Reid J, Shewchun J, Garside B K, Ballik E A
Appl Opt. 1978 Jan 15;17(2):300-7. doi: 10.1364/AO.17.000300.
A laser absorption spectrometer is described which employs a wavelength-tunable Pb(1-x) Sn(x) Se diode in conjunction with a multipass White cell and which is capable of measuring SO(2) concentrations in the low ppb range. We describe in some detail the modulation techniques used in signal detection which enable us to measure absorption coefficients as low as 10(-7) m(-1). In addition, calibration of the instrumentation using small sample cells is described, and the question of interference from unwanted molecular species is discussed. The instrumentation allows the measurement, basically at the same time, of a large number of other atmospheric gases which are of significance in pollution studies. For example, the present diode operates over 1050-1150 cm(-1) and can measure SO(2), O(3), N(2)O, CO(2), H(2)O, NH(3), and PAN. The addition of a second diode to the system will allow most gases of any atmospheric importance to be monitored. In general, these gases have much stronger ir absorption bands than SO(2) and hence can be detected at concentrations much less than 1 ppb.
描述了一种激光吸收光谱仪，它采用波长可调谐的Pb(1-x)Sn(x)Se二极管与多程怀特池相结合，能够测量低至十亿分比范围的SO₂浓度。我们详细描述了信号检测中使用的调制技术，这些技术使我们能够测量低至10⁻⁷ m⁻¹的吸收系数。此外，还描述了使用小型样品池对仪器进行校准的方法，并讨论了来自不需要的分子种类的干扰问题。该仪器基本上可以同时测量大量在污染研究中有重要意义的其他大气气体。例如，目前的二极管在1050 - 1150 cm⁻¹范围内工作，可以测量SO₂、O₃、N₂O、CO₂、H₂O、NH₃和PAN。在系统中添加第二个二极管将能够监测任何具有大气重要性的大多数气体。一般来说，这些气体的红外吸收带比SO₂强得多，因此可以在远低于1 ppb的浓度下被检测到。
