Peer-Reviewed Journal Details
Mandatory Fields
Hawe, E; Chambers, P; Fitzpatrick, C; Lewis, E
Measurement Science & Technology
CO2 monitoring and detection using an integrating sphere as a multipass absorption cell
Optional Fields
integrating sphere carbon dioxide spectroscopy near infrared multipass absorption cell GAS-DETECTION LASER-DIODES MU-M
This paper describes a multipass absorption sensor based on an integrating sphere. The sphere has an internal coating which is highly reflective ( over 95%) in the near infrared region and this allows for the detection of CO2 at two regions in the spectrum: 2 mu m and 1.57 mu m. CO2 was detected around the 2 mu m region using a light emitting diode as the emitter and a photodiode as the detector, while detection at the 1.57 mu m region took place using a broadband ASE source as the emitter and a miniature spectrometer as a detector. A 2 in diameter ( 50.8 mm) integrating sphere was used as an absorption gas cell. This paper reports the generation of effective optical path lengths of 114 cm at the 1.57 mu m region and 40 cm at the 2 mu m region. Experimental results demonstrating the detection of CO2 using a 2 in diameter integrating sphere are presented and simulation results based on larger integrating spheres are also reported. Further simulations conducted in the mid- infrared region suggest the possibility of detecting trace levels of CO2 ( less than 200 ppm) using a 2 in diameter integrating sphere.
Grant Details