Nuclear astrophysics studies at the LENA facility: The -ray detection system

The detection system of The Laboratory for Experimental Nuclear Astrophysics is described, including methods for measuring weak capture- γ -ray resonances. Improved γ γ -coincidence techniques are detailed, as well as the reduction of cosmic muon-induced background in the energy region of E γ = 0.6 – 9.0 MeV by the use of compact cosmic muon anti-coincidence shields. These techniques reduced background count rates in the regions of E γ = 0.6 – 3.0 and 3.0–9.0 MeV with respect to unshielded singles count rates by factors of 3600 and 21, respectively.