Investigation of magnetic-field effects on photomultiplier tubes for the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory
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.
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BibTeX
@misc{kobayashi2026investigation,
title = {{Investigation of magnetic-field effects on photomultiplier tubes for the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory}},
author = {Yukiho Kobayashi and Dai Tateishi and Yuji Sunada and Takuto Kiyomoto and Nobuaki Sasaki and Kazuki Abe and Franca Cassol and Shuichi Gunji and Daniela Hadasch and Dirk Hoffmann and Julien Houles and Yusuke Inome and Hideaki Katagiri and Hidetoshi Kubo and Junko Kushida and Daniel Mazin and Masaya Mizote and Tsutomu Nagayoshi and Takeshi Nakamori and Kyoshi Nishijima and Seiya Nozaki and Hideyuki Ohoka and Akira Okumura and Reiko Orito and Takayuki Saito and Shunsuke Sakurai and Mitsunari Takahashi and Yukikatsu Terada and Masahiro Teshima and Tokonatsu Yamamoto and Tatsuo Yoshida},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19633},
eprint = {2609.19633},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05769627v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Investigation of magnetic-field effects on photomultiplier tubes for the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory
AU - Yukiho Kobayashi
AU - Dai Tateishi
AU - Yuji Sunada
AU - Takuto Kiyomoto
AU - Nobuaki Sasaki
AU - Kazuki Abe
AU - Franca Cassol
AU - Shuichi Gunji
AU - Daniela Hadasch
AU - Dirk Hoffmann
AU - Julien Houles
AU - Yusuke Inome
AU - Hideaki Katagiri
AU - Hidetoshi Kubo
AU - Junko Kushida
AU - Daniel Mazin
AU - Masaya Mizote
AU - Tsutomu Nagayoshi
AU - Takeshi Nakamori
AU - Kyoshi Nishijima
AU - Seiya Nozaki
AU - Hideyuki Ohoka
AU - Akira Okumura
AU - Reiko Orito
AU - Takayuki Saito
AU - Shunsuke Sakurai
AU - Mitsunari Takahashi
AU - Yukikatsu Terada
AU - Masahiro Teshima
AU - Tokonatsu Yamamoto
AU - Tatsuo Yoshida
PY - 2026
DA - 2026/09/17
PB - HAL
DO - 10.48550/arxiv.2609.19633
UR - https://hal.science/hal-05769627v1
AB - 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.
ER -