Kryostat

To achieve the physics program of Nucleus we plan to use a newest-generation dry dilution refrigerator, which can be operated strictly without the use of cryogenic liquids such as liquid He and N (except for the limited amount of the He3/He4 mixture). Such a system is the absolute requirement for the use in the special environment of a nuclear power reactor. Special emphasis is put on the low-noise aspects of the system, in particular on the decoupling of the vibrational noise induced by the pulse-tube cooler. Ultimately, an advanced decoupling of pulse-tube and the Nucleus cryogenic detectors is needed to reach our physics goals. Further, we require a system that is fully automated and allows a maintenance-free operation over the time scale of 1 year or more. The subject of this procurement procedure is the award of a supply contract for a dry dilution refrigerator for Nucleus.