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Improving the Detection Limit in a Capillary Raman System for In Situ Gas Analysis by Means of Fluorescence Reduction

Rupp, Simone; Off, Andreas; Seitz-Moskaliuk, Hendrik; James, Timothy M.; Telle, Helmut H.

Raman spectroscopy for low-pressure or trace gas analysis is rather challenging, in particular in process control applications requiring trace detection and real-time response; in general, enhancement techniques are required. One possible enhancement approach which enjoys increasing popularity makes use of an internally-reflective capillary as the gas cell. However, in the majority of cases, such capillary systems were often limited in their achievable sensitivity by a significant fluorescence background, which is generated as a consequence of interactions between the laser light and optical glass components in the setup. In order to understand and counteract these problems we have investigated a range of fluorescence-reducing measures, including the rearrangement of optical elements, and the replacement of glass components--including the capillary itself--by metal alternatives. These studies now have led to a capillary setup in which fluorescence is practically eliminated and substantial signal enhancement over standard Raman setups is achieved. With this improved (prototype) setup, detection limits of well below 1 mbar could be obtained in sub-second acquisition times, demonstrating the potential of capillary Raman spectroscopy for real-time, in situ gas sensing and process control applications, down to trace level concentrations.

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DOI: 10.5445/IR/1000049762
DOI: 10.3390/s150923110
Zitationen: 10
Web of Science
Zitationen: 9
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Theoretische Physik (ITP)
Institut für Technische Physik (ITEP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2015
Sprache Englisch
Identifikator ISSN: 0746-9462
KITopen-ID: 1000049762
HGF-Programm 51.03.01 (POF III, LK 01)
Erschienen in Sensors
Band 15
Heft 9
Seiten 23110-23125
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Schlagwörter Raman spectroscopy; capillary; gas analysis; process control; real-time monitoring; instrument development; fluorescence reduction
Nachgewiesen in Web of Science
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