Design and Manufacture of the Low-Resistance ${\rm Nb}_{3}{\rm Sn}$ Joints for the CHMFL 40 T Hybrid Magnet

Two kinds of Nb
₃
Sn CICC joints have been designed for the superconducting coils of the 40 T hybrid magnet. The “terminal joint” is for the joints between the terminals of the superconducting coils. The “interlayer joint” is for the joints between the layers of the coils. Both the terminal joint and the interlayer joint are fabricated before heat treatment. The interlayer joint is not processed any more after heat treatment. The copper soles of the terminal joints are attached to each other with PbSn solder to join the superconducting coils to each other and to the current leads that connect to the power supply. Two full-size joints are being manufactured and will be tested in the High Magnetic Field Laboratory, Chinese Academy of Sciences (CHMFL). This paper will describe an overview of the joints' design and fabrication, and the predicted joint resistances will be also presented.