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High repetition rate Bose-Einstein condensate production in a compact, transportable vacuum system

TitleHigh repetition rate Bose-Einstein condensate production in a compact, transportable vacuum system
Publication TypeThesis
Year of Publication2008
AuthorsSquires, MB

This thesis reports on the design and implementation of a compact (5 × 10 × 30 cm) two chamber system for rapidly producing 87Rb Bose-Einstein condensates (BEC) on an atom chip with the future goal of a transportable BEC based sensor. We present the first use of anodic bonding to fabricate multi-chamber vacuum systems suitable for BEC production. Anodic bonding is a method for joining silicon and Pyrex and is superior to epoxy based construction because anodically bonded vacuum systems can be baked at temperatures > 300°C. The improved vacuum quality is a key aspect of reproducibly building compact BEC quality vacuum systems. In the two chamber vacuum system the first chamber operates a 2D+ magneto-optical trap (MOT) at a Rb pressure of ~ 10−7 torr and produces a flux of cold atoms that loads a 3D MOT in the second, low pressure (< 10−9 torr) chamber. When loaded to saturation the 3D MOT contains ~ 500 × 106 87Rb atoms. The laser cooled atoms are magnetically transferred to an atom chip where the atoms are cooled to degeneracy by forced RF evaporation in a tight magnetic trap (1.8×3.0×0.6 kHz). The system performance is demonstrated by three modes: the rapid production of sequential BECs of 1 × 105 atoms with a period of < 3.8 s, the number optimized production of a BEC of 4 × 105 atoms in < 10 s, and the speed optimized production of a BEC of 5×104 atoms in 2.65 s. Initial experiments demonstrating key elements of rotation sensor are also presented. Specifically splitting atoms on a chip in a compact vacuum system and guiding atoms around a curve. Also presented in this thesis is a rubidium dispenser based on a gold/rubidium alloy that has potential as a clean source of rubidium in cold atom experiments.