van der Stam K M R, van Ooijen E D, Meppelink R, Vogels J M, van der Straten P
Atom Optics and Ultrafast Dynamics, Utrecht University, TA Utrecht, The Netherlands.
Rev Sci Instrum. 2007 Jan;78(1):013102. doi: 10.1063/1.2424439.
We describe the setup to create a large Bose-Einstein condensate containing more than 120 x 10(6) atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0 x 10(10) atoms with a temperature of 320 microK and a density of about 1.0 x 10(11) atoms/cm(3). The sample is spin polarized in a high magnetic field before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the three-body losses at the end of the evaporation, the magnetic trap is decompressed in the axial direction.
我们描述了用于创建一个包含超过120×10⁶个原子的大型玻色 - 爱因斯坦凝聚体的装置设置。在实验中，一束热原子束被塞曼减速器减速，并被捕获在一个暗点磁光阱（MOT）中。我们实验中的典型暗点磁光阱包含2.0×10¹⁰个原子，温度为320微开尔文，密度约为1.0×10¹¹个原子/厘米³。在原子被加载到磁阱之前，样品在高磁场中进行自旋极化。与无自旋极化的实验相比，在高磁场中进行自旋极化会使转移效率提高2倍。在磁阱中，通过蒸发冷却在50秒内将原子云冷却至简并态。为了抑制蒸发末期的三体损失，磁阱在轴向方向上进行减压。
