Low noise, open-source QEPAS system with instrumentation amplifier

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Electronics Engineering

Background:

• Quartz Enhanced Photoacoustic Spectroscopy (QEPAS) is an ultrasensitive trace gas sensing technique.
• System performance in QEPAS relies heavily on adequate electronic amplification matched to quartz characteristics.

Purpose of the Study:

• To present an open-source electronic circuit designed for QEPAS signal amplification.
• To evaluate the performance of the developed circuit compared to traditional methods.

Main Methods:

• The proposed circuit integrates a buffer, an instrumentation amplifier, and a digitally controlled gain stage.
• Experimental comparison with a commonly used transimpedance amplifier was conducted.

Main Results:

• The open-source circuit achieved a signal-to-noise ratio approximately 23 dB better than the transimpedance amplifier.
• This improvement demonstrates the potential for enhancing QEPAS sensitivity.

Conclusions:

• The developed open-source circuit offers a significant advancement for QEPAS systems.
• The circuit has the potential to improve QEPAS sensitivity by an order of magnitude, enabling more precise trace gas detection.