1. Cantilever-enhanced photoacoustic measurement of light-absorbing aerosols
- Author
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Karhu, Juho, Kuula, Joel, Virkkula, Aki, Timonen, Hilkka, Vainio, Markku, and Hieta, Tuomas
- Subjects
Physics - Instrumentation and Detectors ,Physics - Atmospheric and Oceanic Physics - 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., Comment: 18 pages, 6 figures
- Published
- 2021