A new way of air shower detection: measuring the properties of cosmic rays with LOFAR

24th European Cosmic Ray Symposium

Nelles, A.^1 ; Buitink, S.^1 ; Corstanje, A.^1 ; Enriquez, J.E.^1 ; Falcke, H.^1,2,3,4 ; Hörandel, J.R.^1,2 ; Rachen, J.P.^1 ; Schellart, P.^1 ; Scholten, O.^5 ; Ter Veen, S.^1 ; Thoudam, S.^1 ; Trinh, T.N.G.^5

Department of Astrophysics, IMAPP, Radboud Unversity, P.O. Box 9010, Njmegen

6500 GL, Netherlands^1

Nikhef, Science Park Amsterdam, Amsterdam

1098 XG, Netherlands^2

Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, Dwingeloo

7990 AA, Netherlands^3

Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn

53121, Germany^4

KVI-CART, University of Groningen, P.O. Box 72, Groningen

9700 AB, Netherlands^5

关键词: Electromagnetic cascades;    Emission mechanism;    Extensive air showers;    Geomagnetic fields;    High-energy cosmic rays;    Precise measurements;    Radio measurements;    Secondary particles;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/632/1/012018/pdf
DOI  :  10.1088/1742-6596/632/1/012018

来源: IOP

【 摘 要 】

High-energy cosmic rays impinging onto the atmosphere of the Earth initiate cascades of secondary particles: extensive air showers. Many of the particles in a shower are electrons and positrons. During the development of the air shower and by interacting with the geomagnetic field, the electromagnetic cascade creates radiation, which we detect at frequencies of tens of MHz with the LOFAR radio telescope in the Netherlands. After many years of struggling to understand the emission mechanisms, the radio community has achieved the breakthrough. We are now able to determine direction, energy, and type of the shower- inducing primary particle from the radio measurements. The large number of antennas at LOFAR allows us to have a high precision and very detailed measurements. We will elaborate on the shower reconstruction, a precise description of the intensity of the radio signal at ground level (at frequencies from 10 to 240 MHz), a precise measurement of the shape of the radio wavefront, and on the reconstruction of the shower energy.