Applied Biosystems Data Explorer 4 Series, User Manual

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Calibrating a PSD Spectrum
Data Explorer
™
Software User’s Guide 8-11
8
8.3.1 Checking Peak Detection
Checking
Before calibrating, check that peaks in all segment traces of
interest are properly peak detected and that noise is not
detected as peaks. Note the following when setting peak
detection parameters:
• Peak detection settings are applied to the currently
displayed composite spectrum or segment traces.
• The default peak detection settings (in
VOYAGERPSD.SET) have different detection ranges for
different mass ranges. You can fine tune ranges and
Filter Width settings in ranges to optimize detection. For
more information, see “Detection Ranges” on page 3-28.
• Fragment ion peaks in segments collected with lower
PSD Mirror Ratios are broader and include more data
points. Use a higher Filter Width setting for these
segments.
• Within a segment, resolution increases with increasing
mass, as the flight time of the fragment ions approaches
the flight time of the precursor. Use a lower Filter Width
setting for higher resolutions.
For more information, see Section 3.2, Peak Detection.
Smoothing
If a segment appears noisy, smooth the trace (for example,
use 25-point Gaussian smoothing) before calibrating.