Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553437
Title: Mid-infrared diagnostics of the gas phase in non-thermal plasma applications
Author: Raja Ibrahim, Raja Kamarulzaman Kamarulzaman
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2012
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Abstract:
This thesis focuses on the utilisation of mid-infrared techniques in technological atmospheric pressure, non-thermal plasma (NTP) diagnostics. Two mid-infrared techniques were demonstrated in this work namely laser absorption and Fourier transform infrared (FTIR) spectroscopy. The performance of external-cavity quantum cascade laser (EC-QCL), a relatively new laser type with broad tuning capability was also demonstrated as potential diagnostics tool for technological NTP applications. A dual plate dielectric barrier discharge (DBD) and a packed-bed NTP reactor were designed and fabricated to perform plasma process. Quantitative analysis of the laser absorption and FTIR spectroscopy techniques for gas detection were validated by using standard gas samples. Real-time CO monitoring by means of in-situ laser absorption spectroscopy measurements were performed for gas phase diagnostics in the decomposition of TEOS by means of plasma-enhanced chemical vapour deposition (PE-CVD) and in CO2 reforming of CH4 by means of NTP. In-line FTIR measurements simultaneously recorded the gas spectrum at the exhaust of the plasma reactors. Information from both measurements was found to provide useful information on the plasma processes and chemistry for the NTP applications. Finally, wavelength stability and linearity performance of a broad tuning range EC-QCL were evaluated by using the Allan variance technique. (LOD) at SNR = 1 was estimated to be ~ 2 ppm, achieved under atmospheric pressure, at the room temperature, and a path length of 41 cm for NO detection produced from the decomposition of dichloromethane (DCM) by means of NTP.
Supervisor: Martin, Philip Sponsor: Ministry of Higher Education (MOHE) of Malaysia
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.553437  DOI: Not available
Keywords: Laser absorption spectroscopy ; Fourier transform infrared spectroscopy ; Non-thermal plasma ; External-cavity quantum cascade laser ; Mid-infrared gas detection
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