A CaMoO₄Crystal Low Temperature Detector for the AMoRE Neutrinoless Double Beta Decay Search

We report the development of a CaMoO₄crystal low temperature detector for the AMoRE neutrinoless double beta decay(0νββ)search experiment. The prototype detector cell was composed of a 216 g CaMoO₄crystal and a metallic magnetic calorimeter. An overground measurement demonstrated FWHM resolution of 6–11 keV for full absorption gamma peaks. Pulse shape discrimination was clearly demonstrated in the phonon signals, and 7.6 σof discrimination power was found for theαandβ/γseparation. The phonon signals showed rise-times of about 1 ms. It is expected that the relatively fast rise-time will increase the rejection efficiency of two-neutrino double beta decay pile-up events which can be one of the major background sources in0νββsearches.