Large Volume Ring-Contact HPGe Detectors RCD) for Low-Background Counting Arrays and Radiopurity-Assay

The Department of Energy DOE) Office of Nuclear Physics Research supports user facilities and researchers studying the physics of rare processes including neutrinoless double-beta decay. These science teams include the Majorana and LEGEND collaborations. The user facilities will require the largest-volume HPGe single-detector elements possible to reduce the intrinsic background to as low a level as possible for adequate sensitivity to these rare processes. As proposed, the Ring Contact HPGe Detectors or RCDs) are inherently the largest volume HPGe single-detector element solutions possible. The novel RCD detector geometry and ring contact provides a unique means of depleting and operating the largest possible volume of HPGe with the lowest applied bias voltage and the highest impurity concentration. A new RCD detector process will be developed. The use of diamond ID saw mechanical preparation will save the maximum volume of valuable refined 76Ge while providing the highest yield. The semiconductor fabrication process will be evolved experimentally through the manufacture of small-scale prototype RCDs to demonstrate the viability of this new detector concept. The RCD detectors will find prominence in both the large-scale low-background DOE experimental efforts and as excellent commercial counting-laboratory resources for physicists, radiochemists and nuclear-forensics laboratories.