Siwei Chen

This breakthrough represents a paradigm shift from simply finding defects to preventing them, establishing the feasibility of AI-driven, closed-loop feedback. It is the critical first step toward an intelligent manufacturing process that can maximize yield and dramatically lower the cost of fusion-grade conductors.

• Integrated a customized X-ray source and a 2D detector in the Advanced MOCVD System to continuously monitor the crystallographic qualities inline as a solid feedback source for real-time closed-loop process control
• Invented a numerical method to automatically detect peak of interest in the 2D XRD exposures and rectify the image with the presence of vibration and curvature
• Reused the developed code to monitor bi-texture quality of buffer templates in an IBAD system by RHEED
• Developed a high precision (>85%) machine learning model to predict the tape performance without delays by post-processing (oxygenation)

[Inline 2D-XRD Setup]

[Animation of 2D-XRD Pattern in Moving Deposition]

[Critical Current (Ic) Prediction based on Inline 2D-XRD vs Measured Ic]

This innovation provided the entire field, for the first time, with the ability to qualify conductors under application-relevant conditions. By extracting their 2D performance distributions for quality assurance, this work builds the industrial and regulatory confidence required to invest in large-scale HTS magnets.

• Designed and developed a reel-to-reel motion system enabling the REBCO tapes going between room environment and 65K vacuum
• Implemented a reciprocal Hall probe scanner and a rotary Hall probe scanner under low temperature
• Successfully measured the 77K/65K critical current density profile of long REBCO tapes with external magnetic field in range 0-5T
• Stay tuned: A 20K, 7.5T version is under active development

[65K 5T Continuous Inspection Setup]

[20K 7.5T Continuous Inspection Setup]

[2D Mapping of Critical Current Density of a HTS Conductor]

This research proved the extendability of the world-record performance in short REBCO samples to production scale. It helped move HTS manufacturing from a bespoke lab-scale process toward a scalable, industrial reality, demonstrating a viable path to producing the kilometer-lengths of wire needed for large-scale applications.

• Fully designed and implemented the pilot-scale Advanced MOCVD system
• Successfully manufactured over 50m uniform high-performance single tape
• Extended the developed MOCVD systems for double-side conductor development and conductive substrate development

[Pilot-Scale Advanced MOCVD System]

This work provides the essential, foundational electromechanical properties when developing high-strength REBCO tapes for high-fields applications. Magnet designers now use this data to build robust, reliable coils that can withstand the immense operational stresses inside a ultra-high-field magnet, directly improving the safety and viability of future magnet designs.

• Built a tensile I-V testing and a torsion I-V testing system
• Extracted the 77K self-field critical current performances under various strains/stresses

This work and its extension on screening current induced strain explained the dynamic eletromagnetic characteristics of HTS coils to better guide the design of non-DC superconducting applications

• Simulated the current distributions in HTS coils with various dimensions by finite element method (utilizing ANSYS)
• Designed and implemented an automated platform for measuring dynamic eletromagnetic properties, including inductance and AC loss, of HTS conductors
• Discovered and verified the nonlinear behavior of the inductance in HTS coils and revised the inductive voltage and stored energy