The Majorana experiment: an ultra-low background search for neutrinoless   double-beta decay
  The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak. 
D. G. Phillips II, E. Aguayo, F. T. Avignone III, H. O. Back, A. S.   Barabash, M. Bergevin, F. E. Bertrand, M. Boswell, V. ...
nucl-ex physics.ins-det