Fig. 1. H₂S absorption line simulation

Fig. 2. Optical path simulation (a) and structure simulation (b) of high temperature long path cell

Fig. 3. Measuring device schematic diagram (a) and photograph (b)

Fig. 4. Software interface diagram home page (a) and settings interface (b)

Fig. 5. Schematic diagram of automatic temperature and pressure control

Fig. 6. Linear relationship between H₂S concentration and 2f signal amplitude

Fig. 7. Measurement photo (a) and on-line measurement results (b) of a pigging station in eastern Sichuan region