A frameless, conduction-cooled NbTi superconducting magnet developed by the research team led by Professor Liang Li and Professor Yunxing Song at the National High Magnetic Field Science Center has successfully achieved stable operation at a peak magnetic field strength of 9.0 T. This milestone represents significant progress in weight reduction, cost-effectiveness, and operational efficiency.

Lightweight, Cost-Effective frameless Design
The new magnet offers distinct advantages over traditional framed low-temperature superconducting magnets, including reduced weight, lower production costs, and substantially fewer training quenches. Building on their previous design, the team introduced a series of optimizations from conceptual design to manufacturing processes. These efforts have resulted in three key breakthroughs:

1: Weight Reduction: The magnet’s weight was reduced from 77 kg to 55 kg, a 30% decrease.

2: Reduced Wire Usage: The total length of superconducting wire was cut from 16.6 km to 13.8 km, saving 17%.

3: Fewer Training Quenches: The number of training quenches was reduced from 6 to 3, a 50% improvement.

Thermal And Electrical Performance under Cryocooling
The magnet is cooled by a single KDE415SA two-stage cryocooler and maintains an operating temperature of 3.8 K at 9.0 T, ensuring a comfortable thermal margin for long-term reliable operation. It features a 100 mm cold bore and achieves magnetic field uniformity within ±0.05% over a 1 cm spherical volume—parameters ideal for high-precision applications.

Applications and Future Development
Owing to its compact size, high field quality, and energy-efficient performance, the 9.0 T frameless NbTi magnet is well suited for integration into scanning tunneling microscopes (STM), physical property measurement systems (PPMS), and magneto-optical research platforms.

Looking ahead, the research team plans to refine coil winding geometries to further improve field homogeneity and cooling efficiency. Additionally, they aim to develop scalable production techniques to support mass manufacturing. These efforts will help advance the commercialization of conduction-cooled low-temperature superconducting magnets, reduce reliance on foreign technologies, and enhance domestic capabilities in cutting-edge scientific instrumentation.