On the continuous loading of a U-magneto-optical trap on an atom-chip in an ultra high vacuum

Here, we report our studies on the continuous loading of a U-magneto-optical trap (U-MOT) on an atom-chip with a rubidium-(Rb)-vapor-generated background using a dispenser source in an ultra high vacuum environment. Using the U-MOT loading curves, the partial pressure due to the Rb vapor and the pressure due to the background gas have been estimated near the MOT cloud position. The estimated pressure due to the Rb vapor increased from Torr to Torr as the Rb-dispenser current was increased from 2.8 to 3.4 A. The increase in dispenser current also resulted in a decrease in loading time as well as the lifetime of the MOT cloud. This study will be useful for magnetic trapping experiments where accurate information of the pressure in a chamber is important for the lifetime of the magnetic trap.