Ultracold 87Rb beam
| Currently, the cold atomic beam apparatus we have constructed is capable of producing a continuous beam of rubidium atoms with an unprecedented total flux of 3.2 x 1012 (1.0 x 1012) atoms/sec at 116 (20) m/sec. This flux is more than an order of magnitude above the absolute best of previous cold atomic sources and opens a new regime in the production of ultracold atomic samples.
A picture of the existing experimental set-up is shown above. Our source of thermal rubidium atoms originates from a rubidium candlestick atomic beam source, which provides an intense, well-collimated beam with a mean velocity of 400 m/s. To utilize this source of hot thermal atoms, the beam is first transversely collimated and cooled to remove as much transverse velocity spread as possible, thus increasing the overall flux. Subsequently, a Zeeman-slower decelerates and longitudinally cools the atomic distribution, and also provides us with a means to tune the final beam velocity.
By matching the transverse cooling structure design to the divergence characteristics of the candlestick, we demonstrate that we are able to utilize a full 50% of the atoms emitted from the source for deceleration. As a final consideration, and for fine pointing of the atomic beam, we also employ a 2" region of optical molasses at the end of the collimator, increasing the total cooling region's length to 8 inches.