Realization of a Magnetically Guided Atomic Beam in the Collisional Regime

We describe the realization of a magnetically guided beam of cold rubidium atoms, with a flux of 7×10⁹ atoms/s, a temperature of 400 μK, and a mean velocity of 1 m/s. The rate of elastic collisions within the beam is sufficient to ensure thermalization. We show that the evaporation induced by a radio-frequency wave leads to appreciable cooling and an increase in the phase space density. We discuss the perspectives to reach the quantum degenerate regime using evaporative cooling.