We analyze the measured critical current reduction in Nb3Sn Rutherford cables under magnet-relevant transverse pressure levels in terms of the filament strain inside their strands. A mechanical 2D model of cables’ cross-section is developed to translate the stress that is applied to the surface of the impregnated cables into a strain distribution on the surface of its strands. The resulting critical current of the cable is then used to estimate the corresponding deviatoric strain on the intra-strand filamentary level, using the well-documented strain scaling relations obtained for the isolated strands. By comparing the thus modelled strain on a strand level with the estimated strain on a filament level, we can identify the main factors that influence the pressure response of these accelerator cables. Such an analysis is presented for four state-of-the-art cable samples that were measured at the University of Twente (combining two cable- and two strand-types) and discussed in terms of cable lay-out and mechanical strand properties.
The HiLumi LHC project was partly financed by the European Commission’s seventh framework programme (FP7).
The EuroCirCol project was funded by European Union’s H2020 framework programme under grant agreement no. 654305.
Corresponding author: Mr. Peng Gao, email@example.com