Characterization of CsI(Tl) Crystals and Implementation of tools for the CALIFA calorimeter at FAIR

Tese de mestrado, Engenharia Física , 2023, Universidade de Lisboa, Faculdade de CiênciasThis work focused on the study of the CALorimeter for In-Flight detection of gamma-rays and high energy charged pArticles (CALIFA), an electromagnetic calorimeter belonging to the Reactions with Relativistic Radioactive Beams (R³B) collaboration, located at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, for a period of six months. The importance of this detector’s operation at high energies and the difficulty of calibrating the thallium-doped cesium iodide crystals (CsI(Tl)) that make up the detector at these energies is discussed. Muon detection is reviewed, focusing on the theory of the energy and angle distributions of these particles on Earth and the energy loss of these particles in CsI(Tl). Quality tests were performed on 128 CsI(Tl) crystals designed to be integrated into CALIFA in the future, and the idea of studying the energy spectrum of the crystals with cosmic muons in two different experimental configurations was introduced. Simulations in TOPAS showed that the energy deposition projected is proportional to the distance traveled by the muon in the scintillator. An integration of cosmic source using CRY (Cosmic Ray Library) was done in R3BRoot. The experimental work of CALIFA started with the calibration of the detector using radioactive sources of gamma rays, followed by a four-phase experimental campaign from May to September 2022. In the first analysis of the resulting data, it was concluded that the existing crystal clustering algorithm is not suitable for the study and that there are two common types of events to be studied: events related to lateral deposits of similar energy per crystal and events that cross the main axis of the crystal. A study was conducted on the use of cosmic muon data as a calibration source for high energies, which showed the possibility of using two calibration points at 20 and 100 MeV