Comparison of TALIF and catalytic probes for the determination of nitrogen atom density in a nitrogen plasma afterglow

摘要: The density of neutral nitrogen atoms in a glass reactor was measured by two absolute methods: two-photon absorption laser induced fluorescence (TALIF) and catalytic probes. source N plasma created quartz tube surfatron microwave generator operating at 2.45 GHz adjustable output power up to 300 W. TALIF measurements were performed using dye which pumped YAG laser. At the exit laser, beam frequency doubled through KDP crystal then mixed BBO crystal. wavelength chosen 206.65 nm so suitable excite from ground state 5d 2D state. Absolute determined calibration with krypton. Simultaneously, atom fiber optics probe (FOCP) well-activated iron tip. Measurements both methods flows between 0.2 2 l min−1, discharge powers 60 rather high flows, increased monotonically increasing power, while lower flow saturation observed. showed somewhat higher values than FOCP attributed accuracy methods. main advantage is broader detection range, an extremely simple inexpensive technique.