Simulation studies for neutron and muon-induced backgrounds in AMoRE-II

The Advanced Mo-based Rare process Experiment (AMoRE) is an experiment to search for neutrino-less double beta decays of Mo100. The second phase of the experiment, AMoRE-II, will be conducted with 200 kg of Mo100-containing crystals. To reach a sensitivity goal at 12-22 meV level in the effective neutrino mass, AMoRE-II is required to have no background at the region of interest. Dominant sources of backgrounds are expected from environmental neutrons, cosmic muons, and muon secondaries. In this study, we perform simulations of the backgrounds from cosmic muon and environmental neutrons with the Geant4 framework. Using those simulated background sources, we have examined the performance of muon veto counters, and shielding structures with polyethylene and additional materials containing hydrogen and boron. We found an optimal background estimation of ckky level of 10^-5 order of magnitude with "the best choice of the setup" which would be acceptable for the AMoRE-II experiment requirement.