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, Nb/sub 3/Sn, Bi-2212 and Bi-2223. Sharp cutoff is critical in the effort to achieve small filament size in multi-filament composites of Nb/sub 3/Sn, 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 Fe/sub 2/O/sub 3/ and Bi-2212 powders were chosen to evaluate its performance. The results show that a sharp cutoff /spl sim/3 microns separation has achieved in both two powders.