Thermonicolet Omnic Software User's Guide 6.1 (PDF) - Charles E ...

To specify or do this...
The number of scans to collect.
The spectral resolution of the data.
The Y-axis format of collected data.
The correction type to use.
Automatically suppress the effects of water
vapor and carbon dioxide.
Check the performance of the spectrometer at the
start of data collection.
A description of the experiment.
Save spectra automatically.
Save interferograms with spectra.
The base name for saving spectra automatically.
Whether and when to collect a background
spectrum or use a stored background.
The title of the experiment.
Set this parameter...
Number Of Scans
Resolution
Final Format
Correction
Automatic Atmospheric
Suppression
Preview Data Collection
Experiment Description
Save Automatically
Save Interferograms
Base Name
Background Handling
Experiment Title
The Estimated Time For This Collection item (if available for your spectrometer)
shows how long the data collection will take. The time is displayed in
hours:minutes:seconds. The total collection time is determined by the number of
scans collected and the resolution.
The Data Spacing item indicates the distance between adjacent data points in the
collected spectrum in wavenumbers. The data spacing is determined by the
settings of resolution and zero filling (set on the Advanced tab).
Specifying the
number of scans
Number Of Scans determines how many scans are performed during a data
collection. If you perform more than one scan, the system averages all of them.
The number of scans, along with the resolution and mirror velocity, affects the
total collection time. For a given resolution, increasing the number of scans
increases the total collection time.
Increasing the number of scans reduces the noise level of the data (increases the
signal-to-noise ratio) and increases the sensitivity; that is, the ability to distinguish
small peaks from noise. However, if you have already collected a large number of
scans, it will take many more scans to achieve a significant increase in sensitivity.
Optimize the Number Of Scans setting whenever you analyze a new type of sample
or use a new sampling technique or accessory. If you’re not sure how long to scan,
start by collecting 16 scans and then measure the signal-to-noise ratio. This will give
an indication of how many scans to collect for the desired results.
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