User`s guide

Chapter 5 Optimizing Instrument Settings
5-42 PerSeptive Biosystems
5
Potential gradient The potential gradient in the ionization region (Figure 5-8) is
determined by the voltages applied to the sample plate
(Accelerating Voltage) and the variable-voltage grid (Grid
Voltage%).
Figure 5-8 Sample Plate and Grids
Sample
plate Accelerating
Voltage at 25,000 V
Variable-voltage
grid at % of
Ground
grid
Ionization
region
Potential
gradient
Accelerating Voltage
Ion source
2.8 mm
Potential
gradient
=
Accelerating Voltage - Grid Voltage
Distance between plate and grid
Grid
voltage
= (Grid Voltage%)(Accelerating Voltage)