[WB7] Evaluation & Flux pinning I

1:45 PM - 2:00 PM JST(4:45 AM - 5:00 AM UTC)

[WB7-02] Big Data Analysis of XRD/SEM for Enhancing the Critical Current of 2G-HTS Tapes

*Vladimir Vyatkin¹, Hoa Dao¹, Deniz Sanal¹, Konstantin Vereshchagin¹, Ivan Veshchunov¹, Kamil Etxagibel¹, Roman Valikov¹, Alexander Borisov¹, Marat Gaifullin¹, Sergey Samoilenkov¹, Valery Petrykin¹, Sergey Lee¹ (1. Faraday Factory Japan (Japan))

Keywords:

2G-HTS,YBCO,Applied superconductivity,XRD,SEM,Critical current,Data-driven manufacturing

Over the past decade, Faraday Factory Japan (FFJ) has produced nearly 10,000 long-length (more than 300 m) second-generation high-temperature superconducting (2G-HTS) tapes for fusion and other high-field applications. For each tape, a comprehensive dataset was compiled, including process logs, X-ray diffraction (XRD), scanning electron microscopy (SEM), and performance metrics such as critical current (Ic) and critical current density (Jc) at 77 K in self-field and, in many cases, Ic and Jc at 20 K and high magnetic field 20 T. To convert this output into practical insight, we developed automated procedures for data reduction and analysis including automatic indexing of XRD and SEM image processing. These workflows eliminate operator bias, provide rapid and reproducible processing, and are suitable for future in-line monitoring and feedback control. Advanced data-driven analysis, including feature extraction, dimensionality reduction, and unsupervised statistical learning, reveals hidden correlations that are difficult to capture through traditional small-batch optimization. XRD analysis highlights performance-linked features such as secondary polycrystalline phases, lattice parameters, peak broadening (Williamson-Hall evaluation of strain and crystallite size), and Y2O3 reflections, whose peak intensities and widths show measurable correlation with critical current. SEM workflows incorporate computational imaging methods (adaptive thresholding, morphological filtering) together with texture descriptors (e.g., fractal dimension, lacunarity) to quantify surface patterns associated with Ic and fabrication parameters. All these parameters were correlated with an extensive set of Ic measurements, both in self-field at liquid-nitrogen temperature and in high magnetic fields at low temperature. The full dataset comprises nearly 10,000 measurements. Each point on the plot corresponds to a critical-current measurement linked to its associated XRD pattern and SEM analysis. This scale enables the identification of trends that would likely remain obscured in limited sample sets. Overall, the study establishes a data-driven framework for understanding and optimizing 2G-HTS tape fabrication and for reinforcing quality control through advanced computational analysis.