Conductor Development for High Energy Physics--Plans and Status of the U.S. Program

AbslraCiIn order to provide a cost effective high field magnet option for the next generation HEP accelerator, higher performance NbJSn superconductor is required. These requirements have been recognized by the DOE, and a conductor development program has been initiated. The goal is to produce a cost-effective conductor with a Jc(noncopper,12T,4.2K) exceeding 3000 A/mm and an effective filament size of less than 40 micrometers. Although the Nb3Sn conductors manufactured at present have produced Jc values in excess of 2200 A/mm2, no conductor being manufactured at present can achieve both the aggressive Jc and effective filament size goals. The first phase of the present program is underway, and is focused on improving the understanding of the factors that control Jc. Samples are being manufactured by industry and are being characterized with respect to Jc and magnetization as a function of composition and heat treatment condition. Using this new knowledge as a base, the program will move into a fabrication scale-up phase where the performance and cost-effectiveness can be demonstrated on production size quantities. The status and accomplishments of this program will be reviewed, and the plans for the scale-up program will be presented.