A tunable diode laser absorption spectroscopy (TDLAS) sensor with a highly sensitive dual-component for methane (CH4) and acetylene (C2H2) detection is reported in this paper for the first time. A multi-pass cell (MPC) design model was established employing a vector-based ray-tracing method. A dual-channel MPC with an interlaced dual hexagonal star pattern was designed to improve gas absorption and realize real-time synchronous detection of CH4 and C2H2. During the simultaneous continuous monitoring of CH4 and C2H2, the sensor exhibited an excellent linear response to concentration variations. The minimum detection limit (MDL) for CH4 reached 132.08 ppb, improving to 77.32 ppb when the average time was increased to 300 s. In the case of C2H2, the MDL was measured at 20.19 ppb and further reduced to 3.50 ppb under the same extended average time.
Liang et al. (Sun,) studied this question.