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T:[email protected]:www.mirico.co.uk
Technology Note
Laser Isotope Ratiometer A field deployable high precision Stable Isotope Analyser About:TheLaserIsotopeRatiometer(LIR)isanewinnovativetechniqueusedtomeasuretheratioofstableisotopesofagivenmolecule.Thecurrentsystemhasbeendemonstratedfor13C:12C(δ13)analysisinCO2.Theinstrumentisdesignedtoofferhighprecision,realtimemeasurementsinacompactandrobustpackage.Theinstrumentwasdesignedtoincludeanon-boardcalibrationsystemforautonomousoperationandenhancedstabilityandaccuracy.LaserbasedtechniqueshavebeendevelopedthatovercomeseverallimitationsofIRMSincludingrealtimeanalysisandportability.However,lasertechniquesdevelopedto-datecommonlyapplyhighprecisionopticalcavitiesasthebasisofoperationwhichrelyonhighreflectivityopticsinordertoachievenearequivalentprecisionasIRMS.Thisaddsconsiderablecomplexityandintroduceslimitationsintermsofsamplehandlingandrobustnesstothesystemdesign.TheLIRusestheadvantagesoftheMid-IRandaninnovativeopticaldesigntoachieveperformancewithoutcompromisetorobustness.Advantages:TheLIRbringssimplicitytostableisotopeanalysis,whetherinthefieldorinalaboratoryenvironment.Theinstrument’sdesignoriginatedaspartofaEuropeanSpaceAgencyprogrammetodemonstratetheLIRforplanetarylanders.Overallthedesignofferscompactness,robustnessandprecisionwithouttheneedforaskilledoperatororexcessiveuseofconsumables.< Fielddeployableanalysercapableofrealtimed13CforCO2.
< Builtinauto-calibrationsystem,farreducedoperationcostsandmaintenance.
< Builtinreferencesystemsensuresstabilityandaccuracyovergreaterperiodoftime.
< Highprecision,<0.15‰in35smeasurement.
< Compact&robust,suitableforfielddeployment.
< Platformsystemthatcanbeconfiguredforotherstableisotopesusingthesameprinciples.
Key Features < High precision and accuracy
< Fast measurements
< Highly robust, field deployable
< Built in permanent calibration
Applications < Environmental Science
< Medical Diagnosis
< Mud Gas Isotope Logging
T:[email protected]:www.mirico.co.uk
Technology Note
OperatingPrinciples:Figure1belowillustratestheprinciplesofoperation.1)Twolasersofwavelengthλ1andλ2,probe
13CO2and12CO2.The
wavelengthsareselectedforoptimummeasurementsoftheisotopesandequaltemperaturedependence.2)Lasersprobethegassample,atthesametimelasersprobeareferencemixture.3)Afastopticalswitchflicksthebeambetweenthegassampleprobeandreferencechamberprobeatarategreaterthan10KHz.Detectorsmeasurethebeams,λ1andλ2measuringthereferencechannelandsamplechannelsimultaneously.Signalprocessingthencalculatesconcentrationprofilesandthestableisotoperatioisderived.
Figure1:SchematicoftheLaserIsotopeRatiometer(LIR).
Temporalmeasurements
Figure2:TemporalrecordofdeltavaluewhileswappingbetweendifferentCO2samples. Showingrapidresponseandhighsensitivity.
DeltaValue
Figure3:Allandeviationplotshowingtheprecisionoftheinstrument.