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本文采用单一波长的 He—Ne(6328)和 He—Cd(4416)激光器组装成单束激光光声测量装置,并以Co的1—(2—吡啶偶氮)—2—萘酚(PAN)络合物的测定为例,探讨了固体激光光声光谱在痕量物质测定上的应用。经稳频切光器调制的激光束入射到密封在光声池中的样品时,样品吸收调制光.产生周期性加热。热传给周围气体,导致容器内气体按调制光的频率产生周期性的压力波动。用灵敏的微音器检测这种压力波动,并通过锁定放大器将音频电压信号放大测量,最后由X-Y函数记录仪记录。用这种装置试验了调制频率和激光功率对光声信号强度的影响;为了使样品分布均匀,以便获得更好的测量精度,还试验了层析硅胶、氧化铝和硫酸钡作为样品载体对光声测量的影响。在
In this paper, a single-beam laser photoacoustic measuring device is assembled with He-Ne (6328) and He-Cd (4416) single-wavelength lasers. Co- PAN) complex as an example, the application of solid-state laser photoacoustic spectroscopy in the determination of trace substances was discussed. When a laser beam modulated by a frequency stabilized chopper is incident on a sample sealed in a photoacoustic cell, the sample absorbs the modulated light, resulting in periodic heating. Heat is transmitted to the surrounding gas, resulting in periodic pressure fluctuations in the gas in the vessel at the frequency of modulated light. Detect this pressure fluctuation with a sensitive microphone and amplify the audio voltage signal with a lock-in amplifier and record it with the X-Y Function Recorder. The effect of modulation frequency and laser power on the photoacoustic signal intensity was tested with this device. In order to obtain uniform distribution of the sample in order to obtain better measurement accuracy, silica gel, alumina and barium sulfate were also tested as sample carriers for light Impact of acoustic measurements. in