126
Thermo Fisher Scientific
Operation Manual HM550
Freezing-on the
specimen
e specimen is frozen-on to the specimen chuck with clinging groves
by means of a freezing medium.
To freeze-on specimens, use the fast freezing device or the active deep
freezing device on the left side of the chamber.
When using the fast freezing device put some freezing compound onto
the specimen stage, which should be outside the chamber at a low posi-
tive temperature. en put the specimen onto the stage and surround it
with some freezing compound. Please note that the frozen tissue re-
mains connected with the freezing medium and the chuck.
en insert the specimen stage into one of the fast freezing stations.
e standard version is equipped with a fast freezing station with 12 sta-
tions. A cryostat with option P has an active deep freezing device with
eight freezing stations and another four stations with Peltier element.
Start the function “Fast freezing of standard instruments” in due time
before freezing-on the specimen. It will take the deep freezing device
approx. 2 - 3 min. to achieve a temperature of max. -60°C.
If the instrument is equipped with a heat extractor (additional equip-
ment) the specimen can be frozen faster and more evenly. Put the
pre-cooled heat extractor onto the specimen from above. is way,
the specimen is frozen at the same time from above and below, which
reduces the formation of artifacts considerably.
Clamp the specimen chuck together with the frozen specimen into the
specimen holder.
For this loosen the orienting lever (standard version) and/or spring-
loaded eccentric lever (version with option O) and insert the chuck into
the specimen clamping. To loosen the chuck, turn the eccentric lever.
Loosen the clamping lever to have the possibility to adjust the specimen
parallel in relation to the cutting edge. Afterwards, press the clamping
lever to the rear.
To position the chuck parallel in relation to the knife, please use the
zero device of the specimen clamp, i.e. the specimen clamping together
with chuck and specimen latches noticeably into the zero position.
Afterwards, clamp the specimen clamping via the clamping lever. e
chuck is now in a parallel position with regard to the knife.
After this orientation, now set the cutting/suction window. Please note
that the lower cutting window limit corresponds with the upper edge of
the specimen.
Orientation and
trimming of specimens
Working with the cryostat
Freezing on the specimen
