Study on the technology of 3W1 superconducting magnet

Introduction The superconducting wiggler magnet named as 3W1 is the key device for the test facility for the High Energy Photon Source (HEPS). The magnet structure is 1430 mm long with a gap of 68 mm, and the designed peak field is 2.6 T. The main magnet part is comprised by 28 main coils and 4 correction coils at both ends. Due to the large gap and high field, the manufacturing process is extremely difficult.
Method During R&D, the problems of coil winding, impregnation, pre-stress evaluation and quench risk control were solved by optimizing the technology. The coils were divided into groups to complete the cryogenic test, and the qualified coils were selected to complete the assembly of the magnet.
Conclusion The bare magnet has been tested with liquid helium bath in April 2018 in IHEP, and the loading current reached up to 345 A resulting in the expected 2.61 T. In this paper, the technology about the coil winding, impregnation, assembling and test is presented in detail.