Neutrons in the low-background Ge-detector vicinity estimated from different activation reactions

Neutrons produced by cosmic-ray muons in a detector shield and other surrounding materials can be captured or scattered by different nuclei in subsequent reactions. The gamma photons emitted after nuclear capture or scattering from produced Ge isotopes are used to estimate the neutron flux. If a bulk sample measured in some low background gamma spectroscopy system contains hydrogen, a high energy photon (of energy 2223 keV) emitted in the process of deuterium production can be used to estimate the flux of thermal neutrons. Results obtained from the interaction of neutrons with H as well as with some Ge isotopes are computed and compared in this paper. The passive lead shield in a detector system is a source of a significant fraction of the gamma radiation induced by capture and inelastic scattering of neutrons. We also used gamma lines emitted by several Pb isotopes to estimate the neutron flux near a detector.