Journal Article

Gaia: segmented germanium detector for high‐energy X‐ray fluorescence and spectroscopic imaging

Pinaroli, Giovanni, Kuczewski, John, Caswell, Thomas, Zhong, Zhong, Siddons, D. Peter, Kuczewski, Anthony J., Koh, Katherine, Krings, Thomas, Vo, Nghia T., Capocasa, Francesca, Fitzgerald, Carter, Shutlz-Johnson, Lorianne, Rumaiz, Abdul K., Finnelli, Kristina, Li, Ji, Drakopoulos, Michael

2026

Overview

We present Gaia, a monolithic array of 96 high‐purity germanium pixel detectors integrated with a custom low‐noise application‐specific integrated circuit (ASIC) and a field‐programmable gate array (FPGA)‐based data acquisition system. The sensor operates at ∼100 K using a commercial closed‐cycle cryocooler, with the in‐vacuum electronics thermally isolated from the cold finger to ensure thermal stability. The system demonstrates an average energy resolution of 711 eV at 122 keV, measured using a 57Co source, and 253 eV at 5.89 keV, measured with 55Fe across all channels. The readout architecture incorporates a high‐performance FPGA paired with a dual‐core ARM processor, forming a complete embedded Linux‐based computing platform. Communication between the processor and FPGA is handled via memory‐mapped I/O, and data are streamed over high‐speed gigabit Ethernet. A full‐scale 384‐pixel Gaia detector, based on this 96‐element module, is currently under fabrication. We present Gaia, a cryogenically cooled monolithic array of 96 high‐purity germanium pixel detectors integrated with a custom low‐noise application‐specific integrated circuit and a field‐programmable gate array‐based data acquisition system. The system achieves an average energy resolution of 711 eV at 122 keV and 253 eV at 5.89 keV, and serves as the foundation for a forthcoming 384‐pixel detector.

• Publisher: International Union of Crystallography,John Wiley & Sons, Inc
• Subject: Cryogenic cooling / Data acquisition / detectors / Energy resolution / Ethernet / Field programmable gate arrays / fluorescence imaging / Germanium / germanium detectors / high energy X-rays / Integrated circuits / MATERIALS SCIENCE / Microprocessors / Pixels / Research Papers / Thermal stability