Object stages for in situ examination
Several special purpose stages can be used for the 1172 and
1174 scanners. The stages are easily installed in place of
the standard specimen holder, and take control signals and
power from a small plug at the base of the sample stage mount.
These special stages are controlled by software independent
of the main scanner control program.
SkyScan's Micro-CT attachment contains several modules to
add a 3D imaging modality to any SEM without compromising
standard imaging modes. The attachment doesn't require any
changes to the standard SEM construction. The attachment can
be installed in any new SEM or retrofitted to old instruments.
The microscanner is supplied with a connection plate to fit
in to a JEOL instruments object manipulator.
MICRO-POSITIONING STAGE
 The
micro-positioning stage helps to achieve exact positioning
of small objects in the middle of the scanning field. Precise
object centering improves all aspects of scan quality, enabling
maximum magnification to be achieved and optimizing scan speed.
This positioning stage has 5mm travel in the X and Y directions,
and axial positioning is attained in a straightforward, user-friendly
procedure, by reference to projection images.
MATERIAL TESTING STAGE
 The
SkyScan Material Testing Stage allows the user to combine
micro-CT imaging with tensile and compression testing. During
scanning the sample is subjected to a controlled load, while
having the loading curve displayed on-screen in real time.
This material testing stage is specially designed for compression
and tension testing using an accurate load cell and displacement
sensor. The stage can be used in 2 modes: a continuous mode
for compression or tension up to the maximum allowable load
or until the maximum displacement; and a predefined mode in
which the user can specify either the load or the displacement
that should be reached. For compression the lower part of
the stage will be moved upwards, for tension downwards. The
loading curve is displayed on-screen in real time; units can
be changed; load/displacement or stress/strain curves can
be displayed and saved. The object can be held under a specific
loading for micro-CT scanning.
The accuracy of the measurement and resolution will be around
0.5% of the load cell’s full scale. This is an important figure
to bear in mind when choosing a load cell. The load cell’s
range should be higher than the load the specimen will be
exposed to. An “oversized” load cell will have a negative
effect on the system’s sensitivity.
- Load ranges: 42N, 210N, 440N
- Displacement sensor accuracy: ± 0.01mm
- Load measurement accuracy: ± 1% of the full range
- Maximum object diameter : 20mm
- Maximum travel: 5.5mm
- Max object height for compression: 23mm
- Max object length for tensile tests: 18mm
COOLING STAGE
 The
cooling stage keeps an object at a cooler-than-ambient or
sub-zero temperature during imaging and micro-CT scanning.
It contains a two-stage solid-state Peltier cooling system
which keeps object temperature at up to 35-40C below ambient
temperature. An internal microprocessor and a precision temperature
sensor provide feedback to the stage control program for temperature
stabilization during scanning at a pre-selected value, with
0.5C accuracy.
In the picture: left - a piece of ice inside the cooling
stage; right - a 3D rendering of an ice crystal scanned at
-22C, 5µm voxel size.
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