Improvements to the muon veto of the Dortmund Low Background Facility.

The Dortmund Low Background Facility is a germanium gamma-ray spectrometry laboratory situated above ground. A massive artificial shielding, corresponding to 10m of water equivalent in combination with an active muon veto results in a background level comparable to laboratories situated underground. Due to the recent completion of the muon veto, the background is lowered by 20% compared to previously reported values (Gastrich et al., 2016). Additionally, Monte Carlo simulations of the cosmic muon induced components of the background spectrum are described.