Martinez, Benjamin, Jr., authorYalin, Azer P., advisorYost, Dylan, committee memberWindom, Bret, committee member2020-06-222020-06-222020https://hdl.handle.net/10217/208423Recent findings show that the oil and natural gas industry is responsible for a large portion of total anthropogenic methane (CH4) emissions. These findings have driven the need for suitable methane detection and quantification methods. Methane emissions on the scale that the oil and gas industry produce (13 Tg[CH4]/year) can cause environmental effects comparable to that of CO2 due to methane's high global warming potential. The present thesis focuses on continued developments and improvements to a laser-based methane sensor that uses the open-path cavity ring-down spectroscopy (CRDS) technique. The sensor is intended for continuous mobile monitoring of methane emissions from the oil and gas industry by deployment on ground and aerial based vehicles. Sensor performance in a range of environmental conditions is characterized and shows the feasibility of deploying the sensor in real world applications. Indoor accuracy tests were done utilizing a closed-path system and verified through comparison with a commercial analyzer. Sensor measurements compared to the commercial analyzer showed good 1:1 agreement. Allan variance studies within laboratory measurements demonstrated the sensor's high sensitivity of ~10 ppb. A heater system was designed and implemented for overall improvement in low temperature conditions. The heater system successfully improved the thermal range of the sensor to temperatures as low as 0°C. Environmental tests also showed the sensor's reliability in harsh winter conditions over a ~70-day period of continuous measurement. The sensor's methane plume detection ability and sensitivity in simulated controlled releases through vehicle deployment is demonstrated and good 1:1 agreement was found comparing against a commercial analyzer in the field. Controlled release experiments demonstrated CH4 measurements more than 400 meters away from the source at an emission rate of 0.5 g[CH4]/s. A retro-fitted closed-path cell was constructed and tested in field campaigns to reduce noise due to Mie scattering. Additional field testing with simulated controlled releases were performed to test a modified, light-weight (4.1 kg) sensor mounted on two unmanned aerial vehicle platforms. Detection of various plumes in the UAV configuration was shown to be feasible with the current mounting method. Sensitivity in UAV flights were as low as 17 ppb which demonstrated the robust opto-mechanical capabilities of the sensor.born digitalmasters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.laser absorptionnatural gasunmanned aerial vehiclemethanecavity ring-down spectroscopyspectroscopyText