Nuclear Structure Studies near 208Pb and γ-ray Imaging Techniques

Abstract: This thesis focuses on a high-resolution γ-ray spectroscopy experiment where the fragmenta- tion of a 208 Pb primary beam was used to populate even-mass nuclei around 208 Pb. It was conducted in 2012 using the Advanced GAmma-ray Tracking Array (AGATA) while it was placed at GSI Darmstadt, Germany. Projectile-like fragments were selected and identified with the GSI Fragment Separator. The final aim is to study the aforementioned nuclei via Cou- lomb excitation. Yet, preceding measurements with stopped beams are necessary for reasons detailed here. Another part of this thesis is devoted to Research & Development (R&D) of position-sensitive scintillation detectors. These two different aspects are linked by studies of position sensitivity in devices utilized for detection of γ rays. Advances in γ-ray tracking algorithms are essential for both applied and basic nuclear physics. Here, the scintillation detector R&D is foreseen to contribute to applications in the realm of medical imaging as well as environmental and safety surveillance, whereas the basic research efforts yield improved nuclear structure information on heavy ions produced in relativistic fragmentation reactions. Paper I summarizes efforts regarding the image reconstruction algorithm when applied on a simulated data-set. In Paper II the performance of the AGATA sub-array is discussed, outlining the important aspects of the offline data processing and analysis. Paper III presents further treatment of the data partially scrutinized in Paper II using AGATA-tailored algorithms, assessing absolute efficiency and peak-to-total, and the performance of tracking algorithms with respect to different parameter-sets. Paper IV highlights an outstanding physics case from a stopped-beam AGATA measurement. In Paper V all aspects of the data analysis established in this thesis are described. The relevance of isomeric state measurements for both the experimental and theoretical aspect of relativistic fragmentation is emphasized.