Collimated, single-pass atom source from a pulsed alkali metal dispenser for laser-cooling experiments

We have developed an improved scheme for loading atoms into a magneto-optical trap (MOT) from a directed rubidium alkali metal dispenser in <10 ^-10Torr ultrahigh vacuum conditions. A current-driven dispenser was surrounded with a cold absorbing "shroud" held at ≤0°C, pumping rubidium atoms not directed into the MOT. This nearly eliminates background atoms and reduces the detrimental rise in pressure normally associated with these devices. The system can be well-described as a current-controlled, rapidly switched, two-temperature thermal beam, and was used to load a MOT with 3 × 10 ⁸ atoms.