Low background measurements using 3-D position-sensitive CdZnTe detectors

There are numerous applications for CdZnTe detectors that require a well characterized background. One such application is the study of neutrino-less double beta decay, which requires a very low background environment. The background has two main contributors, the natural background surrounding the detector system and the internal background due to the natural radioactive decay from components in the system. In order to understand the internal background present in the Polaris 18-detector CdZnTe array system, a lead cave was designed and built at the University of Michigan. The system was well-calibrated and measurements were taken over the course of several months to better characterize the internal background from the components of the Polaris system.