摘要
低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)利用稀土永磁材料钕铁硼或镨铁硼在低温下的剩磁及内禀矫顽力大幅增大的特性,通过使磁体工作在50-150 K的低温环境,获得相比于常规真空内波荡器(In-vacuum Undulator,IVU)高30%-50%的磁场性能。在磁气隙一定的条件下,CPMU可以在较小的周期长度下获得较大的磁场强度,这对于提升同步辐射光的亮度具有重要意义。本文介绍了上海光源(Shanghai Synchrotron Radiation Facility,SSRF)钕铁硼CPMU磁体冷却技术的研究进展,对CPMU的静态热负载进行了详细的理论分析及实验研究。CPMU静态热负载的理论分析方法在CPMU样件低温冷却实验装置得到了验证,并在完整钕铁硼CPMU样机中得到了应用。
Background： The magnetic performance of the cryogenic permanent magnet undulator （CPMU）, whose magnets work at the temperature of 50-150 K, can be enhanced by 30%-50% compared with that of the conventional in-vacuum undulator （IVU）. As the magnetic characteristics of both the remanence and the intrinsic coercivity of NdFeB and PrFeB increase substantially with the decreasing of working temperature, the CPMU can gain higher peak field within shorter magnetic period under a given magnetic gap, which is of great significance to improve the brightness of the synchrotron radiation light source. Purpose： This study aims to investigate the sources of the static heat loads of the CPMU and develop methods of evaluating and testing the heat loads. Methods： The thermal conduction and the thermal radiation of the CPMU were analyzed theoretically. Two methods of analyzing the practical static heat loads of the CPMU were proposed, compared and tested by using the CPMU test device without magnet arrays. Results： The method of analyzing the test heat loads that utilizes the measured temperatures of the girders and liquid nitrogen （LN2） tubes is better than the one that calculates the heat loads with the LN2 flow rate and temperature rise in the tube. Conclusion： The results were applied to the development of a full scale NdFeB based CPMU prototype.
出处
《核技术》
CAS
CSCD
北大核心
2017年第8期24-30,共7页
Nuclear Techniques
基金
国家自然科学基金(No.11175238)资助~~
