Calibration of The Extended Quadrahedral NaI(Tl) Spectrometer by Cosmic Muons

The results of the extended quadrahedral NaI(Tl) spectrometer`s calibration by cosmic muons are presented. The signal amplitude and energy resolution of the spectrometer have complex dependencies on the voltage at the photomultiplier and the entry point of the particle into the spectrometer in the transverse direction. When the voltage across the photomultiplier divider photomultiplier is U = 1150 V the homogeneous signals area is observed at about 90% of the spectrometer length, the energy resolution is about 7%.