Open photoacoustic sensor as smoke detector

Keller, A.; Ruegg, Michael; Förster, Martin; Loepfe, M.; Pleisch, R.E.; Nebiker, P.W.; Burtscher, H.

doi:10.1016/j.snb.2004.03.013

Cited by 50 publications

(31 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2, 3, 4, 5, and 6. It is clearly visible that a cell of such dimensions (ducts 100 mm long and 1 mm in diameter, buffers of 250 cm 3 ) is characterized by a signal-to-noise ratio much better than in the case when only one of the dimensions is optimal. When comparing a cell with 'optimal' dimensions to an open cell presented in [7] and [27], the signal-to-noise ratio is greater by almost 60 dB (Fig.…”

Section: Modeling Resultsmentioning

confidence: 99%

“…To amplify the signal, the acoustic resonance of the chamber may be used. There are a number of open windowless cells reported in the literature, and in most cases, signal amplification is based on the standing wave resonances [1][2][3][10][11][12][13][14]. Such cells are usually of relatively large volumes, so their applications are strongly limited.…”

Section: Open Photoacoustic Helmholtz Cellmentioning

confidence: 99%

“…This is due to the fact that they allow for straightforward gas or liquid exchange between the cell and the environment, what simplifies measurement instrumentation and processes [1][2][3]. The consequence of opening the cell to the environment is that along with the gas, external acoustic noise penetrates the cell's interior.…”

Section: Introductionmentioning

confidence: 99%

“…The consequence of opening the cell to the environment is that along with the gas, external acoustic noise penetrates the cell's interior. This is not crucial in the case of smoke detectors, when the amount of absorbent is significant, and the induced photoacoustic signal is strong [3]. The A. Geras (B) Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland e-mail: antonina@geras.pl problem arises when there is a demand for sensing low concentrations of a substance.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Signal-to-Noise Analysis of the Improved Open Photoacoustic Helmholtz Cell

Geras

2014

Int J Thermophys

View full text Add to dashboard Cite

Open photoacoustic cells are often used in continuous-flow photoacoustic measurements. Such cells are sensitive to external noise penetration. The improved open photoacoustic Helmholtz cell has much better external noise attenuation than the previously known designs. This paper describes how mechanical dimensions of such a cell influence its signal-to-noise ratio. The analysis was performed by means of computer simulations based on the loss-improved transmission line model. This research showed that the mechanical parameters affect signal-to-noise noticeably and, if they are properly chosen and applied in the design of the improved open cell, the resulting signal-to-noise ratio may be improved by almost 60 dB in comparison to previous designs of open photoacoustic Helmholtz cells.

show abstract

Section: Modeling Resultsmentioning

confidence: 99%

Section: Open Photoacoustic Helmholtz Cellmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Signal-to-Noise Analysis of the Improved Open Photoacoustic Helmholtz Cell

Geras

2014

Int J Thermophys

View full text Add to dashboard Cite

show abstract

“…(a) the resonance frequency change can be calculated from the measured temperature [8], (b) inside the cell, there is a speaker [9][10][11] which is used to determine the frequency response of the cell. The PA resonance frequency can be either directly measured or calculated from another mode since the ratio between modes is constant for the same cell [12], (c) the resonance frequency can be determined by estimating maximum amplitude based on the amplitude response obtained by:…”

Section: Introductionmentioning

confidence: 99%

The Tracking Resonance Frequency Method for Photoacoustic Measurements Based on the Phase Response

Suchenek

2017

Int J Thermophys

View full text Add to dashboard Cite

One of the major issues in the use of the resonant photoacoustic cell is the resonance frequency of the cell. The frequency is not stable, and its changes depend mostly on temperature and gas mixture. This paper presents a new method for tracking resonance frequency, where both the amplitude and phase are calculated from the input samples. The stimulating frequency can be adjusted to the resonance frequency of the cell based on the phase. This method was implemented using a digital measurement system with an analog to digital converter, field programmable gate array (FPGA) and a microcontroller. The resonance frequency was changed by the injection of carbon dioxide into the cell. A theoretical description and experimental results are also presented.

show abstract

Direct Absorption and Photoacoustic Spectroscopy for Gas Sensing and Analysis: A Critical Review

Fathy

Sabry

Hunter

et al. 2022

Laser & Photonics Reviews

View full text Add to dashboard Cite

Optical spectroscopy has a broad scientific basis in chemistry, physics, and material science, with diverse applications in medicine, pharmaceuticals, agriculture, and environmental monitoring. Fourier transform infrared (FTIR) spectrometers and tunable laser spectrometers (TLS) are key devices for measuring optical spectra. Superior performance in terms of sensitivity, selectivity, accuracy, and resolution is required for applications in gas sensing. This review deals with gas measurement based on either direct optical absorption spectroscopy or photoacoustic spectroscopy. Both approaches are applicable to FTIR spectroscopy or TLS. In photoacoustic spectroscopy, cantilever-based photoacoustic spectroscopy is focused due its high performance. A literature survey is conducted revealing the recent technological advances. Theoretical fundamental detection limits are derived for TLS and FTIR, considering both direct absorption and photoacoustic spectroscopies. A theoretical comparison reveals which technology performs better. The minimum normalized absorption coefficient and normalized noise equivalent absorption coefficient appear as key parameters for this comparison. For TLS-based systems, direct absorption spectroscopy is found to be the best for lower laser power and longer path length. For FTIR-based systems, direct absorption is found to be the best for low temperature sources, higher spectrometer throughput, faster mirror velocity, and longer gas cells.

show abstract

Open photoacoustic sensor as smoke detector

Cited by 50 publications

References 13 publications

Signal-to-Noise Analysis of the Improved Open Photoacoustic Helmholtz Cell

Signal-to-Noise Analysis of the Improved Open Photoacoustic Helmholtz Cell

The Tracking Resonance Frequency Method for Photoacoustic Measurements Based on the Phase Response

Direct Absorption and Photoacoustic Spectroscopy for Gas Sensing and Analysis: A Critical Review

Contact Info

Product

Resources

About