分类： 核科学技术 >> 粒子加速器 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Beam position monitors (BPMs) have been widely used in all kinds of measurement systems, feedback systems and other areas in particle accelerator field these days. The malfunction of a single BPM can cause serious consequences such as the failure of the orbit feedback and the transverse feedback. A troubleshooting has been made to prevent the defective BPMs from affecting the accuracy and stability of the storage ring in Shanghai Synchrotron Radiation Facility (SSRF). Different types of malfunctions have been successfully identified by using the idea of principal component analysis (PCA).
分类： 核科学技术 >> 核科学与技术 提交时间： 2024-03-08
摘要： Various electromagnetic signals are excited by the beam in the acceleration and beam-diagnostic elements of a particle accelerator. It is important to obtain time-domain waveforms of these signals with high temporal resolution for research, such as the study of beam-cavity interactions and bunch-by-bunch parameter measure#2;ments. Therefore, a signal reconstruction algorithm with ultrahigh spatiotemporal resolution and bunch phase compensation based on equivalent sampling is proposed in this paper. Compared with traditional equivalent sampling, the use of phase compensation and setting the bunch signal zero-crossing point as the time reference can construct a more accurate reconstructed signal. The basic principles of the method, simulation, and experi#2;mental comparison are also introduced. Based on the beam test platform of the Shanghai Synchrotron Radiation Facility (SSRF) and the method of experimental verification, the factors that affect the reconstructed signal qual#2;ity are analyzed and discussed, including the depth of the sampled data, quantization noise of analog-to-digital converter (ADC), beam transverse oscillation, and longitudinal oscillation. The results of the beam experiments show that under the user operation conditions of the Shanghai Synchrotron Radiation Facility (SSRF), a beam excitation signal with an amplitude uncertainty of 2% can be reconstructed.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
CAI Xiao-Lu
FAN Guang-Wei
XU Hang-hua
AN Zhen-Dong
FAN Gong-Tao
XU Ben-Ji
LI Yong-Jiang
Pan Qiang-Yan
YAN Zhe
XU Wang
摘要： The ambiguity of the structure of 12Be especially in the configuration of 12Be ground state has attracted a lot of attention recently. We notice that the nuclear reaction cross section R at low energy region is sensitive to the surface structure of 12Be, which is greatly impacted by the ground state configuration of 12Be especially by the occupancy probability of the s orbital component. By using existed interaction cross section data of 12Be on C at 790 MeV/nucleon and Glauber model, the upper limit of the s orbital occupation probability of 12Be ground state is roughly determined to be about 56% with Single Particle Model calculations. This demonstrates that the method is very promising to determine the s orbital component of 12Be with proper nuclear-matter density distribution calculations for different orbitals of 12Be ground state. Hence we bring forward to determine the s orbital component of 12Be by measuring the R of 12Be on C and Al at several tens of MeV/nucleon. In this paper, the feasibility and detailed experimental scheme of the R measurement are carefully studied. The precision of the s orbital occupation probability of 12Be ground state is expected to achieve 9% by using the proposed 2% R data.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2025-02-04
Wang, Cheng
Tan, Jianhao
Nie,Yuancun
Su, Dinghui
Gao, Zihe
Guo, Yusen
Zhang, Yuxin
He, Jianhua
Fang, Wencheng
Zhao, Zhentang
摘要： Radio frequency (RF) cavities for advanced storage rings, also known as diffraction-limited storage rings, are under development. To this end, a competitive and promising approach involves normal-conducting continuous wave technology. The design and preliminary test of a 499.654MHz RF cavity for the Wuhan Advanced Light Source (WALS) based on specific beam parameters were conducted at the SSRF. Multi-objective evolutionary algorithms have been utilized to optimize RF properties, such as the power loss and power density, resulting in better performance in the continuous wave mode. Further improvements were made to suppress multipacting effects in the working area. To operate stably with the beam, higher-order mode dampers were applied to better address the coupling bunch instability than in previous designs, along with thermal analysis to achieve the desired RF performance. Comprehensive simulation studies demonstrated the stable operation of the RF cavity at the defined beam parameters in the WALS design. A prototype RF cavity was then developed, and the RF performance results in a low-power test showed good agreement with the design and simulation, exhibiting readiness for high-power experiments and operation.
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