Conveners
M1Or3F: Nb3Sn, MgB2, BSCCO Wires and Joints
- Fang Wan (Fermi National Accelerator Lab)
- Dongliang Wang (Institute of Electrical Engineering, CAS)
In this paper we will report the recent progress of making ternary APC (Artificial Pinning Center) Nb3Sn conductor using internal oxidation technique in Hyper Tech. Our ternary APC Nb3Sn conductors with Ta and either Zr or Hf doping demonstrated substantial grain refinement and significantly increased Jc,nonCu, while retaining the high Bc2 values of the best ternary Nb3Sn conductors. The...
The goal of building economic 16 T accelerator magnets requires Nb3Sn conductors with Jc much higher than state of the art. Thus, a lot of efforts in the Nb3Sn community have been focused on improving Jc (while keeping RRR and effective subelement size deff in the acceptable range). However, a very important factor that is also critical for this application but has been overlooked is the...
APC Nb3Sn wires are made using an internal oxidation process to create ZrO2 or HfO2 nanoparticles during diffusional growth of Nb3Sn. These particles introduce a second pinning mechanism, as well as refine the grain size, strengthening the grain-boundary pinning above that in non-oxidized Nb3Sn. The two mechanisms taken together increase...
It is very desirable to reduce the long training for Nb3Sn magnets. Increasing the specific heat (Cp) of Nb3Sn conductors can significantly increase their energy margin, and thus may be a promising approach to reduce the magnet training. We developed a design to add high-Cp materials into Nb3Sn strands in 2017, which is compatible with standard Nb3Sn wire production process, and this design...
Currently, the record critical current density (Jc) achieved in Bi-2212 short samples is around 9600 A/mm¬2 at 5 T in 4.2 K. However, even this very high Jc is still less than 1% of the depairing current density (Jd) of Bi-2212. The 1% Jc/Jd value in Bi-2212 suggests that the long-range filament connectivity in Bi-2212 is rather poor. There are multiple intrinsic and extrinsic factors that can...
Superconducting magnets equipped with the persistent current circuit have been extensively used for NMR and MRI systems with high resolution cooled by liquid helium. In those systems, superconducting joints with very low joint resistance are essential for realization of the closed circuit. However, practical superconducting joints connecting HTS tapes have never been developed mainly due to...
