The Research On Magnetic Properties Of Permanent Magnet And Magnetic Field Of Prototype For Cryogenic Permanent Magnet Undulator

This dissertation is mainly about the application fundamental problems ofNd(Pr)FeB permanent magnet(PM) for Synchrotron Radiation Cryogenic PermanentMagnet Undulator(CPMU). The main research contents include: design andpreparation of Nd(Pr)FeB, cryogenic magnetic properties, demagnetizing field ofHalbach PM component, magnetic field of80cycles CPMU20prototype etc.The first chapter is introduction part, firstly briefly introduces features ofsynchrotron radiation and situation of Shanghai Synchrotron Radiation Facility(SSRF).And then introduces technical characteristics of insert device especially undulators,such as development process, magnetic structure, magnetic properties, radiationcharacteristics, magnetic field design, PM and soft, etc. Finally have introducedsituation and technology significance of CPMU at home and abroad, and then givesresearch content and technique route of this dissertation.The second chapter is basic theory of applied magnetism, firstly summarizes fourclassical physics foundation for applied magnetism: exchange interaction, anisotropy,magnetostriction, demagnetization. Then introduced contents include: components,magnetic properties parameters, magnetic microstructure, design and preparation.Finally, introduces three typical cryogenic magnetic properties characteristics for thesingle crystal RE2Fe14B: magnetic polarization, anisotropy, spin orientation.The third chapter is preparation of PM, it focus on introduction development ofPrFeB, comparison difference in design, preparation process, microstructure, magneticproperties and orientation degree for PrFeB(P42H and P46H). Then introducepreparation of NdFeB(N48H), and studied coating vacuum performance of N48H.The fourth chapter is cryogenic magnetic properties of PM, it focus onintroduction measurement method and variation law of magnetic properties at lowtemperature for domestic polycrystalline PM sucn as N50M, N48H, P42H, P46H andso on. Then have introduced cryogenic moment measurement for bulk PM.The fifth chapter are demagnetizing field and cryogenic magnetic field, firstlythrough Radia have studied demagnetization field changes law and working point ofPM and irreversible demagnetization experiments of five cycles Halbach magneticcircuit PM assembly etc. Then have studied PM design and cryogenic magnetic fieldvariation law of first CPMU20prototype o for SSRF.The research work of this dissertation has laid technical foundation for CPMU ofSSRF practical engineering, it also provides important reference for design anddevelopment of the other similar cryogenic PM device in the other industries such asspace, scientific research, medical and so on.