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B.Azmoun, S.Stoll Brookhaven National Lab. Transmittance: HBD East and West (Dec. 2008) HBD Meeting 12-16-08. Gas Flow Circuit. Anlz. Trans. HBD-W. HBD-E. Anlz. Trans. Anlz. Trans. Reproducibility/System stability. X-sections used for Fits. Transmittance. Calc. T =. Fitting Fcn.
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B.Azmoun, S.Stoll Brookhaven National Lab Transmittance: HBD East and West (Dec. 2008)HBD Meeting 12-16-08
Gas Flow Circuit Anlz Trans. HBD-W HBD-E Anlz Trans. Anlz Trans.
Transmittance Calc. T = Fitting Fcn.
Outlook/Conclusions • Still need to Measure Trans. of gas from aux. gas feed (Standalone Mode) gives measure of contaminants coming from trans. Monitor itself. (If contamination is coming from trans. Mon. itself, then why does input cell show zero absorbance?) • Compare gas scans performed when gas is purged through trans. cells for only 60min. before scan and for 1 full day before scan to ensure we purge long enough through cells before a scan is started. For the scans shown, gas only purged through the cells for 1hr. before start of scan. (Still doesn’t explain discrepancy btw water anlz. and trans.) • Perhaps absorbance in gas is neither due to O2 nor H2O, but is rather due to some unidentifiable substance this hypothesis reconciles the observed low levels of H2O given by the analyzers and the larger levels implied by the trans. scans • Interestingly, now that the O2 sensors have been replaced and calibrated, the O2 trans. and analyzer levels match up almost perfectly (as was the case two years ago); only the water levels are discrepant (water analyzers are new and can only be calibrated at factory) • Will perform scans in CF4 this week…is there a difference? • New CF4 bottles from Airgas show much larger O2 contamination (~7ppm) than the old Spectra bottles (~0ppm)