Small-Size Resonant Photoacoustic Cell of Inclined Geometry for Gas Detection

TL;DR

This paper presents a compact, inclined-geometry photoacoustic cell designed for efficient trace gas detection, featuring background cancellation and environmental isolation, with demonstrated high sensitivity in prototype experiments.

Contribution

The paper introduces a novel small-sized resonant photoacoustic cell with inclined geometry that enhances detection performance and reduces size compared to existing designs.

Findings

Effective cancellation of window background noise.

Achieved minimal detectable absorption of ~1.2×10^{-8} cm^{-1} W Hz^{-1/2}.

Demonstrated high sensitivity in prototype experiments.

Abstract

A photoacoustic cell intended for laser detection of trace gases is represented. The cell is adapted so as to enhance the gas-detection performance and, simultaneously, to reduce the cell size. The cell design provides an efficient cancellation of the window background (a parasite response due to absorption of laser beam in the cell windows) and acoustic isolation from the environment for an acoustic resonance of the cell. The useful photoacoustic response from a detected gas, window background and noise are analyzed in demonstration experiments as functions of the modulation frequency for a prototype cell with the internal volume ~ 0.5 cm^3. The minimal detectable absorption for the prototype is estimated to be ~ 1.2 10^{-8} cm^{-1} W Hz^{-1/2}.