Expansion of the LOFAR Radboud Air Shower Array and Updated Calibration of the LOFAR Antennas

Jun 15, 2018, 11:50 AM


Dr Katharine Mulrey (Vrije Universiteit Brussel)


The LOFAR radio telescope measures radio emission from air showers in
great detail. Now, we seek to extend our data taking capabilities.
In this contribution we discuss the expansion of the LOFAR Radboud Air
Shower Array (LORA). LORA is a particle detector array located at the
dense LOFAR core and is used to trigger the read-out of the LOFAR
antennas. By doubling the size of the array, we increase its
effective area, allowing us to trigger on higher energy cosmic rays
which are more likely to produce a strong radio signal. In addition,
the expansion reduces the composition bias inherent in detecting low
energy showers. We also revisit the calibration of the LOFAR antennas
in the range of 30-80 MHz. Using the galactic background and a
detailed model of the LOFAR signal chain, we find a calibration that
provides an absolute energy scale and allows us to study frequency
dependent features in measured signals.

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