Magnetic Shielding With YBCO Coated Conductors: Influence of the Geometry on Its Performances

• Published in: IEEE transactions on applied superconductivity Vol. 23; no. 3; p. 8200504
• Main Authors: Wera, L., Fagnard, J. F., Levin, G. A., Vanderheyden, B., Vanderbemden, P.
• Format: Journal Article Conference Proceeding Web Resource
• Language: English
• Published: New York, NY IEEE 01.06.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; ATTENUATION; COATINGS; Conductors; COPPER OXIDE; Direct current; Electric connection. Cables. Wiring; Electrical & electronics engineering; ELECTRICAL CONDUCTORS; Electrical engineering. Electrical power engineering; Electromagnetic compatibility; Electromagnetism; Engineering, computing & technology; Exact sciences and technology; High temperature superconductors; Information, signal and communications theory; Ingénierie électrique & électronique; Ingénierie, informatique & technologie; MAGNETIC FIELD; Magnetic field measurement; Magnetic fields; Magnetic induction; magnetic measurements; Magnetic noise; Magnetic shielding; Magnetic shields; Shields; SHIELDS (MAGNETIC); Studies; Superconducting magnets; SUPERCONDUCTIVITY; SUPERCONDUCTORS; Telecommunications and information theory; Various equipment and components; YBCO coated conductors; YTTRIUM OXIDE; Performance evaluation; Closed loop; External field; Magnetic screen; Magnetic induction; Stacking; YBCO coated conductors; Electromagnetic shielding; Aspect ratio; Coated material; Magnetic shielding; Air gap; Electrical conductor; Magnetic field; Double layers; Magnetic properties
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2012.2235514

A superconducting magnetic shield can be built as a stack of several sections of milled 2G coated conductors. Each section consists of a closed loop where persistent currents can flow and provide a strong attenuation of external dc magnetic fields. The purpose of the present work is to study experimentally several geometries of such magnetic shields made out of YBa 2 Cu 3 O 7 (YBCO) coated conductors from SuperPower. Our aim is to investigate in detail the influence of the aspect ratio and the number of layers of the assembly on the magnetic shielding properties. In order to do so, the magnetic shield is subjected to an axial quasi-static ("dc") magnetic field ramped slowly at a fixed sweep rate. A Hall probe is used to measure the local magnetic induction inside the assembly as a function of the applied magnetic induction. Results show that the shielding factor, SF, (defined as the ratio between the applied magnetic induction and the magnetic induction measured inside the shield) is improved for increasing aspect ratios of the global coated conductor assembly and that the threshold magnetic induction (defined for SF = 10) increases with the number of layers. Using a double layer of 18 sections at T = 77 K, dc magnetic fields up to 56 mT can be shielded by a factor larger than 10. Finally, the effect of an air gap of constant width between coated conductor sections is also characterized.