Continuous CO2 emissions tester uses QC laser

Scientists from the Swiss materials science and technology institution EMPA (www.empa.ch) have integrated a 4.3-µm-wavelength, pulsed, few-milliwatt power, distributed-feedback quantum-cascade laser from Alpes Lasers (Neuchatel, Switzerland) into a test instrument that continuously measures the level of fossil-fuel versus biological or natural emissions of carbon dioxide (CO2)

Scientists from the Swiss materials science and technology institution EMPA (www.empa.ch) have integrated a 4.3-µm-wavelength, pulsed, few-milliwatt power, distributed-feedback quantum-cascade laser from Alpes Lasers (Neuchatel, Switzerland) into a test instrument that continuously measures the level of fossil-fuel versus biological or natural emissions of carbon dioxide (CO2). EMPA researcher Lukas Emmenegger says, “The continuous measurement of all major CO2 isotopes ... was not possible before this new measurement technology was developed.”

Source light is input to a multipass cell to increase the interaction between the light and the weakly absorbing gas present in the absorption cell. A room-temperature mercury-cadmium-telluride detector measures the intensity of the light traversing the cell while the laser is driven to sweep across a small spectral range where heavy and light (isotopically different) CO2 are present. The absorption for the different CO2 isotopes is compared (as they do not exhibit absorption at the same wavelength) and the total amount of CO2 is also measured. Biological processes respirate CO2 with a different isotopic ratio than that for CO2 produced by burning fossil fuel, allowing the system to distinguish between the two. Contact Antoine Muller at antoine.muller@alpeslasers.ch.

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