Investigation of magnetic-field effects on photomultiplier tubes for the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory
Year: 2026
Type: preprint
Abstract: Photomultiplier tubes (PMTs) are widely used in imaging atmospheric Cherenkov telescopes. Their response can depend on the telescope pointing direction through changes in their orientation relative to the geomagnetic field. Such a dependence was indicated during the calibration campaign of the CTAO LST-1. In this work, the LST-1 calibration data are analyzed to quantify the gain dependence in terms of the geomagnetic field, and dedicated laboratory measurements are performed to test the hypothesis that the observed dependence originates from magnetic-field effects. Both the on-site and laboratory measurements show a consistent dependence of the PMT gain on the magnetic field, while the laboratory measurements further separate the effects on the gain and the excess noise factor. These results provide a clearer understanding of the gain variation observed in LST-1 in terms of magnetic-field effects.
Source: arXiv (Cornell University)
Authors: Kobayashi, Yukiho, Tateishi, Dai, Sunada, Yuji, Kiyomoto, Takuto, Sasaki, Nobuaki, Abe, Kazuki, Cassol, Franca, Gunji, Shuichi, Hadasch, Daniela, Hoffmann, Dirk, Houles, Julien, Inome, Yusuke, Katagiri, Hideaki, Kubo, Hidetoshi, Kushida, Junko, Mazin, Daniel, Mizote, Masaya, Nagayoshi, Tsutomu, Nakamori, Takeshi, Nishijima, Kyoshi, Nozaki, Seiya, Ohoka, Hideyuki, Okumura, Akira, Orito, Reiko, Saito, Takayuki, Sakurai, Shunsuke, Takahashi, Mitsunari, Terada, Yukikatsu, Teshima, Masahiro, Yamamoto, Tokonatsu, Yoshida, Tatsuo
Institutions: Institute for Cosmic Ray Research, The University of Tokyo, Saitama University, Tokai University, Centre National de la Recherche Scientifique, Aix-Marseille Université, Centre de physique des particules de Marseille, Institut National de Physique Nucléaire et de Physique des Particules, Yamagata University, Ibaraki University, Max Planck Institute for Physics, Konan University, Institute for Space-Earth Environmental Research, Nagoya University, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Tokushima University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213581319