Speaker
Description
The knowledge of the atmospheric muon flux in cosmic rays at ground level is of considerable interest in various particle physics and applied physics experiments, in particular to calibrate Monte Carlo models used in atmospheric shower simulations and for precision studies of muon neutrino oscillations. In the literature there is no systematic study of the muon component at ground level at different energies and at different measurement points on the Earth's surface (latitude, longitude and altitude). Of particular interest for experiments is the knowledge of the muon component at low energies where contamination by electrons-positrons and protons can occur.
The ACROMASS (Atmospheric Cosmic Ray Observatory using a Magnetic Altazimuth Silicon Spectrometer) experiment of the National Institute for Nuclear Physics (INFN Italy) aims to study the main components of secondary cosmic rays at ground level with particular attention to low-energy components. It is a development of the previous experiment called ADAMO (INFN Florence - Italy) [1] whose data are currently used in some muon generators used for simulations such as EcoMug [2-3]. The ADAMO experiment consisted of a magnetic spectrometer made up of silicon microstrip detectors immersed in a magnetic field of approximately 0.4T. It did not allow the discrimination of the different components of cosmic rays at ground level. ACROMASS includes the addition of other sub-detectors such as a TOF (Time-of-flight) and an electromagnetic calorimeter that have the task of performing Particle-Identification (PID).
In this work, the TOF subdetector designed for the ACROMASS experiment will be presented, which aims at discriminating between muons and protons at low momentum p<1GeV/c. The detector, consisting of fast segmented plastic scintillators and silicon photomultipliers as light sensors, is coupled to a high temporal resolution readout electronics, the SAMPIC module from CEA/IRFU and CNRS/IN2P3/LAL (France) [4]. It is a digitizer already used in other experiments (for nuclear and subnuclear physics and for biomedical imaging) that allows to have temporal resolutions of the order of 100 ps. In the work, the detector and the first tests carried out on its operation in terms of temporal performance will be presented.
References:
[1] Bonechi, L. et al., Development of the ADAMO detector: test with cosmic rays at different zenith angles, 29th International Cosmic Ray Conference, 9 pp 283, 2005
[2] Pagano, D. et al., EcoMug: An Efficient COsmic MUon Generator for cosmic-ray muon applications, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1014 pp 165732, 2021, doi: https://doi.org/10.1016/j.nima.2021.165732
[3] Frosin, F., Optimizing sea level muon flux modelling: A 2D fit approach and integration into Geant4 generators, Journal of Physics G: Nuclear and Particle Physics, Accepted Manuscript online 17 February 2025, doi: 10.1088/1361-6471/adb6c3
[4] Breton, D. et al., Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC waveform digitizer, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 835 pp 51-60, 2016, doi: https://doi.org/10.1016/j.nima.2016.08.019
