Simulations of background sources in AMoRE-I experiment

The first phase of the Advanced Mo-based Rare process Experiment (AMoRE-I), an experimental search for neutrinoless double beta decay (0V beta beta) of Mo-100 in calcium molybdate (Ca-40(100) MoO4) crystal using cryogenic detection techniques, is in preparation at the YangYang underground laboratory (Y2L) in Korea. A GEANT4 based Monte Carlo simulation was performed for the first-phase AMoRE detector and shield configuration. Background sources such as U-238, Th-232 U-235, and Pb-210 from inside the crystals, surrounding materials, outer shielding walls of the Y2L cavity were simulated. The estimated background rate in the region of interest was estimated to be < 1.5 x 10(-3) counts/keV/kg/yr (ckky). The effects of random coincidences between backgrounds and two-neutrino double beta decays of Mo-100 as a potential background source were estimated to be < 2.3 x 10(-4) ckky.