This research paper presents the investigations on the impact of Earth’s magnetic field on the efficiency of 3-inch photomultiplier tubes used in the KM3NeT neutrino telescope. The research...Show moreThis research paper presents the investigations on the impact of Earth’s magnetic field on the efficiency of 3-inch photomultiplier tubes used in the KM3NeT neutrino telescope. The research includes measurements of three Hamamatsu PMTs. The measurements show that the efficiency of the PMTs are directional-dependent. However, this significance is most probably not caused by Earth’s magnetic field only. Further investigation is needed to determine where these external effects come from.Show less