Oxygen sensor errors in helium-air mixtures

Oxygen sensors play a vital role in ensuring the safety of employees and users at National High Magnetic Field Laboratory. While most oxygen have accurate linear responses nitrogen/argon environments, studies highlighted phenomenon helium-air mixtures with certain types sensors. A controlled experiment was performed to observe behavior two sensors: orifice membrane. The sensor showed large deviation up 13% measured reading above actual content mixture test, while membrane remained within 3% value throughout its range.