Connecticut College, New London, Connecticut usa general Physics Institute, Russian Academy of Sciences, Moscow, Russia
CARBON AND OXYGEN ISOTOPE MEASUREMENTS OF CO
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A7.CARBON AND OXYGEN ISOTOPE MEASUREMENTS OF CO2 BASED ON OFF-AXIS INTEGRATED CAVITY OUTPUT SPECTROSCOPY Hans-Jürg Jost, Bay Area Environmental Research Institute, Sonoma, CA, USA James R. Podolske, NASA Ames Research Center, Moffett Field, CA, USA Todd R. Sauke, NASA Ames Research Center, Moffett Field, CA, USA H. William Wilson, Western Washington University, Belingham, WA, USA To reduce uncertainties in the quantification of the carbon cycling in the environment high temporal resolution isotope measurements of carbon dioxide play a central role. They will help in establishing the relative size of carbon sinks on land and in the oceans. The current state of the art method to measure carbon isotopes is the Isotope Ratio Mass Spectroscopy (IRMS). It is very accurate, but it also has limitations: real-time, in-situ measurements are not easily practicable due to the sample preparation and complex analysis instruments required. Therefore, the amount of available data is highly limited by these sampling requirements. Recent advances make laser spectroscopy a possible alternative to IRMS. The high temporal resolution and in-situ capabilities make it very attractive for airborne and ground based applications. We present results from a dual cavity system based on a laser operating at 1.63m currently under construction. One cavity contains the sample gas, the other a standard. We configure the system for Off-axis Integrated Cavity Output Spectroscopy (OAICOS), which is a very robust setup and overcomes the difficulties of coupling laser and cavity in more traditional cavity ringdown setups. A8.Detection of High temperature water vapor with VCSEL near 940 nm H. Koivikko, T. Laurila and R. Hernberg Optics Laboratory, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere, Finland In this work, we report on our investigation of the potential of VCSELs for detecting high temperature water vapor. Detection of high temperature water vapor is an attractive tool for monitoring combustion processes, since water vapor yields information on process performance and gas dynamic parameters. In sensor applications tunable diode laser spectroscopy is an acknowledged and sensitive method to detect and monitor gas components. Vertical cavity surface-emitting diode lasers (VCSELs) have many advantages over the traditional edge emitting diode lasers. VCSELs are easy to use, have good beam quality, large tuning range, narrow line width and they operate in a single mode. Despite these advantages, VCSELs have been rarely used for spectroscopic applications since they are available only in limited wavelength regions. The absorption of the laser beam as it propagates through the medium is described by the Beer-Lambert law  ,
where S is the line strength, is the line profile, P is the partial gas pressure and N is the molecular number density of the gas. Accurate room temperature line strengths can be obtained from the HITRAN database [1]. However, the database predicts poorly the high temperature behavior of the line strengths. Therefore, in order to achieve accurate concentration measurements at high temperature, experimental data is needed. We have determined high temperature line strengths for water vapor in combustion environment. VCSELs emitting near 940 nm were used as a light source. High temperature water vapor was produced in a hydrogen oxygen premixed flat flame. Temperature of the flame was changed by adjusting the fuel mixture. A dual-beam setup was used to account for the absorption due to the ambient air. The measurement setup was tested at room temperature and the obtained line strength values were in agreement with those from HITRAN. The obtained results for the high temperature line strengths agreed qualitatively well with the theoretical predictions. [1] L. S. Rothman et al., "The HITRAN molecular spectroscopic database and HAWKS (HITRAN ATMOSPHERIC WORKSTATION): 1996 edition", J. Quant. Spectrosc. Radiat. Transfer 60, 665-710 (1998). Directory: 2003 2003 -> Tr-41. 4-03-05-024 Telecommunications 2003 -> Review of some tsunamis in canada 2003 -> The skill of multi-model seasonal forecasts of the wintertime North Atlantic Oscillation 2003 -> 2930 Kerry Forest Parkway 2003 -> Canadian Interuniversity Sport (cis) Athletes of the Week 2003 -> Senior Airman Jason Plite Hometown 2003 -> Technical announcements: My apologies for the comparison pages; they were 2003 -> Pool Play Round 1 9: 20: 00 am 2003 -> 2004 Division II men's Golf Championships Final Round Results deland, fla 2003 -> Go Figure Edited by Kostya Kennedy and Mark Bechtel 645 Passing yards, an ncaa division II record, by University of Indianapolis quarterback Matt Kohn, in a 59-52 victory over Michigan Tech Download 1.65 Mb. Share with your friends:
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