Leica CM1950 Manuel D’Utilisation
42
Operating Manual V 1.1 – 05/2007
8.
Working with the Instrument
8.4
Working with the Precooled Cryostat
8.4.1 Preparatory Work
•
Lock the handwheel in the top (12 o’clock) position.
•
Cut the specimen to size outside of the cryostat.
•
Select the precooled specimen disc, cover it with freezing compound,
then attach and orient the specimen.
then attach and orient the specimen.
•
Attach the specimen disc and specimen to the Peltier position on the
freeze shelf. Activate the Peltier element and wait until the specimen is
completely frozen.
freeze shelf. Activate the Peltier element and wait until the specimen is
completely frozen.
Specimens that have been frozen on the Peltier element are often
too cold and split apart during sectioning. Allow time for the speci-
mens to become acclimated.
too cold and split apart during sectioning. Allow time for the speci-
mens to become acclimated.
•
Insert the specimen disc into the specimen head.
•
Fold the anti-roll guide away and to the side. Insert a precooled knife or
blade.
blade.
Before using them for the first time, degrease new knives using
acetone or alcohol.
acetone or alcohol.
•
Approach the specimen with the knife or blade holder:
•
To do so, open the clamping lever of the base, approach the
specimen and close the lever again.
specimen and close the lever again.
•
Open the lever of the orientation. Orient the specimen (move it into
a favorable position relative to the knife/blade) and close the lever again.
a favorable position relative to the knife/blade) and close the lever again.
•
Approach the knife or blade holder using the coarse feed buttons and
gentle movements of the handwheel.
gentle movements of the handwheel.
If the sections are cracked, the specimen head temperature is too
cold. Set a warmer temperature.
cold. Set a warmer temperature.
If the sections smear, the specimen head temperature is too warm.
Set a colder temperature.
Set a colder temperature.