Carbon dioxide monitoring is significant in the environmental field since this gas plays an important role in the greenhouse effect. In order to determine CO2 concentration and to develop simulation models, it is necessary to carry out measurements which are accurate and comparable in time and space, i.e. SI-traceable. Non-dispersive infrared (NDIR) analysers are employed for CO2 measurements, as they are precise and stable. In order to achieve traceability, such instruments have to be characterized and calibrated. At the Istituto di Metrologia "G. Colonnetti"--CNR, a procedure for calibrating NDIR analysers for CO2 at atmospheric level was developed, which enables to calculate a correction for the analyser output. In addition, a complete uncertainty analysis was carried out and a correct traceability chain was established. The goal of the present work is the study of the stability of a NDIR analyser by repeating calibrations during three years and comparing the correction curves obtained to identify a proper re-calibration interval for such analysers. The investigated instrument has good repeatability and reproducibility, hence satisfactory stability during time, as shown by the short-term and long-term compatibility of calibration curves.
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Micromachines (Basel)
September 2024
School of Information Science and Engineering (ISE), Shandong University, Qingdao 266237, China.
A carbon dioxide (CO) gas sensor based on non-dispersive infrared (NDIR) technology has been developed and is suitable for use in portable devices for high-precision CO detection. The NDIR gas sensor comprises a MEMS infrared emitter, a MEMS thermopile detector with an integrated optical filter, and a compact gas cell with high optical coupling efficiency. A dual-ellipsoid mirror optical system was designed, and based on optical simulation analysis, the structure of the dual-ellipsoid reflective gas chamber was designed and optimized, achieving a coupling efficiency of up to 54%.
View Article and Find Full Text PDFRev Sci Instrum
August 2024
Key Laboratory of Micro/nano Devices and Systems, Ministry of Education, North University of China, Tai Yuan 030051, China.
Sensors (Basel)
June 2024
State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Co., Ltd., Beijing 100088, China.
Increasing concerns about air quality due to fossil fuel combustion, especially nitrogen oxides (NO) from marine and diesel engines, necessitate advanced monitoring systems due to the significant health and environmental impacts of nitrogen dioxide (NO). In this study, a gas detection system based on the principle of the non-dispersive infrared (NDIR) technique is proposed. Firstly, the pyroelectric detector was developed by employing an ultra-thin LiTaO (LT) layer as the sensitive element, integrated with nanoscale carbon material prepared by wafer-level graphics technology as the infrared absorption layer.
View Article and Find Full Text PDFSensors (Basel)
January 2022
Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
Automobile exhaust gases, such as carbon dioxide (CO), carbon monoxide (CO), and propane (CH), cause the greenhouse effect, photochemical smog, and haze, threatening the urban atmosphere and human health. In this study, a non-dispersive infrared (NDIR) multi-gas detection system consisting of a single broadband light source, gas cell, and four-channel pyroelectric detector was developed. The system can be used to economically detect gas concentration in the range of 0-5000 ppm for CH, 0-14% for CO, and 0-20% for CO.
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August 2021
Photonics Research Group, INTEC, Ghent University-Imec, Technologiepark 126, 9052 Gent, Belgium.
In this paper, we present a fully integrated Non-dispersive Infrared (NDIR) CO sensor implemented on a silicon chip. The sensor is based on an integrating cylinder with access waveguides. A mid-IR LED is used as the optical source, and two mid-IR photodiodes are used as detectors.
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