The development of a cryogenic detector with CaMoO4 crystals for neutrinoless double beta decay search

The search for neutrinoless double beta decay (O nu f beta beta) is a key experiment for evaluating the mass of the neutrino and for determining the Majorana/Dirac nature of neutrinos. A scintillating CaMoO4 crystal is a good material for use in investigating O nu beta beta with cryogenic detectors. The high transition energy (Q = 3034 key) and nearly 10% natural abundance of Mo-100, together with the scintillating property of the crystal, provide favorable conditions to search for O nu beta beta of Mo-100. We report a prototype experiment operating at low temperatures using a CaMoO4 crystal as a particle absorber. Prior to testing of isotopically-enriched (CaMoO4)-Ca-40-Mo-100 crystals, a CaMoO4 crystal with Mo of natural isotopic composition was tested. Using a metallic magnetic calorimeter as a temperature sensor, we achieved high energy resolutions for alpha particles and low-energy gamma rays. This experiment shows the feasibility of scaling up the crystal size to perform a high sensitivity search for O nu beta beta decay of Mo-100. (C) 2011 Elsevier B.V. All rights reserved.