Charged impurities in a BEC

We present an apparatus for studying the interactions between a 87Rb BEC and ions or other impurity particles. Our system is unique among BEC machines in that we have the ability to cancel stray electric fields with high precision. This allows us to do controlled experiments in which a single or small number of charged impurities interact with a BEC for a significant amount of time. Furthermore, this system allows for sub-micron- resolution spatial imaging of ions or Rydberg atoms. This creates the possibility of high-resolution tomography of structures in a BEC or a cold atom cloud.