Critical Current Measurements on<tex>$rm Nb_3rm Sn$</tex>Conductors for the NED Project

Abstract

The Next European Dipole (NED) project is a EU funded program aiming at the realization of a 15 T accelerator-type of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn dipole magnet. The objective of NED phase one is developing high performance Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn conductor in collaboration with European industry. The envisaged Rutherford type of cable consists of about 40 superconducting strands exhibiting a noncopper critical current density of 1500 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 4.2 K and 15 T. In the frame of conductor development, adequate critical current measurements in terms of accuracy and reproducibility should be ensured to qualify the ambitious strands produced. Therefore, a NED working group focuses at the establishment and implementation of appropriate and standardized procedures for sample preparation and mounting, critical current measurement, data analysis and reporting. A cross-calibration program between the institutes involved has been initiated by exchanging samples of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn conductor from a single billet for critical current measurements, prepared at each institute. The experimental results of this program and the conclusive procedures for NED critical current measurements are presented and discussed