ИСТИНА

The JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) collaboration constructs a series of balloon and orbital telescopes to detect fluorescent UV emission from the Earth atmosphere, with the primary aim to study ultrahigh energy cosmic rays (UHECRs) from space. The detectors have wide field-of-view (more than 20 degrees FOV), high temporal resolution (1-2.5 μs) and sensitivity provided by a large aperture. Nowadays one of these detectors is operating onboard the ISS (Mini-EUSO). The next one is planned to be launched in the spring of 2023 (EUSO-SPB2) and the other one is in preparation stage (K-EUSO). These projects use the same photo-detection modules (PDMs) composed of 36 multi-anode photomultiplier tubes (MAPMTs) with 2304 channels in total. Mini-EUSO uses one PDM, EUSO-SPB2 uses three and K-EUSO will use more than 40 PDMs. It is supposed to present the methods of absolute calibration for EUSO-SPB2 PDMs in different modes of operation and internal PDM structure.