No abstract

No abstract

Abstract-The Nb 3 Sn strand chosen for the next step in the magnet R&D of the U.S. LHC Accelerator Research Program is the 54/61 sub-element Restacked Rod Process by Oxford Instruments, Superconducting Technology. To ensure that the 0.7 mm RRP strands to be used in the upcoming LARP magnets are suitable, extensive studies were performed. Measurements included the critical current, I c , using the voltage-current (V-I) method, the stability current, I S , as the minimal quench current obtained with the voltage-field (V-H) method, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment temperature and durations on I c and I S were also studied. Using strand billet qualification and tests of strands extracted from cables, the short sample limits of magnet performance were obtained. The details and the results of this investigation are herein described.

Abstract-The first step in the magnet R&D of the U.S. LHC Accelerator Research Program (LARP) is fabrication of tech nology quadrupoles TQSOl and TQCOl. These are twolayer magnets which use cables of same geometry made of 0.7 mm MJR Nb 3 Sn. Through strand billet qualification and tests of strands extracted from the cables, predictions of magnet performance are made. Measurements included the critical current, I c , using the voltagecurrent (VI) method at constant field, the stability current, Is, as the minimal quench current obtained with the voltagefield (VH) method at constant current in the sample, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment duration and temperature on I c and Is were also studied. The Nb 3 Sn strand and cable samples, the equipment, measurement procedures, and results are described. Based on these results, strand specifications were formulated for next LARP quadrupole models.

No abstract