Time-Projection Chamber (TPC) detectors have been used extensively in particle physics experiments. While a gas detector with sufficient mass to be sensitive to neutralinos would have an enormous volume, this technology does offer the possibility of detecting the direction of WIMP recoil. Due to the Earth's motion around the Sun, the WIMP recoil events are expected to be highly asymmetric [63]. Buckland et al. [15] report their development of a 50 g H prototype detector. This detector, developed at UCSD, has been tested with neutron source and is potentially scalable to larger masses.