FEI Quanta FEG 250, User'S Operation Manual

Page: 170 / 228

System Options: Cooling Stage / Waterless Cooling Stage
9-22
FIGURE 9-19 COOLING STAGE ASSEMBLY
• The mounting adapter enables to attach the Cooling stage to the
microscope stage.
• The Cooling stage base holds the thermoelectric module and the
specimen holder with the use of a thermal grease. Water hoses
and the inner cable are connected permanently to the base.
• The thermoelectric module is a small wafer composed of PN
semiconductor layers. When current passes through these
elements, one side of the wafer heats and the opposite one cools.
Reversing the polarity switches cold and hot sides. This is referred
to as the
Peltier effect .
• The thermistor is placed near the sample (inside of the Specimen
holder – a plate into which the Sample holder is inserted), thus
giving accurate temperature readings.
• The Delrin cover keeps the entire assembly together.
• The cooling stage comes with different Sample holders , which are
used for various sample types (see consumables below).
– The Flat holder should be used for flat samples (sheets,
powders, etc.). It can also be used for bulk samples up to 4 mm.
– The Dual cup holder is reversible. It has a shallow cup on one
side (for powders, tiny particles, or beads). A larger cup on the
other side should be used for thick liquids, and bulk samples
between 4 mm and 8 mm.
– The Deep cup holder should be used for all other liquids and bulk
samples larger than 8 mm.
– The Wet STEM holder could fit the sample grid for a STEM
observation.
Note:
All of the sample holders have a groove cut beneath the cup
bottom. This allows a condensation to escape from beneath the
holder, so that the liquid do not force the sample holder out from
the specimen holder.