A 3 Tesla Superconducting Magnet for Hall Sensor Calibration

A 3 T superconducting magnet with a 70 mm diameter warm bore and energy storage of 47 kJ has been successfully fabricated and tested, which can be used to calibrate Hall sensors in high magnetic field as well as conduct superconducting experiments. The magnet consists of three solenoid coils and an iron yoke. The homogeneity of the magnetic field in the region of interest (ROI) is +/- 6.0 x 10(-5). The coils of the magnet were fabricated with NbTi-Cu superconducting wire and the stray magnetic field is shielded by an iron yoke. The coils and yoke are fully immersed in a helium vessel. The optimized structural design, stress and quench simulation, fabrication and test results are presented in this paper.

3T超导螺线管的研制

超导螺线管广泛应用于核磁共振仪、粒子探测器等设备。本文设计了中心场值为3T，中心附近Φ30mm区域内均匀度达到1×10-4的超导螺线管。磁体线圈采用多芯NbTi-Cu复合超导线绕制，并利用铁轭屏蔽漏场。磁体采用温孔冷铁轭、全浸泡冷却方式结构。同时，为了减少辐射漏热，采用液氮冷屏、真空多层绝热结构。 本文重点对带有冷铁轭的超导螺线管的磁场进行了优化设计。设计过程中结合了专业磁场计算软件OPERA和多种优化方法。线圈采用六次槽型结构，利用遗传算法和优选法优化线圈尺寸；铁轭采用正交试验设计优化尺寸。 利用有限元软件ANSYS对超导磁体进行电磁力分析，并且对降温后线圈、支撑筒和箍筒的热应力进行了模拟计算。估算了支撑系统的传导漏热、磁体的辐射漏热以及剩余气体漏热。详细介绍了超导磁体绕制工艺，超导磁体液氦杜瓦的加工工艺，并且对杜瓦的绝热工艺进行了介绍。最后介绍了超导螺线管的总体加工进展