B1.4 A Humidity-independent Photoacoustic Sensor
- SMSI 2021
2021-05-03 - 2021-05-06
- SMSI 2021 - Sensors and Instrumentation
- B1 Gas Sensors I
- E. Ambra, G. Pang, C. Haish - Technical University of Munich, Munich (Germany)
- 109 - 110
Photoacoustic spectroscopy is routinely used to characterize absorption of gas and aerosols in various environments. To obtain accurate absorption measurements in atmospheric science, where variations in humidity exist, the photoacoustic signal’s dependence from relative humidity must be investigated in-depth. For this purpose, we used a resonant photoacoustic cell embedded with a piezoMEMS microphone, which is insensitive to humidity. We scanned the light modulation frequency around the theoretical resonance value and acquired the microphone signal through a lock-in amplifier. From the results, we can affirm that the overall photoacoustic sensor response is independent of the humidity parameter only if we consider the photoacoustic signal amplitude at the exact resonance frequency, which shifts with humidity.