{"status":"OK","msg":"Details loaded!","speaker":{"id":15,"speaker":"Jorge Eduardo Fernandez","sarx_lecture":"The X-ray characteristic line in the framework of the Boltzmann transport equation","sarx_lecture_abstract":"The emission of characteristic lines after x-ray excitation is usually explained as the consequence of two independent and consecutive physical processes: the photoelectric ionization produced by the incoming photons and the successive spontaneous atomic relaxation. However, this is not the only mechanism for the formation of the characteristic lines. In first place, the photoelectric effect is not the only ionization mechanism driven by the incoming photons. As it has been recently shown [1], Compton ionization is another possible process which contributes not negligibly to the ionization of the shells L and M. In second place, secondary electrons from these two interactions, photoelectric and Compton, are also able to ionize the atom by means of the so called impact ionization. This contribution has been recently described showing that it can be more relevant at monochromatic energies which are specific of certain lines and elements [2,3]. A third mechanism of line modification is the so called self-enhancement produced by absorption of the tail of the Lorentzian distribution of the characteristic line [4,5]. These four effects concur to the formation of the characteristic line and must be considered to obtain a precise picture in terms of the shell and the element.\r\n\r\nThis article furnishes a review of these contributions and their formal theoretical descriptions. It is given a complete picture of the photon kernel describing the emission of characteristic x- rays comprising the major photoelectric contribution and the three effects of lower extent. The line formed with all these contributions can then be followed along successive photon interactions in deterministic or Monte Carlo photon codes to describe better the multiple scattering effects.","earj_lecture":"","earj_lecture_abstract":"","country":"Italia","institution":"Universit\u00e0 di Bologna (Italia)","earj":0,"sarx":1,"duration":30,"short_bio":"Jorge Eduardo Fernandez Invitti has completed his studies at the Faculty of Mathematics, Astronomy and Physics of the State University of C\u00f3rdoba, Argentina, earning the Licentiate Degree in Physics (1977), and the Ph.D. in Physics (1985) with a theoretical-experimental dissertation on a spectroscopic absolute method of analysis with nuclear techniques. Has obtained the acknowledgement for his Licentiate Degree in Physics earning the corresponding Italian Degree \u201cLaurea in Physics\u201d at the University of Bologna (1991). Has followed specialization courses at several academic institutions in Italy and abroad between 1980 and 1989. Has obtained several scholarships in Italy and abroad between 1979 and 1991 [among these, CONICET, Argentina; ICTP(IAEA-UNESCO); ENEA, Italia]. Has been research staff of CONICET, Argentina (1985-1993). From 1994-2005 was affiliated researcher of the Italian National Institute for Physics of Matter (INFM). From 1995-2005 was head of the research group Atomic and Molecular Physics of the local Unit INFM of Bologna. From 2005 is Associate Researcher of the Italian National Institute of Nuclear Physics (INFN). Has been faculty at the State University of Cordoba (different positions) from 1979 to 1993 (last being Adjunct Professor, 1985-1993). In 1994 became Faculty (1994-2001, Research Assistant Professor of Measurements and Nuclear Instrumentation) at the Engineering Faculty of the University of Bologna. Actually is Associate Professor of Nuclear Reactor Physics, at the Engineering School of the University of Bologna. From 2016 is Director, Buenos Aires Campus of the University of Bologna (also named, in the Statuto of the University of Bologna: Centro di Studi Avanzati di Buenos Aires or, for the Argentinian Government: \"Alma Mater Studiorum - Universit\u00e0 di Bologna Representaci\u00f3n en la Rep\u00fablica Argentina\"), Argentina. This branch has the accreditation of the Ministry of Educacion of Argentina as the only foreign university to deliver degrees with legal value under the law of Argentina.","cvlink":"https:\/\/www.unibo.it\/sitoweb\/jorge.fernandez\/cv-en","picture":"http:\/\/sarx2016.nbcgib.uesc.br\/speaker\/15\/picture","email":"jorge.fernandez@unibo.it","cvfile":null,"created_at":"-0001-11-30 00:00:00","updated_at":"2016-09-21 05:47:15","lecture":"The X-ray characteristic line in the framework of the Boltzmann transport equation","abstract":"The emission of characteristic lines after x-ray excitation is usually explained as the consequence of two independent and consecutive physical processes: the photoelectric ionization produced by the incoming photons and the successive spontaneous atomic relaxation. However, this is not the only mechanism for the formation of the characteristic lines. In first place, the photoelectric effect is not the only ionization mechanism driven by the incoming photons. As it has been recently shown [1], Compton ionization is another possible process which contributes not negligibly to the ionization of the shells L and M. In second place, secondary electrons from these two interactions, photoelectric and Compton, are also able to ionize the atom by means of the so called impact ionization. This contribution has been recently described showing that it can be more relevant at monochromatic energies which are specific of certain lines and elements [2,3]. A third mechanism of line modification is the so called self-enhancement produced by absorption of the tail of the Lorentzian distribution of the characteristic line [4,5]. These four effects concur to the formation of the characteristic line and must be considered to obtain a precise picture in terms of the shell and the element.
\r\n
\r\nThis article furnishes a review of these contributions and their formal theoretical descriptions. It is given a complete picture of the photon kernel describing the emission of characteristic x- rays comprising the major photoelectric contribution and the three effects of lower extent. The line formed with all these contributions can then be followed along successive photon interactions in deterministic or Monte Carlo photon codes to describe better the multiple scattering effects."}}