This Small Business Innovation Research Phase I project focuses on the development of a proof-of-concept ultra-portable CO2 isotope ratio monitor. Carbon isotope ratio monitoring is essential for discerning natural versus anthropogenic emissions sources of CO2. Widespread measurement of differentiated carbon isotopes will provide major steps towards building more accurate models of climate change. However, isotopic ratio monitoring is notoriously difficult, even for the gold standard gas sensors based on mass spectroscopy, which can take up an entire room and require skilled technicians to operate. Phase I will explore the development of sensor components suitable for battery powered, easy-to-use, laser spectroscopic CO2 isotope ratio monitors using novel high-efficiency infrared quantum cascade lasers (QCLs). The broader/commercial impact of this work targets improved atmospheric monitoring, climate change analysis, and carbon capture/sequestration/verification. Carbon sequestration sites will require fine grained leak detection when captured into underground geological features, and isotopic ratio monitoring will allow such detection to be greatly improved. Additionally, data generated by such carbon isotope ratio sensors will answer many critical questions related to the human impact of burning fossil fuels.
This Phase I SBIR project developed an initial proof-of-concept prototype sensor to measure carbon dioxide isotope ratios in the atmosphere. We implemented and tested the required gas handling components, laser control components, optical configurations, and detection circuitry. We drew favorable conclusions for highest risk technical issues to enable ultra-portable shoebox sized isotope ratio sensors which can run on batteries. The sensor we are developing for isotope ratio monitoring of carbon dioxide will be able to determine whether the detected concentration is primarily natural or man-made, which will help society by: 1) enabling more precise measurements of carbon sources and sinks to improve climate science; 2) enabling localization of excessive emitters of carbon dioxide to enable carbon markets and carbon trading systems necessary for cap-and-trade; 3) Providing a map of real-time carbon emission which is useful for research, policy, and education; and 4) Enabling extremely sensitive leak detection of CO2 in underground carbon capture applications. Additional applications exist for industrial process control applications and medical breath analysis for H. Pylori infection in gastrointestinal ulcers. We implemented a mid-infrared laser absorption spectrometer to achieve the isotope ratio monitoring at sensitivities necessary for these applications. By developing low power, compact, sensor components, we can now produce precision isotope ratio monitors using low cost optical configurations which are robust, and have the potential to survive in portable or outdoor year-round sensing applications. Furthermore, we developed a full proof-of-concept sensor to have an extremely compact size, which will enable many new applications.
