Metrohm NIRS XDS Process Analyzer – DirectLight/NonContact - Manual (Page 87)

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11.3 Interactance Reflectance Purge on the Tip Probe
The Interactance Reflectance Purge on the Tip
Probe is quite similar to the Interactance
Reflectance Probe. It uses the same type of fiber
bundle with concentric light paths. Please see the
section Interactance Immersion Probe on page 15.
11.4 Transmission Probe
11.4.1 XDS PA Microbundle
The Transmission Probes require special methods
of calibration. One fiber bundle carries “white
light” from the instrument to the sample. The
other fiber bundle is used to return light to the
instrument, to be broken down in the
monochromator to individual wavelengths, then
measured for spectral response. Absorbance of the
sample is then determined.