Comparison of Photoacoustic Behaviors between Helmholtz Cell and its Remodified One

Abstract

This paper presents method and performance of the Helmholtz photoacoustic resonant cell and its remodified one which both were designed and tested respectively based on the measurement of the CO2 contribution of the photoacoustic signal in experiments. The average optical power at the laser operating point was 800mW for the10.653um laser (CO2 detection). On-line and real time measurement CO2/N2 mixtures (CO2 300ppm) were then performed. The Helmholtz photoacoustic resonant cell and its remodified one test of the carbodioxide conducted at their respective resonant frequency demonstrated signals about 43mV and 67mV, signal-to-noise (S/N) values about 47dB and 51dB respectively. According to test results, the remodified one also has a better quality factor. All this demonstrate the remodified Helmholtz cell can preferably improve excitation of acoustical signal.