Brazil). Dept. Acadêmico de Ambiente, Saúde e Segurança; Lima, F.R.A., E-mail: falima@cnen.gov.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife-PE (Brazil)

    2017-07-01

    Computational Exposure Models (MCEs) allow the simulation of the interaction of radiation with matter by means of Monte Carlo (MC) techniques. Generally, MCEs are composed of phantom, simulator algorithms of radioactive sources and an MC code to simulate the transport, interaction of the radiation with matter and to evaluate the energy deposited in regions of interest. To compose an MCE for simulations in mammography, the construction of a catalog of X-ray spectra was started, based on the catalog model constructed and using until then in MCEs by the Group of Research in Numerical Dosimetry and by the Group of Research in Computational Dosimetry & Embedded Systems (both referenced in this work as GDN). Potential of 25 kV and 35 kV and used target / filter were applied to the tube: Mo / Mo. The file containing the spectra was read correctly by EGSnrc.

  18. Large Charge-Transfer Energy in LiFePO4 Revealed by Full-Multiplet Calculation for the Fe L3 -edge Soft X-ray Emission Spectra.

    Science.gov (United States)

    Asakura, Daisuke; Nanba, Yusuke; Makinose, Yuki; Matsuda, Hirofumi; Glans, Per-Anders; Guo, Jinghua; Hosono, Eiji

    2018-04-17

    We analyzed the Fe 3d electronic structure in LiFePO 4 /FePO 4 (LFP/FP) nanowire with a high cyclability by using soft X-ray emission spectroscopy (XES) combined with configuration-interaction full-multiplet (CIFM) calculation. The ex situ Fe L 2,3 -edge resonant XES (RXES) spectra for LFP and FP are ascribed to oxidation states of Fe 2+ and Fe 3+ , respectively. CIFM calculations for Fe 2+ and Fe 3+ states reproduced the Fe L 3 RXES spectra for LFP and FP, respectively. In the calculations for both states, the charge-transfer energy was considerably larger than those for typical iron oxides, indicating very little electron transfer from the O 2p to Fe 3d orbitals and a weak hybridization on the Fe-O bond during the charge-discharge reactions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Evolution of Cygnus X-3 through its Radio and X-ray States

    International Nuclear Information System (INIS)

    Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

    2009-01-01

    Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

  20. Evolution of Cygnus X-3 through its Radio and X-ray States

    Science.gov (United States)

    Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

    2009-05-01

    Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

  1. Diagnostic X-ray spectrometry using a commercial CdZnTe detector

    International Nuclear Information System (INIS)

    Becker, P.H.B.

    1998-01-01

    X ray spectrometry using Ge or Si detectors is an established tool to measure characterization parameters of X-ray beams. This work describes how a commercial CdZnTe was used to perform diagnostic X-ray spectrometry. Spectra were measured for two X-ray machines and compared with similar data found in the literature with an agreement of 2% rms

  2. Wavelength dispersive X-ray absorption fine structure imaging by parametric X-ray radiation

    International Nuclear Information System (INIS)

    Inagaki, Manabu; Sakai, Takeshi; Sato, Isamu; Hayakawa, Yasushi; Nogami, Kyoko; Tanaka, Toshinari; Hayakawa, Ken; Nakao, Keisuke

    2008-01-01

    The parametric X-ray radiation (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a monochromatic and coherent X-ray source with horizontal wavelength dispersion. The energy definition of the X-rays, which depends on the horizontal size of the incident electron beam on the generator target crystal, has been investigated experimentally by measuring the X-ray absorption near edge structure (XANES) spectra on Cu and CuO associated with conventional X-ray absorption imaging technique. The result demonstrated the controllability of the spectrum resolution of XANES by adjusting of the horizontal electron beam size on the target crystal. The XANES spectra were obtained with energy resolution of several eV at the narrowest case, which is in qualitative agreement with the energy definition of the PXR X-rays evaluated from geometrical consideration. The result also suggested that the wavelength dispersive X-ray absorption fine structure measurement associated with imaging technique is one of the promising applications of PXR. (author)

  3. X ray Production. Chapter 5

    Energy Technology Data Exchange (ETDEWEB)

    Nowotny, R. [Medical University of Vienna, Vienna (Austria)

    2014-09-15

    The differential absorption of X rays in tissues and organs, owing to their atomic composition, is the basis for the various imaging methods used in diagnostic radiology. The principles in the production of X rays have remained the same since their discovery. However, much refinement has gone into the design of X ray tubes to achieve the performance required for today’s radiological examinations. In this chapter, an outline of the principles of X ray production and a characterization of the radiation output of X ray tubes will be given. The basic processes producing X rays are dealt with in Section 1.4.

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

    Science.gov (United States)

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

    2018-01-23

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

  5. Polarization dependence of resonant X-ray emission spectra in 3dn transition metal compounds with n=0, 1, 2, 3

    International Nuclear Information System (INIS)

    Matsubara, Masahiko; Kotani, Akio; Shin, Shik; Uozumi, Takayuki; Harada, Yoshihisa

    2002-01-01

    The polarization dependence of 2p → 3d → 2p resonant X-ray emission spectroscopy (RXES) in 3d 1 , 3d 2 and 3d 3 systems (TiF 3 , VF 3 and Cr 2 O 3 , respectively) is measured and analyzed by means of the MX 6 (M denotes a transition metal and X denotes a ligand, respectively) cluster model. The results are compared with a previous one for the 3d 0 system (TiO 2 ). Generally, with increasing 3d electron number, the spectral structure of RXES becomes more complicated by the influence of the crystal field and the multiplet coupling effect. Moreover, we point out that the selection rules on the polarization dependence of RXES change with the 3d electron number and that a drastic resonance enhancement corresponding to the excitation to an antibonding state in the 3d 0 system is almost absent for the 3d n systems with n=1, 2 and 3. (author)

  6. Electron–Positron Pair Creation Close to a Black Hole Horizon: Redshifted Annihilation Line in the Emergent X-Ray Spectra of a Black Hole. I.

    Science.gov (United States)

    Laurent, Philippe; Titarchuk, Lev

    2018-06-01

    We consider a Compton cloud (CC) surrounding a black hole (BH) in an accreting BH system, where electrons propagate with thermal and bulk velocities. In that cloud, soft (disk) photons may be upscattered off these energetic electrons and attain energies of several MeV. They could then create pairs due to photon–photon interactions. In this paper, we study the formation of the 511 keV annihilation line due to this photon–photon interaction, which results in the creation of electron–positron pairs, followed by the annihilation of the created positrons with the CC electrons. The appropriate conditions for annihilation-line generation take place very close to a BH horizon within (103–104)m cm from it, where m is the BH hole mass in solar units. As a result, the created annihilation line should be seen by the Earth observer as a blackbody bump, or the so-called reflection bump at energies around (511/20) (20/z) keV, where z ∼ 20 is a typical gravitational redshift experienced by the created annihilation-line photons when they emerge. This transient feature should occur in any accreting BH system, either galactic or extragalactic. Observational evidences for this feature in several galactic BH systems is detailed in an accompanying paper. An extended hard tail of the spectrum up to 1 MeV may also be formed due to X-ray photons upscattering off created pairs.

  7. Synthesis, spectra and X-ray crystallography of dipyridin-2-ylmethanone oxime and its CuX2(oxime)2 complexes: Thermal, Hirshfeld surface and DFT analysis

    Science.gov (United States)

    Warad, Ismail; Abdoh, Muneer; Al Ali, Anas; Shivalingegowda, Naveen; Kumara, Karthik; Zarrouk, Abdelkader; Lokanath, Neartur Krishnappagowda

    2018-02-01

    Dipyridin-2-ylmethanone oxime (C11H9N3O), was prepared using di-2-pyridyl ketone. The oxime ligand and its neutral CuX2 (oxime)2 (X = Cl or Br) complexes have been identified with the aid of several spectroscopic techniques such as: IR, EI-MS, EA, UV-visible, TG, 1H-NMR and finally the structure of the free oxime ligand was confirmed by X-ray diffraction studies. The oxime crystallizes in the monoclinic space group P21/c, with cell parameters a = 8.8811 (8) Å, b = 10.6362 (8) Å, c = 11.2050 (8) Å, β = 109.085 (4) º, V = 1000.26 (14) Å3 and Z = 4. The molecular conformation is stabilized by a strong intramolecular Osbnd H⋯N hydrogen bonding between the hydroxyl group of the oxime moiety and the nitrogen of the pyridine ring. Since the oxime structure was solved by XRD, the ligand structure parameters like bond length and angles were compared to the DFT computed one, the UV-visible to TD-SCF and Hirshfeld surface to MEP analysis.

  8. X-ray refractometer

    International Nuclear Information System (INIS)

    Tur'yanskij, A.G.; Pirshin, I.V.

    2001-01-01

    Paper introduces a new circuit of X-ray refractometer to study angular and spectral features of refracted radiation within hard X-ray range. Refractometer incorporates two goniometers, two crystal-analyzers and three radiation detectors. The maximum distance between radiation source focal point and a receiving slit of the second goniometer is equal to 1.4 m. For the first time one obtained refraction patterns of fine-film specimens including C/Si stressed structure. Paper describes a new technique of refractometry via specimen oscillation at fixed position of a detecting device. Paper presents the measurement results of oscillation refraction patterns for specimens of melted quartz and ZnSe single crystal [ru

  9. X-ray radiotherapy

    International Nuclear Information System (INIS)

    Tronc, D.

    1995-01-01

    Full text: The most common form of radio therapy is X-ray therapy, where a beam of photons or their parent electrons break down hydrogen bonds within the body's cells and remove certain DNA information necessary for cell multiplication. This process can eradicate malignant cells leading to complete recovery, to the remission of some cancers, or at least to a degree of pain relief. The radiotherapy instrument is usually an electron linac, and the electrons are used either directly in 'electrotherapy' for some 10% of patients, or the electrons bombard a conversion target creating a broad beam of high energy photons or 'penetration X-rays'. The simplest machine consists of several accelerating sections at around 3 GHz, accelerating electrons to 6 MeV; a cooled tungsten target is used to produce a 4 Gray/min X-ray field which can be collimated into a rectangular shape at the patient position. This tiny linac is mounted inside a rotating isocentric gantry above the patient who must remain perfectly still. Several convergent beams can also be used to increase the delivered dose. More sophisticated accelerators operate at up to 18 MeV to increase penetration depths and decrease skin exposure. Alternatively, electrotherapy can be used with different energies for lower and variable penetration depths - approximately 0.5 cm per MeV. In this way surface tissue may be treated without affecting deeper and more critical anatomical regions. This type of linac, 1 to 2 metres long, is mounted parallel to the patient with a bending magnet to direct the beam to the radiotherapy system, which includes the target, thick movable collimator jaws, a beam field equalizer, dose rate and optical field simulation and energy controls. There are over 2000 acceleratorbased X-ray treatment units worldwide. Western countries have up to two units per million population, whereas in developing countries such as Bangladesh, the density is only one per 100 million. Several

  10. X-ray generator

    Energy Technology Data Exchange (ETDEWEB)

    Zucarias, A; Shepherd, J W

    1982-09-08

    An X-ray tube has a tubular envelope with a cathode for directing an electron beam onto a focal spot area of a spaced anode target to generate X-rays. The target is mounted for axial rotation on one end of a rotor disposed in an end portion of the envelope and encircled by a stator of an alternating current induction motor. An annular shield of high permeability magnetic material extends transversely between the electron beam and the stator of the induction motor for shunting stray or fringe electromagnetic fields established by the stator away from the electron beam to avoid consequent lateral deflections of the electron and corresponding lateral movements of the focal spot area.

  11. X-ray microtomography

    International Nuclear Information System (INIS)

    Dunsmuir, J.H.; Ferguson, S.R.; D'Amico, K.L.; Stokes, J.P.

    1991-01-01

    In this paper the authors describe the application of a new high-resolution X-ray tomographic microscope to the study of porous media. The microscope was designed to exploit the properties of a synchrotron X-ray source to perform three dimensional tomography on millimeter sized objects with micron resolution and has been used in materials science studies with both synchrotron and conventional and synchrotron sources will be compared. In this work the authors have applied the microscope to measure the three dimensional structure of fused bead packs and berea sandstones with micron resolution and have performed preliminary studies of flow in these media with the microscope operated in a digital subtraction radiography mode. Computer graphics techniques have been applied to the data to visually display the structure of the pore body system. Tomographic imaging after flow experiments should detect the structure of the oil-water interface in the pore network and this work is ongoing

  12. X-ray spectra of He-like ions of Ga and Ge, excited in the low-inductance spark plasma

    International Nuclear Information System (INIS)

    Aglitsky, E.V.; Antsiferov, P.S.; Panin, A.M.

    1984-01-01

    The spectra of Ga XXX and Ge XXXI ions in the interval 1.2-1.4 A excited in the low-inductance vacuum spark plasma have been obtained for the first time. The resonance line 1s 2 -1s2p of Ga XXX and Ge XXXI and a group of satellites, corresponding to transitions in Ga XXIX and Ge XXX can be seen distinctly in the spectra. The spectra were obtained by an electronic-optical image-intensifier tube for one discharge. (orig.)

  13. X-ray diffraction

    International Nuclear Information System (INIS)

    Einstein, J.R.; Wei, C.H.

    1982-01-01

    We have been interested in structural elucidation by x-ray diffraction of compounds of biological interest. Understanding exactly how atoms are arranged in three-dimensional arrays as molecules can help explain the relationship between structure and functions. The species investigated may vary in size and shape; our recent studies included such diverse substances as antischistosomal drugs, a complex of cadmium with nucleic acid base, nitrate salts of adenine, and proteins

  14. X-ray apparatus

    International Nuclear Information System (INIS)

    Tomita, Chuji.

    1980-01-01

    A principal object of the present invention is to provide an X-ray apparatus which is such that the distance between the surface of the patient's table and the floor on which the apparatus is installed is sufficiently small in the horizontal position of the patient's table of the roentgenographical pedestal and that the rotation of the pedestal from the horizontal position to a tilted position and further to the vertical position of the table can be carried out smoothly. (auth)

  15. X-ray Ordinance

    International Nuclear Information System (INIS)

    Kramer, R.; Zerlett, G.

    1983-01-01

    This commentary, presented as volume 2 of the Deutsches Strahlenschutzrecht (German legislation on radiation protection) deals with the legal provisions of the ordinance on the protection against harmful effects of X-radiation (X-ray Ordinance - RoeV), of March 1, 1973 (announced in BGBl.I, page 173), as amended by the ordinance on the protection against harmful effects of ionizing radiation, of October 13, 1976 (announced in BGBl. I, page 2905). Thus volume 2 completes the task started with volume 1, namely to present a comprehensive view and account of the body of laws governing radiation protection, a task which was thought useful as developments in the FRG led to regulations being split up into the X-ray Ordinance, and the Radiation Protection Ordinance. In order to present a well-balanced commentary on the X-ray Ordinance, it was necessary to discuss the provisions both from the legal and the medical point of view. This edition takes into account the Fourth Public Notice of the BMA (Fed. Min. of Labour and Social Affairs) concerning the implementation of the X-ray Ordinance of January 4, 1982, as well as court decisions and literature published in this field, until September 1982. In addition, the judgment of the Federal Constitutional Court, dated October 19, 1982, concerning the voidness of the law on government liability, and two decisions by the Federal High Court, dated November 23, 1982, concerning the right to have insight into medical reports - of great significance in practice - have been considered. This commentary therefore is up to date with current developments. (orig.) [de

  16. X-Ray Calorimeter Arrays for Astrophysics

    Science.gov (United States)

    Kilbourne, Caroline A.

    2009-01-01

    High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

  17. Producing x-rays

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.; Jung, R.G.; Applebaum, D.C.; Fairand, B.P.; Gallagher, W.J.

    1977-01-01

    A method of producing x-rays by directing radiant energy from a laser onto a target is described. Conversion efficiency of at least about 3 percent is obtained by providing the radiant energy in a low-power precursor pulse of approximately uniform effective intensity focused onto the surface of the target for about 1 to 30 nanoseconds so as to generate an expanding unconfined coronal plasma having less than normal solid density throughout and comprising a low-density (underdense) region wherein the plasma frequency is less than the laser radiation frequency and a higher-density (overdense) region wherein the plasma frequency is greater than the laser radiation frequency and, about 1 to 30 nanoseconds after the precursor pulse strikes the target, a higher-power main pulse focused onto the plasma for about 10 -3 to 30 nanoseconds and having such power density and total energy that the radiant energy is absorbed in the underdense region and conducted into the overdense region to heat it and thus to produce x-rays therefrom with the plasma remaining substantially below normal solid density and thus facilitating the substantial emission of x-rays in the form of spectral lines arising from nonequilibrium ionization states

  18. High-energy X-ray observations of extragalactic objects

    International Nuclear Information System (INIS)

    Pietsch, W.; Reppin, C.; Truemper, J.; Voges, W.; Lewin, W.; Kendziorra, E.; Staubert, R.

    1981-01-01

    During a balloon flight from Alice Springs, Australia, six extragalactic sources which are known as potential X-ray sources have been observed in hard X-rays (E > 20 keV). We present X-ray spectra of 3C 273 and Cen-A as well as upper limits on 3C 120, MKN 509, NGC 5506, and MR 2251-178. (orig.)

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... the body. X-rays are the oldest and most frequently used form of medical imaging. A bone ... bones. top of page How should I prepare? Most bone x-rays require no special preparation. You ...

  20. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... evaluation. National and international radiology protection organizations continually review and update the technique standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

  1. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... can be taken to the patient in a hospital bed or the emergency room. The x-ray ... position possible that still ensures x-ray image quality. top of page Who interprets the results and ...

  2. Bone X-Ray (Radiography)

    Medline Plus

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

  3. X-ray detector array

    International Nuclear Information System (INIS)

    Houston, J.M.

    1980-01-01

    The object of the invention (an ionization chamber X-ray detector array for use with high speed computerised tomographic imaging apparatus) is to reduce the time required to produce a tomographic image. The detector array described determines the distribution of X-ray intensities in one or more flat, coplanar X-ray beams. It comprises three flat anode sheets parallel to the X-ray beam, a plurality of rod-like cathodes between the anodes, a detector gas between the electrodes and a means for applying a potential between the electrodes. Each of the X-ray sources is collimated to give a narrow, planar section of X-ray photons. Sets of X-ray sources in the array are pulsed simultaneously to obtain X-ray transmission data for tomographic image reconstruction. (U.K.)

  4. Bone X-Ray (Radiography)

    Medline Plus

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

  5. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... changes seen in metabolic conditions. assist in the detection and diagnosis of bone cancer . locate foreign objects ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

  6. Bone X-Ray (Radiography)

    Medline Plus

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

  7. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... up in shades of gray and air appears black. Until recently, x-ray images were maintained on ... Safety page for more information about radiation dose. Women should always inform their physician or x-ray ...

  8. Bone X-Ray (Radiography)

    Medline Plus

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

  9. Bone X-Ray (Radiography)

    Medline Plus

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

  10. Bone X-Ray (Radiography)

    Medline Plus

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

  11. X-ray Spectrometry: Basic principles

    International Nuclear Information System (INIS)

    Carvalho, R.M.; Teixeira, G.J.; Cardoso, R.S.; Peixoto, J.G.P.

    2017-01-01

    The application of X rays requires a study of its spectrum. Intrinsic difficulties of the own method and of all the instrumentation necessary for the accomplishment of this practice were related. The objective was to demonstrate the use of a commercial spectrometer using at room temperature and compare it with spectra theoretically obtained by simulation. As an initial result was that both instrumentation is compatible to be used in an X-ray beam, with and without scattering material and its theoretical data were obtained. (author)

  12. X-Ray Exam: Hip

    Science.gov (United States)

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

  13. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small ...

  14. Bone X-Ray (Radiography)

    Medline Plus

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

  15. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... The x-ray tube is connected to a flexible arm that is extended over the patient while an x-ray film holder or image recording plate is placed beneath the patient. top of page How does the procedure work? X-rays are a form of radiation like ...

  16. X-Ray Exam: Ankle

    Science.gov (United States)

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

  17. Handbook of X-Ray Astronomy

    Science.gov (United States)

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

    2011-01-01

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

  18. Testing warm Comptonization models for the origin of the soft X-ray excess in AGNs

    Science.gov (United States)

    Petrucci, P.-O.; Ursini, F.; De Rosa, A.; Bianchi, S.; Cappi, M.; Matt, G.; Dadina, M.; Malzac, J.

    2018-03-01

    The X-ray spectra of many active galactic nuclei (AGNs) show a soft X-ray excess below 1-2 keV on top of the extrapolated high-energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred, ionized reflection or the high-energy tail of thermal Comptonization in a warm (kT 1 keV), optically thick (τ ≃ 10-20) corona producing the optical/UV to soft X-ray emission. The purpose of the present paper is to test the warm corona model on a statistically significant sample of unabsorbed, radio-quiet AGNs with XMM-Newton archival data, providing simultaneous optical/UV and X-ray coverage. The sample has 22 objects and 100 observations. We use two thermal Comptonization components to fit the broadband spectra, one for the warm corona emission and one for the high-energy continuum. In the optical/UV, we also include the reddening, the small blue bump, and the Galactic extinction. In the X-rays, we include a warm absorber and a neutral reflection. The model gives a good fit (reduced χ2 uniformly distributed in the 0.1-1 keV range, while the optical depth is in the range 10-40. These values are consistent with a warm corona covering a large fraction of a quasi-passive accretion disk, i.e., that mostly reprocesses the warm corona emission. The disk intrinsic emission represents no more than 20% of the disk total emission. According to this interpretation, most of the accretion power would be released in the upper layers of the accretion flow.

  19. The broadband microwave spectra of the monoterpenoids thymol and carvacrol: Conformational landscape and internal dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, D.; Shubert, V. A. [Max Planck Institute for the Structure and Dynamics of Matter, Hamburg (Germany); The Center for Free-Electron Laser Science, Hamburg (Germany); Giuliano, B. M. [Center for Astrobiology, INTA-CSIC, Torrejón de Ardoz, Madrid (Spain); Schnell, M., E-mail: melanie.schnell@mpsd.mpg.de [Max Planck Institute for the Structure and Dynamics of Matter, Hamburg (Germany); The Center for Free-Electron Laser Science, Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Hamburg (Germany)

    2014-07-21

    The rotational spectra of the monoterpenoids thymol and carvacrol are reported in the frequency range 2–8.5 GHz, obtained with broadband Fourier-transform microwave spectroscopy. For carvacrol four different conformations were identified in the cold conditions of the molecular jet, whereas only three conformations were observed for thymol. The rotational constants and other molecular parameters are reported and compared with quantum chemical calculations. For both molecules, line splittings due to methyl group internal rotation were observed and the resulting barrier heights could be determined. The experimental barrier heights, 4.0863(25) kJ/mol for trans-carvacrol-A, 4.4024(16) kJ/mol for trans-carvacrol-B, and 0.3699(11) kJ/mol for trans-thymol-A, are compared with similar molecules.

  20. The broadband microwave spectra of the monoterpenoids thymol and carvacrol: Conformational landscape and internal dynamics

    International Nuclear Information System (INIS)

    Schmitz, D.; Shubert, V. A.; Giuliano, B. M.; Schnell, M.

    2014-01-01

    The rotational spectra of the monoterpenoids thymol and carvacrol are reported in the frequency range 2–8.5 GHz, obtained with broadband Fourier-transform microwave spectroscopy. For carvacrol four different conformations were identified in the cold conditions of the molecular jet, whereas only three conformations were observed for thymol. The rotational constants and other molecular parameters are reported and compared with quantum chemical calculations. For both molecules, line splittings due to methyl group internal rotation were observed and the resulting barrier heights could be determined. The experimental barrier heights, 4.0863(25) kJ/mol for trans-carvacrol-A, 4.4024(16) kJ/mol for trans-carvacrol-B, and 0.3699(11) kJ/mol for trans-thymol-A, are compared with similar molecules