Multifilamentary Round Wires of REBCO Coated Conductors for High Field Accelerators

There is substantial interest in upgrading existing High Energy Physics accelerators including the Large Hadron Collider in CERN, Switzerland to higher energy levels so as to probe deeper into the subatomic scale and unlock the mysteries of the Universe. Such upgrades to higher energy levels would require use of High Temperature Superconductor (HTS) magnets which can generate magnetic field levels of 20 T and beyond. However, in order to use HTS tapes in ultra-high field accelerator magnets, challenges with flat geometry and wide profiles, anisotropic properties and losses during magnet ramping have to be overcome. The overarching objective of the proposed program is to develop RE-Ba-Cu-O (REBCO, RE=rare earth) HTS wires with performance and features that can enable future accelerator magnets for high energy accelerators. The approach is to develop multifilamentary, ultra-small-diameter round REBCO wires with high engineering current density using ultra-thin REBCO tapes. In the Phase I SBIR program, AMPeers and its Research Institution partner, the University of Houston, successfully achieved the overarching goal of fabricating round, multifilamentary REBCO wires of just 1.6 mm in diameter! Additionally, meter-lengths of round REBCO wires were produced with a critical current of of 440 A at 77 K, self-field. Short wires, with critical current in excess of 495 A at 77 K, self- field (engineering current density, Je ~ 250 A/mm2) have also been demonstrated. In the Phase II project, the round multifilamentary ultra-small diameter REBCO wire technology will be scaled up to manufacturing of 50 meter lengths with an engineering current density of 250 A/mm2 at 4.2 K, 20 T. A supplementary objective of the Phase II project is to demonstrate even higher performance round ultra-small diameter REBCO wires with engineering current density of 600 A/mm2 at 4.2 K, 20 T and 80 times lower AC losses than that of standard REBCO tapes. Achievement of round, multifilamentary, ultra-small diameter REBCO wires in long lengths in the proposed program will meet the needs of High Energy Accelerators that would operate at 20 T and beyond for High Energy Physics. The new technology would also be highly impactful in the commercial market for accelerators which includes proton beam therapy in medicine, treatment of water and flue gases, pharmaceutical drug development and nuclear forensics and cargo screening for security. The outcome of the proposed program can be impactful on even a larger scale for electric power applications such as transformers and rotating machinery including utility generators, electric motors, wind generators and airborne generators. A new type of superconductor wire technology that can enable ultra- high field magnets will be developed in this program. This new superconductor wire would lead to high- energy accelerators that will unlock the mysteries of the Universe as well enable several commercial products that serves the medicine, energy, environment and security markets.