Simulations of background sources in AMoRE-Ⅰ experiment

摘要

The first phase of the Advanced Mo-based Rare process Experiment (AMoRE-I), an experimental search for neutrinoless double beta decay (0vββ) of ~(100)Mo in calcium molybdate (~(40)Ca~(100)MoO_4) 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 ~(238)U, ~(232)Th, ~(235)U, and ~(210)Pb 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 × 10~(-3) counts/keV/kg/yr (ckky). The effects of random coincidences between backgrounds and two-neutrino double beta decays of ~(100)Mo as a potential background source were estimated to be ＜2.3 × 10~(-4) ckky.