A Test on CaMoO4 crystal coupled with a LAAPD for double beta decay experiment

A search for the 0 nu beta beta is one of the most promising ways to clarify the nature and the mass of neutrinos. A high sensitivity to Mo-100 0 nu beta beta search can be achieved by using a CaMoO4 crystal. We have studied the energy resolution of a small CaMoO4 crystal coupled with a large area avalanche photo diode(LAAPD) photo sensor recording the full waveform of the signal. The energy resolution for 662 keV gammas measured at low temperature was 4.2 +/- 0.2% in standard deviation. The contamination from 2 nu beta beta decay events in the 0 nu beta beta search window is studied by using a Monte-Carlo simulation. With the expected energy resolution of 4.5% (FWHM) at 3 MeV and 1.5 kg year data, we can confirm the claim of m(beta beta) = 0.32 +/- 0.03 eV, even after considering the uncertainties of the nuclear matrix elements from the current theoretical calculations.