Gamma ray detection characteristics of CsI(Li), CsI(K) and CsI(Rb) Scintillators

CsI single crystals doped with lithium, potassium or rubidium were grown by using Czochralski method at Ar gas atmosphere. The energy resolutions of CsI( Li:0.2 mole%), CsI(K:0.5 mole%) and CsI(Rb:1.5 mole%) scintillators were 14.5%, 15.9 % and 17.0 % for 137Cs(0.662 MeV), respectively. The energy calibration curves of CsI(Li), CsI(K) and CsI(Rb) scintillators were linear for γ-ray energy. The time resolutions of CsI(Li0.2 mole%), CsI(K:0.5 mole %) and CsI(Rb:1.5 mole %) scintillators measured by CFT(constant -fraction timing method) were 9.0 ns, 14.7 ns and 9.7 ns, respectively. The fluorescence decay times of CsI(Li:0.2 mole%) scintillator has a fast component and slow one of τ1=41.2 ns and τ2=483 ns, respectively. The fluorescence decay times of CsI(K:0.5 mole%) scintillator were τ1=47.2 ns and τ2=417 ns. And the fluorescence decay times of CsI(Rb:1.5 mole %) scintillator were τ1=41.3 ns and τ2=553 ns. The phosphorescence decay times of CsI(Li:0.2 mole%), CsI(K:0.5 mole%) and CsI(Rb:1.5 mole%) scintillators were 0.51 s, 0.57 s and 0.56 s, respectively