Precision (n,$\gamma$) cross-section measurement of Cu at 8 and 12 MeV for shielding designs for the next generation of $\mathbf{0\nu\beta\beta}$ decay experiments.

Renewed interest in observing $0\nu\beta\beta$ decay reactions has sparked efforts to experimentally verify the existence of such decays, and produce new physics beyond the Standard Model. These reactions, with half-lives around 10$^{27}$ years, require an extensive understanding of background sources. The potential for neutron induced excitation of the shielding and detector materials is important for understanding and designing future $0\nu\beta\beta$ decay experiments. Gamma transitions at 2041, 2615, and 3062 keV directly obscure $0\nu\beta\beta$ decay detection of $^{76}$Ge at 2040 keV. Due to lack of experimental information in the nuclear database, high-resolution $\gamma$-ray spectra from the interaction of mono-energetic and pulsed neutrons were measured at TUNL. The emitted gamma rays were detected with 3 HPGe segmented clover detectors at 62$^{\circ}$, 90$^{\circ}$, and 135$^{\circ}$. From these data, partial cross-sections for prominent $\gamma$ transitions in $^{63,65}$Cu were derived at En=8 and 12 MeV. This experimental information will also help to understand the existing $0\nu\beta\beta$ data and serve as a benchmark for statistical model calculations. Supported in part by DOE grant DE-FG02-97ER41033 and NSF grant NSF-PHY-05-52723.