Abstract:

Directional detection of dark matter can provide unambiguous observation of dark matter (DM) interactions even in presence of insidious backgrounds.

The DM-TPC collaboration is developing a detector with the goal of measuring the direction and sense ("head-tail") of nuclear recoils produced in spin-dependent DM interactions.

The detector consists of a low pressure TPC with optical readout filled with CF4 gas at low pressure. A collision between a WIMP with a gas molecule results in a nucleus recoil of about 1 mm. The measurement of the energy loss along the recoil allows us to determine the sense and the direction of the recoil.

Results from a prototype detector operated in a low-energy neutron beam clearly demonstrate the suitability of this approach to measure directionality.

In particular, the first observation of the "head-tail" effect for low-energy neutrons had been recently published  by our Collaboration.

A full-scale (~1m3) module is now being built. This detector, which

will be operated underground in 2008-2009, will allow us to set

limits on spin-dependent Dark Matter interactions using a directional detector.