Metrohm NIRS XDS SmartProbe Analyzer - Manual (Page 62)

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The OpQual tab brings up the display shown. This shows results of the Noise Test for each of the four
wavelength regions. These regions are:
• 400-700nm
• 700-1100nm
• 1100-1700nm
• 1700-2500nm
For each region, results are given for
• Peak-to-Peak Noise (P-P)
• Root-Mean-Square Noise (RMS)
• Bias (A measure of baseline energy changes)
Each of these parameters is described in more detail in the Diagnostics Section of the Vision Manual.
If the test is reported as “Passed” the user may proceed with sample analysis.
The XDS instrument contains internal wavelength reference materials, which are used as a means to
maintain monochromator wavelength measurement. These internal wavelength materials are
protected and are moved by software command, transparent to the user. When Performance Test is
run, the relative wavelength positions and repeatability of these wavelength materials are monitored
and reported.
Note that these internal wavelength materials need not be precisely on the assigned nominals. These
nominals are arbitrary. The internal wavelength materials are a method to assure stable readings on
the external wavelength standard, measured at the sample plane.
Increasing noise in Performance Test may indicate a gradually failing lamp. Performance Test is very
sensitive to any optical changes in the instrument, including noise caused by lamp issues. Be sure the
instrument is warmed up, then run the test again. If it continues to fail, consider a lamp change to
remedy the problem.
7.2.2 Wavelength Certification
Wavelength Certification is used to confirm the peak positions of the instrument to a defined,
external wavelength standard.
Click on Diagnostics,
Wavelength Certification, Run
Wavelength Certification.