Speaker
Description
The Segmented Inverted Coaxial Germanium (SIGMA) detector is a p-type, large-volume High Purity Germanium (HPGe) detector developed for gamma-ray tracking and imaging. Highly segmented germanium detectors are well-suited to a wide range of applications, including spectroscopic gamma-ray imaging for nuclear decommissioning and deployment in portable detector arrays at international accelerator facilities for nuclear structure and astrophysics studies. However, analysing multi-interaction events, where an incident photon deposits energy at multiple spatial locations, becomes complex, as a combination of different events produces induced image charges that are similar and hard to distinguish without intrinsic azimuthal information.
In this work, a simplified, next-generation SIGMA-like design is proposed to reduce technical risk, improve manufacturability, and preserve high-precision performance. As a proof-of-concept, a novel Segmented Point-contact (SPOT) Broad Energy Germanium (BEGe) detector has been designed and evaluated via simulation. The AGATA Detector Library (ADL) was used to model the detector’s electric and weighting potentials and to generate charge signals via charge-transport simulations. A signal database, or basis, covering the detector volume was produced, with electronic noise and preamplifier response incorporated to produce realistic charge signals.
The detector sensitivity, defined by differences in the charge signal shape across the detector volume, was quantified for SPOT and compared to a conventional BEGe detector. The position resolution of SPOT is assessed using signal-comparison Pulse-Shape Analysis (PSA), in which a χ² minimisation algorithm determines the gamma-ray interaction point by matching experimental signals to the simulated basis. These results show that SPOT has improved azimuthal resolution through segmentation and highlight its potential as a simpler alternative for high-resolution gamma-ray tracking applications.