Experimental Layer-Wound Mock-Up Coil for HTS MRI Magnet Using BSCCO Tape

• Published in: IEEE transactions on applied superconductivity Vol. 19; no. 3; pp. 2309 - 2312
• Main Authors: Minfeng Xu, Laskaris, E.T., Budesheim, E., Conte, G., Xianrui Huang, Stautner, W., Thompson, P.S., Amm, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bismuth compounds; Coils; Coils (windings); Construction; Current density; Density; Electrical engineering. Electrical power engineering; Electromagnets; Electronics; Exact sciences and technology; High current; High temperature superconductors; Insulation; Magnetic field induced strain; Magnetic resonance imaging; magnetic resonance imaging (MRI); Materials; Reduction; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Stainless steels; Steel; Superconducting devices; Superconducting tapes; Testing; Various equipment and components; Winding; windings; Wounds; High strength current; High-temperature superconductors; Lap joint; High density; Magnet; Electrical insulation; Nuclear magnetic resonance imaging; magnetic resonance imaging (MRI); Superconducting magnet; High current; Stainless steel; Superconducting tapes; Imaging; windings; Current density; High temperature superconductor; Machine windings
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2009.2018107

Typical coils with BSCCO tape are wound in a pancake or double-pancake style to minimize the strain in the tape by reducing or eliminating the edge-wise bending. Stainless steel reinforced tapes are frequently used in the winding process to increase the strength and reduce the strain due to winding tension and handling. However, an MRI magnet requires high current density in the winding pack. This high current density in the winding pack gives a higher field in the imaging volume and also allows for a reduction in the overall magnet size. Layer winding was preferred for a better tolerance control and for a reduction in the number of joints, which are known sources of resistance and therefore locations of instability in the coil. A mock-up coil was wound using a high-current-density type of BSCCO tape without the typical stainless steel reinforcement. The coil was layer-wound which involved a few inline lap joints embedded in the winding pack. The test of the coil reveals a few issues that need to be addressed. Investigations and analysis lead to a better understanding of the issues. This paper discusses the lessons learned and solutions for using non-reinforced tape in a layer-wound coil, while controlling insulation dimensions within the build.