Characterization of a low background counting facility at Kimballton Underground Research Facility *

We report on the characterization of a new low-background counting facility at the Kimballton Underground Research Facility in Virginia. The facility consists of a shielded, high-purity germanium detector deployed at a depth of approximately 300 meters water equivalent. Exploiting gamma ray spectroscopy in a low cosmic-ray flux environment facility can be used to screen materials for applications in low-background experiments, such as neutrinoless double-beta decay or dark matter searches. We describe the performance of a GEANT4 simulation, which we use for geometrical efficiency and sample self-shielding calculations and present the sensitivity to isotopes of common interest --- ²³⁸U, ²³²Th and ⁴⁰K. As the background goals in next-generation rare decay searches become ever-more stringent, high-sensitivity radio-purity screening facilities will continue to play an important role in supporting this science.