Enhanced Performance of Multifilamentary MgB₂ Wires at a 2.5 km Scale Through Pyrene Doping

Carbon doping has proven to be a highly effective strategy for enhancing the electrical properties of MgB2 wires, especially under a high magnetic field. However, unreacted doping material can persist as impurities due to uneven mixing or incomplete reactions, thereby detrimentally affecting electrical properties and their uniformity. In this study, we explore the application of pyrene doping to 18-multifilamentary MgB2 wires with a total length of 2.5 kilometers. The aim of this study is to minimize residues and maximize high-field critical current properties. Our investigation includes X-ray diffraction refinement, scanning electron microscopy observations, and a comprehensive characterization of critical current properties. We are presently evaluating the viability of applying this doping material and method in large-scale commercial production.