Barium Daughter Tagging Using Single Molecule Fluorescence Imaging

The existence of Majorana fermions is of great interest as it may be related to the asymmetry between matter and anti-matter particles in the universe. However, the search for them has proven to be a difficult one. Neutrino-less Double Beta decay (NLDB) offers a possible opportunity for direct observation of a Majorana fermion. A robust observation of neutrinoless double beta decay is considered the most promising method to determine the Majorana nature of the neutrino. The detection of the single barium ion produced as a result of the double beta decay of xenon 136 would enable a new class of ultra-low background neutrinoless double beta decay experiments, which the NEXT collaboration is working to achieve. We will present recent progress toward realization of a barium tagging scheme in high pressure xenon gas, including, ion mobility in high pressure gas, custom fluorophores for barium sensing, and a high pressure optical system. This R&D adapts techniques from biochemistry and microscopy to yield a novel technology with potential to enable background free, ton-scale neutrinoless double beta decay searches.