What is Nondispersive IR (NDIR) Spectrometry?
Filter-based nondispersive techniques allow for the manufacturing of low-cost, robust sensors that offer the advantages of IR absorption methods and are well suited for the production environment. Although single-wavelength detection can be done, dual-wavelength sensors allow for real-time correction of the sensor baseline. A low-cost, filter-based NDIR sensor can then be implemented for production scale process monitoring and control. Response times for this type of sensor are typically on the order of tens of milliseconds. Noise levels are in the microtorr range, with exact numbers depending on the specific design. Multiple filters can be used, allowing simultaneous analysis of several gases by a single sensor. Q. What is Differential Optical Absorption Spectroscopy (DOAS) DOAS is a method to determine concentrations of trace gases by measuring their specific narrow band absorption structures in the IR, UV and visible spectral regions. A typical DOAS instrument consists of a continuo
