Interchangeable Range of Ozone Concentration Simulation for Low Cost Reconfigurable Brass Gas Cell

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Tay Ching En Marcus ◽  
Michael David ◽  
Maslina Yaacob ◽  
Mohd Rashidi Salim ◽  
Mohd Haniff Ibrahim ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
Ozone Concentration ◽  
Path Length ◽  
Low Cost ◽  
Cell Structure ◽  
Optical Path Length ◽  
Optical Path ◽  
Concentration Measurement ◽  
Gas Cell ◽  
Wide Range

Ultraviolet absorption spectroscopy is reliable for ozone concentration measurement. Concentration range and optical path length are inversely related based on theoretical calculation and observation of previous work. However, gas cells for ozone application are typically not expandable. In addition, they incur cost for custom fabrication. Here we design a reconfigurable brass gas cell that may interchange optical path length between 5.6 cm and 10.8 cm. Components are available at low cost, easy to joint and ready to use. Theoretical background and gas cell structure are discussed. Practical transmittance values between e-0.65 and e-0.05 are proposed for theoretical calculation of concentration via Beer-Lambert law. The concentration values are used in SpectralCalc.com gas cell simulation to obtain transmittance. Both approaches yield comparable result. Simulation result shows concentration range of 5.6 cm optical path length gas cell (31.82 ppm to 413.67 ppm) is wider than concentration range of 10.8 cm optical path length gas cell (16.50 ppm to 214.49 ppm). Simulation condition is at transmittance from 0.5291 to 0.9522, sampling wavelength 253.65 nm, temperature 300 K and pressure 1 atm. Thus, we strongly recommend short optical path length gas cell (5.6 cm) for wide range of concentration measurement (31.82 ppm to 413.67 ppm).

Doubled Optical Path Length for Photonic Bandgap Fiber Gas Cell Using Micromirror

2011 ◽  
Vol 50 (6) ◽  
pp. 06GM01 ◽  
Author(s):  
Xuefeng Li ◽  
Jinxing Liang ◽  
Hiroshi Oigawa ◽  
Toshitsugu Ueda
Keyword(s):  
Path Length ◽  
Photonic Bandgap ◽  
Optical Path Length ◽  
Optical Path ◽  
Gas Cell ◽  
Photonic Bandgap Fiber

Low cost and miniaturized NDIR system for CO2 detection applications

Sensor Review ◽  
2020 ◽  
Vol 40 (6) ◽  
pp. 637-646
Author(s):  
Mohammad Makhdoumi Akram ◽  
Alireza Nikfarjam ◽  
Hassan Hajghassem ◽  
Mohammad Ramezannezhad ◽  
Massoud Iraj
Keyword(s):  
Curve Fitting ◽  
Path Length ◽  
Low Cost ◽  
Experimental Tests ◽  
Optical Path Length ◽  
Optical Path ◽  
Practical Situation ◽  
Entrance Angle ◽  
Content Type ◽  
Simulation Results

Purpose The importance of Carbon dioxide (CO2) gas detection as a greenhouse and exhale breathe gas is an undeniable issue. This study aims to propose a new miniaturized, low cost and portable no dispersive infrared (NDIR) system for detecting CO2 gas. Design/methodology/approach Poly(methyl methacrylate) (PMMA)-based channels with Au coating because of its high reflection properties in IR region were used in this work. The optical windows were fabricated using PDMS polymer which is cost effective and novel in comparison to other conventional methods. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed with four types of channel using both simulation and experimental tests. Findings The simulation results indicate that the 0 degree light entrance angle is the most efficient angle among different investigated conditions. The experimental data are in agreement with the simulation results regarding the loss and optical path length in different types of channel. The experimental tests were performed for the 0.5% up to 20% of CO2 concentration under constant temperature and humidity condition. The results show that the device with 5  and 2 cm channels length were saturated in 4% and 8% concentration of CO2 gas, respectively. Response and recovery times were depending on gas concentration and channels specifications that in average found to be 10 S and 14 S, respectively, for the largest size channel. Moreover, the environment humidity effect on detection system performance was investigated which had no considerable influence. Also, the saturation fraction absorbance value for devices with various dimensions were 0.62 and 0.8, respectively. Practical implications According to the performed curve fitting for practical situation and selected CO2 concentration range for experimental tests, the device is useful for medical and environmental applications. Originality/value PMMA with Au deposition layer was used as a basic material for this NDIR system. Besides, a novel PDMS optical window helps to have a low cost device. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed using both simulation and experimental tests. Using narrowband optical filter (100 nm bandwidth) helps to have a system with good CO2 selectivity. In addition, experimental tests with different channel dimensions and lengths covered a considerable range of CO2 concentration useful for medical and environmental applications. Finally, curve fitting was adopted for a modified Beer–Lambert law as a practical situation.

Infrared Absorption Coefficients for Certain Pollutant Gases

1972 ◽  
Vol 26 (3) ◽  
pp. 372-378 ◽  
Author(s):  
P. Campani ◽  
C. S. Fang ◽  
H. W. Prengle
Keyword(s):  
Infrared Spectroscopy ◽  
Quantitative Analysis ◽  
Path Length ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Optical Path Length ◽  
Optical Path ◽  
Absorption Coefficients ◽  
Wide Range ◽  
Pollutant Gases

Quantitative analysis of gas mixtures by infrared spectroscopy requires a knowledge of the absorption coefficients,: kν−, as a function of optical path length and temperature. For the majority of pollutant gases, information is scarce or incomplete. The objective of this work was to determine absorption coefficients for CH4, C2H4, CO2, CO, SO2, NO2, NO, and H2S. Measurements were made at room temperature and elevated temperatures for certain wave lengths, and kν− was determined over a very wide range of optical path length, x. The validity of the Bouguer-Beer law was confirmed for a limiting range of x, and for larger values of x, kν− decreased and was correlated as a function of x and T.

Incident Angle Approach to Sensitivity Enhancement for Ozone Sensor

2015 ◽  
Vol 735 ◽  
pp. 255-259
Author(s):  
Michael David ◽  
Tay Ching En Marcus ◽  
Maslina Yaacob ◽  
Mohd Rashidi Salim ◽  
Nabihah Hussin ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Light Source ◽  
Path Length ◽  
Incident Angle ◽  
Optical Path Length ◽  
Sensitivity Enhancement ◽  
Optical Path ◽  
Internal Diameter ◽  
Gas Cell ◽  
Optical Gas Sensor

The design and mathematical model of a reflective type optical gas sensor is presented. Light source is radiated at an incident angle for 10 cm gas cell with an internal diameter of 0.4 cm. At an incident angle of 1o, optical path length obtained is 342.7886 cm, at 27o incident angle, optical path length is 10.4926 cm and at an incident angle of 28o, optical path length is 9.9631 cm. The model is most efficient at lower incident angles, precisely between (1o and 27o). Effects of variation in diameter and length of gas cell are also demonstrated.

scholarly journals Optical Path Length Calibration: A Standard Approach for Use in Absorption Cell-Based IR-Spectrometric Gas Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Javis Anyangwe Nwaboh ◽  
Oliver Witzel ◽  
Andrea Pogány ◽  
Olav Werhahn ◽  
Volker Ebert
Keyword(s):  
Absorption Spectroscopy ◽  
Path Length ◽  
Line Strength ◽  
Optical Path Length ◽  
Comparison Method ◽  
Optical Path ◽  
Infrared Light ◽  
Strength Parameter ◽  
Gas Cell ◽  
System Of Units

We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is a priori known and desirably traceable to the international system of units (SI), and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.

Doubled Optical Path Length for Photonic Bandgap Fiber Gas Cell Using Micromirror

2011 ◽  
Vol 50 (6S) ◽  
pp. 06GM01 ◽  
Author(s):  
Xuefeng Li ◽  
Jinxing Liang ◽  
Hiroshi Oigawa ◽  
Toshitsugu Ueda
Keyword(s):  
Path Length ◽  
Photonic Bandgap ◽  
Optical Path Length ◽  
Optical Path ◽  
Gas Cell ◽  
Photonic Bandgap Fiber
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