Development of bubble chambers with sensitivity to WIMPs

We constructed a small bubble chamber, with special features needed to search for WIMPs: long sensitive time periods, intrinsic insensitivity to minimum ionizing particles and target liquids with high sensitivity to both spin-dependent and -independent couplings. Stereo photography of bubbles allows rejection of events occuring at the chamber walls and discrimination of neutron backgrounds. The chamber can be operated with a variety of liquids, including CF3Br, CF3I, C3F8 and liquid xenon. A >60% live time fraction has been achieved and sensitivity to nuclear recoils demonstrated. Detectors of this type may be scalable to very large size at modest cost.