Buffer gas cooling and trapping of atoms with small effective magnetic moments

We have extended buffer gas cooling to trap atoms with small effective magnetic moments µeff . For µeff ≥ 3µB, 1012 atoms were buffer gas cooled, trapped, and thermally isolatedin ultra high vacuum with roughly unit efficiency. For µeff < 3µB, the fraction of atoms remaining after full thermal isolation was limitedby two processes: windfrom the rapid removal of the buffer gas anddesorbing helium films. In our current apparatus we trap atoms with µeff ≥ 1µB, andthermally isolate atoms with µeff ≥ 1.8µB. This triples the number of atomic species which can be buffer gas cooledandtrappedin thermal isolation. Extrapolation of our results andsimulations of the loss processes indicate that it is possible to trap and evaporatively cool 1µB atoms using buffer gas cooling.Physic