Method for cooling an object with the aid of superfluid helium (He II) and apparatus for implementing the method

An apparatus for cooling a substrate which has a cooling conduit provided with an inlet and an outlet, comprising

• a means containing a closed He II circuit comprising first, second and third heat-exchangers being in flow communication with one another;
• a housing containing a helium II heating bath of a fountain effect pump,
• a housing containing a helium II re-cooling bath having an inlet,
• a vessel containing helium,
• a pressure equalizing conduit,
• a housing containing a helium II supply bath, and
• a superfilter of a fountain effect pump;
• said first heat-exchanger being positioned in the re-cooling bath and connected to the inlet of the cooling conduit of the substrate to be cooled;
• said second heat-exchanger being positioned in the heating bath of the fountain effect pump and having its inlet connected to an outlet of the cooling conduit of the substrate to be cooled.
• said third heat-exchanger being positioned in the re-cooling bath and having an inlet of said third heat-exchanger connected to an outlet of the second heat-exchanger and an outlet of said third heat-exchanger opened up into the supply bath which is in flow communication with, and supplies helium II to, said superfilter of the fountain effect pump;
• and
• said vessel containing helium and said helium supply bath being in flow communication with one another by means of the pressure equalizing conduit.