A bubble chamber for dark matter detection (the COUPP project status)

Heavy-liquid bubble chambers can be made stable-enough to be used in searches for Weakly Interacting Massive Particles (WIMPs). Advantages of this approach are optimal choice of target liquid-CF3I, maximally sensitive to both spin-dependent (SD) and spin-independent (SI) WIMP interactions, low cost, good scalability, room temperature operation, extraordinary intrinsic rejection of minimally-ionizing backgrounds, and a number of features permitting rejection of irreducible neutron backgrounds. A 2 kg prototype chamber is currently operating at the depth of 300 meters water equivalent (m.w.e.) NuMi gallery of Fermilab. Even with the small prototype mass, results competitive in the SI channel and surpassing current limits in the SD channel are expected