High temperature, robust Herriott cell for sensitive NH3 spectroscopy to optimize NOx removal

Ammonia plays an important role in the NO
_x
removal in combustion processes. However, a too high concentration of NH
₃
results in unconverted ammonia that pollutes the environment and damages the combustion plant. Today's available ammonia sensors are either not suitable for high temperature applications that are common in combustion processes or do not have the needed accuracy to control the ammonia concentration. The authors present a robust and cost-efficient extractive gas sensor suitable for detection of NH
₃
with a precision of 50 ppb.