We demonstrate and characterize a high-flux beam source for cold, slow atoms or molecules. The desired species is vaporized using laser ablation, then cooled by thermalization in a cryogenic cell of buffer gas. The beam is formed by particles exiting a hole in the buffer gas cell. We characterize the properties of the beam (flux, forward velocity, temperature) for both an atom (Na) and a molecule (PbO) under varying buffer gas density, and discuss conditions for optimizing these beam parameters. Our source compares favorably to existing techniques of beam formation, for a variety of applications.

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Buffer gas cooling was extended to trap atoms with small magnetic moment µ. For µ ≥ 3µ B , 10 12 atoms were buffer gas cooled, trapped, and thermally isolated in ultra high vacuum with roughly unit efficiency. For µ < 3µ B , the fraction of atoms remaining after full thermal isolation was limited by two processes: wind from the rapid removal of the buffer gas and desorbing helium films. In our current apparatus we trap atoms with µ ≥ 1.1µ B , and thermally isolate atoms with µ ≥ 2µ B . Extrapolation of our results combined with simulations of the loss processes indicate that it is possible to trap and evaporatively cool µ = 1µ B atoms using buffer gas cooling.