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arXiv 2023年

作者： Chen, Tao Duan, Zhe Ji, Daheng Wang, Dou Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing10049 China University of Chinese Academy of Sciences 19A Yuquan Road Beijing10049 China

acceleration of polarized electron (positron) beams in a booster synchrotron may suffer from depolarization due to crossings of many spin depolarization resonances, and this could limit its applications. We have studied the structure of spin depolarization resonances of a 100 km-scale booster lattice of the Circular Electron Positron Collider (CEPC). The lattice has 8 arc regions with hundreds of FODO cells, interleaved with straight sections, leading to a high periodicity. Our analysis shows the contributions to the strength of intrinsic and imperfection spin resonances add up coherently near the super-strong resonances beyond 120 GeV, but mostly cancel out and result in generally weak resonance strengths at lower beam energies. Detailed simulations confirm that beam polarization can be mostly maintained in the fast acceleration to 45.6 GeV and 80 GeV, but that severe depolarization may occur at even higher energies. This study suggests the possibility of acceleration of polarized electron (positron) beams to ultra-high beam energies without the help of Siberian snakes, and supports injecting highly polarized beams into the collider rings as an attractive solution for resonant depolarization measurements and longitudinally polarized colliding beam experiments for future 100 km-scale circular e+e− colliders. Copyright © 2023, The Authors. All rights reserved.

关键词： Depolarization

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A PID algorithm based on convolutional neural network for pointing stabilization control of synchrotron radiation beams 4

A PID algorithm based on convolutional neural network for po...

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4th International Conference on Mechanical Engineering, Intelligent Manufacturing, and Automation technology, MEMAT 2023

作者： Hu, Zhaohui Liang, Gaoqi Xiu, Qinglei Wei, Yadong Institute of Science & Technology Innovation Dongguan University of Technology Dongguan523808 China School of Automation Guangdong University of Technology Guangzhou510006 China Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Spallation Neutron Source Science Center Dongguan523803 China State Key Laboratory of Particle Detection and Electronics Beijing100049 China

ISBN: (纸本)9781510674820

A PID algorithm using a fixed set of parameters in synchrotron radiation beam control systems does not meet the need to control various environmental vibrations. This study proposes a vibration identification method based on convolutional neural network(CNN) to improve the PID algorithm. Firstly, the genetic algorithm is used to rectify the optimal control parameters for various types of vibration in advance, and then the CNN recognizes the vibration types to assist the PID algorithm in selecting the corresponding optimal control parameters online, so as to realize the optimal control under various vibrations. A set of mixed vibration signal inputs are applied to the beam control system to detect the final beam position deviation displacement. The experiment shows that the beam deviation displacement under the improved PID method is smaller and has better results than the traditional PID control method © 2024 SPIE.

关键词： Genetic algorithms

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Multishelled CuO/Cu_(2)O induced fast photo-vapour generation for drinking water

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Nano Research 2022年第5期15卷 4117-4123页

作者： Xuanbo Chen Ping Li Jiao Wang Jiawei Wan Nailiang Yang Bo Xu Lianming Tong Lin Gu Jiang Du Jianjian Lin(✉) Ranbo Yu Dan Wang Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China State Key Laboratory of Biochemical Engineering Key Laboratory of Science and Technology on Particle MaterialsChinese Academy of SciencesBeijing 100190China Key Laboratory of Eco-chemical Engineering College of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China Henan Province Industrial Technology Research Institute of Resources and Materials Green Catalysis CenterCollege of ChemistryZhengzhou UniversityZhengzhou 450001China University of Chinese Academy of Sciences Beijing 100049China Center for Nano-chemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Solar thermal interfacial water evaporation is proposed as a promising route to address freshwater scarcity,which can reduce energy consumption and have unlimited application *** large semiconductor family with controllable bandgap and good chemo-physical stability are considered as good candidates for ***,the evaporation rate is not satisfactory because the rational control of nano/micro structure and composition is still in its infancy ***,by systemically analyzing the photo-thermal evaporation processes,we applied the hollow multishelled structure(HoMS)into this *** from the multishelled and hierarchical porous structure,the light absorption,thermal regulation,and water transport are simultaneously optimized,resulting in a water evaporation rate of 3.2 kg·m^(-2)·h^(-1),which is among the best performance in solar-vapour *** collected water from different water resources meets the World Health Organization standard for drinkable ***,by using the CuO/Cu_(2)O system,reactive oxygen species were generated for water disinfection,showing a new route for efficient solar-vapour generation and a green way to obtain safe drinking water.

关键词： multishelled structure hollow structure water evaporation nano/micro structure

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Instability issues in CEpC 58

Instability issues in CEpC

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58th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e" Colliders, eeFACT 2016

作者： Wang, N. Gong, D.J. Zheng, H.J. Zhang, Y. Sun, Y.S. Xu, G. Wang, Y.W. Wang, D. Qin, Q. Gao, J. Chou, W. He, J. Zhou, D. Ohmi, K. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China KEK Ibaraki Japan

ISBN: (纸本)9783954501878

The CEPC is a high-energy circular electron-positron collider under design. Large bunch population is required to achieve the design luminosity. Instabilities driven by the coupling impedance are possible limitations for reaching high machine performance. An updated impedance model, including the resistive wall and the main vacuum components, has been obtained for the main ring. Based on the impedance model, the collective instability issues of the beam with the partial-double ring design are discussed. Copyright © 2017 CC-BY-3.0 and by the respective authors

关键词： Luminance

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Interpretation of new measurements of B/C and diffuse gamma rays using freshly accelerated cosmic rays interacting with surrounding medium 38

Interpretation of new measurements of B/C and diffuse gamma ...

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38th International Cosmic Ray Conference, ICRC 2023

作者： Zhang, Pei-Pei He, Xin-Yu Liu, Wei Guo, Yi-Qing Yuan, Qiang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China School of Astronomy and Space Science University of Science and Technology of China Anhui Hefei230026 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China

Big progresses have been achieved in the measurements of cosmic rays and gamma rays in recent years. The diffuse γ-ray emission above 100 TeV was measured by the Tibet-ASγ experiment. Hardenings of the boron-to-carbon and boron-to-oxygen ratios at about 100 GeV/n have been revealed by the DAMPE experiment. These observations indicate modifications to the traditional cosmic-ray propagation and/or interaction model. In this contribution, we propose that the secondary particles produced by the hadronic interactions of freshly accelerated cosmic rays with the interstellar gas near the sources, can naturally account for the diffuse emission and the secondary-to-primary ratios. This model can be further tested by recent measurements with LHAASO. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmic rays

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A stopping layer concept to improve the spatial resolution of gas-electron-multiplier neutron detector

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Chinese physics B 2022年第5期31卷 225-230页

作者： Jianjin Zhou Jianrong Zhou Xiaojuan Zhou Lin Zhu Jianqing Yang Guian Yang Yi Zhang Baowei Ding Bitao Hu Zhijia Sun Limin Duan Yuanbo Chen School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Spallation Neutron Source Science Center Dongguan 523803China State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

In recent years,gas electron multiplier(GEM)neutron detectors have been developing towards high spatial resolution and high dynamic counting *** propose a novel concept of an Al stopping layer to enable the detector to achieve sub-millimeter(sub-mm)spatial *** neutron conversion layer is coated with the Al stopping layer to limit the emission angle of ions into the drift *** short track projection of ions is obtained on the signal readout board,and the detector would get good spatial *** spatial resolutions of the GEM neutron detector with the Al stopping layer are simulated and optimized based on Geant4 Garfield *** spatial resolution of the detector is 0.76 mm and the thermal neutron detection efficiency is about 0.01%when the Al stopping layer is 3.0μm thick,the drift region is 2 mm thick,the strip pitch is 600μm,and the digital readout is ***,the GEM neutron detector with a simple detector structure and a fast readout mode is developed to obtain a high spatial resolution and high dynamic counting *** could be used for the direct measurement of a high-flux neutron beam,such as Bragg transmission imaging,very small-angle scattering neutron detection and neutron beam diagnostic.

关键词： high spatial resolution Al stopping layer GEM neutron detector spallation neutron source

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Preparation for CSST:Star-galaxy Classification using a Rotationally Invariant Supervised Machine Learning Method

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Research in Astronomy and Astrophysics 2024年第9期24卷 136-146页

作者： Shiliang Zhang Guanwen Fang Jie Song Ran Li Yizhou Gu Zesen Lin Chichun Zhou Yao Dai Xu Kong Institute of Astronomy and Astrophysics Anqing Normal UniversityAnqing 246133China Deep Space Exploration Laboratory/Department of Astronomy University of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Tsung-Dao Lee Institute and Key Laboratory for Particle Physics Astrophysics and CosmologyMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China Department of Physics The Chinese University of Hong KongShatinN.T.Hong KongS.A.R.China School of Engineering Dali UniversityDali 671003China

Most existing star-galaxy classifiers depend on the reduced information from catalogs,necessitating careful data processing and feature *** this study,we employ a supervised machine learning method(GoogLeNet)to automatically classify stars and galaxies in the COSMOS *** traditional machine learning methods,we introduce several preprocessing techniques,including noise reduction and the unwrapping of denoised images in polar coordinates,applied to our carefully selected samples of stars and *** dividing the selected samples into training and validation sets in an 8:2 ratio,we evaluate the performance of the GoogLeNet model in distinguishing between stars and *** results indicate that the GoogLeNet model is highly effective,achieving accuracies of 99.6% and 99.9% for stars and galaxies,***,by comparing the results with and without preprocessing,we find that preprocessing can significantly improve classification accuracy(by approximately 2.0% to 6.0%)when the images are *** preparation for the future launch of the China Space Station Telescope(CSST),we also evaluate the performance of the GoogLeNet model on the CSST simulation *** results demonstrate a high level of accuracy(approximately 99.8%),indicating that this model can be effectively utilized for future observations with the CSST.

关键词： methods:data analysis techniques:image processing stars:imaging

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Design, Construction and Testing of Prototype Cryogenic Circulation Centrifugal Pump for High Energy Photon Source

SSRN

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SSRN 2024年

作者： Han, Ruixiong Zhang, Xiangzhen Ge, Rui Geng, Haipeng Xu, Hao Lin, Hao Jiang, Yongcheng Zhang, Jiehao Sang, Minjing Zhao, Tongxian Zhang, Zhuo Xu, Miaofu Ma, Changcheng Ye, Rui Yang, Xiaocheng Chang, Zhengze Li, Mei Sun, Liangrui Zhu, keyu Li, Shaopeng Beijing100049 China Key Laboratory of Particle Acceleration Physics & Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China School of mechanical engineering Xi'an Jiaotong University Xi'An710049 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University Xi'An710049 China

A cryogenic circulation pump (CCP), is the key equipment of the cooling system for the cryogenic permanent magnet undulator (CPMU) and synchrotron monochromator in High Energy Photon Source(HEPS) , which is including a motor at room temperature, an impeller and a volute in the cryogenic environment. The mechanic structure of the CCP is designed according to the operation parameters, and steady-state analysis of internal flows in volute is performed by the numerical simulation, meanwhile, the experimental investigation of the CCP is carried out in the liquid nitrogen (LN2) cryogenic system. The performances of the CCP are verified experimentally, and the results are shown that the calculated performances of the CCP are in reasonable agreement with the experimental results, which indicates that thermal calculation model of the CCP is more accurate. Moreover, the deviations of pressure drop and head between the calculation and measurement are analyzed in this paper. © 2024, The Authors. All rights reserved.

关键词： Photons

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Semileptonic decays meson to S-wave charmonia and X(3872) within the covariant light-front approach

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The European Physical Journal C 2023年第10期83卷 1-14页

作者： Sun, Zhi-Jie Wang, Si-Yang Zhang, Zhi-Qing Yang, You-Ya Zhang, Zi-Yu Institute of Theoretical Physics School of Sciences Henan University of Technology Zhengzhou China Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE) Central China Normal University Wuhan China

In this work, we investigate the semileptonic decays of $$B_{c}$$ meson to $$\eta _{c}(1S,2S,3S)$$ , $$\psi (1S,2S,3S)$$ and X(3872) within the framework of covariant light-front quark model (CLFQM). We combine the helicity amplitudes via the corresponding form factors to obtain the branching ratios of the semileptonic decays $$B_{c}\rightarrow \eta _{c}(1S, 2S, 3S)\ell \nu _{\ell }$$ , $$B_{c}\rightarrow \psi (1S, 2S, 3S))\ell \nu _{\ell }$$ and $$B_{c}\rightarrow X(3872)\ell \nu _{\ell }$$ , with $$\ell =e,\mu ,\tau $$ . In view of the $$R_{J/\Psi }$$ anomaly released by the LHCb collaboration, it is necessary to systematically calculate the ratios $$R_X$$ with $$X=\psi (1S,2S,3S),\eta _c(1S,2S,3S),X(3872)$$ , which are helpful for checking the lepton flavor universality (LFU). We also take into account another two physical observables, the longitudinal polarization fraction $$f_{L}$$ and the forward–backward asymmetry $$A_{FB}$$ , which can provide new clues for understanding the $$R_{J /\Psi }$$ anomaly. Such theoretical predictions are necessary and interesting, and can be tested in future LHCb experiments.

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A rotating coilmeasurement system based on CMM for high-gradient small-aperture quadrupole in HEPS-TF

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Radiation Detection technology and Methods 2021年第1期5卷 8-14页

作者： Mei Yang Fusan Chen Baogui Yin Ran Liang Shuai Li Yingshun Zhu Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of ScienceBeijing 1000049China China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of SciencesDongguan 523803China Dongguan Neutron Science Center Dongguan 523808China University of Chinese Academy of Sciences Beijing 100049China

Purpose A new rotating coil measurement system based on the coordinate measurement machine(CMM)is developed for measuring high-gradient small-aperture quadrupole magnet in the Test Facility of High Energy Photon Source(HEPS-TF).Methods The CMMand two groups of Newport translate stages are combined to align the rotating coil relative to the magnet mechanical center.A high precision ceramic skeleton with bucked coil is made as a measurement *** integrated field gradient,harmonics,magnetic center offset and excitation curve of a high-gradient small-aperture quadrupole prototype magnet are *** The rotating coil is aligned to the magnet mechanical center within 10μ*** reproducibility of higher harmonics is within 0.2×10–*** repeatability of the magnet center in horizontal direction is under 1.5μm,while that in vertical direction is less than 2.5μm in different *** architecture of the measurement system,the measuring procedure and some primary results of the quadrupole prototype magnet are illustrated in this *** A rotating coil measurement system based on CMM has been well developed,and the collimation efficiency and precision are *** harmonic changes caused by iron fingers are measured by the measurement *** difference between the measurement result and the OPERA-3D simulation result is less than 0.5×10–*** performance of this measurement system can meet the magnet measurement requirements of HEPS-TF.

关键词： Small-aperture quadrupole Rotating coil CMM Digital bucking Magnetic field measurement system

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