Abstract
The AMoRE (Advanced Mo-based Rare process Experiment) project is a series of experiments that use advanced cryogenic techniques to search for the neutrinoless double-beta decay of 100Mo. The work is being carried out by an international collaboration of researchers from eight countries. These searches involve high precision measurements of radiation-induced temperature changes and scintillation light produced in ultra-pure 100Mo-enriched and 48Ca-depleted calcium molybdate (48deplCa100MoO4) crystals that are located in a deep underground laboratory in Korea. The 100Mo nuclide was chosen for this 0νββ decay search because of its high Q-value and favorable nuclear matrix element. Tests have demonstrated that CaMoO4 crystals produce the brightest scintillation light among all of the molybdate crystals, both at room and at cryogenic 48deplCa100MoO4 crystals are being operated at milli-Kelvin temperatures and read out via specially developed metallic-magnetic-calorimeter (MMC) temperature sensors that have excellent energy resolution and relatively fast response times. The excellent energy resolution provides good discrimination of signal from backgrounds, and the fast response time is important for minimiz- ing the irreducible background caused by random coincidence of two-neutrino double-beta decay events of 100Mo nuclei. Comparisons of the scintillating-light and phonon yields and pulse shape discrimination of the phonon signals will be used to provide redundant rejection of alpha-ray-induced backgrounds. An effective Majorana neutrino mass sensitivity that reaches the expected range of the inverted neutrino mass hierarchy, i.e., 20-50 meV, could be achieved with a 200 kg array of 48deplCa100MoO4 crystals operating for three years.
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