FT-IRr and Quantum Cascade Laser Spectroscopy Towards a Hand-held Trace Gas Sensor for Benzene, Toluene, and Xylenes (BTX) PDF Download

Author: Christina Rachel Young
Publisher:
ISBN:
Category : Detectors
Languages : en
Pages :

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Author: Tomás Henrique Passos Pinto
Publisher:
ISBN:
Category : Laser spectroscopy
Languages : en
Pages : 188

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Author: Michael Telfer McCulloch
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: David Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This project was initially the continuation of a previous PhD students work. This changed slightly to incorporate the initial steps of development of a new system. However the main underlying focus was the absorption of infrared light by molecular gases using a still relatively new light source. This thesis will present the results of experimental work carried out during studies on the detection of gases and the nonlinear optical effects that arise from the absorption of light from a rapid frequency swept laser. A bench mounted two channel quantum cascade laser absorption spectrometer was used during experiments to observe and reduce nonlinear effects that arise from tuning the lasers during the absorption of light by several atmospherically important gases. These gases include the oxides of nitrogen (nitrous oxide, nitrogen dioxide and nitric oxide), methane and ammonia. The pulsed laser systems used as part of the spectrometer have also been put to use performing measurements on gaseous hydrocarbon combustion (methane and ethylene flames), to determine the feasibility of making measurements within the combustion zone of a jet engine and in conjunction with a continuous wave device during pump-probe experiments at the Chemistry Department of Oxford University. A portable four channel spectrometer was used at the beginning of the project to make measurements of the exhaust fumes of diesel powered vehicles. It will also cover the initial steps and tests performed in the early stages of development of a continuous wave quantum cascade laser based spectrometer for high speed detection of trace gases.

Author: Jagadeeshwari Manne
Publisher:
ISBN:
Category : Biotechnological process control
Languages : en
Pages : 298

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Author: F. T. Arecchi
Publisher: Springer Science & Business Media
ISBN: 1461337151
Category : Science
Languages : en
Pages : 500

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Author: Matthieu Baudelet
Publisher: Elsevier
ISBN: 085709873X
Category : Technology & Engineering
Languages : en
Pages : 601

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Laser spectroscopy is a valuable tool for sensing and chemical analysis. Developments in lasers, detectors and mathematical analytical tools have led to improvements in the sensitivity and selectivity of spectroscopic techniques and extended their fields of application. Laser Spectroscopy for Sensing examines these advances and how laser spectroscopy can be used in a diverse range of industrial, medical, and environmental applications. Part one reviews basic concepts of atomic and molecular processes and presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation. In addition, it explains the selectivity, sensitivity, and stability of the measurements, the construction of databases, and the automation of data analysis by machine learning. Part two explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media. These chapters discuss imaging methods using laser-induced fluorescence and phosphorescence spectroscopies before focusing on light detection and ranging, photothermal spectroscopy and terahertz spectroscopy. Part three covers a variety of applications of these techniques, particularly the detection of chemical, biological, and explosive threats, as well as their use in medicine and forensic science. Finally, the book examines spectroscopic analysis of industrial materials and their applications in nuclear research and industry. The text provides readers with a broad overview of the techniques and applications of laser spectroscopy for sensing. It is of great interest to laser scientists and engineers, as well as professionals using lasers for medical applications, environmental applications, military applications, and material processing. - Presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation - Explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media - Considers spectroscopic analysis of industrial materials and their applications in nuclear research and industry

Author: Paul Richie Black
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This thesis explains the development of a quantum cascade laser based gas sensor and the verification of performance of the resulting product. The capability to detect trace levels of multiple species in varying physical conditions, specifically high temperature is shown.Optical designs capable of allowing the measurement technique to be used in a variety of applications have been developed, specifically multi-pass gas absorption cells. The accurate, precise and high speed analysis of the resulting data is made possible by spectral analysis algorithms. These developments and techniques were then applied to high temperature spectroscopic measurements. Spectra recorded at Rutherford Appleton Laboratory were used to calibrate high temperature measurements. The performance of the technology was thoroughly tested at the National Physical Laboratory. The resulting sensors have since been used to study the exhaust gases produced by a variety engine types ranging from cars to ships as well as atmospheric measurements.

Author:
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ISBN:
Category :
Languages : en
Pages : 43

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We have developed a compact, robust, atmospheric trace gas detector based on mid-infrared absorption spectroscopy using pulsed quantum cascade (QC) lasers. The spectrometer is suitable for airborne measurements of ammonia, nitric acid, formaldehyde, formic acid, methane, nitrous oxide, carbon monoxide, nitrogen dioxide and other gases that have line-resolved absorption spectra in the mid-infrared spectral region. The QC laser light source operates near room temperature with thermal electric cooling instead of liquid nitrogen which has been previously required for semiconductor lasers in the mid-infrared spectral region. The QC lasers have sufficient output power so that thermal electric cooled detectors may be used in many applications with lower precision requirements. The instrument developed in this program has been used in several field campaigns from both the Aerodyne Mobile Laboratory and from the NOAA WP3 aircraft. The Phase II program has resulted in more than 10 archival publications describing the technology and its applications. Over 12 instruments based on this design have been sold to research groups in Europe and the United States making the program both a commercial as well as a technological success. Anticipated Benefits The development of a sensitive, cryogen-free, mid-infrared absorption method for atmospheric trace gas detection will have wide benefits for atmospheric and environmental research and broader potential commercial applications in areas such as medical diagnostic and industrial process monitoring of gaseous compounds. Examples include air pollution monitoring, breath analysis, combustion exhaust diagnostics, and plasma diagnostics for semi-conductor fabrication. The substitution of near-room temperature QC lasers for cryogenic lead salt TDLs and the resulting simplifications in instrument design and operation will greatly expand the range of applications.

Author: Wolfgang Demtröder
Publisher: Springer Science & Business Media
ISBN: 1468413422
Category : Science
Languages : en
Pages : 495

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Book Description
This volume contains the lectures and seminars presented at the NATO Advanced Study Institute on "Applied Laser Spectroscopy" the fourteenth course of the Europhysics School of Quantum Electronics, held under the supervision of the Quantum Electronics Division of the European Physical Society. The Institute was held at Centro "I Cappuccini", San Miniato, Tuscany, Italy, September 3-15,1989. The Europhysics School of Quantum Electronics was started in 1970 with the aim of providing instruction for young researchers and advanced students already engaged in the area of quantum electronics or wishing to switch to this area from a different background. Presently the school is under the direction of Professors F.T. Arecchi and M Inguscio, University of Florence and Prof. H. Walther University of Munich and has the headquarters at the National Institute of Optics (INO), Firenze, Italy. Each time the directors choose a subject of particular interest, alternating fundamental topics with technological ones, and ask colleagues specifically competent in a given area to take the scientific responsibility for that course.