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Manipulation of Giant Multipole Resonances via Vortex γ Photons

Physical Review Letters 2023年第20期131卷 202502-202502页

作者： Zhi-Wei Lu Liang Guo Zheng-Zheng Li Mamutjan Ababekri Fang-Qi Chen Changbo Fu Chong Lv Ruirui Xu Xiangjin Kong Yi-Fei Niu Jian-Xing Li Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices School of Physics Xi’an Jiaotong University Xi’an 710049 China School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China Frontiers Science Center for Rare Isotopes Lanzhou University Lanzhou 730000 China Key Laboratory of Nuclear Physics and Ion-beam Application (MoE) Institute of Modern Physics Fudan University Shanghai 200433 China Department of Nuclear Physics China Institute of Atomic Energy P.O. Box 275(7) Beijing 102413 China China Nuclear Data Center China Institute of Atomic Energy P.O. Box 275(41) Beijing 102413 China

Traditional photonuclear reactions primarily excite giant dipole resonances, making the measurement of isovector giant resonances with higher multipolarities a great challenge. In this Letter, the manipulation of collective excitations of different multipole transitions in even-even nuclei via vortex γ photons is investigated. We develop the calculation method for photonuclear cross sections induced by the vortex γ photon beam using the fully self-consistent random-phase approximation plus particle-vibration coupling (RPA+PVC) model based on Skyrme density functional. We find that the electromagnetic transitions with multipolarity J<|mγ| are forbidden for vortex γ photons due to the angular momentum conservation, with mγ being the projection of total angular momentum of γ photon on its propagation direction. For instance, this allows for probing the isovector giant quadrupole resonance without interference from dipole transitions using vortex γ photons with mγ=2. Furthermore, the electromagnetic transition with J=|mγ|+1 vanishes at a specific polar angle. Therefore, the giant resonances with specific multipolarity can be extracted via vortex γ photons. Moreover, the vortex properties of γ photons can be meticulously diagnosed by measuring the nuclear photon-absorption cross section. Our method opens new avenues for photonuclear excitations, generation of coherent γ photon laser and precise detection of vortex particles, and consequently, has significant impact on nuclear physics, nuclear astrophysics and strong laser physics.

关键词： Electromagnetic transitions Equations of state of nuclear matter Gamma-ray strength functions Giant resonances Models & methods for nuclear reactions nuclear reactions nuclear transition rates Photonuclear reactions Polarization phenomena Resonance reactions

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Measurement of the Pu239(n,f) cross section from 4 keV to 100 MeV using the white neutron source at the CSNS Back-n facility

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Physical Review C 2023年第2期107卷 024606-024606页

作者： Yijia Qiu Changlin Lan Yonghao Chen Liyang Jiang Jie Bao Yiwei Yang Zhongwei Wen Rong Liu Xichao Ruan Jingyu Tang Jie Ren Hantao Jing Guangyuan Luan Ruirui Fan Yangbo Nie Xianlin Yang Xiaojun Li Han Yi Wei Jiang Tao Ye Yi Yang Shilong Liu Jincheng Wang School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China Institute of High Energy Physics Chinese Academy of Sciences (CAS) Beijing 100049 China Spallation Neutron Source Science Center Dongguan 523803 China Key Laboratory of Nuclear Data China Institute of Atomic Energy Beijing 102413 China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China

The neutron-induced fission cross section of Pu239 was measured relative to U235(n,f) at the back-streaming white neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS). A multicell fast fission ionization chamber was used to perform the measurement. The reliability of the measurement was verified by the high consistency of U235's resonances between the measurement and the evaluation data. The Pu239 fission cross sections from 4keV to 100MeV are obtained with 1.7–5.8 % uncertainty when unfolding uncertainties are excluded. The total uncertainties including the unfolding errors, which reflect the effect of the double-bunch unfolding method, are 2.6–15 % from 10keV to 100MeV.

关键词： Fission A ≥ 220 Spectrometers & spectroscopic techniques

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Current Status and Development Trend Analysis of Neutron Logging in Uranium Mines in China

Current Status and Development Trend Analysis of Neutron Log...

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2021 International Conference on Advances in Optics and Computational sciences, ICAOCS 2021

作者： Liu, Zhifeng Ding, Chenglong Wang, Ruyang Cao, Junwu Jiangxi Engineering Technology Research Center of Nuclear Geoscience Data Science and System East China University of Technology Nanchang Jiangxi330013 China East China University of Technology China 6th Gas Production Plant of Changqing Oilfield China Jiangxi Engineering Laboratory on Radioactive Geoscience and Big Data Technology East China University of Technology Nanchang Jiangxi330013 China

Neutron logging is a method of measuring uranium fission neutrons by bombarding uranium in ore beds with neutrons emitted by neutron sources or neutron generators. The pulsed neutron logging technology of uranium ore has been popularized and applied in the United States, Russia, Australia and other countries. The key technology is almost monopolized by these countries, but the technology is prohibited in China. In the field of uranium logging, natural gamma logging has always been used in China for uranium quantification, which is characterized by large error, low efficiency, high cost and technical and economic bottlenecks. Due to the fact that the research and application of pulsed neutron log in the field of petroleum exploration and production is relatively mature in China, it is urgent to develop relevant logging instruments and uranium quantitative interpretation methods as independent intellectual property rights. This will lead to a change in the backward appearance of uranium logging. This paper analyzes the research status and development trend of neutron logging in uranium at home and abroad. © Published under licence by IOP Publishing Ltd.

关键词： Uranium

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Jet charge identification in ee-Z-qq process at Z pole operation

arXiv

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arXiv 2023年

作者： Cui, Hanhua Zhao, Mingrui Wang, Yuexin Liang, Hao Ruan, Manqi Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Beijing100049 China Science and Technology on Nuclear Data Laboratory China Institute of Atomic Energy Beijing China Neils Bohr Institute University of Copenhagen Copenhagen Denmark China Center of Advanced Science and Technology Beijing100190 China

Accurate jet charge identification is essential for precise electroweak and flavor measurements at the high-energy frontier. We propose a novel method called the Leading Particle Jet Charge method (LPJC) to determine the jet charge based on information of the leading charged particle. Tested on Z → bb¯ and Z → cc¯ samples at center-of-mass energy of 91.2 GeV, the LPJC achieves an effective tagging power ϵeff of 20%/9% for c/b jet, respectively. In combination with the Weighted Jet Charge method (WJC), we develop a Heavy Flavor Jet Charge method (HFJC), which achieves an effective tagging power ϵeff of 39%/20% for c/b jet, respectively. This paper also discusses the dependencies between jet charge identification performance and the fragmentation process of heavy flavor jets, as well as critical detector performances. © 2023, CC BY.

关键词： Charged particles

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Measurement of the neutron capture cross sections of rhenium up to stellar s- and r-process temperatures at the China Spallation Neutron Source Back-n facility

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Physical Review Research 2024年第1期6卷 013225-013225页

作者： Gaole Yang Zhendong An Wei Jiang Xiankai Li Weiwei Qiu Zhengfa Liao Ziyue Zhuang Xiaoping Zhang Shengli Chen Chenchen Guo Erxi Xiao Xiao Fang Xinxiang Li Hongwei Wang Xinrong Hu Bing Jiang Wenqing Shen Jincheng Wang Jie Ren Xichao Ruan Dexin Wang Su-Yalatu Zhang Wen Luo Zhichao Zhu Haoyang Lan Zongwei Cao Xu Ma Yingdu Liu Pusen Wang Yi Yang Ping Su Xiangai Deng Wanbing He Yugang Ma Chunwang Ma Yuting Wang Zhitao Dai Ertao Li Pengqin He RenGuang Tang Tao Zhou Jing Wang Han Yi Yue Zhang Yonghao Chen Ruirui Fan Keqing Gao Qiang Li Kang Sun Zhixin Tan Minhao Gu Hantao Jing Jingyu Tang Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China School of Physics and Astronomy Sun Yat-sen University Zhuhai 519082 China State Key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology Macau 999078 China CNSA Macau Center for Space Exploration and Science Macau 999078 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Spallation Neutron Source Science Center Dongguan 523803 China School of Nuclear Science and Technology University of South China Hengyang 421001 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai 519082 China University of Chinese Academy of Sciences Beijing 100049 China Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201210 China Key Laboratory of Nuclear Data China Institute of Atomic Energy Beijing 102413 China College of Mathematics and Physics Inner Mongolia Minzu University Tongliao 028000China Institute of Nuclear Physics Inner Mongolia Minzu University Tongliao 028000 China Shool of Materials Science and Engineering Xiangtan University Xiangtan 411100 China Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Department of Nuclear Science and Technology Fudan University Shanghai 200433 China Institute of Particle and Nuclear Physics Henan Normal University Xinxiang 453007 China School of Physics Henan Normal University Xinxiang 453007 China Shenzhen Center Cancer hospital Chinese Academy of Medical Sciences Shenzhen 518100 China Institute for Advanced Study in Nuclear Energy and Safety College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060 China School of Nuclear Science and Technology University of Science and Technology of China Hefei 230027 China

The neutron capture measurement of natural rhenium was performed with the time-of-flight technique at the Back-n facility of the China Spallation Neutron Source in the energy range from 1 to 500 eV of the resolved resonance region (RRR) and from 5 to 400 keV in the unresolved resonance region (URR). Prompt γ-rays originating from neutron-induced capture events were detected by four C6D6 detectors. The pulse height weighting technique and the double-bunch unfolding method based on the Bayesian theory were used in the data analysis. To obtain reliable measurement results, background subtraction, normalization, and corrections were carefully considered. The multilevel R-matrix Bayesian code SAMMY was used to extract the resonance parameters in the RRR. An absence of resonance near 392 eV is observed in our measurement, which has been observed in previous works. The average cross sections in the URR of natural rhenium relative to Au197 were obtained in logarithmical equidistant energy bins with 20 bins per energy decade. The talys code was used to describe the average cross sections in the URR; the Maxwellian-averaged cross sections (MACSs) of Re185 and Re187 are given from kT=5 to 100 keV. At a thermal energy of kT=30 keV, the MACS value for Re185 (1469±127 mb) is in good agreement with the Karlsruhe Astrophysical database of Nucleosynthesis in Stars (KADoNIS) recommended value (1535±62 mb) within the error bars. By contrast, the value of 1361±118 mb for Re187 shows a discrepancy with the KADoNiS recommended value (1160±57 mb).

关键词： nuclear astrophysics nuclear reaction rates nuclear reactions Radiative capture Resonance reactions r process s process 150 ≤ A ≤ 189 nuclear data analysis & compilation

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VG-Net: Sensor Time Series Anomaly Detection with Joint Variational Autoencoder and Graph Neural Network

VG-Net: Sensor Time Series Anomaly Detection with Joint Vari...

引用

Smart World Congress (SWC), IEEE

作者： Shuai Wang Shenghao Liu Xiaoxuan Fan Haijun Wang Yinxin Zhou Hanjun Gao Hongwei Lu Xianjun Deng Hubei Key Laboratory of Distributed System Security Hubei Engineering Research Center on Big Data Security School of Cyber Science and Engineering Huazhong University of Science and Technology Wuhan China Hunan Technical College of Railway High-speed China Nanjing University of Posts and Telecommunications China China National Nuclear Power Co Ltd China

ISBN: (数字)9798331520861

ISBN: (纸本)9798331520878

Intelligent Cyber-Physical Systems typically utilize sensors to gather a significant amount of raw data which often possesses temporal and high-dimensional characteristics. Ensuring the data reliability is crucial for the normal operation of the system. While most existing methods are capable of identifying anomalies in high-dimensional time series data from sensors, they often lack adequate accuracy and fail to adequately consider the correlation between sensor nodes. To address these limitations, we propose an unsupervised framework which is a combination of variational autoencoder and graph neural network(VG-Net). By jointly optimizing the reconstruction module and the prediction module, VG-Net effectively models the correlation between sensor nodes while simultaneously detecting anomalies. The reconstruction module is responsible for modeling the latent representation space and reconstructing the time series data through variational autoencoder. The prediction module leverages bidirectional long short term memory networks and neural tensor network to learn the relationships between sensor nodes, and uses graph neural network to predict the future behavior of the data. Experiments on eight real and synthetic datasets demonstrate that, compared with existing methods, VG-Net can accurately model the relationship between sensor nodes and enhance the anomaly detection performance of high-dimensional time series data.

关键词： Time series analysis Autoencoders Sensor phenomena and characterization Predictive models data models Graph neural networks Reliability Anomaly detection Intelligent sensors Synthetic data

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Tensor and Minimum Connected Dominating Set based Confident Information Coverage Reliability Evaluation for IoT

IEEE Transactions on Sustainable Computing

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IEEE Transactions on Sustainable Computing 2024年

作者： Xiao, Ziheng Zhu, Chenlu Feng, Wei Liu, Shenghao Deng, Xianjun Lu, Hongwei Yang, Laurence T. Park, Jong Hyuk Hubei Key Laboratory of Distributed System Security Hubei Engineering Research Center on Big Data Security School of Cyber Science and Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China Artificial Intelligence and Intelligent Transportation Joint Technical Center of HUST and Hubei Chutian Intelligent Transportation Company Ltd United States Network and Industrial Control Information Security Technology Department China Nuclear Power Operation Technology Company Ltd. 1011 Xiongchu Avenue Hubei Wuhan430070 China The Department of Computer Science and Engineering Seoul National University of Science and Technology Seoul01811 Korea Republic of

Internet of Things (IoT) reliability evaluation contributes to the sustainable computing and enhanced stability of the network. Previous algorithms usually evaluate the reliability of IoT by enumenating the states of nodes and networks, which are difficult to handle IoT with hundreds of nodes because the computational cost. In this paper, a novel algorithm, TMCRA, is proposed to evaluate the reliability of IoT in complex network environment, which consider both coverage and connectivity. For coverage, TMCRA employs the Confident Information Coverage (CIC) model to divide the target area into independent grids and calculates the coverage rate. In terms of connectivity, TMCRA forming the Virtual Backbone Network (VBN) based on two proposed methods: TMA and MGIN, and evaluate connectivity by analyzing the VBN rather than the whole network. The TMA and MGIN are two algorithms for constructing Minimum Connected Dominant Sets (MCDS), which are suitable for different scale networks. Finally, based on the data of coverage and connectivity, TMCRA utilizes tensors for the unified modeling and representation of network structure, and calculates IoT reliability based on the tensors. Simulations are carried out for various sizes of IoT to show the advantages and effectiveness of the proposed approach in reliability evaluation. © 2016 IEEE.

关键词： data reliability

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Random node reinforcement and K-core structure of complex networks

arXiv

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arXiv 2022年

作者： Ma, Rui Hu, Yanqing Zhao, Jin-Hua Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou510006 China Department of Statistics and Data Science College of Science Southern University of Science and Technology Shenzhen518055 China School of Data Science and Engineering South China Normal University Shanwei516622 China

To enhance robustness of complex networked systems, a simple method is introducing reinforced nodes which always function during failure propagation. A random scheme of node reinforcement can be considered as a benchmark for finding an optimal reinforcement solution. Yet there still lacks a systematic evaluation on how node reinforcement affects network structure at a mesoscopic level upon failures. Here we study this problem through the lens of K-cores of networks. Based on an analytical percolation framework, we first show that, on uncorrelated random graphs, with a critical size of reinforced nodes, an abrupt emergence of K-cores is smoothed out to a continuous one, and a detailed phase diagram is derived. We then show that, with a cost-benefit analysis on random reinforcement, for proper weight factors in cost functions with constant and increasing marginal costs, a gain function shows a unimodality, thus we can analytically find an optimal reinforcement fraction by locating the maximal gain. In all, our framework offers a gain-oriented analytical perspective to designing robust interconnected systems. Copyright © 2022, The Authors. All rights reserved.

关键词： Reinforcement

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Observation of the Exotic 02+ Cluster State in He8

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Physical Review Letters 2023年第24期131卷 242501-242501页

作者： Z. H. Yang Y. L. Ye B. Zhou H. Baba R. J. Chen Y. C. Ge B. S. Hu H. Hua D. X. Jiang M. Kimura C. Li K. A. Li J. G. Li Q. T. Li X. Q. Li Z. H. Li J. L. Lou M. Nishimura H. Otsu D. Y. Pang W. L. Pu R. Qiao S. Sakaguchi H. Sakurai Y. Satou Y. Togano K. Tshoo H. Wang S. Wang K. Wei J. Xiao F. R. Xu X. F. Yang K. Yoneda H. B. You T. Zheng School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China RIKEN Nishina Center 2-1 Hirosawa Wako Saitama 351-0198 Japan Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Fudan University Shanghai 200433 China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan University Shanghai 200438 China Department of Physics Hokkaido University 060-0810 Sapporo Japan Institute of Modern Physics Chinese Academy of Science Lanzhou 730000 China Nuclear Reaction Data Centre Hokkaido University 060-0810 Sapporo Japan School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing 100191 China Department of Physics Kyushu University 819-0395 Fukuoka Japan Rare Isotope Science Project Institute for Basic Science Daejeon 34000 Republic of Korea Department of Physics Tokyo Institute of Technology 2-12-1 Oh-Okayama Meguro Tokyo 152-8551 Japan

We report here the first observation of the 02+ state of He8, which has been predicted to feature the condensatelike α+n2+n2 cluster structure. We show that this state is characterized by a spin parity of 0+, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

关键词： Direct reactions nuclear structure & decays

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Objective Source Inversion of Continuous Atmospheric 37Cs Releases Following the Fukushima Accident

SSRN

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SSRN 2022年

作者： Dong, Xinwen Fang, Sheng Zhuang, Shuhan Xu, Yuhan Zhao, Yungang Sheng, Li Institute of Nuclear and New Energy Technology Collaborative Innovation Centre of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education Tsinghua University Beijing100084 China Key Laboratory of Beam Technology Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing100875 China CTBT Beijing National Data Centre Beijing Radionuclide Laboratory Beijing100085 China Beijing100081 China

11 years after the Fukushima accident, the independent objective estimates of the atmospheric 137Cs release still suffer from discontinuities such as negative release terms, oscillations, and temporal gaps, leading to noticeable differences from the subjective estimate. In this paper, we propose an objective method that provides a continuous source term by sequentially combining the joint estimation model and total variation regularization. The joint estimation model corrects the model–observation discrepancies and reduces oscillations, while the total variation regularization imposes a piecewise-constant prior and recovers information about the release that may be missing as a result of insufficient observations. An adaptive parameterization is proposed to correct negative values. Validation against the Fukushima accident demonstrates that the retrieved source term is continuous, better agreeing with the recognized subjective source term than nine published estimates both qualitatively and quantitatively. It agrees with the timing of on-site gamma dose rate peaks, significantly improves the air concentration simulations, and reproduces the fine details to the south of the nuclear power plant and in the Chiba area. The estimation error of the proposed method varies smoothly in a limited range with different regularization parameters, enabling automatic parameterization and demonstrating the potential for operational inversions. © 2022, The Authors. All rights reserved.

关键词： Parameterization

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