Hyper Tech has developed the tube type strands with and without artificial pinning center (APC). For the regular tube type strands, our standard conductor with 217 filament arrays have been generated with 12 T non-Cu Jc values of about 2400-2500 A/mm2 with filament size of 35 micros at the 0.7 mm strand. We also made 547 filament conductors with 12 T non-Cu Jc values of about 2000-2200 A/mm2 with filament size of 25 micros at the 0.85 mm strand, which has very low AC losses. For the tube type strands with APC, our recent APC Nb3Sn wires with Ta and Zr doping demonstrated substantial grain refinement and significantly increased Jc,nonCu, while retaining the high Bc2 values of the best ternary Nb3Sn conductors. The non-Cu Jcs of these APC conductors has reached nearly 1500 A/mm2 at 16 T/4.2 K, which approaches the current CERN FCC spec. Their layer Jc reaches 4700 A/mm2 at 16 T/4.2 K - more than double the present best ternary Nb3Sn conductors. In this paper, we will report the progress on both wires and share the recent breakthroughs.
This work was supported by the US Department of Energy, Office of High Energy Physics, Grants No. DE-SC0017755 and DE-SC0013849; Office of Fusion Energy Science, Grant No. DE-SC0017754.