A Infrared detector (IR) uses an ability of gases with two ore more atoms to absorb infrared (IR) light, e.g. carbon dioxide, methane. Infrared detectors use wavelengths specific corresponding to vibration or rotation of a bond between two atoms in the gas molecule. The higher gas concentration the lower IR signal (approx. logarithmic function).
- Does not require oxygen for the measurement
- Impossible to damage by catalytic poisons
- DIrty optics warning
- Working up to 80% optics obscuration
- Good selectivity
- Higher costs