AMoRE: a search for neutrinoless double-beta decay of 100Mo using low-temperature molybdenum-containing crystal detectors

The AMoRE is an experiment to search for neutrinoless double-beta decay of 100 Mo in molybdate crystal scintillators using a cryogenic detection technique. The crystals are equipped with metallic magnetic calorimeter (MMC) sensors that detect both phonon and photon signals at temperatures of a few tens of mK. Simultaneous measurements of thermal and scintillation signals produced by particle interactions in the crystals by MMC sensors provide high energy resolution and efficient particle discrimination. AMoRE-Pilot, an R&D phase with six (CaMoO4)-Ca-48depl-Mo-100 crystals and a total mass of similar to 1.9 kg in the final configuration, operated at the 700 m deep Yangyang underground laboratory (Y2L). After completion of the AMoRE-Pilot run at the end of 2018, AMoRE-I with a similar to 6 kg crystal array comprised of thirteen (CaMoO4)-Ca-48depl-Mo-100 and five (Li2MoO4)-Mo-100 crystals is currently being assembled and installed at Y2L. We have secured 110 kg of Mo-100-isotope-enriched MoO3 powder for the production of crystals for the AMoRE-II phase, which will have similar to 200 kg of molybdate crystals and operate at Yemilab, a new underground laboratory located similar to 1, 100 m deep in the Handeok iron mine that is currently being excavated and with a scheduled completion date of December 2020. AMoRE-II is expected to improve the upper limit on the effective Majorana neutrino mass to cover the entire inverted hierarchy neutrino mass region: 20-50 meV, in the case when no such decays are observed. Results from AMoRE-Pilot and progress of the preparations for AMoRE-I and AMoRE-II are presented.