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arXiv · 2106.12389

Cantilever-enhanced photoacoustic measurement of light-absorbing aerosols

Juho Karhu·Joel Kuula·Aki Virkkula·Hilkka Timonen·Markku Vainio·Tuomas Hieta
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Abstract

Photoacoustic detection is a sensitive method for measurement of light-absorbing particles directly in the aerosol phase. In this article, we demonstrate a new sensitive technique for photoacoustic aerosol absorption measurements using a cantilever microphone for the detection of the photoacoustic signal. Compared to conventional diaphragm microphones, a cantilever offers increased sensitivity by up to two orders of magnitude. Here we reached a noise level of 0.013 Mm$^{-1}$ (one standard deviation) with a sampling time of 20 s, using a simple single-pass design without a need for a resonant acoustic cell. We demonstrate the method in measurements of size-selected nigrosin particles and ambient black carbon. Due to the exceptional sensitivity, the technique shows great potential for applications where low detection limits are required, for example size-selected absorption measurements and black carbon detection in ultra clean environments.

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Juho Karhu, Joel Kuula, Aki Virkkula, Hilkka Timonen, Markku Vainio, Tuomas Hieta. 2021-06-23. Cantilever-enhanced photoacoustic measurement of light-absorbing aerosols. https://arxiv.org/abs/2106.12389

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