Laserless slow atom source for loading atom traps

Abstract

Permanent magnets are used to selectively remove the fast atoms from an atomic beam and to guide the remaining slow atoms into a trapping region. The permanent magnets establish a quadrupole field which extends along the axis of a bent vacuum nipple. A threshold velocity is set by the radius of curvature of the bent nipple and the strength of the magnets. Only those atoms which are slower than the threshold are transmitted to the trapping region. For a 30 cm radius of curvature and a Maxwellian velocity distribution at the atomic beam source, a flux of 10\sp9 atoms/s is expected to be delivered to the trapping region. Experimentally, a flux of only 10\sp6 atoms/s is observed. The flux deficit is attributed to an attenuation of slow atoms resulting from collisions within the nozzle of the recirculating oven which is used to produce the atomic beam