Methods for deploying ultra-clean detectors

Next-generation underground experiments, such as searches for neutrinoless double-beta decay and dark matter experiments, will perform high-sensitivity measurements that require extremely low backgrounds. The {\sc{Majo\-ra\-na}} Collaboration~\footnote{F.T. Avignone III (2007) arXiv:0711.4808v1} proposes such an experiment to search for neutrinoless double-beta decay using an array of germanium crystals enriched in $^{76}$Ge. The design of the {\sc{Majo\-ra\-na}} experiment must minimize backgrounds while meeting criteria for electrical signal quality, structural integrity, and thermal cooling characteristics. Recent work has addressed detector deployment in ultra low-background environments. Advances have been made in fabrication of radiologically pure copper parts. Prototype designs for detector support structures reduce backgrounds by minimizing component mass and making use of ultra-pure materials. This talk will describe the design and use of cryostat test-stands to investigate the performance of prototype designs for detector strings. While {\sc{Majo\-ra\-na}} uses germanium detectors, the design considerations and progress made by the collaboration are applicable to other detector technologies and fields of research.