The ASTRI Mini-Array, consisting of nine innovative Imaging Atmospheric Cherenkov Telescopes, is an INAF project dedicated to studying gamma-ray sources that emit at very high energies in the TeV range. It is located at the Teide Astronomical Observatory (Tenerife, Canary Islands), where seven of the nine telescopes have been installed. Two of them (ASTRI-1 and ASTRI-3) already acquire Cherenkov data, undergoing the commissioning and science verification phase, while the remaining units, currently under completion, are expected to be completed by the end of 2026. Each telescope uses a compact dual-mirror Schwarzschild–Couder optical design, which ensures good image quality across the wide field of view (10.5°). The camera is equipped with silicon photomultiplier (SiPM) sensors that, together with custom-designed front-end electronics, ensure high sensitivity and excellent long-term stability. The analysis of muon ring images, commonly detected by Imaging Atmospheric Cherenkov Telescopes during regular observations, is a standard technique to calibrate the optical throughput and monitor the optical point spread function. This method relies on reconstructing the characteristic ring-like pattern observed on the focal plane during muon-induced Cherenkov photon imaging. It enables inference of the overall optical efficiency from the evaluation of the amount of Cherenkov light reaching the telescope’s primary mirror. Moreover, since the divergence of Cherenkov photons is negligible, the observed ring width is entirely determined by the telescope’s optical aberrations. This technique has been integrated into the ASTRI Mini-Array calibration plan as one of the key methods. In this contribution, we present results from the analysis of muon events and the reconstruction procedures applied using A-MuSoft, one of the calibration software tools developed for the ASTRI Mini-Array telescopes, based on data collected by the two operating telescopes, ASTRI-1 and ASTRI-3.
Using muon rings for the optical calibration of ASTRI Mini Array telescopes / Mineo, T., Mollica, D., Bigongiari, C., Saturni, F.G., Casaburo, F., Cusumano, G.. - (2026). (SPIE Astronomical Telescopes + Instrumentation Copenaghen ) [10.1117/12.3104354].
Using muon rings for the optical calibration of ASTRI Mini Array telescopes
Casaburo, Fausto;
2026
Abstract
The ASTRI Mini-Array, consisting of nine innovative Imaging Atmospheric Cherenkov Telescopes, is an INAF project dedicated to studying gamma-ray sources that emit at very high energies in the TeV range. It is located at the Teide Astronomical Observatory (Tenerife, Canary Islands), where seven of the nine telescopes have been installed. Two of them (ASTRI-1 and ASTRI-3) already acquire Cherenkov data, undergoing the commissioning and science verification phase, while the remaining units, currently under completion, are expected to be completed by the end of 2026. Each telescope uses a compact dual-mirror Schwarzschild–Couder optical design, which ensures good image quality across the wide field of view (10.5°). The camera is equipped with silicon photomultiplier (SiPM) sensors that, together with custom-designed front-end electronics, ensure high sensitivity and excellent long-term stability. The analysis of muon ring images, commonly detected by Imaging Atmospheric Cherenkov Telescopes during regular observations, is a standard technique to calibrate the optical throughput and monitor the optical point spread function. This method relies on reconstructing the characteristic ring-like pattern observed on the focal plane during muon-induced Cherenkov photon imaging. It enables inference of the overall optical efficiency from the evaluation of the amount of Cherenkov light reaching the telescope’s primary mirror. Moreover, since the divergence of Cherenkov photons is negligible, the observed ring width is entirely determined by the telescope’s optical aberrations. This technique has been integrated into the ASTRI Mini-Array calibration plan as one of the key methods. In this contribution, we present results from the analysis of muon events and the reconstruction procedures applied using A-MuSoft, one of the calibration software tools developed for the ASTRI Mini-Array telescopes, based on data collected by the two operating telescopes, ASTRI-1 and ASTRI-3.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
