The 76Ge double beta decay experiment at Homestake

An ultralow background intrinsic Ge detector has been developed over several generations of experiments. The radioactive background from construction materials has been reduced by more than two orders of magnitude. The sources of background in a standard commercial cryostat have been identified and eliminated. Data taken with this 135 cm3 prototype installed in the Homestake Gold Mine are presented. A large (1440 cm3) detector and data acquisition system now under construction are also described.