Neutron inelastic scattering processes as a background for double-β decay experiments

We investigate several Pb(n, n'gamma) and Ge(n, n'gamma) reactions. We measure gamma-ray production from Pb(n, n'gamma) reactions that can be a significant background for double-P decay experiments which use lead as a massive inner shield. Particularly worrisome for Ge-based double-beta decay experiments are the 2041-keV and 3062-keV gamma rays produced via Pb(n, n'gamma). The former is very close to the 76 Ge double-decay endpoint energy and the latter has a double escape peak energy near the. endpoint. We discuss the implications of these gamma rays on past and future double-P decay experiments and estimate the cross section to excite the level that produces the 3062-keV gamma ray. Excitation gamma-ray lines from Ge(n, n'gamma) reactions are also observed. We consider the contribution of such backgrounds and their impact on the sensitivity of next-generation searches for neutrinoless double-beta decay using enriched germanium detectors.