Thermal conductivity gas sensor based on LiNbO/sub 3/ SAW resonators

摘要: A new thermal conductivity detector based on a lithium niobate surface acoustic wave (SAW) resonator has been fabricated for use in gas chromatograph. The device exploits the large temperature coefficient of LiNbO/sub 3/ to detect low concentrations CO/sub 2/ air by sensing change helium carrier and exiting capillary chromatograph column. is maintained at 150 degrees C held close proximity (0.2-0.3 mm) exit column which 50 C. Heat loss from primarily due such that changes constituency result resonator. monitored recording resulting frequency 342-MHz SAW resonator-controlled oscillator circuit. entire system small, battery powered, can monitor greenhouse gases remote field sites throughout world. >