Highly sensitive photoacoustic gas sensor with micro-embedded acoustic resonator for gas leakage detection

Abstract

In this work, a photoacoustic (PA) gas sensor with a micro-embedded acoustic resonator for gas leakage detection was demonstrated. The micro-embedded acoustic resonator was fabricated by putting a leaky hollow-core fiber (L-HCF) into a cylindrical buffer chamber. The L-HCF was utilized as the PA cavity and the light transmission media simultaneously. The optimal inner diameter of the L-HCF was 1.7 mm. The embedded acoustic resonator was experimentally proven to be equivalent to a T-type half-open acoustic resonator, but the structure became much more compact. The volume of the amount of gas in the cell was only ∼0.3 mL, and the gas diffusion time to fill the sensor under room temperature (25°C) and ambient pressure (101 kPa) was ∼44 s. Trace acetylene (C2H2) in pure nitrogen (N2) was chosen as the target gas, and the minimum detectable limit (MDL) reached 29 ppb when the lock-in integration time was 1 s. The normalized noise equivalent absorption (NNEA) coefficient was calculated to be 3.0 × 10−9 W·cm-1·Hz-1/2. The micro-resonant PA gas sensor, with merits of compactness, low gas consumption, and low cost, has the potential to be a remote gas sensing scheme in fields of environmental protection, industrial process monitoring, and so on.

A mini-resonant photoacoustic sensor based on a sphere-cylinder coupled acoustic resonator for high-sensitivity trace gas sensing

“…An Allan-Werle deviation [49] , [50] , [51] , [52] , [53] analysis has been performed to evaluate the detection limit of the sensor and long-term stability. When the temperature, the modulation current, and the modulation frequency of the laser are set to 25 ℃, 63.9 mA, and 2240 Hz, respectively, the WMS-2 f peak signals are continuously measured and recorded.…”

Silicon-Cantilever-Enhanced Single-Fiber Photoacoustic Acetylene Gas Sensor

“…However, TDLAS is easily affected by the power influence of the light source, and the actual detection accuracy is low [14]. Compared with these dissolved gas analysis methods, PAS has the advantages of no carrier gas, no frequent calibration, a small gas sample amount and high sensitivity, which is gradually replacing traditional dissolved gas analysis methods and has received widespread attention in recent years [15][16][17][18][19][20][21]. A different resonance principle and photoacoustic cells with different shapes were proposed.…”

High-Precision Photoacoustic Nitrogen Dioxide Gas Analyzer for Fast Dynamic Measurement

“…Photoacoustic (PA) spectroscopy (PAS) is one of the most promising methods for trace gas detection. − Compared with the methods mentioned above, PAS has the advantages of high sensitivity, fast response, and portability. − There are a number of PAS systems used to detect NO 2 . − Saarela et al used ten light-emitting diodes (LEDs) to excite the PA signal in NO 2 . The total optical power of the LEDs was 9 W. A detection limit of 10 ppb was achieved by using two pressure transducers with an acquisition time of 2.1 s. However, the divergence angle of the LEDs is approximately 100°.…”