Gas detection using an integrating sphere as a multipass absorption cell

Hawe, Eamonn; Dooly, Gerard; Chambers, Paul; Fitzpatrick, Colin; Lewis, Elfed

doi:10.1117/12.685113

Cited by 10 publications

(13 citation statements)

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“…We can use Eq. (12) to predict the response of the sphere at higher concentrations than were used experimentally. Figure 13 shows the response of the sphere extrapolated to a methane concentration of 100 vol.%, compared with the equivalent response for a conventional cell whose single path length is equal to the value of Z eff (1.252 m) calculated for the optimized model (see Table 2).…”

Section: Discussionmentioning

confidence: 99%

“…More recent work at the University of Limerick has resulted in broadband spectroscopic sensors for CO 2 (at 1.57μm and 2μm) [12] and NO 2 and SO 2 (in the UV/visible) [13] . Finally, a commercial non-dispersive infrared (NDIR) gas sensor designed by City Technology Ltd. takes the form of an integrating cavity, using deliberately roughened, gold coated internal surfaces [14] .…”

Section: Introductionmentioning

confidence: 99%

“…Our total experimental error results from the combined effects of a 0.3% error in our transmission reading and the error in the gas concentration. For the purpose of comparison, the latter has been transformed to an equivalent transmission error using Eq (12). and combined with the former to yield a total effective error of between 0.4% and 0.5% on the transmission data.Visual inspection reveals that the agreement between the simplified model and our experimental data is within our estimated experimental error.…”

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confidence: 99%

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Using integrating spheres as absorption cells: path-length distribution and application of Beer's law

2009

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We have modeled the path-length distribution in an integrating sphere used as a multipass optical cell for absorption measurements. The measured radiant flux as a function of analyte concentration is nonlinear as a result, deviating from that expected for a single path length. We have developed a full numerical model and introduce a new analytical relationship that describes this behavior for high reflectivity spheres. We have tested both models by measuring the optical absorption of methane at 1651 nm in a 50 mm diameter sphere, with good agreement with experimental data in the absorption range of 0-0.01 cm(-1). Our results compare well with previous work on the temporal response of integrating spheres.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Using integrating spheres as absorption cells: path-length distribution and application of Beer's law

2009

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“…Throughout the years, massive efforts have been directed towards improving detection limits by achieving long interaction pathlengths. Prominent examples include the use of conventional multipass gas cells [1][2][3][4], sophisticated high-finesse cavities [5][6][7][8], gas-filled holey fibers [9][10][11], integrating spheres [12][13][14], and diffusive reflectors [15,16]. Despite this rich flora of approaches, there is a continuous struggle to reduce size, gas volume, cost and alignment complexity.…”

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confidence: 99%

Disordered, Strongly Scattering Porous Materials as Miniature Multipass Gas Cells

Svensson

Adolfsson²,

Lewander

et al. 2011

Phys. Rev. Lett.

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We investigate the interaction of light and gas in strongly scattering nano- and macroporous media. Manufacturing and structural characterization of ZrO(2), Al(2)O(3) and TiO(2) ceramics with different pore sizes, measurements of optical properties using photon time-of-flight spectroscopy, and high-resolution laser spectroscopy of O(2) at 760 nm are reported. We show that extreme light scattering can be utilized to realize miniature spectroscopic gas cells. Path length enhancement factors up to 750 are reached (5.4 m path through gas for light transmitted through a 7 mm ZrO(2) with 49% porosity and 115 nm pores).

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“…where a(v) is the expected level of attenuation experienced by a optical radiation over a single pass through the sphere [11]. The multiplier is the average number of reflections a photon will undergo within the sphere.…”

Section: Integrating Sphere Theorymentioning

confidence: 99%

Hazardous gas detection using an integrating sphere as a multipass gas absorption cell

Hawe

Fitzpatrick

Chambers

et al. 2008

Sensors and Actuators A: Physical

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Gas detection using an integrating sphere as a multipass absorption cell

Cited by 10 publications

References 0 publications

Using integrating spheres as absorption cells: path-length distribution and application of Beer's law

Using integrating spheres as absorption cells: path-length distribution and application of Beer's law

Disordered, Strongly Scattering Porous Materials as Miniature Multipass Gas Cells

Hazardous gas detection using an integrating sphere as a multipass gas absorption cell

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