A study of radio frequency spectrum emitted by high energy air showers with LOFAR
1 Department of Astrophysics/IMAPP, Radboud University, P.O. Box 9010, 6500 GL Nijmegen ( The Netherlands )
2 Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels ( Belgium )
3 Astron, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo ( The Netherlands )
4 Nikhef, Science Park 105, 1098 XG Amsterdam ( The Netherlands )
5 University of California Irvine, Irvine, CA 92697, ( USA )
6 KVI-CART, Zernikelaan 25, 9747 AA Groningen ( The Netherlands )
7 University of Groningen, Zernikelaan 25, 9747 AA Groningen ( The Netherlands )
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Published online: 15 March 2017
The high number density of radio antennas at the LOFAR core in Northern Netherlands allows to detect radio signals emitted by cosmic ray induced air showers, and to characterize the geometry of the observed cascade in a detailed way. We present here a study of the radio frequency spectrum in the 30 – 80 MHz regime, and its correlation with some geometrical parameters of the extensive air shower. An important goal of this study is to find a correlation between the frequency spectrum and the primary particle type. Preliminary results on how the frequency spectrum changes as function of distance to the shower axis, and as function of primary particles mass composition are shown. The final aim of this study is to find a method to infer information of primary cosmic rays in an independent way from the well-established fluorescence and surface detector techniques, in view of affirming the radio detection technique as reliable method for the study of high energy cosmic rays.
© The Authors, published by EDP Sciences, 2017
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