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

Abstract

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 )= a 1( Z , A ) E a 2( Z , A ) , for 1,2,3 H 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 a 2( p )– a 2( d ) and a 2( p )– a 2( 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 a 2 for protons, and in the value of the spread of a 2 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 Δ E (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 , 36 Ar -induced reactions. The preliminary correlation functions for two protons with small relative momenta are presented.