  QCD at non-zero baryon density is expected to have a critical point where the
zero-density cross-over turns into a first order phase transition. To identify
this point we scan the density-temperature space using a canonical ensemble
method. For a given temperature, we plot the chemical potential as a function
of density looking for an "S-shape" as a signal for a first order transition.
We carried out simulations using Wilson fermions with $m_\pi \approx 1{GeV}$ on
$6^3\times 4$ lattices. As a benchmark, we ran four flavors simulations where
we observe a clear signal. In the two flavors case we do not see any signal for
temperatures as low as $0.83 T_c$. Preliminary results for the three flavor
case are also presented.
