New size sorting technology for superconducting powders

A new technique is being developed to make it possible to achieve defect-free particle size sorting of the precursor powders for multi-filament superconductors, Nb₃Sn, Bi-2212 and Bi-2223. Sharp cutoff is critical in the effort to achieve small filament size in multi-filament composites of Nb₃Sn, Bi-2212 and Bi-2223. Accelerator Technology Corp. (ATC) has developed an approach using a slot-geometry virtual impactor to critically remove the coarse particles. Representative Fe₂O₃ and Bi-2212 powders were chosen to evaluate its performance. The results show that a sharp cutoff ∼3 microns separation has achieved in both two powders.