Traceable amount of substance fraction measurements in gases through infrared spectroscopy at PTB

Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

^a volker.ebert@ptb.de

Abstract

Gas analysis has become an important task in various fields of science and industry, especially through techniques based on laser spectroscopy. Common applications are, for example, the monitoring of the atmosphere to assess human impact on ecosystems and the climate, the monitoring of airborne molecular contamination to supervise sensitive high-tech processes like semiconductor manufacturing, or the analysis of combustion processes. High resolution laser spectroscopy lends itself particularly well for gas analysis, as it is fast, selective, and the results can be made traceable to the SI units. Traceability is of particular importance to maximize the reliability of measurement results, especially if such measurements are the input for complicated models like those used in climate research or if impacting political decisions. In this contribution we give an overview on our approach to achieve traceability of results from spectroscopic amount fraction measurements of H₂O, CO₂, and NH₃ including the TILSAM method (traceable infrared laser-spectrometric amount fraction measurement). We discuss how this method applies to tunable diode-laser absorption spectroscopy (TDLAS), cavity ring-down spectroscopy (CRDS), and photoacoustic spectroscopy (PAS). This research is partly embedded in projects within the European Metrology Research Programme (EMRP).