USD HPGe Detector Capabilities and an R&D Path to Orthogonal-Strip Ge for Medical Imaging

We summarize the end-to-end high-purity germanium (HPGe) detector capabilities at the University of South Dakota and outline a measured path toward an orthogonal-strip Ge radiation detector for medical imaging. Using USD-grown single-crystal Ge, our group has fabricated and tested planar, PPC, mini-PPC, mini-ICPC, and hybrid-planar test devices. Standardized process flows (lithography, contact formation, passivation) are coupled to cryogenic I–V, C–V, and γ-ray spectroscopy to benchmark leakage, depletion, and energy response, providing a reproducible baseline for strip detectors. On the design side, finite-element field and capacitance simulations inform strip pitch, edge termination, and guard structures to control interstrip capacitance and charge sharing.

This poster reports the first step toward an orthogonal-strip prototype: (i) simulation-driven geometry selection, (ii) small-area test layouts exploring pitch and termination options, and (iii) a focused measurement plan using collimated sources to map charge sharing, cross-talk, and position response. Near-term milestones include locking process recipes, stabilizing cryogenic readout for multi-channel operation, and fabricating a coupon with a few orthogonal strips to establish noise, capacitance, and energy-resolution targets. These results establish the technical basis and performance metrics for scaling to larger-format orthogonal-strip HPGe suitable for high-fidelity medical imaging.