DMTPC: Dark matter detection with directional sensitivity
  The Dark Matter Time Projection Chamber (DMTPC) experiment uses CF_4 gas at
low pressure (0.1 atm) to search for the directional signature of Galactic WIMP
dark matter. We describe the DMTPC apparatus and summarize recent results from
a 35.7 g-day exposure surface run at MIT. After nuclear recoil cuts are applied
to the data, we find 105 candidate events in the energy range 80 - 200 keV,
which is consistent with the expected cosmogenic neutron background. Using this
data, we obtain a limit on the spin-dependent WIMP-proton cross-section of 2.0
\times 10^{-33} cm^2 at a WIMP mass of 115 GeV/c^2. This detector is currently
deployed underground at the Waste Isolation Pilot Plant in New Mexico.
