  By correlating nuclear recoil directions with the Earth's direction of motion
through the Galaxy, a directional dark matter detector can unambiguously detect
Weakly Interacting Massive Particles (WIMPs), even in the presence of
backgrounds. Here, we describe the Dark Matter Time-Projection Chamber (DMTPC)
detector, a TPC filled with CF4 gas at low pressure (0.1 atm). Using this
detector, we have measured the vector direction (head-tail) of nuclear recoils
down to energies of 100 keV with an angular resolution of <15 degrees. To study
our detector backgrounds, we have operated in a basement laboratory on the MIT
campus for several months. We are currently building a new, high-radiopurity
detector for deployment underground at the Waste Isolation Pilot Plant facility
in New Mexico.
