分类： 物理学 >> 核物理学 提交时间： 2024-06-11
Yu-Ning Yang
Fang Yan
Zi-Hao Wang
Xiang-Yu Tan
Wen-Jie Wu
Xiang-Rong Fu
Jun Lei
Guo-Ping Lin
Gang Xu
Wei-Min Pan
摘要： 高能光子源 （HEPS） 对存储环板的振动水平有严格的限制。如果振动水平超过规格限值，会影响设备的正常运行，影响实验终端的采样效率。随着周边城市基础设施建设的不断扩大，为了控制外部振动源，有必要研究HEPS场地的振动传播特性。为了评估外部振动对HEPS关键组件的影响，已经进行了一系列测量。振动台用于人工生成频率为 7Hz 至 100 Hz 的垂直正弦激励。沿裸露地面测量振动响应，分析不同频率的振动衰减。根据测量数据的拟合结果，得到衰减公式和关键参数范围。同时，通过在HEPS现场行驶的50吨起重机的振动数据验证了衰减公式。测量数据与上述拟合公式非常吻合。测量数据与拟合曲线之间的差异在 $35 %$ 以内。本研究将为HEPS校园周边外部行驶载荷的相关调控奠定基础，同时为地面振动传播的研究方法提供参考。
分类： 物理学 >> 核物理学 提交时间： 2023-06-16
摘要： Abstract Main quadrupole magnets are critical for the Circular Electron and Positron Collider (CEPC), and are specifically designed as dual aperture quadrupole (DAQ) magnets. However, the field crosstalk between the two apertures presents challenges. As the CEPC will work at four beam energies of Z, W, Higgs and ttbar mode, the DAQ magnets will operate at four field gradients spanning from 3.18 to 12.63 T/m. The first short quadrupole magnet prototype with the bore diameter of 76 mm and magnetic length of 1.0 m revealed the problems of large magnetic field harmonics and a magnetic center shift within the beam energy range. Accordingly, a compensation method was proposed in this work to solve the field crosstalk effect. By adjusting the gap height at the middle of the two apertures, the field harmonics and magnetic center shift are significantly reduced. After optimization, the short prototype was modified using a new scheme. The field simulations are validated from the magnetic measurement results. Further, the multipole field meets the requirements at the four beam energies. The detailed magnetic field optimization, field harmonics adjustment, and measurement results are presented herein.
分类： 核科学技术 >> 核科学与技术 提交时间： 2023-06-16
Wang, Hao
Lai, Yuecheng
Zhong, Jiajun
Liu, Yunpeng
Yao, Lei
Qian, Lixiong
Xing, Xueqing
Chen, Zhongjun
Mo, Guang
Wu, Zhonghua
摘要： In certain exceptional cases, capillary samples must be used to measure X-ray absorption spectra (XAS). However, the inhomogeneous thickness of capillary samples causes XAS distortion. This study discusses the distortion and correction of the XAS curve caused by the inhomogeneous thickness of capillary samples. The relationship between the distorted XAS curve mdeq (measured values) and the real absorption coefficient msdeq (true values) of the sample was established. The distortion was slight and negligible when the vertical size (2h) of the X-ray beam spot was smaller than 60% of the capillary tubes inner diameter (2Rin). When h/Rin >1, X-ray leakage is inevitable and should be avoided during measurement. Partial X-ray leakage caused by an X-ray beam spot size larger than the inner diameter of the capillary tube leads to serious compressed distortion of the XAS curve. When h/Rin <1, the distorted XAS data were well corrected. Possible errors and their influence on the corrected XAS are also discussed. Simulations and corrections for distortions verify the feasibility and effectiveness of the corrected method.
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