124,406 research outputs found
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
No full textData from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius A. Also the events detected simultaneously by the surface and fluorescence detectors (the ‘hybrid’ data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.http://www.elsevier.com/wps/find/journaldescription.cws_home/523319/description#descriptio
The Pierre Auger Observatory III: Other Astrophysical Observations - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4805.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger Observator
The Pierre Auger Observatory I: The Cosmic Ray Energy Spectrum and Related Measurements - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4809.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the cosmic ray energy spectrum at the highest energies with the Pierre Auger Observatory
The Pierre Auger Observatory II: Studies of Cosmic Ray Composition and Hadronic Interaction models - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4804.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers
Symmetry characterization of unoccupied states in thick alkaline layers by spin-resolved Auger electron spectroscopy using primary excitation by circularly polarized light
No full textStoppmanns P, David R, Müller N, Heinzmann U, Grieb H, Noffke J. Symmetry characterization of unoccupied states in thick alkaline layers by spin-resolved Auger electron spectroscopy using primary excitation by circularly polarized light. Journal of physics: condensed matter. 1994;6(23):4225-4232.CVV Auger electrons emitted from K, Rb and Cs layers are studied using spin-resolved spectroscopy. Oriented 3p, 4p and 5p hole states are excited by circularly polarized radiation in normal incidence. The photon energies range from 12 to 24 eV. With all three materials, the degree and sign of the Auger electron spin polarization vary with the photon energy. As an atomic model of the Auger process predicts, and as a comparison of measurements with the calculated densities of states shows, the spin polarization is essentially determined by the symmetry of the final states reached in the primary (photo)excitation. Just above the excitation threshold, the preferential spin direction of the Auger electrons is measured to be parallel to the spin of the exciting photons corresponding to a predominantly s-like symmetry of the unoccupied final states reached by the excitation. At higher photon energies the preferential spin direction changes to be antiparallel to the photon spin, corresponding to the mainly d-like symmetry of unoccupied states reached by the excitation
Auger-induced charge migration
No full textNovel perspectives of controlling molecular systems have recently arisen from the possibility of generating attosecond pulses in the ultraviolet regime and tailoring electron dynamics in its natural time scale. The cornerstone mechanism is the so-called charge migration, he production of a coherent charge transfer with subfemtosecond oscillations across a molecule. Typically, charge migration is induced by the ionization of valence molecular orbitals. However, recent technological developments allow the generation of attosecond pulses in the x-ray regime. In this case, the absorption of photons creates core-hole states. In light elements, core-hole states mainly decay by Auger processes that, driven by electron correlations, involve valence orbitals. We theoretically demonstrate in a fluoroacetylene molecule a double-hole charge migration triggered by attosecond core-electron photoionization, followed by Auger electron relaxations. This opens a new route for inducing with x rays charge transfer processes in the subfemtosecond time scale
Detailed assignment of normal and resonant Auger spectra of Xe near the L edges
No full textWe present a comprehensive experimental and theoretical investigation on the LMM, LMN, and LNN normal Auger spectra of xenon, which reveal excellent agreement with theory when core-hole lifetimes of the two-hole final states are taken into account. Generally, the spectra turned out to be highly complex due to a strong overlap of the Auger transitions subsequent to 2s(1/2)(-1), 2p(1/2)(-1), and 2p(3/2)(-1) ionization. This overlap is due to the splitting of the three initial L core holes and the different final M and N core holes being on the same order of magnitude of several hundred eV. The Auger transitions are assigned in detail based on the theoretical results. Most of the MM, MN, and NN final states are described well based on jj coupling. In addition, we present a detailed assignment of the resonant LM45M45 Auger transition subsequent to the 2s -> 6p, 7p and 2p -> 5d, 6d excitations
Bryobia (Bryobia) gigas Auger, Arabuli and Migeon 2015
No full textBryobia (Bryobia) gigas Auger, Arabuli and Migeon, 2015 Four females of this species were collected from soil litter, Attabiyyat, south-west of Latakia city, Syria (35°30’24” N, 35°46’49” E), 23 April 2019. This species has been already collected from Bituminaria bituminosa (L.) in Syria (Zeity and Srinivasa, 2019) but this host plant was no present in the place where we collected these specimens.Published as part of Barbar, Ziad & Auger, Philippe, 2020, New records of the genusBryobia (Acari: Tetranychidae) from Syria with description of a new species, pp. 268-288 in Acarologia 60 (2) on page 281, DOI: 10.24349/acarologia/20204367, http://zenodo.org/record/450336
Étude des électrons Auger K et L du 137Ba
No full textUsing a double focusing magnetic spectrometer with iron-free coils, the energies and relative intensities of the groups of Auger K lines resulting from the decay of 137Cs have been determined. Auger L electrons have been studied also.Les spectres d'électrons Auger K et L résultant de la décroissance du 137Cs ont été étudiés en utilisant un spectromètre magnétique à double focalisation, sans fer, et des sources minces uniformes. Les techniques de post et préaccélération des électrons employées avec des fenêtres minces ont permis l'étude du spectre Auger L
Auger Lineshape analysis of porous silicon: Experiment and theory
No full textDifferent samples of porous Si have been investigated through Auger electron spectroscopy, The Si LVV lineshape of porous Si is different with respect to that of pure Si and the main peak is shifted to lower kinetic energies. Porous Si is modeled by a first-principle calculation of the electronic states of thin silicon wires (LMTO-ASA method). The main experimental finding is related to the new properties of the valence states in porous Si. The calculated Auger lineshape provides an interpretation of the characteristic shape of the measured spectra. We prove that the confinement shift is not detected by the Si L(2.3)VV Auger signal and that the Si atoms probed are bonded with H and H-2
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