Study on the stability of NdFeB in IVU for synchrotron radiation and free-electron lasers
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作者
He, Yongzhou; Dong, Jian; Yu, Cheng; Zhou, Shudong; Zhu, Ya; Wang, Hongcui; Yang, Jie; Zhang, Wei; Yin, Lixin
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刊物名称
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
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年、卷、文献号
2025, ,
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关键词
He, Yongzhou; Dong, Jian; Yu, Cheng; Zhou, Shudong; Zhu, Ya; Wang, Hongcui; Yang, Jie; Zhang, Wei; Yin, Lixin
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摘要
Pursuing high magnetic fields is one of the main development directions for in-vacuum undulators (IVUs) in synchrotron radiation sources and free-electron laser facilities. Compared to SmCo IVUs and Nd (Pr)FeB cryogenic permanent magnet undulators (CPMUs), NdFeB IVUs have a higher cost-performance ratio and thus holds greater potential for widespread application. This paper analyzes the advantages and disadvantages of several small magnetic gap IVUs and CPMUs, describes the preparation of NdFeB permanent magnets for IVUs, and presents experimental studies on their stability. Based on this research, an IVU with a period length of 18.5 mm was designed and developed for the Brazil SIRIUS light source using NdFeB permanent magnets produced in China. Magnetic field measurements indicate that the stability of NdFeB is good at temperatures up to 200 degrees C, with no significant demagnetization observed in the undulator's magnetic circuit. The stability of NdFeB is closely related to its inherent magnetic field uniformity. Compared to SmCo IVU, the peak magnetic field is increased by approximately 20%, and the magnetic field phase error is significantly improved.
