Manual Calibration
5.3.2 Manually Calibrating
This section describes:
•Before calibrating Voyager data
•Manually calibrating a single spectrum
•Applying new constants to the data file
•Exporting calibration constants (.CAL file)
•Applying new constants to additional files
Before you calibrate Voyager data, do the following to improve mass accuracy:
•Baseline correct— The Centroid% peak detection value is derived from a percentage of the peak height, which is measured from 0 (not from the local baseline). For information, see Section 5.8.2, Using Baseline Correction.
•Noise filter or use default smoothing— Use the method appropriate for your data to remove noise spikes. For more information, see Section 5.7, Noise Filtering/Smoothing.
It is critical to perform both these functions, which affect the peak centroid, before calibration. It is also good practice to perform the same processing functions on calibrants and unknowns.
NOTE: If you are calibrating Mariner data, baseline correction and noise filtering or smoothing are not recommended before calibrating. Due to the shorter flight times and fewer data points associated with Mariner data, these functions may affect peak shape, which in turn affect mass accuracy.
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