Subjects: Physics >> Nuclear Physics submitted time 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
Abstract： High Energy Photon Source (HEPS) has rigorous restrictions on the vibration levels of the storage ring slab. If the vibration level exceeds the specification limit, it can impact the normal operation of the equipment and influence the sampling efficiency of the experimental terminal. With grandually increasing constructions of the surrounding urban infrastructure, to control the outer vibration sources, it is necessary to study the vibration propagation characteristics on HEPS site. For evaluating the impact of external vibrations on the critical components of HEPS, a series of measurements have been conducted. A shaker was used to artificially generate vertical sinusoidal excitations with frequencies 7Hz up to 100 Hz. The vibration responses were measured along the bare ground, the vibration attenuation of different frequencies are analyzed. A decay formula together with the range of key parameters are obtained according to the fitting results of the measurement data. In the meanwhile, the attenuation formula is validated by the vibration data of a 50t crane traveling on HEPS site. The measurement data fitted nicely with the above mentioned fitting formula. The discrepancy between the measured data and the fitted curve are within 35%. This study will be a basis for the establishment of related regulation for external travel loads around HEPS campus and in the meanwhilie it will provides as a reference for the research methodology of the vibration propagation on the ground.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2023-06-16
Abstract： 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.
Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2023-06-16
Wang, Hao
Lai, Yuecheng
Zhong, Jiajun
Liu, Yunpeng
Yao, Lei
Qian, Lixiong
Xing, Xueqing
Chen, Zhongjun
Mo, Guang
Wu, Zhonghua
Abstract： 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 m’deq (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 tube’s 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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