| 1. |
- Nelles, A., et al.
(författare)
-
Calibrating the absolute amplitude scale for air showers measured at LOFAR
- 2015
-
Ingår i: Journal of Instrumentation. - 1748-0221 .- 1748-0221. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These pulses have been measured successfully in the past few years at the LOw-Frequency ARray (LOFAR) and are used to study the properties of cosmic rays. For a complete understanding of this phenomenon and the underlying physical processes, an absolute calibration of the detecting antenna system is needed. We present three approaches that were used to check and improve the antenna model of LOFAR and to provide an absolute calibration of the whole system for air shower measurements. Two methods are based on calibrated reference sources and one on a calibration approach using the diffuse radio emission of the Galaxy, optimized for short data-sets. An accuracy of 19% in amplitude is reached. The absolute calibration is also compared to predictions from air shower simulations. These results are used to set an absolute energy scale for air shower measurements and can be used as a basis for an absolute scale for the measurement of astronomical transients with LOFAR.
|
|
| 2. |
- Panchal, N., et al.
(författare)
-
A compact cosmic muon veto detector and possible use with the Iron Calorimeter detector for neutrinos
- 2017
-
Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221 .- 1748-0221. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- The motivation for a cosmic muon veto (CMV) detector is to explore the possibility of locating the proposed large Iron Calorimeter (ICAL) detector at the India based Neutrino Observatory (INO) at a shallow depth. An initial effort in that direction, through the assembly and testing of a similar to 1 m x 1 m x 0.3 m plastic scintillator based detector, is described. The plan for making a CMV detector for a smaller prototype mini-ICAL is also outlined.
|
|
| 3. |
- Senniappan, Mohanraj, et al.
(författare)
-
Signal extraction in atmospheric shower arrays designed for 200 GeV–50 TeV γ-ray astronomy
- 2021
-
Ingår i: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221 .- 1748-0221. ; 16:07
-
Tidskriftsartikel (refereegranskat)abstract
- We present the SEMLA (Signal Extraction using Machine Learning for ALTO) analysis method, developed for the detection of E>200 GeV γ rays in the context of the ALTO wide-field-of-view atmospheric shower array R&D project. The scientific focus of ALTO is extragalactic γ-ray astronomy, so primarily the detection of soft-spectrum γ-ray sources such as Active Galactic Nuclei and Gamma Ray Bursts. The current phase of the ALTO R&D project is the optimization of sensitivity for such sources and includes a number of ideas which are tested and evaluated through the analysis of dedicated Monte Carlo simulations and hardware testing. In this context, it is important to clarify how data are analysed and how results are being obtained. SEMLA takes advantage of machine learning and comprises four stages: initial event cleaning (stage A), filtering out of poorly reconstructed γ-ray events (stage B), followed by γ-ray signal extraction from proton background events (stage C) and finally reconstructing the energy of the events (stage D). The performance achieved through SEMLA is evaluated in terms of the angular, shower core position, and energy resolution, together with the effective detection area, and background suppression. Our methodology can be easily generalized to any experiment, provided that the signal extraction variables for the specific analysis project are considered.
|
|
