Light yield non-proportionality and intrinsic energy resolution of doped CsI scintillators

The light yield non-proportionality and energy resolution of doped CsI scintillators have been studied for gamma-ray energies ranging from 16.6-1274.5 keV. The light yield non-proportionality of about 20% and the energy resolution of 7.6 š 0.4% for 662 keV gamma-rays have been achieved for empty set 25 mm × 25 mm CsI(Na) crystal, coupled to an XP 5200 photomultiplier tube. The intrinsic resolution of the crystals vs. energy of gamma-rays has been determined after correcting the measured resolution for photomultiplier tube statistics. The different shapes of intrinsic resolution curves observed with various samples of doped CsI are discussed