| Summary: | 碩士 === 國立清華大學 === 物理系 === 101 === We transferred the cold 85Rb from magnetic-optical-trap (MOT) to another ultra-high vacuum chamber (science cell), in order to increase the lifetime of the ultra-cold atoms. Two chambers are connected using a 3 mm×63 mm tube as a differential pump to maintain a large pressure difference. In the experiment, we caught and transferred the atoms by a moving magnetic quadrupole trap which is mounted on a linear track. We have successfully transfer 24% of the MOT atoms to the science cell after optimizing various experiment parameters, such as: magnetic capture strength, magnetic trap depth, moving acceleration, moving speed and etc.
We measured the quantity of the atom using the methods of the absorption image and the fluorescence image. 1.6×108 atoms are trapped in the MOT, and 3.85×107 atoms are transferred to the science cell. In the first chamber (MOT), the lifetime of the 85Rb atom is about 2.2sec.After transporting, the lifetime is increased to 20 sec. The total transfer sequence is only 2 sec and the lifetime of the cold atom has been inceased by an order of magnitude.
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