Evaluation of carbon tetrafluoride as a xenon surrogate for underground gas transport

Detection of radioxenon is a critical component of underground nuclear explosion monitoring. Sulfur hexafluoride (SF6) has historically served as a Xe tracer. This work explores the use of carbon tetrafluoride (CF4) as an alternative for field tests given its general suitability as a tracer and reduced greenhouse gas potential compared to SF6. Gas Chromatography–Mass Spectrometry measurements characterized the diffusive behavior of CF4 in a 2-bulb apparatus to determine how well int approximates Xe. The measured diffusion coefficient of SF6 was 78% of that of Xe, agreeing with literature values, while CF4 diffused at 97% the rate of Xe.