Development And Quenching Study Of Undulator Magnets Based On Second Generation High Temperature Superconductors

Nowadays,undulators have become one of the key devices of synchrotron light sources.Although the technology of traditional permanent magnet undulator or even low-temperature superconducting undulator is relatively mature,further improvement of on-axis magnetic field is limited by the performance of permanent magnets or lowtemperature superconductors.Compared with low-temperature superconductors,the second-generation(2G)high-temperature superconductors(HTS)have higher properties.Therefore,the application of the 2G HTS on undulators can achieve higher on-axis magnetic field.In this thesis,two types of 2G HTS undulator magnets were designed and manufactured.Quench behavior of the undulator magnet with "vertical racetrack" windings was numerically simulated and experimentally studied.This thesis explored the technique of superconducting joint,which is one of the key processes to the development of the undulator magnet with "vertical racetrack" windings.This work provided the possibility of manufacturing HTS undulator magnets with resistive joints.Subsequently,a 3-period undulator prototype with "vertical racetrack" windings was designed and manufactured.The excitation and quench test was conducted on the undulator prototype.The equivalent circuit analysis model of the undulator prototype was established.The experiment and numerical analysis were compared.Results showed that the analytical model is reasonable.This thesis proposed the 2G HTS undulator magnet with "horizontal racetrack" windings for the first time.The magnetic field of this type of undulator magnet was optimized and analyzed considering different width of tape,thickness of pole,operating temperature and magnetic gap.A continuous winding scheme was invented for undulator magnet.Corresponding experimental research was carried out on the bending radius of the superconducting tape,which is one of the main problems in this scheme.After that,the 2G HTS undulator prototype with "horizontal racetrack" windings was successfully fabricated and tested.The on-axis magnetic field measured from the undulator protype agreed with the numerical results.The feasibility of 2G HTS undulator with non-insulated coils operating at liquid nitrogen temperature was verified.The results showed that the 2G HTS undulator has great application prospect.In this thesis,the exploration of the 2G HTS undulators of two structures can provide a reference for the future design of superconducting undulators.