分类： 物理学 >> 核物理学 提交时间： 2025-03-10
摘要： Hefei advanced light facility (HALF) is a 4th-generation diffraction-limited synchrotron light source which started construction in 2023. The storage ring has an extremely low emittance of less than 100 pm·rad with an energy of 2.2 GeV. It contains 20 superperiods of the modified hybrid 6-bend achromat with a circumference of about 480 m. A real storage ring is different from the ideal model due to various sources of errors, such as misalignment of components, imperfect magnetic fields, RF cavities, etc. As a result of strong nonlinear effects and small dynamic apertures, the errors have a serious effect on the low-emittance storage ring, which brings great difficulties to its commissioning. To figure out the practical performance of the machine with those errors, the start-to-end commission simulation is performed in this study, which also helps to verify the effectiveness of the commissioning of the HALF storage ring. In addition, the commissioning simulation process provides the basis for the development of the commissioning software for the HALF storage ring. Details and results of the commissioning simulation are reported in this paper.
分类： 物理学 >> 核物理学 提交时间： 2025-01-02
摘要： Hefei advanced light facility (HALF) is a 4th-generation diffraction-limited synchrotron light source which started construction in 2023. The storage ring has an extremely low emittance of less than 100 pm·rad with an energy of 2.2 GeV. It contains 20 superperiods of the modified hybrid 6-bend achromat with a circumference of about 480 m. A real storage ring is different from the ideal model due to various sources of errors, such as misalignment of components, imperfect magnetic fields, RF cavities, etc. As a result of strong nonlinear effects and small dynamic apertures, the errors have a serious effect on the low-emittance storage ring, which brings great difficulties to its commissioning. To figure out the practical performance of the machine with those errors, the start-to-end commission simulation is performed in this study, which also helps to verify the effectiveness of the commissioning of the HALF storage ring. In addition, the commissioning simulation process provides the basis for the development of the commissioning software for the HALF storage ring. Details and results of the commissioning simulation are reported in this paper.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-04-07
摘要： Beams usually do not travel through the magnet centers due to errors in storage rings. The beam deviatingfrom the quadrupole centers is affected by additional dipole fields due to magnetic field feed-down. The beambased alignment (BBA) is often performed to find a golden orbit, on which the beam circulates around thequadrupole center axes. For storage rings with a large number of quadrupoles, the conventional BBA procedureis time-consuming, especially in the commissioning phase due to the necessary iterative process. Additionally,the conventional BBA method can be affected by strong coupling and nonlinearity of the storage ring optics.In this work, a novel method based on a neural network is proposed to find the golden orbit in a much shortertime with reasonable accuracy. This golden orbit can be directly used for operation, or can be adopted as thestarting point for the conventional BBA. The method is demonstrated in the HLS-II storage ring for the firsttime, through simulation and online experiments. The results of the experiments show that the golden orbitobtained using this new method is consistent with that from the conventional BBA. The development of thisnew method and corresponding experiments are reported in this paper.
分类： 物理学 >> 核物理学 提交时间： 2023-08-11
摘要： Multi-objective evolutionary algorithms (MOEAs) are typically used to optimize two or three objectives in the accelerator field and perform well. However, the performance of these algorithms may severely deteriorate when the optimization objectives for an accelerator [A1]are equal to or greater than four. Recently, many-objective evolutionary algorithms (MaOEAs) that can solve problems with four or more optimization objectives have received extensive attention. In this study, two diffraction-limited storage ring (DLSR) lattices of the ESRF-EBS [A2]type with different energies were designed and optimized using three MaOEAs and a widely used MOEA. The initial population[A3] was found to have a significant impact on the performance of the algorithms and was carefully studied. The performances of the four algorithms were compared, and the results demonstrated that the grid-based evolutionary algorithm (GrEA) had the best performance. MaOEAs were applied in many-objective optimization of DLSR lattices for the first time, and lattices with natural emittances of 116 pm∙rad and 23 pm∙rad were obtained at energies of 2 GeV and 6 GeV, respectively, both with reasonable dynamic aperture and local momentum aperture (LMA). This work provides a valuable reference for future multi-objective optimization of DLSRs.
分类： 物理学 >> 核物理学 提交时间： 2024-09-13
摘要： In conventional isochronous mass spectrometry (IMS) performed at a storage ring, the precision of mass measurement for short-lived nuclei depends on the precise determination of the revolution times (Ts) of stored ions. However, the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions, resulting in limited mass resolving power. In this work, we measure the betatron tune Q (the number of betatron oscillations within a single revolution) of the ions, and construct a correlation between T and Q. From this correlation, the T are transformed corresponding to a fixed Q with higher resolution. Using the transformed Ts, we re-determine the masses of 63Ge, 65As, 67Se, and 71Kr, which agree well with the mass values measured by the newly developed IMS (Bρ-IMS). We also study the systematics of Coulomb displacement energies (CDEs) and find that the anomalous staggering in CDEs is removed using the new mass values. This method of T transformation is very useful for the conventional IMS equipped with a single time-of-flight detector.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： High precision time measurement is required in the readout of the neutron wall and TOF walls in the external target experiment of the Cooling Storage Ring (CSR) project in the Heavy Ion Research Facility in Lanzhou (HIRFL). Considering the time walk correction, both time and charge are measured in the readout electronics. In this 16-channel measurement module, time and charge information are digitized by TDCs at the same time based on the Time-Over-Threshold (TOT) method; meanwhile, by employing high-density ASIC chips, the electronics complexity is effectively reduced. Test results indicate that this module achieves a time resolution better than 25 ps and a charge resolution better than 5% over the input amplitude range from 50 mV to 3 V.
分类： 物理学 >> 核物理学 提交时间： 2025-05-06
Luo, Mr. Yinfang
Lv, Mr. Jiahao
Xing, Dr. Yuan-ming
Zhang, Prof. Yuhu
Zhang, Mr. Min
Wang, Prof. Meng
Litvinov, Prof. Yuri
Zhou, Prof. Xiaohong 周小红
摘要： The technique of Bρ-defined isochronous mass spectrometry (Bρ-IMS), established at a storage ring, serves as a valuable tool for determining the masses of short-lived nuclei. In the previous Bρ-IMS experiments, the effects of magnetic field drifts have to be corrected in order to improve the mass resolving power of Bρ-IMS [Eur. Phys. J. A 59, 27 (2023)]. The correction procedures are complicated and require multiple reference ions with well-known masses in each injection, which may not be the cases in the measurements of exotic nuclei with tiny production yields. In this study, we propose a novel approach of Bρ-IMS that requires only one reference ion for mass determination in an individual injection, avoiding the tedious and complicated correction procedures. This approach achieves the mass precision comparable to that of previous Bρ-IMS results, and is approved to be suitable for future mass measurements of exotic nuclei with extremely low production yields.
分类： 物理学 >> 核物理学 分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2016-11-25
摘要： Changes in beam position within charged particle accelerator storage rings have been observed due to changes in gravity （Δg） caused by the moon and sun. The terrestrial tidal model has been used to explain this type of beam instability. Further analysis reveals that these instabilities arise from changes in the electron beam energy, rather than from movements of the accelerator components due to terrestrial tidal forces. We suggest a potential model to better explain this type of instability. Consider a charged particle beam ring rotating with the earth, perpendicular to the moon's line of gravity. We induce an electromotive force along the ring, referred to as electro-gravitational induction (EGI). The circular motion of the charged particles causes the accumulation of the EGI in the storage ring, turn by turn. We used existing data from storage ring beam signals to estimate the maximum value of the gravity coefficient of the induced electromotive force.
点击量
待评议
点击量
下载量
评论
通过
