This PNNL conference paper (PNNL-SA-126698), with authors including McDonald and Marianno, evaluates a high-rate variant of the GeGI, the GeGI-s, for screening swipe samples in the National Technical Nuclear Forensics mission. The GeGI-s is a modified GeGI-4 planar HPGe detector capable of several million counts per second, allowing high-activity samples to be placed directly on the detector face. Its energy resolution and pixelization let it generate isotope-specific spatial maps of material on a swipe. The study characterized the detector's spatial efficiency response by rastering a collimated beam across the face, finding it largely uniform with two correctable non-uniformities.
