Performance of MgB2 Superconductor Developed for High-Efficiency Klystron Applications

An 8-km long MgB ₂ wire for a prototype klystron magnet was made and evaluated. The wire was made by a typical in situ method; it has 10 filaments and 0.67 mm in outer diameter. The homogeneity of I _c of this wire was evaluated by several methods. Deviation of I _c values in short sample wires was very small. In addition, the current sharing temperature of the MgB ₂ magnet (made of two reels of wire 2.9 km long each) agreed well with the estimated value of the I _c -B-T properties in short sample wires. Based on the obtained results, it can be said that the I _c properties of the entire wire length are quite uniform.