Thermo Fisher Scientific (bremen) Gmbh

Hans-Juerg Jost

Joshua B Paul

James J Scherer

Hans-Juergen Schlueter

Eric Wapelhorst

Nils Stoebener

Tim Stoltmann

A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

High-accuracy mid-IR laser-based gas sensor

A system for controlling flow of gas in a continuous flow isotope ratio analyser is provided. The system comprises gas inlet and gas outlet lines for providing gas into and from a measuring cell, and at least one switchable flow restriction on the gas inlet line, for selectively controlling gas flow into the isotope ratio analyser. Also provided is a method for determining an isotope ratio using the system according to the invention.

Flow reduction system for isotope ratio measurements

A gas sensor system includes a laser module, optical chamber module, and a gas sensor cell. The laser chamber module includes two laser light sources producing laser light emissions at wavelengths &#x3bb;and &#x3bb;, respectively. Each beam path optionally includes an optical isolator. The beam paths enter the housing of the optical chamber module where they are combined into a third wavelength, &#x3bb;. The housing of the optical chamber module includes an inlet and an outlet for passing a selected target gas. The gas sensor cell mates to the inlet of the housing. The target gas passes through the adjacent gas cell and into the optical chamber module through the inlet. The target gas exits the optical chamber module through the outlet. Within the optical chamber module, a nonlinear crystal receives the laser light emissions at wavelengths &#x3bb;and &#x3bb;and generates the third wavelength, &#x3bb;. The wavelength &#x3bb;is selected to be at the mid-IR spectral absorption feature of the target gas, i.e. a strong absorption line in the vibrational spectrum of a specific chemical species that is targeted by the gas sensor. The third wavelength &#x3bb;is generated by the interaction of the electric fields of the two laser emissions. The nonlinear optical crystal may be periodically poled, and configured to frequency-convert the first and second laser beams. The residual light from the two laser sources is removed from the mid-infrared beam with an absorptive and/or reflective optical filter.

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Helsinki, Finland

Hans-Juerg Jost