Date of Award


Document Type

Master Thesis

Degree Name

Masters of Science (Research)


Applied Physics & Instrumentation

First Advisor

Dr. Síle Nic Chormaic

Second Advisor

Dr. Niall Smith


Carbon monoxide is a major trace gas pollutant with road traffic being responsible for most emissions. Work has been done on the development of a carbon monoxide sensor, which is potentially capable of measuring the gas in vehicle exhaust emissions. This is based on tunable diode laser absorption spectroscopy The device must distinguish carbon monoxide from other gas species and from particulate matter. The device should also operate with a response time of the order of one second, have the potential for portability and a capacity for remote operation. Experimental work presented compares and contrasts the characteristics of the free-running diode laser and the external cavity diode laser. The suitability of the external cavity diode laser as a carbon monoxide sensor is discussed. Two experimental methods used to evaluate the sensitivity of the device are described along with possible device improvements based on experimental results. The device’s potential for use as a portable sensor has been demonstrated by using low voltage DC components. Control software for the portable DC components has been written using LabVIEW programming language and the program functionality is fully described. The feasibility of using the sensor as a portable device for measurement of carbon monoxide in vehicle exhaust or for remote operation to measure stack emissions has been also been demonstrated by using fibre optic technology. The operation of a prototype carbon monoxide sensor developed by collaborative partners is discussed. Experimental data showing absorption due to the presence of carbon monoxide using equipment supplied by collaborative partners is also presented.


Submitted to the Higher Education and Training Awards Council, September, 2003.

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