Optimizing AGATA Array Performance for High-Energy Gamma-Ray Spectroscopy

The AGATA (Advanced GAmma Tracking Array) campaign at Laboratori Nazionali di Legnaro (LNL) is dedicated to advancing nuclear structure studies using both stable and future radioactive beams. A crucial aspect of this effort is the precise characteri- zation of the AGATA array, particularly in terms of absolute gamma-ray efficiency and energy calibration. Accurate calibration is essential for optimizing tracking algorithms, validating Monte Carlo GEANT4 simulations, and ensuring reliable experimental propos- als. While previous AGATA campaigns at GSI and GANIL employed various radioactive sources for calibration, the 2–5 MeV energy range remains largely unexplored, limiting high-energy discrete gamma-ray spectroscopy. To address this gap, dedicated calibration measurements with radioactive sources were proposed, specifically targeting this underexplored energy region. The efficiency calibration at high energies was extended using the well-characterized 66Zn(p,n) reaction, which produces 66Ga. This isotope emits several γ rays up to 4.8 MeV, providing coverage beyond the energy range of standard calibration sources. The reaction has a peak cross section of about 680 mb for a 13 MeV proton beam on an enriched Zn target, making it a reliable method for generating high-energy reference lines for efficiency determination. These calibration efforts will reduce uncertainties in high-energy discrete gamma-ray efficiency measurements, improve the accuracy of tracking algorithms, and enhance the reliability of nuclear structure studies. Furthermore, they support the increasing interest in high-energy discrete gamma-ray spectroscopy, enabling more precise investigations of nuclear states and reaction mechanisms. This thesis aims to provide well-calibrated energy sources and an experimental effi- ciency. The results of this study will contribute to improving the accuracy and reliability of AGATA’s high-energy gamma-ray spectroscopy capabilities, ensuring its continued success in advancing nuclear structure research at modern radioactive beam facilities.