Abstract
The LOw Frequency ARay (LOFAR) is a multi-purpose radio antenna array aimed to detect radio signals in the frequency range 10 - 240 MHz, covering a largesurface in Northern Europe with a higher density in the Netherlands. Analytical calculations and simulation studies performed in the 2000s indicate a dependence of the radio frequency spectrum on cosmic-ray characteristics. The high number density of radio antennas at the LOFAR core allows to characterise the observed cascade in a detailed way. The radio signal emitted by air showers in the atmosphere has been studied accurately in the 30 - 80 MHz frequency range. The analysis has been conducted on simulated eventsand on real data detected by LOFAR since 2011. The final aim of this study is to find an independent method to infer information of primary cosmic rays for improving the reconstruction of primary particle parameters. Results show a strong dependence of the frequency spectrum on the distance to the shower axis for both real data and simulations. Furthermore, results show that this method is very sensitive to the precision in reconstructing the position of the shower axis at ground, and to different antenna calibration procedures. A correlation between the frequency spectrum and geometrical distance to the shower maximum development Xmax has also been investigated.
Highlights
− the antenna signal in the time-domain is converted into the frequency-domain by applying a Fast Fourier Transform (FFT)
The radio signal emitted by air showers in the atmosphere has been studied accurately in the 30 − 80 MHz frequency range
The analysis has been conducted on simulated events and on real data detected by LOw Frequency ARay (LOFAR) since 2011
Summary
− the antenna signal in the time-domain is converted into the frequency-domain by applying a Fast Fourier Transform (FFT). Results show that the linear-fit slope of the frequency spectrum strongly depends on the distance to the shower axis for both real data and simulations, as depicted in Fig. It has been found that the linear-fit slope as function of distance to the shower axis is extremely sensitive to the selected frequency range. The frequency spectrum depends on the geometrical distance of the observer to Xmax (hereafter, Dmax), as shown for simulations in Fig. (3) at a given distance to the shower axis the linear-fit slope is correlated to Dmax by the following function: p0 · exp(−p1 · Dmax) + p2 + p3 · Dmax. Final results on the dependence of the linear-fit slope as function of Dmax for real data are still under investigation, and they will be discussed in a forthcoming publication
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
