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Proceedings Paper

Carbon dioxide detection at 2 µm using an integrating sphere as an optical absorption cell
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Paper Abstract

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 the detection of carbon dioxide (CO2) gas at 2 &mgr;m. CO2 was detected using a light emitting diode as the emitter and a photodiode as the detector. A two inch (50.8 mm) diameter integrating sphere was used as an absorption gas cell. A method of calculating the effective path length of the integrating sphere is also presented. The latter is shown to be dependant on the reflectance of the sphere's internal surface, the sphere's port fraction and the level of attenuation of the optical signal due to the gas present in the sphere. Effective optical path lengths of 40 cm at the 2 &mgr;m region are reported. Experimental results demonstrating the detection of CO2 using a two inch diameter integrating sphere are presented and these are compared to simulation results based on a CO2 absorption over a 40 cm path length at 2 &mgr;m.

Paper Details

Date Published: 2 July 2007
PDF: 4 pages
Proc. SPIE 6619, Third European Workshop on Optical Fibre Sensors, 66191H (2 July 2007); doi: 10.1117/12.738407
Show Author Affiliations
Eamonn Hawe, Univ. of Limerick (Ireland)
Paul Chambers, Univ. of Limerick (Ireland)
Colin Fitzpatrick, Univ. of Limerick (Ireland)
Elfed Lewis, Univ. of Limerick (Ireland)


Published in SPIE Proceedings Vol. 6619:
Third European Workshop on Optical Fibre Sensors

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