Calibration of the TAIGA-IACT imaging Camera with a nanosecond pulsed LED light source

The imaging atmospheric Cherenkov telescopes of the TAIGA-IACT experiment are part of the TAIGA (Tunka Advanced Instrument for cosmic rays and Gamma Astronomy) astrophysical complex. Each TAIGA-IACT telescope is equipped with a segmented mirror in the Davis-Cotton design with a diameter of 4.3 m. An imaging camera is installed in the focal plane of the telescope, consisting of approximately 600 photomultiplier tubes (PMTs) with a photocathode diameter of 15 mm. The imaging cameras of the atmospheric Cherenkov telescopes require regular calibration of the PMT parameters and the electronic readout chains to ensure the reliability of experimental data. This work describes the methods used to calibrate the PMTs and the readout channels of the imaging camera of the third TAIGA-IACT atmospheric Cherenkov telescope. The conversion factors from ADC counts to the number of photoelectrons, as well as the relative quantum sensitivity coefficients of the PMTs, were obtained using a nanosecond light source during a calibration carried out in March 2024.