Abstract Cavity ringdown spectroscopy CRDS has been applied

Abstract Cavity ringdown spectroscopy (CRDS) has been applied to two areas: trace gas monitoring of NOx intermediates in flames and early fire sensing by detecting small changes in CO, CO 2, C 2 H 2, and HCN concentrations. NOx emission into the atmosphere results in acid rain, ground level ozone, and other environmental and health problems. Increased knowledge of NOx intermediates and reaction mechanisms in flames may help foster new ideas for controlling NOx emissions from industries, vehicles, and other toxic gas emitters, thus creating a healthier environment. Early detection of fires is a major concern for high value facilities, commercial aircraft, and commercial buildings. Using CRDS as a fire sensor, very small changes in fire gases can be detected, providing increased time for fire rescue. Detecting four gases simultaneously could also provide information to responders such as location, nature, and fuel of the fire. Using CRDS, concentration measurements of HCN and C 2 H 2 have been obtained from multiple flame systems, including a methane flame doped with a nitrogen-containing fuel (pyridine). It was determined that HCN significantly increases in a pyridine-doped flame compared to a pure methane flame. In a test facility at NIST, a CRDS sensor monitored concentrations of CO, CO 2, C 2 H 2, and HCN near-simultaneously as multiple fuels were burned. The CRDS sensor observed increased concentrations of all four of these gases faster compared to commercial fire alarms detecting the fire.

This Week • Labview program for ATI is working • Collected CO 2 spectra for width fitting – 60 Torr Absorbance, cm-1 FWHM ~ 0. 018 cm-1 Wavenumber, cm-1

Next Week • Flame sampling for HCN in methane neat? • Work on C program to control CRDS for ATI