X-Ray Photon

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A. N. Hopersky - One of the best experts on this subject based on the ideXlab platform.

  • X-Ray-Photon Compton scattering by a linear molecule
    Journal of Physics B, 2015
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, V.a. Yavna, Sergey Novikov, K. Kh. Ikoeva
    Abstract:

    We formulate a nonrelativistic quantum theory for the nonresonant inelastic scattering process of an X-Ray Photon by a free linear molecule outside of the impulse approximation framework. We find a strong orientation effect dependent on changes in the schemes of the proposed experiments. Calculations of the absolute values and forms for the double differential scattering cross sections are carried out for the HF molecule and have a predictive character. The presented theory is of a general nature, and its applicability to a particular linear molecule is constrained only by the demand of correctness of nonrelativistic methods for constructing molecular scattering orbitals.

  • Compton scattering of an X-Ray Photon by an open-shell atom
    Journal of Experimental and Theoretical Physics, 2012
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky
    Abstract:

    A nonrelativistic quantum theory for the nonresonant Compton scattering of an X-Ray Photon by a free many-electron atom with an open shell in the ground state has been constructed in the single-configuration Hartree-Fock approximation outside the impulse approximation widely used in the literature. The transition to an atom with closed shells reproduces the results obtained previously in [6, 7]. The results of a test calculation for atoms with open (Ti, Fe) and closed (Zn) 3d core shells are presented. The effects of the radial relaxation of one-electron states in the field of core vacancies have been taken into account. The results of the calculation agree well with the experimental results [15, 16]. It has been established that the results of the impulse approximation in the investigated X-Ray Photon energy ranges disagree with those of our theory not only quantitatively but also qualitatively. In particular, the impulse approximation near the elastic (Thomson and Rayleigh) scattering line leads to a gross overestimation of the contributions from the deep atomic shells involved in the inelastic Photon scattering only virtually to the scattering probability. The presented theory is general in character and its applicability to a particular element of the Mendeleev table with an open core shell or to a many-electron atomic ion is limited only by the requirement that the nonrelativistic Hartree-Fock approximation be properly used in describing the scattering-state wave functions.

  • Intershell correlations in nonresonant Compton scattering of an X-Ray Photon by an atom
    Journal of Experimental and Theoretical Physics, 2011
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, K. Kh. Ikoeva, O Khoroshavina
    Abstract:

    The role of intershell correlations in nonresonant Compton scattering of an X-Ray Photon by a free multielectron atom is studied theoretically for the Ar atom. The results of calculation are of a predictive nature. The developed mathematical formalism is general in nature and can be applied to a wide set of elements from the Periodic Table, for which the description of the wavefunctions of scattering states in the nonrelativistic Hartree-Fock approximation remains correct.

  • X-Ray Photon Compton scattering by an atom with d symmetry in the core
    Journal of Physics B, 2011
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, K. Kh. Ikoeva, O Khoroshavina
    Abstract:

    The absolute values and the form of doubly differential cross-sections of the nonresonance Compton X-Ray Photon scattering by an atom with d symmetry in the core are studied by the example of a Zn atom beyond the impulse approximation. The effects of radial relaxation of atomic shells in the field of core vacancies and elastic (Thomson and Rayleigh) scattering are considered. The calculation results have a predictive character and correspond well with the results of the experiment devoted to the measurement of absolute values of the single differential cross-section of Compton scattering in the works by Singh et al (2004 Nucl. Instrum. Methods Phys. Res. B 222 1) and Kumar et al (2002 Nucl. Instrum. Methods Phys. Res. B 194 99) for the Zn atom.

  • X-Ray Photon Compton scattering by an atomic ion
    Journal of Physics B, 2011
    Co-Authors: A. N. Hopersky, A. S. Kasprzhitsky, A. M. Nadolinsky, O Khoroshavina, V.a. Yavna
    Abstract:

    The angular and energy dependence of the differential cross sections of the linear polarized X-Ray Photon nonresonance Compton scattering by a Ne atom and by Ne-like ions Si4+, Ar8+ is studied in theory. The many-particle effects of the electron shell radial relaxation in the vacancy field and of the core shell stabilization are taken into consideration. The calculation results have a predictive character, and if the energies of the incident Photon are 11 and 22 keV, the results correspond well with the results of the synchrotron experiment in the work by Jung et al (1998 Phys. Rev. Lett. 81 1596) for the Ne atom.

A. M. Nadolinsky - One of the best experts on this subject based on the ideXlab platform.

  • X-Ray-Photon Compton scattering by a linear molecule
    Journal of Physics B, 2015
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, V.a. Yavna, Sergey Novikov, K. Kh. Ikoeva
    Abstract:

    We formulate a nonrelativistic quantum theory for the nonresonant inelastic scattering process of an X-Ray Photon by a free linear molecule outside of the impulse approximation framework. We find a strong orientation effect dependent on changes in the schemes of the proposed experiments. Calculations of the absolute values and forms for the double differential scattering cross sections are carried out for the HF molecule and have a predictive character. The presented theory is of a general nature, and its applicability to a particular linear molecule is constrained only by the demand of correctness of nonrelativistic methods for constructing molecular scattering orbitals.

  • Compton scattering of an X-Ray Photon by an open-shell atom
    Journal of Experimental and Theoretical Physics, 2012
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky
    Abstract:

    A nonrelativistic quantum theory for the nonresonant Compton scattering of an X-Ray Photon by a free many-electron atom with an open shell in the ground state has been constructed in the single-configuration Hartree-Fock approximation outside the impulse approximation widely used in the literature. The transition to an atom with closed shells reproduces the results obtained previously in [6, 7]. The results of a test calculation for atoms with open (Ti, Fe) and closed (Zn) 3d core shells are presented. The effects of the radial relaxation of one-electron states in the field of core vacancies have been taken into account. The results of the calculation agree well with the experimental results [15, 16]. It has been established that the results of the impulse approximation in the investigated X-Ray Photon energy ranges disagree with those of our theory not only quantitatively but also qualitatively. In particular, the impulse approximation near the elastic (Thomson and Rayleigh) scattering line leads to a gross overestimation of the contributions from the deep atomic shells involved in the inelastic Photon scattering only virtually to the scattering probability. The presented theory is general in character and its applicability to a particular element of the Mendeleev table with an open core shell or to a many-electron atomic ion is limited only by the requirement that the nonrelativistic Hartree-Fock approximation be properly used in describing the scattering-state wave functions.

  • Nonresonance Compton scattering of an X-Ray Photon by an atom with the core of the d symmetry
    Optics and Spectroscopy, 2012
    Co-Authors: A. N. Khopersky, A. M. Nadolinsky, K. Kh. Ikoeva, O Khoroshavina
    Abstract:

    Using the Zn atom as an example, beyond the scopes of the impulse approximation and the incoherent scattering-function approximation, we study the absolute value and the shape of the double differential nonresonance Compton scattering cross section of an X-Ray Photon by an atom with the core of the d symmetry. We take into account the effects of radial relaxation of shells in the field of core vacancies and of elastic (Thomson and Rayleigh) scattering. Calculation results have a predictive character and, for the incident Photon energies of 14.93 and 22.10 keV and the scattering angles of 141° and 133°, agree well with experimentally determined values of the differential Compton scattering cross section.

  • Nonresonance Compton scattering of an X-Ray Photon by a Ni-like atomic ion
    Optics and Spectroscopy, 2012
    Co-Authors: A. N. Khopersky, A. M. Nadolinsky, K. Kh. Ikoeva, O Khoroshavina, A. S. Kasprzhitskii
    Abstract:

    The absolute values and the shape of the double differential cross section for nonresonance Compton scattering of an X-Ray Photon by an atomic ion with d symmetry in the core are studied theoretically beyond the impulse approximation for the example of the Ni-like atomic ions Zn^2+, Kr^8+, and Mo^14+. It is established that, as the nuclear charge of an ion increases, (a) in all the scattering channels, the leading harmonics of transition to states of the continuous spectrum are concentrated and (b) the integral intensities of nonresonance Compton scattering are increasingly redistributed to the energy region of resonance Lands-berg-Mandelstam-Raman scattering between the threshold of termination of the Compton profile and the line of elastic (Thomson and Rayleigh) scattering. The calculated results are predictive in character.

  • Intershell correlations in nonresonant Compton scattering of an X-Ray Photon by an atom
    Journal of Experimental and Theoretical Physics, 2011
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, K. Kh. Ikoeva, O Khoroshavina
    Abstract:

    The role of intershell correlations in nonresonant Compton scattering of an X-Ray Photon by a free multielectron atom is studied theoretically for the Ar atom. The results of calculation are of a predictive nature. The developed mathematical formalism is general in nature and can be applied to a wide set of elements from the Periodic Table, for which the description of the wavefunctions of scattering states in the nonrelativistic Hartree-Fock approximation remains correct.

V.a. Yavna - One of the best experts on this subject based on the ideXlab platform.

  • X-Ray-Photon Compton scattering by a linear molecule
    Journal of Physics B, 2015
    Co-Authors: A. N. Hopersky, A. M. Nadolinsky, V.a. Yavna, Sergey Novikov, K. Kh. Ikoeva
    Abstract:

    We formulate a nonrelativistic quantum theory for the nonresonant inelastic scattering process of an X-Ray Photon by a free linear molecule outside of the impulse approximation framework. We find a strong orientation effect dependent on changes in the schemes of the proposed experiments. Calculations of the absolute values and forms for the double differential scattering cross sections are carried out for the HF molecule and have a predictive character. The presented theory is of a general nature, and its applicability to a particular linear molecule is constrained only by the demand of correctness of nonrelativistic methods for constructing molecular scattering orbitals.

  • X-Ray Photon Compton scattering by an atomic ion
    Journal of Physics B, 2011
    Co-Authors: A. N. Hopersky, A. S. Kasprzhitsky, A. M. Nadolinsky, O Khoroshavina, V.a. Yavna
    Abstract:

    The angular and energy dependence of the differential cross sections of the linear polarized X-Ray Photon nonresonance Compton scattering by a Ne atom and by Ne-like ions Si4+, Ar8+ is studied in theory. The many-particle effects of the electron shell radial relaxation in the vacancy field and of the core shell stabilization are taken into consideration. The calculation results have a predictive character, and if the energies of the incident Photon are 11 and 22 keV, the results correspond well with the results of the synchrotron experiment in the work by Jung et al (1998 Phys. Rev. Lett. 81 1596) for the Ne atom.

  • Effect of the Deep Vacancy Auger-Decay When Anomalous Elastic X-Ray Photon Scattering by an Atom
    Scattering of Photons by Many-Electron Systems, 2009
    Co-Authors: A. N. Hopersky, V.a. Yavna
    Abstract:

    In the third chapter, the results of the theoretical studies on the role of the many-particle phenomenon of postcollision interaction in the absorption and anomalous elastic scattering of X-Ray Photon near inner-shell ionization threshold are presented. Outside the frame of the quantum-mechanical perturbation theory, the analytical solution of the Schrodinger equation is obtained for the nonrelativistic wave function of the system of the atomic continua interacting electrostatically.

  • Research Results of the Process of the Anomalous Elastic X-Ray Photon Scattering by a Many-Electron System
    Scattering of Photons by Many-Electron Systems, 2009
    Co-Authors: A. N. Hopersky, V.a. Yavna
    Abstract:

    In the first chapter, a review of the modern state of experimental and theoretical studies on the anomalous elastic scattering of an X-Ray Photon by a many-electron system is given. The principal attention is paid to the theoretical models for the differential cross-section of the process on whose base the method of this monograph is developed. The modern situation is characterized and the aims of the studies are specified.

  • Resonant inelastic scattering of an X-Ray Photon by a linear molecule
    Optics and Spectroscopy, 2008
    Co-Authors: A. M. Nadolinsky, V.a. Yavna, A. N. Hopersky, A. S. Kasprzhitskiĭ
    Abstract:

    The double differential cross section of resonant inelastic scattering of a linearly polarized X-Ray Photon by a spatially oriented HF molecule in a gas phase is theoretically described in the energy range of the ionization threshold of the deep molecular orbital 1σ. The effects of radial relaxation of the wave functions of the core and excited scattering states in fields of the formed core vacancies, the vibronic effects, and the effects of Auger and radiative decays of the vacancies are taken into account in the nonrelativistic Hartree-Fock approximation. The results of the calculations are predictive and agree well with the results of the experimental measurements of the K α emission spectrum of the HF molecule at an incident Photon energy of 2 keV, which considerably exceeds the energy of the 1σ ionization threshold.

Sebastian Moeller - One of the best experts on this subject based on the ideXlab platform.

  • Nanosecond X-Ray Photon Correlation Spectroscopy on Magnetic Skyrmions
    Physical Review Letters, 2017
    Co-Authors: Maasa H Seaberg, B. Holladay, Giacomo Coslovich, Michael Sikorski, J. C. T. Lee, J. D. Koralek, Sergio A. Montoya, Georgi L. Dakovski, A. H. Reid, Sebastian Moeller
    Abstract:

    We report an X-Ray Photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant X-Ray magnetic scattering, we studied spontaneous fluctuations on nanosecond time scales in thin films of multilayered Fe/Gd that exhibit ordered stripe and Skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the Skyrmion phase and near the stripe-Skyrmion boundary. This technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

Kadda Medjoubi - One of the best experts on this subject based on the ideXlab platform.

  • Analytical model of single-X-Ray Photon counting pixel-array detectors
    Journal of Instrumentation, 2014
    Co-Authors: J. Marchal, J Mcgrath, Kadda Medjoubi
    Abstract:

    Single-X-Ray-Photon counting pixel array detectors are now widely used on synchrotron beamlines for X-Ray diffraction and imaging experiments. Efforts have been carried out in the recent years to extend X-Ray detector system analysis to include charge-sharing effects and characteristic X-Ray re-absorption on image quality parameters such as MTF, NPS and DQE. These efforts led to the formulation of an analytical model of single-X-Ray-Photon counting pixel array detectors which is presented in this contribution to the IWORID-2013 conference. This model links together imaging and spectroscopic performance of pixel array detectors. It provides a framework for optimising the design of single-energy threshold, multiple-energy thresholds and energy-sensitive pixel array detectors. This analytical model is applied to typical silicon- and CdTe-based pixel sensor geometries associated to single-X-Ray processing read-out electronics.

  • Sampling function of single-X-Ray-Photon counting hybrid pixel detectors: combining an analytical approach to Monte-Carlo simulations and Finite-Element-Modeling
    Journal of Instrumentation, 2013
    Co-Authors: J Mcgrath, J. Marchal, Kadda Medjoubi
    Abstract:

    Spectroscopic and imaging performance parameters of hybrid pixel detectors operated in single-X-Ray Photon-counting mode can be inferred from the dependence of their sampling function (or aperture function) on the detection energy threshold. In a previous paper, it was shown that this dependence could be modelled using a simple analytical method. Measurements were performed on typical synchrotron X-Ray detectors and fitted to the analytical formulas in order to obtain detector parameters such as charge-sharing width, energy dispersion and fill-factor at 50% threshold. In the present paper, we use Monte-Carlo (MC) and Finite-Element-Modeling (FEM) software tools to perform a more detailed simulation of image formation processes taking place in Photon-counting hybrid pixel detectors of various pixel sizes associated to standard silicon sensor thickness and exposed to 15 keV monochromatic X-Rays. We show that the MC/FEM simulation results can be used to produce detector parameters required in the analytical expressions of the sampling function of these detectors.

  • Development of a PCI express based readout electronics for the XPAD3 X-Ray Photon counting imager
    2010 17th IEEE-NPSS Real Time Conference, 2010
    Co-Authors: A. Dawiec, Kadda Medjoubi, B. Dinkespiler, P. Breugnon, K. Arnaud, S. Godiot, S. Hustache, F. Bompard, P.-y. Duval, J.-f. Berar
    Abstract:

    XPAD3 is a large surface X-Ray Photon counting imager with high count rates, large counter dynamics and very fast data readout. Data are readout in parallel by a PCI Express interface using DMA transfer. The readout frame rate of the complete detector comprising 0.5 MPixels amounts to 500 images per second without dead-time.

  • Development of a PCI Express Based Readout Electronics for the XPAD3 X-Ray Photon Counting Image
    2010
    Co-Authors: A. Dawiec, Kadda Medjoubi, B. Dinkespiler, P. Breugnon, K. Arnaud, S. Godiot, S. Hustache, J.-f. Berar, P.-y. Duval, N. Boudet
    Abstract:

    XPAD3 is a large surface X-Ray Photon counting imager with high count rates, large counter dynamics and very fast data readout. Data are readout in parallel by a PCI Express interface using DMA transfer. The readout frame rate of the complete detector comprising 0.5 MPixels amounts to 500 images per second without dead-time.

  • Development of the XPAD3 X-Ray Photon counting imager DAQ electronics
    2009 1st International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, 2009
    Co-Authors: A. Dawiec, Kadda Medjoubi, B. Dinkespiler, P. Breugnon, K. Arnaud, S. Godiot, S. Hustache, J.-f. Berar, N. Boudet, C. Morel
    Abstract:

    Experiments on high flux and high brilliance third generation synchrotron X-Ray sources and on low dose Photon counting cone beam micro-CT imaging require detectors with large surface, high count rates, large counter dynamics, adjustable energy threshold and last but not least fast readout system. The XPAD3 X-Ray Photon counting imager is a large-surface (12 × 7.5 cm2) hybrid pixel detector with fast data readout electronics.

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