Design, fabrication, and characterization of a high-field high-temperature superconducting Bi-2212 accelerator dipole magnet
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43 PARTICLE ACCELERATORS↗
Engineering topics
Trociewitz, Ulf
Publications and source records attributed to Trociewitz, Ulf.
Densified superconductor materials and methods
Methods of pre-densifying a metal wire containing superconductor materials are provided. Superconductor materials containing the pre-densified wires also are provided. The wires may be pre-densified by subjecting a metal wire that includes one or more filament cavities in which a superconductor precursor powder is disposed to a temperature and a first pressure for a time sufficient to densify the superconductor precursor powder to form a pre-densified metal wire, wherein the temperature is less than the melting point of the superconductor precursor powder, and the first pressure is sufficient, at the temperature, to compress at least a portion of the metal wire.
Matras, Maxime R.↗
Stable, predictable and training-free operation of superconducting Bi-2212 Rutherford cable racetrack coils at the wire current density of 1000 A/mm 2
High-temperature superconductors (HTS) could enable high-field magnets stronger than is possible with Nb-Ti and Nb 3 Sn, but two challenges have so far been the low engineering critical current density J E , especially in high-current cables, and the danger of quenches. Most HTS magnets made so far have been made out of REBCO coated conductor. Here we demonstrate stable, reliable and training-quench-free performance of Bi-2212 racetrack coils wound with a Rutherford cable fabricated from wires made with a new precursor powder. These round multifilamentary wires exhibited a record J E up to 950 A/mm 2 at 30 T at 4.2 K. These coils carried up to 8.6 kA while generating 3.5 T at 4.2 K at a J E of 1020 A/mm 2 . Different from the unpredictable training performance of Nb-Ti and Nb 3 Sn magnets, these Bi-2212 magnets showed no training quenches and entered the flux flow state in a stable manner before thermal runaway and quench occurred. Also different from Nb-Ti, Nb 3 Sn, and REBCO magnets for which localized thermal runaways occur at unpredictable locations, the quenches of Bi-2212 magnets consistently occurred in the high field regions over a long conductor length. These characteristics make quench detection simple, enabling safe protection, and suggest a new paradigm of constructing quench-predictable superconducting magnets from Bi-2212.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗