TY - JOUR

T1 - Signal Enhancement of a Differential Photoacoustic Cell by Connecting the Microphones via Capillaries

AU - Boyko, Andrey

AU - Lange, Birgit

AU - Eckert, Sebastian

AU - Mayorov, Fedor

AU - Brinkmann, Ralf

N1 - The research in this paper was funded by the European Union – Regional Development Fund (ERDF) and the Federal State Government of Schleswig-Holstein for the project “Cross-Innovation-Center-TANDEM Phase III (TANDEM III-CIC)” according to the guideline called “Richtlinie für die Gewährung von Zuwendungen zur Förderung von anwendungsorientierter Forschung, Innovationen, zukunftsfähigen Technologien und des Technologie- und Wissenstransfer (FIT-Richtlinie)” with application numer 124-20-003 and project number LPW-E/1.1.1/1521.

PY - 2024/4

Y1 - 2024/4

N2 - Differential photoacoustic spectroscopy (DPAS) cells are usually excited on the first longitudinal ring mode, with a microphone situated in the middle of each of the two resonator tubes. However, it is known from other photoacoustic spectroscopy cell designs that connecting the microphones via a capillary can lead to signal enhancement. By means of finite element method (FEM) simulations, we compared such a photoacoustic spectroscopy (PAS) cell with a capillary to a DPAS cell with a capillary attached to each of the two resonators and showed that the behavior of both systems is qualitatively the same: In both the PAS and the DPAS cell, in-phase and anti-phase oscillations of the coupled system (resonator–capillary) can be excited. In the DPAS cell, capillaries of suitable length also increase the pressure signal at the microphones according to the FEM simulations. For different capillary diameters (1.2 mm/1.7 mm/2.2 mm), the respective optimal capillary length (36–37.5 mm) and signal amplification was determined (94%, 70%, 53%). According to the results of these FEM simulations, a significant increase in sensitivity can, therefore, also be achieved in DPAS cells by expanding them with thin tubes leading to the microphones.

AB - Differential photoacoustic spectroscopy (DPAS) cells are usually excited on the first longitudinal ring mode, with a microphone situated in the middle of each of the two resonator tubes. However, it is known from other photoacoustic spectroscopy cell designs that connecting the microphones via a capillary can lead to signal enhancement. By means of finite element method (FEM) simulations, we compared such a photoacoustic spectroscopy (PAS) cell with a capillary to a DPAS cell with a capillary attached to each of the two resonators and showed that the behavior of both systems is qualitatively the same: In both the PAS and the DPAS cell, in-phase and anti-phase oscillations of the coupled system (resonator–capillary) can be excited. In the DPAS cell, capillaries of suitable length also increase the pressure signal at the microphones according to the FEM simulations. For different capillary diameters (1.2 mm/1.7 mm/2.2 mm), the respective optimal capillary length (36–37.5 mm) and signal amplification was determined (94%, 70%, 53%). According to the results of these FEM simulations, a significant increase in sensitivity can, therefore, also be achieved in DPAS cells by expanding them with thin tubes leading to the microphones.

KW - coupled acoustic resonators

KW - gas detection

KW - photoacoustic spectroscopy

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85190279050&origin=inward&txGid=63dac39d22c360d626373a71ab4c6c2e

UR - https://www.mendeley.com/catalogue/9c3839d7-5764-33c6-969e-b99672aa946a/

U2 - 10.3390/s24072105

DO - 10.3390/s24072105

M3 - Article

C2 - 38610317

VL - 24

JO - Sensors

JF - Sensors

SN - 1424-3210

IS - 7

M1 - 2105

ER -