Neutrinos and Dark Matter

Completion of the DEAP-3600 Acrylic Vessel Inner Surface Sanding

To listen for interactions between DEAP’s argon detector and dark matter, the collaboration had to create one of the most radiogenically clean environments in the entire universe. To do this, the collaboration fabricated its inner detector, a sphere of radius 85 cm, from ultra-pure acrylic, and designed and implemented an 18 feet tall sanding robot (the Resurface) capable of removing the innermost layer of the acrylic sphere in a contained environment (with the aim of removing any contamination introducted during installation). This never-before-attempted, large-scale robot, a true experiment within the experiment, was deployed at the center of the DEAP vessel in October 2014 and after a month of operation, had successfully removed 500 microns uniformly from the detector surface, thus returning the purity levels of the acrylic back to production standards.