Bomem-GRAMS User's Guide
Bomem-GRAMS User's Guide
Bomem-GRAMS User's Guide
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Chapter 4<br />
The Collect Menu<br />
g Spectra are acquired over<br />
the full spectral range unless<br />
specified otherwise in the<br />
Save Option parameter.<br />
• Acquisition type determines the type of data acquisition that will be used.<br />
Background: reference spectra<br />
Normal: normal spectra<br />
Kinetic: multifiles<br />
• Spectral Range Start and End define the displayed spectral region. g<br />
• General Param allows setting the following parameters:<br />
Initial Delay: delay in seconds before any scans are acquired.<br />
Number of Scans: number of scans to be averaged (coadded) together.<br />
Note: A scan is defined as a forward and a reverse sweep of the scan<br />
mechanism. Therefore, a single scan will result in two<br />
interferograms. The interferograms for forward sweeps and<br />
reverse sweeps are not combined, they are averaged separately.<br />
The forward and reverse sweep information is combined during<br />
the transformation from interferograms to spectra after the phase<br />
correction.<br />
• Use Auto Gain: When selected, determines the optimal gain setting using<br />
the first scan acquired.<br />
h When the Acquisition type is<br />
Kinetic, the gain is<br />
recalculated for each sub-file.<br />
The ZPD must be as close as possible to the maximum allowed ZPD without<br />
exceeding it. After the gain is determined, all scans are acquired using this<br />
gain setting. h All spectra are normalised with respect to the gain used so that<br />
they can be compared directly without scaling.<br />
The actual gain selected can be observed in real time with the Instrument<br />
Status and Control command (see Section 4.1.4 on page 27). The gain used<br />
is also stored in the resulting spectrum file in the audit log (see Appendix C<br />
on page 45).<br />
i When the Data type is<br />
transmittance or absorbance,<br />
a single beam file is also<br />
saved.<br />
• File Name indicates the name under which the files will be saved. This name<br />
can have a maximum length of 144 characters. The extension of the file is<br />
determined automatically and will depend on the type of data acquisition<br />
used. i The extension of the file will be one of the following:<br />
.interferogram.spc<br />
.background.spc<br />
.single beam.spc<br />
.transmittance.spc<br />
.absorbance.spc<br />
<strong>Bomem</strong>-<strong>GRAMS</strong> <strong>User's</strong> <strong>Guide</strong> 25
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