Speaker
Thomas Asch
(FZ Karlsruhe)
Description
Ultra high energy cosmic rays (UHECRs) generate in the atmosphere
secondary particles, in particular a high number of e + e − pairs. The
geosynchrotron theory predicts pulsed, coherent radio emission from the
deflection of these light charged particles in the earth’s magnetic field.
Within the framework of LOPES (Lofar PrototypE Station), 30 short dipole
antennas (LOPES30) are triggered by the air-shower experiment
KASCADEGrande for UHECR with an energy above ≈ 5 · 10 16 eV. An
enhancement of that technique is given by LOPES STAR (Self - Triggered
Array of Radiodetectors) with the challenge to provide an independent, self
triggered radio detector for UHECRs. Radio data is taken in a frequency
range from 40 - 80 MHz on the one hand in self - trigger mode and on the
other hand by using an external trigger from KASCADE-Grande. The high
frequency data is digitised for a given time in the 2. Nyquist Zone and
needed to be reconstructed before the analysis in the time domain is
performed. The methods and first results from LOPES STAR are described.
Author
Thomas Asch
(FZ Karlsruhe)
