Virtual depth by active background suppression: Revisiting the cosmic muon induced background of GERDA Phase II

Understand

In-situ production of long-lived isotopes by cosmic muon interactions may generate a non-negligible background for deep underground rare event searches.

• Previous Monte Carlo studies for the GERDA experiment at LNGS identified the delayed decays of $^{77}$Ge and its metastable state $^{77m}$Ge as dominant cosmogenic background in the search for neutrinoless double beta decay of $^{76}$Ge.
• This might limit the sensitivity of next generation experiments aiming for increased $^{76}$Ge mass at background-free conditions and thereby define a minimum depth requirement.
• A re-evaluation of the $^{77(m)}$Ge background for the GERDA experiment has been carried out by a set of Monte Carlo simulations.