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5 First Operating Steps | 5.6 Finding Appropriate Detector Settings
ZEISS
5.6.7 Using the Variable Stage Bias
5.6.7.1 Setting up the Beam Deceleration for BSD Imaging
Beam deceleration is mostly used when imaging specimens with BSE detectors. By means of stage
biasing, a negative potential is applied to the specimen. This reduces the electron beam’s landing
energy, which enables you to obtain more specimen surface detail, especially at low magnifica-
tions. At high magnifications, you can obtain better image resolutions. The effectiveness strongly
depends on the specimen type. For metallic specimens, image improvements can easily be
achieved.
Beam deceleration can only be applied in HV mode. A potential in the range of 0 to −5 kV is used.
If the EHT voltage is set to 5 kV and a stage bias potential of −4 kV is applied, the landing energy
of the primary electrons is reduced to 1 kV.
The beam deceleration kit is mounted through a plate on the chamber door. A specially designed
specimen holder is generally used. This is to isolate the specimen holder, i.e. the bias is only ap-
plied to the specimen.
Fig. 41: Beam deceleration kit (left) and 9-stub beam deceleration specimen holder (middle and right)
CAUTION
Risk of electrical shock by stage on bias voltage
If you open the chamber door while the stage is still on bias voltage, then contact may cause
electrical shock.
4
Always switch off the beam deceleration before you open the chamber door.
NOTICE
Touch alarm disabled
When beam deceleration or stage bias is activated, the stage touch alarm is automatically de-
activated. A warning is displayed to inform you that the touch alarm is not enabled. This
means that any stage collisions will not be detected.
4
Move the stage carefully.
Prerequisite
ü
The stage has been initialized before fitting the beam deceleration specimen holder.
ü
HV mode is active.
ü
The beam deceleration specimen holder is fitted.
Procedure
1. In the
Stage Navigation Bar
, click
Settings
.
INFO:
To open the
Stage Navigation Bar
, navigate to
View > Toolbars
and activate
Stage Navigation Bar (for Widescreen users)
. Alternatively, you can access the
Stage
Navigation Bar
via
Stage > Navigation
.
à
The
Stage Navigation Settings
dialog is displayed.
2. Activate the
Safe Navigation
checkbox.
3. In the
Stage Navigation Settings
dialog, click
Sample Holder Gallery
.
88
Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006
Summary of Contents for EVO
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