The M ajorana D emonstrator will search for the neutrinoless double-beta<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mo stretchy="false">(</mml:mo><mml:mi>β</mml:mi><mml:mi>β</mml:mi><mml:mfenced separators="|"><mml:mrow><mml:mn fontstyle="italic">0</mml:mn><mml:mi>ν</mml:mi></mml:mrow></mml:mfenced><mml:mo stretchy="false">)</mml:mo></mml:math>decay of the isotope<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2" />Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The D emonstrator is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the D emonstrator and the details of its design.

The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment