Imaging of single barium atoms in solid xenon for nEXO

Neutrinoless double beta decay has become of interest in recent decades to prove whether the neutrino is its own anti particle. Experiments in enriched liquid Xenon in EXO-200 are ongoing. To achieve a greater sensitivity, a much larger next generation double beta decay experiment, nEXO, is planned. Searches for neutrinoless double beta decay in nEXO can be improved through barium tagging. In liquid 136Xe, double beta decay leaves a daughter 136Ba atom. If this daughter is identified and tagged, the only remaining background in the nEXO detector is 2nbb decay. A test apparatus with a Ba$+$ ion beam has been used to deposit a small number of Ba atoms in the area of a fixed laser beam. Images down to the level of a single Ba atom in the laser beam have been observed.