Radon Mitigation for the SuperCDMS-SNOLAB Dark Matter Experiment

Experiments that seek to detect very rare processes, such as interactions of the dark matter particles thought to make up 85\% of the mass of the universe, may suffer background interactions from radon daughters that have plated out onto detector surfaces. To reduce these backgrounds, an ultra-low-radon cleanroom was built at the South Dakota School of Mines \& Technology. Cleanroom air is supplied by an optimized vacuum-swing-adsorption radon mitigation system that has achieved a $> 300\times$ reduction from an input activity of 58.6 $\pm$ 0.7 Bq/m$^{3}$ to a cleanroom activity of 0.13 $\pm$ 0.06 Bq/m$^{3}$. Expected backgrounds due to radon daughters for the SuperCDMS dark matter search will be presented.