The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform

Tamas Keszthelyi - One of the best experts on this subject based on the ideXlab platform.

  • laser assisted nuclear Photoeffect re examined
    International Journal of Nuclear Energy Science and Technology, 2014
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    In a recent article of Dadi and Muller the modification of nuclear Photoeffect due to intense laser field is discussed. The paper is criticised from the point of view of gauge invariance. The S-matrix element and the cross-section of the laser-assisted nuclear Photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The γ-photon energy dependence of the laser-free cross-section obtained in the plane wave and long-wavelength Coulomb–Volkov approximations are compared. The laser-assisted partial cross-sections with laser photon energy 2 keV and some different polarisation states of γ-photon of energy 3 MeV are numerically investigated.

  • near threshold laser modified proton emission in the nuclear Photoeffect
    Physical Review A, 2013
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    The change of the probability of proton emission in nuclear Photoeffect due to an intense coherent (laser) field is discussed near the threshold, where the hindering effect of the Coulomb field of the remainder nucleus is essential. The ratio of laser-assisted and laser free differential cross section is deduced and found to be independent of the polarization state of the $\gamma $ field and the two types of initial nuclear state considered. The numerical values of this ratio are given at some characteristic parameters of the intense field.

  • Laser-assisted nuclear Photoeffect reexamined
    arXiv: Nuclear Theory, 2013
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    The S-matrix element and the cross section of the laser-assisted nuclear Photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The \gamma-photon energy dependence of the laser free cross section obtained in the plane wave and long-wavelength Coulomb-Volkov approximations are compared. Numerically the laser-assisted partial cross sections with laser photon energy 2 keV and some different polarization states of \gamma-photon of energy 3 MeV are investigated.

Jan Hlavka - One of the best experts on this subject based on the ideXlab platform.

  • the Photoeffect in powdered semiconductors
    Semiconductor Science and Technology, 1997
    Co-Authors: Jan Hlavka
    Abstract:

    A simple technique makes possible the measurement of spectral dependences of the Photoeffect and Photoeffect time relaxations in powdered semiconductors. Our qualitative explanation of the Photoeffect in powdered semiconductors is presented. The Photoeffect onsets observed in CdS, GaAs, Ge, Si, and ZnO are in good agreement with the energy gaps of these materials. Both the spectral dependences and the time relaxations of the Photoeffect are strongly dependent on the quality of the particle surface. The extrinsic Photoeffect was observed in GaAs and CdS.

  • Photoeffect in porous silicon
    Journal of Applied Physics, 1997
    Co-Authors: Jan Hlavka
    Abstract:

    A new contactless technique makes possible the measurement of spectral dependences of the Photoeffect and the Photoeffect time relaxations in porous silicon. From these Photoeffect measurements the following results have been obtained. The onset of excess carrier generation at about 1.35 eV was found. The Photoeffect time relaxation constant ranges from 0.15 to 10 ms. The dominant components of the measured Photoeffect were produced in the depletion space charge regions near both surfaces. Strong trapping of excess carriers near the sample surfaces was observed.

Peter Kalman - One of the best experts on this subject based on the ideXlab platform.

  • laser assisted nuclear Photoeffect re examined
    International Journal of Nuclear Energy Science and Technology, 2014
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    In a recent article of Dadi and Muller the modification of nuclear Photoeffect due to intense laser field is discussed. The paper is criticised from the point of view of gauge invariance. The S-matrix element and the cross-section of the laser-assisted nuclear Photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The γ-photon energy dependence of the laser-free cross-section obtained in the plane wave and long-wavelength Coulomb–Volkov approximations are compared. The laser-assisted partial cross-sections with laser photon energy 2 keV and some different polarisation states of γ-photon of energy 3 MeV are numerically investigated.

  • near threshold laser modified proton emission in the nuclear Photoeffect
    Physical Review A, 2013
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    The change of the probability of proton emission in nuclear Photoeffect due to an intense coherent (laser) field is discussed near the threshold, where the hindering effect of the Coulomb field of the remainder nucleus is essential. The ratio of laser-assisted and laser free differential cross section is deduced and found to be independent of the polarization state of the $\gamma $ field and the two types of initial nuclear state considered. The numerical values of this ratio are given at some characteristic parameters of the intense field.

  • Laser-assisted nuclear Photoeffect reexamined
    arXiv: Nuclear Theory, 2013
    Co-Authors: Peter Kalman, Tamas Keszthelyi
    Abstract:

    The S-matrix element and the cross section of the laser-assisted nuclear Photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The \gamma-photon energy dependence of the laser free cross section obtained in the plane wave and long-wavelength Coulomb-Volkov approximations are compared. Numerically the laser-assisted partial cross sections with laser photon energy 2 keV and some different polarization states of \gamma-photon of energy 3 MeV are investigated.

P Chou - One of the best experts on this subject based on the ideXlab platform.

  • some Photoeffect roles in rapid isothermal processing
    Applied Physics Letters, 1991
    Co-Authors: Rakesh K Singh, Randhir P. S. Thakur, Sucharita Sinha, P Chou
    Abstract:

    When compared to furnace processing, for identical and lower substrate temperatures, more photons are available in the visible and ultraviolet regions for rapid isothermal processing (RIP) based on incoherent radiation as the energy source. In this letter, we provide experimental evidence for Photoeffects in RIP for a wide variety of materials. As compared to furnace processed samples, rapid isothermal annealed phosphosilicate glass films on Si substrate show a higher value of refractive index, a lower flatband charge density, and a lower thermal stress. High‐temperature superconducting thin films on Y‐Ba‐Cu‐O deposited by RIP assisted metalorganic chemical vapor deposition on yttrium stabilized zirconia substrate show a larger grain size, a higher value of the transition temperature than their furnace counterpart. The microscopic understanding of a particular deposition or annealing process is necessary to take full advantage of Photoeffects in RIP.

T.k. Umesh - One of the best experts on this subject based on the ideXlab platform.

  • A method to determine the K-shell Photoeffect cross sections of some rare earth elements
    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2020
    Co-Authors: M.l. Mallikarjuna, S.b. Appaji Gowda, K.e. Ganesh, R. Gowda, T.k. Umesh
    Abstract:

    K-shell Photoeffect cross sections of the rare earth elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er have been obtained by a new method, for energies above the K-edge of these elements. In this method, the K-shell Photoeffect cross sections of rare earth elements at energies above the K-shell threshold are obtained by using log-log plot of the experimentally measured total attenuation cross sections of their simple compounds. The method does not require any knowledge of the contributions of other competing processes. A simple formula has been obtained by studying the variation these K-shell Photoeffect cross sections versus E and Z. This formula provides for an easy and rapid evaluation of the K-shell Photoeffect cross sections for any element in the range >57 and

  • a method to determine the k shell Photoeffect cross sections of some rare earth elements
    Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2004
    Co-Authors: M.l. Mallikarjuna, Ramakrishna Gowda, K.e. Ganesh, S Appaji B Gowda, T.k. Umesh
    Abstract:

    K-shell Photoeffect cross sections of the rare earth elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er have been obtained by a new method, for energies above the K-edge of these elements. In this method, the K-shell Photoeffect cross sections of rare earth elements at energies above the K-shell threshold are obtained by using log-log plot of the experimentally measured total attenuation cross sections of their simple compounds. The method does not require any knowledge of the contributions of other competing processes. A simple formula has been obtained by studying the variation these K-shell Photoeffect cross sections versus E and Z. This formula provides for an easy and rapid evaluation of the K-shell Photoeffect cross sections for any element in the range >57 and <68 and for energies up to 84.3 keV. (C) 2003 Elsevier B.V. All rights reserved.