Basic Research on High Field Superconducting Magnet for High Energy Accelerators

在CERN大型强子对撞机加速器的合作框架下，研制了能产生10 T磁场的双极和四极强超导磁体，目标工作磁场为8.4 T的双极磁体是CERN大型强子对撞机主双极磁体研制的补充工作，通过密切的相互交流，研制成功了10 T磁场的双极磁体。在1997财政年度，对1996财政年度制造的1 m模型磁体进行了测试，主要是通过将其加热到室温的热循环效应来获得性能。结果表明，所研制的超导四极磁体性能良好，热循环效应相对较小，离束流碰撞点最近的聚焦超导四极磁体的靶场梯度为240 T/m，是迄今为止所研制的最强的磁体。内线圈直径为70 mm，线圈中的最大场超过9.6 T。1997财年的主要目的是在1995财年和1996财年设计工作的基础上制造和测试第一个模型四极。在制造过程中，我们与CERN的工作人员就线圈支撑结构的机械性能和测试项目进行了密切的沟通。在制作第一个模型之前，已经获得了磁体中所需的容许尺寸和应力的基本数据。我们测试了该模型，并在第一次淬火时获得了205 T/m的额定操作场梯度。通过训练（逐渐增加失超电流），磁体成功激发超过240 T/m的设计值，并最终显示出250 T/m的世界最强场梯度。为了将这些研究成果付诸实践，公司内部进行了人员交流，并召开了5次技术会议。1998年3月在欧洲核子研究中心召开了技术会议，讨论和总结了这一研究与发展所取得的成果。

High field supercondung magnets which can generate field of 10 T have benn developed in a frame work of the collaborative work for the LHC acclerator at CERN.They are dipole and quadrupole magnets.The dipole magnet whose targeted operation field is 8.4 T has been developed as a complementary work to the CERN R & D for the LHC main dipole magnet by taking close mutual communication. In FY1997, an 1 m model magnet fabricated in FY1996 has been tested mainly to obtain the performance by effect of thermal cycle in which it is warmed up to the room temperature. As a result, the developed magnet whowed a good performance with relatively small thermal cycle effect.The target field gradient of the closest focusing superconducting quadrupole magnet to a beam colliding point is the strongest one of 240 T/m ever built. The inner coil diameter is 70 mm and the maximum field in the coil is over 9.6 T.In FY1997, the main purpose is fabrication and test of the first model quadrupole in a base of the design works in FY1995 and 1996. When it was fabricated, we took close communication with CERN staff for mechanical properties of the coil suport structures and items to be tested. The basic data of necessary tolerable size and stresses in the magnet have been obtained prior to the fabrication of the first model. We tested the model and obtained the rated operational field gradient of 205 T/m at the first quench. By training (gradual increasing the quench currents), the magnet was successfully excited over the design value of 240 T/m and finally showed the strongest field gradient of 250 T/m in the world. The fruitful results will be reflected to the fabrication of the practical magnet.In order to put these R & D in practice, the staff exchange has been carried out each other, and five technical meetings have been held. Moreover, the technical meeting was held at CERN in March 1998 in order to discuss and summarize these obtained results of this R & D.