Operating Procedures: Optimizing Imaging
5-12
User Manual
C O N F I D E N T I A L –
limited rights
Feb 2018
Revision A
Direct Adjustments
This control page serves for fine-tuning the beam geometry to achieve the best focus and brightness.
Electron Beam tab
•
Source Tilt
2D box – serves for correction of signal intensity by
changing the effective angle of the beam coming from the
source into the electron column.
Move the crosshair in order to get the electron beam spot into
the display center.
•
Clicking the
Auto
button sets the Source Tilt automatically.
•
In the
Crossover
mode (activated with the button), the image
shows the electron source position instead of the sample surface.
•
Crossover Zoom
slider – set the Crossover image magnification.
•
Lens Alignment
2D box – optimizes the primary beam passage
through the final lens so that image shift during focusing is
suppressed.
Try to minimize the image shift by the crosshair movement.
•
Lens Modulator
(useful for HV > 3 kV) /
HV Modulator
(useful
for HV
3 kV) button – starts automatic objective current /
accelerating voltage oscillation (periodically under- and over-focuses imaging in a narrow range) to facilitate the
above mentioned optimization.
When the accelerating voltage is above 3 kV, Lens Modulator
is automatically selected, otherwise the HV Modulator is. You
can choose either one manually.
•
Amplitude
slider – sets the modulation amplitude.
Electron Stigmator Centering tab
•
Stig. Center X
/
Y
2D box – serves for minimization of image
shift during astigmatism correction. The crosshair indicates
the actual stigmator setting.
Try to minimize the image shift by the crosshair movement.
•
Modulator X
/
Y
button – starts automatic modulation of the
respective stigmator to enable the stigmator centering
procedure. Modulation occurs in a narrow range around the
current stigmator setting.
•
Amplitude
slider – sets the modulation amplitude.
Electron Focus tab
•
Focus Centering
2D box – serves for minimization of image
shifting during focusing if HV
3 kV. It is a complementary
function to Lens Alignment and it is not applied for HV > 3 kV.
Try to minimize the image shift by the crosshair movement.
•
Modulator
button – starts modulation of the corresponding
electron optical components to enable the focus centering
procedure.
•
Amplitude
slider – sets the modulation amplitude.
•
Apply Focus Centering
check box – if selected, the result of the
focus centering procedure is applied.