Multi-species, real time, high sensitivity, and compact in-situ sensor for environmental monitoring
Lead Research Organisation:
Science and Technology Facilities Council
Department Name: RAL Space
Abstract
The ability to carry out real-time (>1 kHz data rate), in-situ, trace concentration measurements (ppb - ppt) of molecules and radicals would be an enabler for a wide range of scientific activities, environmental sciences being a major beneficiary. Currently gas chromatography, mass spectrometry (GC/MS) or electrochemical sensors cannot offer these combined attributes. Real-time air-quality measurements, lower troposphere urban chemistry studies (pollutant pathways), anthropogenic and biogenic emission measurements, flux exchange monitoring, to name only a few, are areas that would benefit greatly from the development of ultra-high sensitivity sensors, suitable for field deployment and operating with high temporal resolution. In this application we propose to demonstrate a novel approach to address these aspirations, which is ground-breaking in the field of ultra-high sensitivity laser based sensors for in-situ monitoring and laboratory studies. The concept exploits aspects of tuneable laser absorption spectroscopy (LAS) with several combined advantages: mid infrared operation targeting intense fundamental ro-vibrational absorption bands, cavity type spectroscopy providing extremely long equivalent absorber path lengths, wide frequency tuneability for multispecies and/or broadband absorber monitoring and compactness and robustness for field deployment. We propose here to develop and demonstrate this novel concept for ultra-trace species monitoring and bring the technology from TRL1 to TRL3.
Publications
Brownsword RA
(2013)
Intracavity widely-tunable quantum cascade laser spectrometer.
in Optics express
| Description | The project has successful demonstrated the physical principle of a mid infrared laser sensor that combines the advantages of 1) broad tunability (~100cm-1), through the use of a quantum cascade laser (QCL) in an external cavity (EC) configuration, 2) enhanced sensitivity (few hundredfold), and 3) a very compact package. Specifically this project has achieved the following: 1. The physical modelling of an external cavity QCL and its use to determine the specification of each component involved in the system. 2. The optical design and implementation of a bench-top EC-QCL source demonstrating an overall frequency tuning range of ~100 cm-1. 3. The development of custom-designed anti-reflection coatings suitable for broadband QCL and the subsequent processing of devices. 4. The study of the EC-QCL source in a novel configuration that demonstrated a sensitivity enhancement in the detection of gaseous samples. 5. The clear demonstration of the sensitivity enhancement through the spectroscopy of two test broadband absorbers: dimethyl carbonate and pentafluoroethane. 6. The understanding and physical modelling of the sensitivity enhancement and the investigation of data reduction to measure sample concentrations with the constraints of practical gas sensors in mind. In addition, sensitivity estimates have been determined for this kind of gas sensor. |
| Exploitation Route | The instrument concept that has been demonstrated aims to provide a real time, high sensitivity, and compact in-situ sensor targeting multiple broadband absorbers. This is of relevance to many users. For example chemical or oil industries, car makers, environmental monitoring sector. A patent describing the approach and the system developed has been submitted. Funding for further development is actively sought as well as industrial partners. |
| Sectors | Chemicals,Environment |
| Description | The findings from the original project have been used for the development of a concept of an analyzer to measure gas dissolved in liquid, particularly as a first step for the measurement of dissolved carbon dioxide in water. This application is highly relevant to the development of high vertical resolution carbon dioxide profiling in ocean, and also for prospective detection of carbon dioxide on the sea floor above off shore carbon capture and storage facilities. The project outcomes have attracted a lot of interest from the carbon capture and storage community. We are currently working with two large industry in this field to develop practical solutions based on this research. |
| First Year Of Impact | 2016 |
| Sector | Energy,Environment |
| Description | CfI 2017 |
| Amount | £120,000 (GBP) |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2017 |
| End | 03/2018 |
| Description | NERC technology proof of concept |
| Amount | £147,091 (GBP) |
| Funding ID | NE/L012367/1 |
| Organisation | Natural Environment Research Council |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2014 |
| End | 03/2015 |
| Title | Enhanced absorption effect in external cavity semiconductor lasers. |
| Description | We have developed a laser system that enhances the absorption signal produced by a molecule when probed by laser radiation. This enhancement effect and the way to obtain it are the inventive steps and yield increased sensitivity in measuring molecular concentration by laser spectroscopy. |
| IP Reference | GB1214899.5 |
| Protection | Patent application published |
| Year Protection Granted | |
| Licensed | No |
| Impact | The demonstration of the concept has provided material to populate a follow on successful grant application to applied the technical approach demonstrated during the project on gas dissolved in liquids. |