• Citer

A Novel Tool for the Absolute End-to-End Calibration of Fluorescence Telescopes - The XY-Scanner

par Abdul Halim, A.;Schlüter, Felix ;Zapparrata, Orazio ; [et al.]
Référence (26 July 2023 through 3 August 2023: Nagoya), 38th International Cosmic Ray Conference, ICRC 2023, Pos proceedings of science (444), 305
Publication Publié, 2024-02-01

Publication dans des actes

• Accès en ligne
• Détails
• Contenu
• Statistiques

Résumé :

The Pierre Auger Observatory uses 27 large-aperture wide-angle Schmidt telescopes to measure the longitudinal profile of air showers using the air-fluorescence technique. Up to the year 2013, the absolute calibration of the telescopes was performed by mounting a uniform large-diameter light source on each of the telescopes and illuminating the entire aperture with a known photon flux. Due to the high amount of work and person-power required, this procedure was only carried out roughly once every three years, and a relative calibration was performed every night to track short-term changes. Since 2013, only the relative calibration has been performed. In this paper, we present a novel tool for the absolute end-to-end calibration of the fluorescence detectors, the XY-Scanner. The XY-Scanner uses a portable integrating sphere as a light source, which has been absolutely calibrated. This light source is installed onto a motorized rail system and moved across the aperture of each telescope. We mimic the illumination of the entire aperture by flashing the light source at ∼1700 positions evenly distributed across the telescope aperture. For the absolute calibration of the light source, we built a dedicated setup that uses a NIST-calibrated photodiode to measure the average photon flux and a PMT to track the pulse-to-pulse stability. We present the laboratory setups used to study the characteristics of the employed light sources and discuss the inter-calibration between selected telescopes.