Verification Testing of MQXFA Nb3Sn Wires Procured Under LARP

TL;DR

This paper discusses the verification testing process for Nb3Sn wires procured for the LHC upgrade, focusing on quality control, measurement techniques, and testing challenges at the NHMFL.

Contribution

It introduces a comprehensive verification testing protocol for Nb3Sn wires, including new RRR test software to meet international standards.

Findings

Successful measurement of critical current (Ic) and RRR

Development of new RRR test software

Overcoming testing challenges with high-sensitivity wires

Abstract

The High-Luminosity LHC Accelerator Upgrade Project (AUP) in the U.S. will construct quadrupole magnets to be delivered to CERN. An initial 3 tons, over 600 km total length of conductor was procured under the LHC Accelerator R&D Program (LARP) for this project. Programs for quality control(QC) at the supplier and quality verification (QV) at the laboratories were solidified into components of the overall quality plan for strand procurement under AUP. Measurements of the critical current (Ic) and residual resistance ratio (RRR), and related probes and techniques, are central to the quality plan. Described below is the verification testing that has taken place at the National High Magnetic Field Laboratory (NHMFL). Testing challenges are presented by the high sensitivity of these wires. In addition, new RRR test software was developed to accommodate challenges presented by meeting international standards with existing configurations of test strands.