Skip to main content
. 2020 May 11;20(9):2745. doi: 10.3390/s20092745

Figure 3.

Figure 3

Comparison between a nowadays commonly used NDIR setup (top) and the URAS setup (bottom). (Top) Two detectors with different spectral response functions act as a measurement and reference channel, respectively. (Bottom) The URAS detector consists of two chambers filled with the gas to be detected and connected via a membrane. The optical path is divided into a reference part with a fixed gas composition and a measurement part containing the analyte.