Leica EM CPD300, Operating Manual

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Page 39 Operating Manual EM CPD300 12/18
8.8 Heating the Sample Chamber
Press the HEAT button and wait until sample chamber is heated up to 35 °C. The
cooling unit automatically keeps the temperature of the pressure chamber at 35

C.
With the rising temperature the pressure in the sample chamber also increases as
shown on the display.
At the time the critical temperature and the critical pressure (31 °C and 73,8 bar for
CO
2
) have been passed, the liquid CO
2
is transformed into the supercritical status.
The system will stop at 35 °C and 79 bar to be safe on the supercritical state. The
change of the physical state can be observed through the front viewing glass.
8.9 Releasing gaseous CO
2
from Sample Chamber
After reaching the supercritical status, choose the GAS-OUT speed (slow, medium or
fast) and press the GAS-OUT button. The temperature will be constant at 35 °C only
when the valve is opening to release the CO
2
, which will change the physical status
from supercritical to gaseous due to the pressure decrease under constant
temperature.
9. Removing Dried Specimen
Close the shut-off valve of the CO
2
bottle.
Open the screw-on cover of specimen sample chamber.
Remove specimen holder with dried specimen from sample chamber for further
processing.
Since the dried specimen is highly hygroscopic, it has to be coated as quickly as
possible with a thin metal- or carbon film to protect it from atmospheric humidity.
If this is not possible, it is recommended to keep the specimen in a desiccator until it
is processed further.
10. Switching off the Unit
Leave the sample chamber open. Leave the CO
2
bottle closed.
Switch off the main switch located on the unit.