Study of super(48)Ca double beta decay by CANDLES

CANDLES is the project to search for double beta decay (DBD) of super(48)Ca by using CaF sub(2) scintillators. The Q-value of super(48)Ca, which is the highest (4.27 MeV) among potential DBD nuclei, is far above energies of gamma -rays from natural radioactivities (maximum 2.615 MeV from super(208)Tl decay), therefore we can naturally expect small backgrounds in the energy region we are interested in. We have constructed the prototype detector, CANDLES III in our laboratory (Osaka U.) at sea level and studied the basic performance of the system, including the light collection, position reconstruction and background rejection. After R&D study we moved the detector system to new experimental room at Kamioka underground laboratory. Herein the expected performances and current status of the CANDLES system are described.