
Optimizing Instrument Settings Parameters
Voyager
™
Biospectrometry
™
Workstation User’s Guide 5-63
5
DE parameters
Improved resolution in Delayed Extraction technology is
achieved by velocity-focusing ions. See “Velocity focusing” on
page 1-15, for more information.
Two instrument settings parameters affect the velocity-
focusing of ions in Delayed Extraction:
• Delay Time—Time in nanoseconds (after the laser
ionizes the sample) at which full Accelerating Voltage is
applied, creating the potential gradient that accelerates
ions.
• Grid Voltage%—Voltage applied to the variable-voltage
grid located above the sample plate. Grid Voltage is a
percentage of Accelerating Voltage.
For a list of Delay Time and Grid Voltage% pairs, see
Appendix E, Grid Voltage% and Delay Time Settings.
Optimum resolution for a given mass range is obtained by
finding the ideal Delay Time and Grid Voltage% combination
for the mass range.
NOTE: Although Guide Wire Voltage% does not affect velocity
focusing of ions, it has a strong impact on resolution in
Reflector mode and sensitivity in all modes. See
Section 5.4.3.3, Optimizing Guide Wire Voltage%.
Relationship
between DE
parameters
Delay Time and Grid Voltage% are interactive parameters. For
each Delay Time there is an optimum Grid Voltage%, and for
each Grid Voltage% there is an optimum Delay Time.
Linear mode
For each optimum Delay Time and Grid Voltage%
combination, there is a sharp optimum in Linear mode
performance. Over a wider mass range, performance is less
optimized.
Reflector mode
For each optimum Delay Time and Grid Voltage%
combination, the mass range across which resolution is
optimized is wider in Reflector mode.
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