IMPROVEMENT IN QCL ABSORPTION BASED CO TRACE GAS SENSOR SYSTEM

Suryakanta R. Patil, Nadir Charniya, Shivangi Chourasia, Alok Verma

Abstract: This paper describe development of Trace gas sensor that can detect Carbon Monoxide (CO) gas by using a wavelength tuned Distributed feedback-Quantum Cascade LASER (DFB-QCL). Trace gas sensor design is based on principle of Direct Infrared Absorption Spectroscopy. High Resolution Transmission Molecular Spectroscopic (HITRAN) Analysis is carried out for selecting fundamental absorption line of CO R(12) near 2190.0175 cm-1 and the characteristics of wavelength tunable DFB-QCL has been analyzed, for detection of CO R(12) at same wavenumber. Fixed length gas cell of 10 cm is used to achieve highest sensitivity and improved detection limit. We are improving the response time and reducing the various noises present in the gas sensor using signal processing with the help of NI LabVIEW software and hardware. Also effect of chopper frequency variation, Mercury Cadmium Telluride (MCT) detector distance variation on Full Width Half Maxima (FWHM), Intensity of DFB-QCL is observed with and without gas sample present in fixed gas cell.

Keywords: CO gas, DFB-QCL, NI LabVIEW, NI USB 6351

DOI: https://doi.org/10.15623/ijret.2014.0311083