A mid-infrared carbon monoxide sensor system using wideband absorption spectroscopy and a single-reflection spherical optical chamber

A mid-infrared carbon monoxide (CO) sensor system based on a dual-channel differential detection method was developed using a broadband light source in the 4.60 mu m wavelength region and a single reflection spherical optical chamber with similar to 0373 mu m absorption path length. CO detection was realized by targeting the wideband strong absorption lines within 4.55-4.6512 mu m. A dual-channel pyroelectric detector as well as a self-developed digital signal processor (DSP) based orthogonal lock-in amplifier was employed to process CO sensing signal. A minimum detection limit of similar to 0.5 ppm in volume (ppmv) was achieved with a measurement time of similar to 6 s, based on an Allan deviation analysis of the sensor system. The response time (1000 -> 0 ppmv) was determined to be similar to 7 s for the CO sensor operation. Due to the characteristics of low detection limit, fast response time and high cost performance, the proposed sensor has relatively good prospect in coal-mining operation. (C) 2017 Elsevier B.V. All rights reserved.