DESIGN, DEVELOPMENT AND VALIDATION OF NOVEL ELECTRICAL CONTACTING SYSTEMS, MECHANICAL ENCAPSULATION SOLUTIONS AND HIGH-RESOLUTION INTEGRATED CHARGE-SENSITIVE PREAMPLIFIERS FOR ADVANCED HIGH-PURITY GERMANIUM DETECTORS

Segmented High-Purity Germanium detectors are widely used in modern gamma spectroscopy experiments due to their outstanding energy resolution and precise position sensitivity. However, detailed technical and manufacturing specifications for these detectors are typically proprietary, as they are provided by commercial manufacturers. To overcome this limitation, the Italian Institute for Nuclear Physics launched the N3G Project, a strategic initiative aimed at designing a new generation of segmented HPGe detectors while simultaneously building the in-house expertise required to develop, operate and maintain them independently. Within this framework, this PhD research provides several original contributions. First, an innovative and flexible interconnection system was developed to electrically interface the detector electrodes with the front-end electronics. In parallel, a vacuum tight capsule was designed and fabricated to house the HPGe crystal. Leak testing of the capsule demonstrated excellent vacuum retention, with a pressure increase of only 2 × 10−5 mbar over five days. In addition, novel integrated charge sensitive preamplifiers were conceived, simulated and experimentally validated. Based on a new architecture, these circuits exhibited excellent linearity and low noise performance. Specifically, an integral non-linearity below 0.3 ‰was achieved across a 15 MeV dynamic range, and an energy resolution of 0.75 keV FWHM was measured for 1 MeV equivalent energy events and a detector capacitance of 15 pF. The results of this work validate the feasibility of developing high-performance HPGe detection systems equipped with fully custom-designed electronics, marking a significant step toward technological advancement in the field of gamma spectroscopy. Beyond their immediate application, the solutions developed also offer valuable design principles applicable to a wide range of detector technologies.