User`s guide

Optimizing Instrument Settings Parameters
Voyager
™
Biospectrometry
™
Workstation User’s Guide 5-79
5
5.4.4.4 Setting Shots/Spectrum
Overview A higher number of Shots/Spectrum can improve
signal-to-noise ratio, and also improve the dynamic range of
the acquisition. However, acquiring a higher number of
Shots/Spectrum increases acquisition time and file size.
When random noise is present in a spectrum, the
improvement in signal-to-noise ratio is approximately
proportional to the square root of the number of
Shots/Spectrum taken.
Manually
accumulating to
override limit
The maximum number of Shots/Spectrum is determined by
the digitizer on your system (see “Shots/Spectrum” on
page 5-19). You can acquire a greater number of
Shots/Spectrum than the maximum number of
Shots/Spectrum noted above by manually accumulating
spectra. For more information, see Section 6.2.2, Manually
Accumulating Spectra from Multiple Acquisitions.
5.4.4.5 Setting Low Mass Gate
Description Low Mass Gate suppresses matrix peaks that can interfere
with ion detection which can saturate the detector as laser
intensity increases. This saturation effect is less pronounced
on systems with Linear High Current Detectors. For serial
numbers of systems that include High Current Detectors, see
page 1-23 and page 1-36.
The detector is not turned on until ions greater in mass than
the mass you enter pass the detector.
NOTE: When Low Mass Gate is enabled, the mass range
below the Low Mass Gate starting mass is still detected, but
detector sensitivity below this mass is decreased by 100 to
1,000 fold. If strong matrix signal is present below the Low
Mass Gate, you can use it for calibration if desired.