Multivariate-coupled-enhanced photoacoustic spectroscopy with Chebyshev rational fractional-order filtering algorithm for trace CH detection.
Shenlong Zha, Hang Chen, Chen Liu, Yuxiang Guo, Hongliang Ma, Qilei Zhang, Lingli Li, Shengbao Zhan, Gang Cheng, Yanan Cao, Pan Pan
Author Information
Shenlong Zha: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Hang Chen: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Chen Liu: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Yuxiang Guo: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Hongliang Ma: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Qilei Zhang: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Lingli Li: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Shengbao Zhan: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
Gang Cheng: State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, China.
Yanan Cao: State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, China.
Pan Pan: School of Electronic Engineering and Intelligent Manufacturing, Anqing Normal University, Anqing, Anhui 246133, China.
An innovative and miniature photoacoustic spectroscopy (PAS) gas sensor based on a multivariate-coupled amplification photoacoustic cell (MVCA-PAC) with a total length of 100���mm was developed to achieve ultra-sensitive trace CH detection. Acoustic pressure distribution simulations reveal that at the first-order resonance frequency, the MVCA-PAC achieves a maximum acoustic pressure approximately 3.9 times higher than that of a conventional photoacoustic cell. The absorption optical path of the MVCA-PAC reached 2068���mm through 22 reflections, resulting in a 2-fold increase in the amplitude of photoacoustic signals compared to the traditional photoacoustic cell with an equivalent absorption optical path. Furthermore, compared to a single-pass photoacoustic cell, the signal intensity of the MVCA-PAC increased by a factor of 4.5. Allan variance analysis indicated a detection limit of 0.572���ppm for CH detection with an averaging time of approximately 300���s. To further improve the measurement precision of the designed sensor, the Chebyshev rational fractional-order filtering (CRFOF) algorithm was introduced for PAS signal processing for the first time. Post-processing results demonstrated a 15.4-fold improvement in measurement precision, achieving a precision of 0.578���ppm. Finally, continuous monitoring of atmospheric CH over a 48-hour period validated the reliability and feasibility of the sensor.
