Metrohm NIRS XDS MasterLab Analyzer - Manual (Page 106)

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minutes, depending upon whether the instrument has been off, or if the transmission detector was
used previously. Once Vision shows the instrument as stable, proceed with tests.
8.1.1 Wavelength Linearization, Reflectance
Wavelength Linearization uses an internal wavelength material set to determine a set of internal,
arbitrary peak positions that the instrument will use to maintain repeatability of wavelength response.
The NIR wavelength positions
of these peaks appear as
shown.
The scale of this display is
marked in encoder pulses,
which do not relate to
nanometers directly.
From the peaks, a linearization
is performed, which allows
assignment of nanometer
values.
The “visible” portion of the
spectrum is similar. A
linearization is applied to this
portion of the spectrum.
Minor artifacts appear in these
raw spectra due to detector
crossover and other
spectroscopic reasons. After
linearization these artifacts are
minimal or not evident, some
being beyond the usable range
of the instrument.
These peak positions are not meant to be
traceable, as the true wavelength calibration
of the instrument is done on an external
standard, traceable to NIST.
The internal wavelength materials are used
to maintain the external wavelength
registration by use of software adjustment
for any external effects on the instrument.
Select Wavelength Linearization from the
Diagnostics menu. The instrument will scan
the ceramic reference.