This system has been has been developed for the specialized field of cryobiology where extremely accurate temperature and position of the sample, as well as cooling rates of up to 5000°C/min are required. The MDBCS196 is the ultimate in cryomicroscopy.
High speed quench cooling is acheived by moving the sample from a copper 'warm post' onto a pre-cooled block, at high speeds.
Because the speed can be varied from 5 to 5000µm/s it is possible to observe the effect of crystallisation at extremly high cooling rates. The position of the sample holder is viewed graphically in a separate software window and can be moved from the post to the aperture in the block by simply clicking the graphic. This method of high speed cooling is even faster than submersing the sample in liquid nitrogen and has enabled cryobioligists to closely investige vitrification phenomena.
The silver block is of a similar construction to the BCS196 but has its cooling pipes at 180° to each other. This reduces the flow of liquid nitrogen needed to cool the block and minimises any vertical movement of the block due to temperature change. Further stability measures have been taken with the design of the sample holder, a very low linear expansion coefficent sample carrier made from invar, ensures that temperature change has no effect on horizontal sample position. This stability is critical to Confocal microscopy and high magnifaction standard microscopy.
Liquid nitrogen is injected directly into the block by the LNP94/2 cooling pump automatically controlled by the TMS94 temperature programmer. Temperature feedback is provided by a class A pt100 platinum resistor to give <0.01s response time.
Recycled nitrogen gas is used to purge the stage of moisture and prevent condensation hence enable the capture of clear highly resolved images.
For seeding a cold spot has been provided on one of the cooling pipes allowing nucleated freezing to be initiated