The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Juri Poutanen - One of the best experts on this subject based on the ideXlab platform.
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compton scattering s matrix and cross section in strong magnetic field
Physical Review D, 2016Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri PoutanenAbstract:Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic (QED) second order perturbation theory is presented for the case of arbitrary initial and final Landau level, electron Momentum along the field and Photon Momentum. Photon polarization and electron spin state are taken into account. The correct dependence of natural Landau level width on the electron spin state is taken into account in general case of arbitrary initial Photon Momentum for the first time. A number of steps in calculations were simplified analytically making the presented recipe easy-to-use. The redistribution functions over the Photon energy, Momentum and polarization states are presented and discussed. The paper generalizes already known results and offers a basis for accurate calculation of radiation transfer in strong B-field, for example, in strongly magnetized neutron stars.
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compton scattering s matrix and cross section in strong magnetic field
Physical Review D, 2016Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri PoutanenAbstract:Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic second-order perturbation theory is presented for the case of arbitrary initial and final Landau level, electron Momentum along the field and Photon Momentum. Photon polarization and electron spin state are taken into account. The correct dependence of natural Landau level width on the electron spin state is taken into account in a general case of arbitrary initial Photon Momentum for the first time. A number of steps in the calculations were simplified analytically making the presented recipe easy to use. The redistribution functions over the Photon energy, Momentum and polarization states are presented and discussed. The paper generalizes already known results and offers a basis for the accurate calculation of radiation transfer in a strong B field, for example, in strongly magnetized neutron stars.
Alexander A Mushtukov - One of the best experts on this subject based on the ideXlab platform.
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compton scattering s matrix and cross section in strong magnetic field
Physical Review D, 2016Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri PoutanenAbstract:Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic (QED) second order perturbation theory is presented for the case of arbitrary initial and final Landau level, electron Momentum along the field and Photon Momentum. Photon polarization and electron spin state are taken into account. The correct dependence of natural Landau level width on the electron spin state is taken into account in general case of arbitrary initial Photon Momentum for the first time. A number of steps in calculations were simplified analytically making the presented recipe easy-to-use. The redistribution functions over the Photon energy, Momentum and polarization states are presented and discussed. The paper generalizes already known results and offers a basis for accurate calculation of radiation transfer in strong B-field, for example, in strongly magnetized neutron stars.
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compton scattering s matrix and cross section in strong magnetic field
Physical Review D, 2016Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri PoutanenAbstract:Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic second-order perturbation theory is presented for the case of arbitrary initial and final Landau level, electron Momentum along the field and Photon Momentum. Photon polarization and electron spin state are taken into account. The correct dependence of natural Landau level width on the electron spin state is taken into account in a general case of arbitrary initial Photon Momentum for the first time. A number of steps in the calculations were simplified analytically making the presented recipe easy to use. The redistribution functions over the Photon energy, Momentum and polarization states are presented and discussed. The paper generalizes already known results and offers a basis for the accurate calculation of radiation transfer in a strong B field, for example, in strongly magnetized neutron stars.
K. Siddappa - One of the best experts on this subject based on the ideXlab platform.
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Incoherent scattering functions of some medium and heavy elements at 4.808 A-1 Photon Momentum transfer
2002Co-Authors: N. Govinda Nayak, Gerald Pinto, K. SiddappaAbstract:Whole atom differential incoherent scattering cross sections for 84.3 keV gamma Photons have been measured for nine elements Cu, Mo, Ag, Cd, Sn, Ta, W, Th and U for 90° scattering of 84.3 keV gamma rays corresponding to the Photon Momentum transfer value X = 4.080 A - 1 . A 100 cc HpGe detector coupled to a PC based 4K analyser was used to detect and record scattered gamma Photons. From the measured cross sections the incoherent scattering functions S(x, Z) were evaluated and compared with the recent experimental values reported in literature and also with the latest theoretical computations based on Hartree-Fock and Thomas-Fermi atomic model predictions. Possible conclusions are drawn on electron binding and other effects.
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Incoherent scattering of 59.54 keV gamma rays for some rare earth elements at low Photon Momentum transfers
Radiation Physics and Chemistry, 2001Co-Authors: N. Govinda Nayak, Gerald Pinto, K. SiddappaAbstract:Abstract Incoherent scattering functions S(x, Z) for six rare earth elements were evaluated from accurately measured whole atom differential incoherent scattering cross sections for 59.54 keV γ-rays scattered at 30°, 45°, 60° and 90° scattering angles corresponding to 1.24, 1.84, 2.40 and 3.39 A−1 Photon Momentum transfers. Our results for S(x, Z) are the first for these rare earth elements.
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Incoherent scattering of 59.54keV gamma rays for some rare earth elements at low Photon Momentum transfers
Radiation Physics and Chemistry, 2001Co-Authors: N Govinda Nayak, Gerald Pinto, K. SiddappaAbstract:Incoherent scattering functions S(x, Z) for six rare earth elements were evaluated from accurately measured whole atom differential incoherent scattering cross sections for 59.54 keV γ-rays scattered at 30°, 45°, 60° and 90° scattering angles corresponding to 1.24, 1.84, 2.40 and 3.39 Å -1 Photon Momentum transfers. Our results for S(x, Z) are the first for these rare earth elements. © 2001 Elsevier Science Ltd. All rights reserved
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Verification of incoherent scattering functions at intermediate Photon Momentum transfer
Journal of Physics B: Atomic Molecular and Optical Physics, 1994Co-Authors: Gerald Pinto, K. M. Balakrishna, N. Govinda Nayak, K. SiddappaAbstract:Experimental whole atom differential incoherent scattering cross sections were measured for Cu, Mo, Ag, Cd, Sn, Pr, Sm, Gd, Dy, Ho, Yb, Ta, W, Th and U for the 90 degrees scattering of 145.4 and 84.3 keV gamma rays. The scattering experiments were conducted in a reflection geometry set up with a graded shielding arrangement. A 133 cm3 HpGe detector was used to detect the scattered gamma rays. The cross sections were measured using Al as standard. From the measured cross sections the incoherent scattering functions were extracted. The results are compared with theory and with the experimental values reported in literature for available cases. The electron binding effects and the validity of the incoherent scattering functions at intermediate Momentum transfer are discussed.
K. Henrichs - One of the best experts on this subject based on the ideXlab platform.
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Magnetic fields alter strong-field ionization
Nature Physics, 2019Co-Authors: A. Hartung, D. Trabert, S. Eckart, S. Brennecke, J. Rist, K. Fehre, M. Richter, H. Sann, S. Zeller, K. HenrichsAbstract:When a strong laser pulse induces the ionization of an atom, Momentum conservation dictates that the absorbed Photons transfer their Momentum to the electron and its parent ion. The sharing of the Photon Momentum between the two particles and its underlying mechanism in strong-field ionization, occurring when the bound electron tunnels through the barrier created by the superposition of the atomic potential and the electric laser field, are still debated in theory^ 1 – 4 after 30 years of research. Corresponding experiments are very challenging due to the extremely small Photon Momentum and their precision has been too limited, so far, to ultimately resolve this debate^ 5 – 8 . By utilizing an experimental approach relying on two counter-propagating laser pulses, we present a detailed study of the effects of the Photon Momentum in strong-field ionization. The high precision of the method and the intrinsically known zero Momentum allow us to unambiguously demonstrate the action of the light’s magnetic field on the electron while it is under the tunnel barrier, which has only been theoretically predicted so far^ 1 – 3 , 9 , thereby disproving opposing predictions^ 5 , 10 , 11 . Our results deepen the understanding of, for example, molecular imaging^ 12 , 13 and time-resolved photoelectron holography^ 14 . Experiments with two counter-propagating laser beams report the observation that the Photon Momentum is shared between the electron and parent ion in strong-field ionization, which results from the Photon’s magnetic field acting on the electron.
A. Hartung - One of the best experts on this subject based on the ideXlab platform.
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Magnetic fields alter strong-field ionization
Nature Physics, 2019Co-Authors: A. Hartung, D. Trabert, S. Eckart, S. Brennecke, J. Rist, K. Fehre, M. Richter, H. Sann, S. Zeller, K. HenrichsAbstract:When a strong laser pulse induces the ionization of an atom, Momentum conservation dictates that the absorbed Photons transfer their Momentum to the electron and its parent ion. The sharing of the Photon Momentum between the two particles and its underlying mechanism in strong-field ionization, occurring when the bound electron tunnels through the barrier created by the superposition of the atomic potential and the electric laser field, are still debated in theory^ 1 – 4 after 30 years of research. Corresponding experiments are very challenging due to the extremely small Photon Momentum and their precision has been too limited, so far, to ultimately resolve this debate^ 5 – 8 . By utilizing an experimental approach relying on two counter-propagating laser pulses, we present a detailed study of the effects of the Photon Momentum in strong-field ionization. The high precision of the method and the intrinsically known zero Momentum allow us to unambiguously demonstrate the action of the light’s magnetic field on the electron while it is under the tunnel barrier, which has only been theoretically predicted so far^ 1 – 3 , 9 , thereby disproving opposing predictions^ 5 , 10 , 11 . Our results deepen the understanding of, for example, molecular imaging^ 12 , 13 and time-resolved photoelectron holography^ 14 . Experiments with two counter-propagating laser beams report the observation that the Photon Momentum is shared between the electron and parent ion in strong-field ionization, which results from the Photon’s magnetic field acting on the electron.