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The set of very tough requirements has been formulated for TF jacket materials with extremely high plasticity at liquid helium temperature. The stainless steel 316LN-IG is recommended to be used for TF jacket tubes. Samples of 316LN-IG tubes (whole tubes and sub-size samples) made of the material from the same electro slag remelt have been tested in different conditions -as received tubes and tubes after prescribed compaction, 2.5% deformation at room temperature and heat treatment at 650 0 C, 200 hours. The tensile tests were carried out at room, liquid nitrogen and liquid helium temperatures down to 4.2 K, meeting corresponding ASME and ASTM requirements. The low temperature testing devices are described. The tests results for sub-size samples and whole tubes show that the latter tests are considerably more representative and important for butt weld qualification at LHe temperature. It was observed that the ferromagnetic properties of all samples and especially of butt welds increase with lowering the temperature and increasing the degree of deformation. At LHe temperature a non-uniform and highly localized serrated deformations were observed.

The article describes the development, fabrication, and test results of a double pancake сoil made using second-generation high-temperature superconductors (HTSC-2G). The HTSC-2G coil is the key element of the cryomagnetic system intended for use as part of an experimental research setup for remotely controlling the expression of neurons by means of constant and low-frequency (up to 100 Hz) magnetic field. This project is a continuation of works [1] carried out on the integrated topic “Electronic Components and Neuromorphic Ccontrol Systems”, which includes, as a constituent part, the development and fabrication of an HTSC-2G cryomagnetic system for studying neuron activity under the effect of external magnetic field. A distinctive feature of the project is the use of a cryomagnetic system with a low energy consumption achieved owing to the use of modern HTSC materials. This will open the possibility to continuously observe the object under study from the start of its exposure to magnetic field to the occurrence of reaction signs. The technology for winding a double pancake HTSC-2G coil is developed and described. For making the coil, an HTSC-2G wire in polyamide varnish insulation was used. The technology of making inner junctions in double pancake HTSC-2G coils with a transition resistance of less than 120 nΩ at 77 K has been developed and successfully tried out. The results from preliminary tests of the HTSC-2G coil in liquid nitrogen are presented.

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Abstract. Design of current lead boxes and joint boxes for 2.5 km long St. Petersbubrg HTS DC cable project (2.5 kA, 20 kV) is described. Maximum internal pressure of sub-cooled nitrogen is 1.4 MPa. Both current lead boxes and joint boxes are equipped with terminals for temperature and pressure measurements. Current leads of different polarities have independent electrical insulators. Two current lead boxes and one joint box have been preliminary tested. The first test results are reported.