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12. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Shower as a Universal Estimator of Cosmic-Ray EnergyA. Aab, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2016, original scientific article Keywords: energija sevanja, radio signal, univerzalni estimator energije kozmičnih žarkov
Published in RUNG: 15.06.2016; Views: 3763; Downloads: 1
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13. Properties of Null HypersurfacesHovhannes Demirtshyan, 2016, master's thesis Abstract: The aim of this thesis is to investigate the effects that a lightlike singular hypersurface can have on a congruence of timelike (spacelike) geodesics and to extend the existing theory to the case of null geodesics.
The introduction discusses the applications of singular hypersurfaces for the description of physical phenomena, their major classfications and includes a short discussion of the two theoretical approaches that exist to study singular hypersurfaces. The second chapter contains detailed description of these approaches. The theoretical frameworks for both cases of lightlike and timelike (spacelike) hypersurfaces are developed. This chapter also discusses the application of these theories to the case when the hypersurface contains a plane fronted lightlike signal.
The final chapter starts with a discussion of the effects that a lightlike singular hypersurface can have on a congruence of timelike (spacelike) geodesics. A new approach to these calculations is presented together with an extension of the theory to the case of a congruence of null geodesics. At
the end of the chapter a concrete example and its similarities with the case of timelike geodesics is discussed.
In conclusion, the thesis suggests a new mathematical framework for describing a congruence of null geodesics crossing a singular null hypersurface. The results may be applied in experimental physics to detect impulsive signals which are located in singular null hypersurfaces and to this end there
is a discussion of the properties and possibilities for a detector of impulsive lightlike signals, which include gravitational waves.
Keywords: singular hypersurface, impulsive signal, gravitational wave, null geodesic, timelike (spacelike) geodesic
Published in RUNG: 16.05.2016; Views: 7471; Downloads: 261
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14. Azimuthal asymmetry in the risetime of the Surface Detector signals of the Pierre Auger ObservatoryIgnacio Minaya, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The azimuthal asymmetry in the risetime of signals in Auger
surface detector stations is a source of information on shower
development. The azimuthal asymmetry is due to a combination of
the longitudinal evolution of the shower and geometrical
effects related to the angles of incidence of the particles
into the detectors. The magnitude of the effect depends upon
the zenith angle and state of development of the shower and
thus provides a novel observable sensitive to the mass
composition of cosmic rays above 3 × 10[sup]18 eV. By comparing
measurements with predictions from shower simulations, we find
for both of our adopted models of hadronic physics (QGSJetII-
04 and Epos-LHC) an indication that the mean cosmic-ray mass
increases with energy, as has been inferred from other studies.
However the absolute values derived for the mass are dependent
on the shower model and on the range of distance from the
shower core selected. Thus the method has uncovered further
deficiencies in our understanding of shower modelling that must
be resolved before the mass composition can be inferred from
(sec θ)max.
Keywords: Pierre Auger Observatory, Surface Detector, risetime of detector signal, azimuthal asymmetry, extensive air showers
Published in RUNG: 03.03.2016; Views: 4703; Downloads: 196
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