Energy calibration of CsI(Tl) scintillator in pulse-shape identification technique

A batch of 16 CsI(Tl) scintillator crystals, supplied by the Bicron Company, has been studied with respect to precise energy calibration in pulse-shape identification technique. The light corresponding to pulse integration within the time interval 1.6–4.5 μs (long gate) and 0.0–4.5 μs (extra-long gate) exhibits a power law relation, L(E,Z,A)=a1(Z,A)Ea2(Z,A), for 1,2,3H isotopes in the measured energy range 5–150 MeV. For the time interval 0.0–0.60 μs (short gate), a significant deviation from the power law relation is observed, for energy greater than ∼30 MeV. The character of the a2(p)–a2(d) and a2(p)–a2(t) correlations for protons, deuterons and tritons, reveals 3 types of crystals in the batch. These subbatches differ in the value of the extracted parameter a2 for protons, and in the value of the spread of a2 for deuterons and tritons. This may be explained by the difference in the energy dependence of the fast decay time component and/or by the difference in the light output ratio of the fast/slow components. An accuracy well inside 1.0% is achieved in the energy calibration of the CsI(Tl) crystals by using the ΔE(Si)–E(CsI(Tl))/PMT method. The batch of 16 CsI(Tl) crystals is utilized to measure the correlations of light charged particles produced in E/A=61 MeV, 36Ar-induced reactions. The preliminary correlation functions for two protons with small relative momenta are presented.