Highly responsive CO2 detection by an improved & Compact compact gas sensor using mid-IR spectroscopy

• Main Authors: Salim, Mohd. Rashidi, Ibrahim, Mohd. Haniff, Azmi, Asrul Izam, Mohd. Noor, Muhammad Yusof, Abdullah, Ahmad Sharmi, Ngajikin, Nor Hafizah, Manap, Hadi, Dooly, Gerard, Lewis, Elfed
• Format: Article
• Published: Universiti Teknikal Malaysia Melaka 2018
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/85513/; https://journal.utem.edu.my/index.php/jtec/article/view/4449

An improved and compact gas sensor using mid-infrared spectroscopy for highly responsive Carbon Dioxide (CO2) detection is presented. The sensing principle is based on open-path direct absorption spectroscopy in the mid-infrared region. The improved reflective structure of optical gas sensor consists of low cost and compact components. Several gas cell configuration which includes SISO, 2-MISO, 4-MISO and 8-MISO were simulated using ZEMAX®12 using non-sequential ray tracing technique to get the optimum radius of the reflective curved surface. Sensitivity analysis has shown that the optimised structure of 4-MISO yields the highest sensitivity and power efficiency of -0.2895%-1 and 12.298% respectively. The developed gas sensing system using the optimised gas cell has shown the capability of accurately detecting CO2 concentration between 1.5% and 5.8% with no cross-sensitivity with other gases present in the gas cell. The newly developed CO2 sensor exhibits high responsivity with the recorded rise time and fall time of less than 1 second respectively.