Three sensitivity improvement strategies for non-dispersive-infrared (NDIR) ethylene gas detectors were defined and examined: the application of low-cost Fresnel lenses, usage of a conically shaped measurement chamber and a simple digital signal processing lead to a seven times better IR-radiation efficiency compared to a system configuration without consideration of these methods. The approaches don't affect IR-detectors, IR-sources or the optical pathway and thus, the methods can be called "passive". It was shown that usage of lock-in amplifiers is not necessary to achieve good sensitivity results and noise equivalent concentrations of about 6 ppmv. © 2011 Published by Elsevier Ltd.
Sklorz, A., & Lang, W. (2011). Strategies for passive sensitivity improvement of NDIR ethylene gas detectors. In Procedia Engineering (Vol. 25, pp. 1153–1156). https://doi.org/10.1016/j.proeng.2011.12.284