The CNES expertise laboratory aims to develop remote solutions for the physicochemical characterization of contaminants that can be used at system integration sites. These tailor-made portable instruments would enable operators to conduct rapid and non-invasive pre-analyses to determine the appropriate course of action if molecular or particulate contamination were to impede the proper integration of a system. Currently, we are focusing on two characterization methods: a fluorescence spectral spotting method (Fig. 1), and a FTIR spectral spotting method (Fig. 2).
A preliminary spectrofluorescence and FTIR bench for proof of concept enabled us to conduct initial measurements to fine-tune the settings effectively. The first method involves exciting a contaminated area under UV-C using an exciter fiber and collecting the fluorescence flux using a collecting fiber connected to a spectrometer (Fig. 3). The second method involves conducting FTIR measurements using a single fiber for both excitation and collection (Fig. 4).
The specificity of these techniques enables operators to pinpoint a point of interest on a sensitive surface to gather the fluorescence or infrared spectrum of a contaminant for comparison with a pre-existing spectrum database. Both methods were tested on epoxy and silicone contaminants. We varied the concentration to determine the detection threshold based on distance and acquisition time.