16 centimeters – that is all. It suffices to keep cryogenic samples at temperatures between minus 150 to almost minus 200 degrees Celsius. This size allows for easy integration in an electron microscope setup. Various types of sample holders can be connected to a tube the size of a little finger, which houses the cooler: a micro-fluidic chip made with lithography techniques. A small box fixed to the tube contains some tubing and enables mounting: no mechanical parts are involved. This means hardly any vibrations – vital for electron microscopy. The Kryoz cold-stage can be combined with a stage offering six degrees of freedom, enabling sample study from any angle.

The ‘secret’ of the cooler chip is that it allows for an expansion cycle of nitrogen gas through the chips’ channels without a compressor. A very important benefit is the temperature gradient over a tiny distance – from room temperature to almost minus 200 over mere centimeters. Only the sample area is cold, all surrounding hardware stays at environmental temperature.

The Kryoz cold-stage is operated with normal nitrogen bottles. The tiny flow makes the system frugal with gas. During non-stop operation, a bottle will last for a whole week.