S. Howard

The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta decay of the isotope 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 DEMONSTRATOR 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 DEMONSTRATOR and the details of its design.

Thermodynamic properties of the Cu−Sn and Cu−Au systems by mass spectrometry

AbstractThe activities and partial molar heats of mixing have been determined in the liquid Cu−Sn system at 1320°C and the liquid Cu−Au system at 1460°C. The experimental technique consisted of the analysis of Knudsen cell effusates with a T.O.F. mass spectrometer. The ion current ratio for the alloy components was measured for each system over a range of temperature and composition and the thermodynamic values calculated by a modified Gibbs-Duhem equation. Both systems exhibited negative deviations from ideal behavior. The results can be partially represented by the equations

The Majorana Demonstrator radioassay program

\begin{gathered} \log \gamma _{Cu} = - 0.0175x^2 _{Sn} - 0.302 (0 \leqslant x_{Cu} \leqslant 0.20) \hfill \\ log \gamma _{Sn} = - 0.342x^2 _{Cu} + 1.084(0 \leqslant x_{Sn} \leqslant 0.20) \hfill \\ \end{gathered}

Thermodynamic properties of the liquid Sn−Ge and Sn−Au systems by mass spectrometry

for the Cu−Sn system at 1320°C and by

Direct activity measurements in liquid Ag-Cu alloys using a valved Knudsen cell-mass spectrometer system

\begin{gathered} \log \gamma _{Cu} = - 0.703x^2 _{Au} - 0.083(0 \leqslant x_{Cu} \leqslant 0.52) \hfill \\ \log \gamma _{Au} = - 1.057x^2 _{Cu} + 0.098(0 \leqslant x_{Au} \leqslant 0.47) \hfill \\ \end{gathered}

Dark matter sensitivities of the MAJORANA demonstrator

for the Cu−Au system at 1460°C.