Study of the identification efficiency of the FAZIA array CsI(Tl) crystals for energetic helium ions

초록

The identification efficiency of selected thallium-doped CsI crystals (100 mm thick) of the Fazia array has been measured for helium ions with energies ranging from about 20 to 150 MeV/u exploiting the fragmentation of energetic12C beams delivered by the synchrotron of the CNAO medical facility in Pavia. Nuclear interactions of energetic He ions occurring within the crystal influence the energy deposition and the light response of the scintillator thus reducing its identification efficiency. As done in previous studies on protons, the measured efficiency is compared with dedicated GEANT4 simulations and a good agreement (within 2%-4%) has been found, confirming the quality of the procedure and the model description. This study complements the rather scarce literature on systematic experimental investigations on the response of CsI(Tl) scintillators to 3He and 4He ions and thus is also valuable for heavy-ion experiments at intermediate energies where energetic light ions, which are important probes to study the details of nuclear interaction, are abundantly produced.

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