Muon calibration of the ASTRI-Horn telescope: preliminary results

Mineo, T.; Maccarone, Maria Concetta; Compagnino, Alessio; Capalbi, M.; Catalano, O.; Contino, G.; Impiombato, D.; Sangiorgi, Pierluca; Garozzo, S.; Marano, D.; Conforti, Vito; Astri, Cta

doi:10.22323/1.358.0744

Cited by 5 publications

(10 citation statements)

References 14 publications

(21 reference statements)

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“…and S2=12 p.e. used by [9] to identify muon signals, that is also suitable to discard the showers being lower than the thresholds adopted for the analysis of Crab Nebula events [5].…”

Section: Discussionmentioning

confidence: 99%

“…In brief, three panels out 18 of the primary mirror were not properly aligned: one of them was covered because not adjustable through the active mirror control, while the other two were found to be misaligned by ∼ 1 • as detected with a dedicated analysis based on the V ariance method [12]. In addition, the secondary mirror experienced a degradation of the reflectivity because of a strong eruption of the Etna volcano on February 2019 and all the following observations were affected by loss of about 25% of the optical throughput respect to the December one [9].…”

Section: The Data Setmentioning

confidence: 97%

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Evaluating the night sky background directly from the signal images detected by the ASTRI telescopes

et al. 2022

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ASTRI-Horn is an Imaging Atmospheric Cherenkov Telescope characterized by a dual-mirror optical system with a primary mirror diameter of 4.3 m and a curved focal surface covered by silicon photomultiplier (SiPM) sensors managed by an innovative fast front-end electronics. ASTRI-Horn is installed in Italy at the INAF “M.C. Fracastoro” observing station (Mount Etna, Italy); it is the prototype of nine similar telescopes forming the ASTRI MiniArray that will be installed at the Teide Astronomical Observatory, in Tenerife (Canary Islands, Spain). In the ASTRI-Horn camera, the output signals from SiPMs are AC coupled to the front-end electronics stopping any slow varying signals. However, the random arrival of the night sky background photons produces fast fluctuations in the signal that the electronics is able to detect. The noise generated by this effect is proportional to the level of the diffuse night sky background. In this work, we present the analysis of the background data in ASTRI-Horn observations during the period December 2018–March 2019, using images of triggered showers. We compare the results relative to 2018 December 7-8 and 2019 March 6-7 nights with the contemporary night sky background fluxes measured by UVscope. This is a small auxiliary instrument mounted on the external structure of the ASTRI-Horn telescope and devoted to the night sky background evaluation in the UV band. A strong correlation between the considered data was detected. This correlation can be a diagnostic tool to assure the proper behavior of the ASTRI-Horn camera in view of the ASTRI MiniArray implementation. ASTRI-Horn is also equipped with the Variance technique able to sample the level of the pixel signals in absence of showers with an high rate. The method presented in this paper, based on shower images, is a new approach that has never been investigated until now. It does not substitute the Variance, that will the baseline for the background evaluation after exhaustive testings, but it is complementary to it when Variance data are available. This is the only one method working very well, that can be applied whenever the standard Variance method is not operative.

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“…and S2=12 p.e. used by [9] to identify muon signals, that is also suitable to discard the showers being lower than the thresholds adopted for the analysis of Crab Nebula events [5].…”

Section: Discussionmentioning

confidence: 99%

Section: The Data Setmentioning

confidence: 97%

Evaluating the night sky background directly from the signal images detected by the ASTRI telescopes

et al. 2022

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“…The values of the correction factor measured on December 2018 and on March 2019 are not compatible, being their ratio 0.77±0.06. However, we know, from the results obtained with the muon ring analysis [9], that the telescope effective area measured in March 2019 was degraded by ∼25% after a strong Etna eruption in February 2019. The lower correlation slope can then be ascribed to the reduction of the optical throughput.…”

Section: Discussionmentioning

confidence: 99%

“…and 2=12 p.e. used by [9] to identify muon signals, that is also suitable to discard the showers being lower than the thresholds adopted for the analysis of Crab Nebula events [5].…”

Section: Astri-horn Data Reduction and Analysismentioning

confidence: 99%

The ASTRI-Horn telescope: comparison with the auxiliary UVscope measurements as calibration tool.

Compagnino¹,

Mineo²,

Maccarone³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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Horn is an Image Atmospheric Cherenkov Telescope located at the INAF "M.C. Fracastoro" observing station (Mt. Etna, Italy) characterized by a dual-mirror optical system and a curved focal plane equipped with SiPM sensors read by an innovative fast front-end electronics based on the peak detector technique. ASTRI-Horn represents the prototype of nine similar telescopes developed for the ASTRI-MiniArray that will be installed at the Teide Astronomical Observatory, in Tenerife (Canary Islands, Spain). The ASTRI-Horn camera is almost blind to the diffuse night sky background (NSB) but is able to detect the (Poissonian) fluctuations produced by the NSB. The noise generated by this effect is proportional to the level of the NSB. In this contribution, we present the analysis of the background data collected with the ASTRI-Horn camera during the period December 2018 March 2019. Moreover we report the comparison of the absolute night sky background measured by the ASTRI-Horn camera and the UVScope instrument, which is capable of counting individual photons in the range 300-650nm, with a time resolution of 10ns. The main result of this work is a strong correlation between the absolute NSB flux measured by UVscope and the fluctuations measured by the ASTRI-Horn camera that can be used as diagnostic tool to ensure the right behavior of the camera in view of the ASTRI-MiniArray implementation.

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“…The right panel of Fig. 2 shows an example of a muon ring observed with ASTRI-Horn and used to quantify the degradation of the mirror reflectivity [8].…”

Section: Calibration With Observational Data Analysismentioning

confidence: 99%