A theoretical-experimental framework for the analysis of the dynamic response of a QEPAS tuning fork device immersed in a fluid medium

Campanale, Angelo; Putignano, Carmine; Carolis, Simone De; Patimisco, Pietro; Giglio, Marilena; Soria, Leonardo

doi:10.1016/j.ymssp.2020.107298

Cited by 6 publications

(1 citation statement)

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“…Apart from theoretical considerations of a tuning fork immersed in a liquid medium [12] and using a QTF to optically analyse solid samples with so-called light-induced thermoelastic spectroscopy (LITES) [13], there are currently no studies of QEPAS on solid or liquid samples. To our knowledge, we performed the first QEPAS measurements on a solid sample and designed a special cell for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Quartz Enhanced Photoacoustic Spectroscopy on Solid Samples

Falkhofen,

Bahr,

Baumann

et al. 2024

Sensors

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Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) is a technique in which the sound wave is detected by a quartz tuning fork (QTF). It enables particularly high specificity with respect to the excitation frequency and is well known for an extraordinarily sensitive analysis of gaseous samples. We have developed the first photoacoustic (PA) cell for QEPAS on solid samples. Periodic heating of the sample is excited by modulated light from an interband cascade laser (ICL) in the infrared region. The cell represents a half-open cylinder that exhibits an acoustical resonance frequency equal to that of the QTF and, therefore, additionally amplifies the PA signal. The antinode of the sound pressure of the first longitudinal overtone can be accessed by the sound detector. A 3D finite element (FE) simulation confirms the optimal dimensions of the new cylindrical cell with the given QTF resonance frequency. An experimental verification is performed with an ultrasound micro-electromechanical system (MEMS) microphone. The presented frequency-dependent QEPAS measurement exhibits a low noise signal with a high-quality factor. The QEPAS-based investigation of three different solid synthetics resulted in a linearly dependent signal with respect to the absorption.

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Section: Introductionmentioning

confidence: 99%