Speaker
Description
SuperCDMS is a dark matter direct detection experiment preparing to begin at SNOLAB. Ambient radon within the underground cavern poses a significant background risk; prompt interstitial radon allowed to accumulate within the experiment’s lead shielding would increase the experiment's projected background rate by a factor of 2.8 to 6.4 (depending on detector type). To mitigate this background, we have designed and are installing the Radon Purge System. The system continuously displaces cavern air by flowing low-radon nitrogen gas into a sealed barrier volume surrounding the inner shielding containing the detector cryostat. Because ambient pressure variations in the cavern can create pressure differentials large enough to structurally damage this barrier, the system uses an adjustable flow rate that dynamically responds to pressure changes. This approach aims to regulate barrier pressure, suppress radon accumulation near the detectors, and provide real-time monitoring of quantities such as barrier radon concentration to ensure robust data quality. This presentation will detail the design,
testing, and current results of the Radon Purge System.