Configuration – Source

Overview

The ‘Source’ tab contains the source, current and electronic lenses settings as shown below.

Source

In terms of hardware for the electron beam, the Cathode used for the Source could be either a W or LaB6 filament, or a Field Emission Gun (FEG). 

In the case of a filament, the only adjustable parameter is the ‘Standby Heat’. 

If a FEG source is present, then additional parameters such as the ‘Serial N° YPS-M20-Zr (Number)’ of the tip, the ‘Heat current (A)’, the ‘Extractor value (kV)’ and the ‘Suppressor value (V)’ need to be set.

Einzel Lens (EI)

The El sub-window contains numerical values for the voltage to be applied to the Einzel Lens with respect to the high voltage of the incident electron beam.

The ‘El theo (kV)’ parameter displays the theoretical voltage computed according to the type parameters. Note that after every tip exchange, one must click on ‘Reset’ to compute theoretical values of lens voltages (El) for each high voltage.

The lens voltage must be determined according to the SXFiveFE_New Tip Assembly.

The Einzel Lens voltages can be tuned anytime if the extractor voltage has changed. This is done by double-clicking on the text field.

C2

In the ‘C2’ (Condenser Lens) sub-window, C2 0, C2 1 and C2 2 are the three adjustable parameters. The first one and the last one correspond, respectively, to the minimum and maximum values to obtain the best beam current, based on a controlled close-loop beam current routine. The second listed parameter is the value used for maximizing the beam current based on the automatic gun alignment routine.

Current

It is in the ‘Current’ sub-window that the maximum beam current ‘I Max (nA)’ emitted by the tip is adjusted. The ‘I Tran (nA)’ current value, based also on a controlled close-loop routine is linked to the Einzel Lens voltage value only for SX-FIVE FE.