Reduce Nb3Sn Strand Deformation when Fabricating High Jc Rutherford Cables

This proposal is submitted in response to the SBIR/STTR High Energy Physics Solicitation Topic 64(a). High-Field Superconductor and Superconducting Magnet Technologies for High Energy Particle Colliders, (a) High-Field Superconducting Wire Technologies for Magnets. The need is for strands that can operate in the 15/17T or higher regime, and have deff values of 40 m or less, with non-Cu Jc values at 3000 A/mm2 (12T-4.2K) or greater and 1500 A/mm2 (15T-4.2K) or greater, and have stable operation throughout their operational fields. Strands close to these values are starting to be obtained, but the instability in the low field and defects due to cabling are issues to be solved. Hyper Tech has a desire to improve the wire design for better cabling while optimizing subelement shape to increase non-copper Jc at high field at 4.2K for high count restack wire. We would like to see the achievement of non-Cu Jcs of about 3000 A/mm2 at 12T-4.2K for the Tube type strands with filament size of 30~35 m for Rutherford cabled used in HEP applications. The goal of this research is to improve wire design for better cabling while optimizing the subelement shape to increase non-copper Jc at 12T-4.2K to above 3000 A/mm2 for tube type strands with filament size of 30~35 m. In order to do so, we plan to increase Cu between subelements and the Cu in the middle of restack wire to improve the wire Rutherford cabling without subelement breakage and merging, and make round subelements to maximize the reaction of available Nb so as to increase the non-Cu Jc. The goal of this Phase I and Phase II program is to develop a conductor with target Jc values of 3000 A/mm2 at 12T-4.2K, 1500-1800 A/mm2 at 15T-4.2 K with a subelement count of more than 200, and d deff values of 35 m or less, and better cabling without subelement breakage and merging. Commercial Applications and Other Benefits: The success of this SBIR will lead to a fully stable strand with high Is and Js for DOE-HEP that will have a demonstrated non-Cu Jc of about 3000A/mm2 (12 T-4.2K) and 1500-1800 A/mm2 (15T-4.2K) while demonstrating that the strand can be fabricated into a Rutherford cable without subelement breakage and merging