| 1. |
- Mulrey, K., et al.
(författare)
-
Calibration of the LOFAR low-band antennas using the Galaxy and a model of the signal chain
- 2019
-
Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 111, s. 1-11
-
Tidskriftsartikel (refereegranskat)abstract
- The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensive air showers, yielding information about the primary cosmic ray. Interpreting the measured data requires an absolute and frequency-dependent calibration of the LOFAR system response. This is particularly important for spectral analyses, because the shape of the detected signal holds information about the shower development. We revisit the calibration of the LOFAR antennas in the range of 30-80 MHz. Using the Galactic emission and a detailed model of the LOFAR signal chain, we find an improved calibration that provides an absolute energy scale and allows for the study of frequency dependent features in measured signals. With the new calibration, systematic uncertainties of 13% are reached, and comparisons of the spectral shape of calibrated data with simulations show promising agreement. (C) 2019 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Mulrey, K., et al.
(författare)
-
Updated Calibration of the LOFAR Low-Band Antennas
- 2019
-
Ingår i: 8th International Conference on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 2018). - : EDP Sciences. - 9782759890804 ; , s. 1-3
-
Konferensbidrag (refereegranskat)abstract
- The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to interpret the data, an absolute, frequency dependent calibration is required. Due to a growing need for a better understanding of the measured frequency spectrum, we revisit the calibration of the LOFAR antennas in the range of 30-80 MHz. Using the galactic radio emission 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 air shower signals.
|
|
| 3. |
- Winchen, T., et al.
(författare)
-
Cosmic ray physics with the LOFAR radio telescope
- 2019
-
Ingår i: 26th Extended European Cosmic Ray Symposium, 6–10 July 2018, Altai State University, Barnaul-Belokurikha, Russian Federation. - : Institute of Physics (IOP). ; , s. 1-6
-
Konferensbidrag (refereegranskat)abstract
- The LOFAR radio telescope is able to measure the radio emission from cosmic ray induced air showers with hundreds of individual antennas. This allows for precision testing of the emission mechanisms for the radio signal as well as determination of the depth of shower maximum X max , the shower observable most sensitive to the mass of the primary cosmic ray, to better than 20 g cm -2 . With a densely instrumented circular area of roughly 320 m 2 , LOFAR is targeting for cosmic ray astrophysics in the energy range 10 16 -10 18 eV. In this contribution we give an overview of the status, recent results, and future plans of cosmic ray detection with the LOFAR radio telescope. © Published under licence by IOP Publishing Ltd.
|
|
| 4. |
- Winchen, T., et al.
(författare)
-
Properties of the Lunar Detection Mode for ZeV-Scale Particles with LOFAR
- 2019
-
Ingår i: 8th International Conference on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 2018). - : EDP Sciences. - 9782759890804 ; , s. 1-3
-
Konferensbidrag (refereegranskat)abstract
- The steep decrease of the flux of ultra-high energy cosmic rays (UHECR) provides a challenge to answer the long standing question about their origin and nature. A significant increase in detector volume may be achieved by employing Earth's moon as a detector that is read out using existing Earth-bound radio telescopes by searching for the radio pulses emitted by the particle shower in the lunar rock. In this contribution we will report on the properties of a corresponding detection mode currently under development for the LOFAR Radio telescope.
|
|
| 5. |
- Winchen, T., et al.
(författare)
-
Status of the lunar detection mode for cosmic particles of LOFAR
- 2019
-
Ingår i: Journal of Physics. - : Institute of Physics (IOP). ; , s. 1-7
-
Konferensbidrag (refereegranskat)abstract
- Cosmic particles hitting Earth's moon produce radio emission via the Askaryan effect. If the resulting radio ns-pulse can be detected by radio telescopes, this technique potentially increases the available collective area for ZeV scale particles by several orders of magnitude compared to current experiments. The LOw Frequency ARray (LOFAR) is the largest radio telescope operating in the optimum frequency regime for this technique. In this contribution, we report on the status of the implementation of the lunar detection mode at LOFAR. © Published under licence by IOP Publishing Ltd.
|
|
