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Production and test of sPHENIX W/SciFiber electromagnetic calorimeter blocks in China

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nuclear science and techniques 2024年第8期35卷 167-176页

作者： Xiao‑Zhou Yu Xi‑Yang Wang Wei‑Hu Ma Shi‑Hong Fu Peng‑Fei Sun Jin‑Xing Song Wan‑Bing He Yang Shen Long Ma Jin‑Hui Chen Huan‑Zhong Huang Si‑Guang Wang Jing Zhou Xiao‑Mei Li Institute of Modern physics Fudan UniversityShanghai 200433China Key laboratory of nuclear physics and Ion‑Beam Application(MOE) Fudan UniversityShanghai 200433China science and technology on nuclear data laboratory China Institute of Atomic EnergyBeijing 102413China department of physics and Astronomy University of CaliforniaLos AngelesCA 90095USA State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China

the sPHENIX experiment is a new generation of large acceptance detectors at the relativistic heavy ion collider at Brookhaven National laboratory,with scientific goals focusing on probing the strongly interacting Quark–Gluon plasma with hard probes of jets,open heavy flavor particles,andγ*** EMCal detector,which covers the pseudo-rapidity region of|η|≤1.1,is an essential subsystem of *** this study,we focused on producing and testing EMCal blocks covering a pseudo-rapidity of|η|∈[0.8,1.1].these,in conjunction with the central pseudo-rapidity EMCal blocks,significantly enhance the sPHENIX physics capability of the jet andγparticle *** this paper,the detector module production and testing of sPHENIX W-powder/scintillating fiber(W/ScFi)electromagnetic calorimeter blocks are *** selection of the tungsten powder,mold fabrication,QA procedures,and cosmic ray test results are discussed.

关键词： sPHENIX tungsten/scintillating fiber electromagnetic calorimeter Cosmic ray test

A polarized^(3)He system based on metastability-exchange optical pumping

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science China(physics,Mechanics & Astronomy) 2024年第7期67卷 72-81页

作者： Yuting Wang Liangyong Wu Kaiyuan Zhang Mei Peng Siyu Chen Haiyang Yan State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China Institute of nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Key laboratory of nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Key laboratory of Neutron physics Institute of Nuclear Physics and ChemistryChina Academy of Engineering PhysicsMianyang 621900China

Hyperpolarized^(3)He nuclei have emerged as a significantly important approach in quantum precision measurement techniques,with extensive applications in fundamental physics,magnetometry,metrology,and *** this study,we report on the design and implementation of a^(3)He polarization system at the China Mianyang Research Reactor(CMRR),utilizing the metastabilityexchange optical pumping(MEOP)*** employed a Merritt coil system consisting of four square coils to furnish a uniform holding *** deployed a 2 W fiber laser to pump the metastable^(3)He atoms and conducted free induction decay(FId)detection of the polarized^(3)He nuclei using both pickup coil and optical *** the optical method,we used a50 m W linearly polarized distributed Bragg reflector(dBR)laser as the *** applied transverse light absorption polarimetry to measure the absolute nuclear polarization of the ground-state^(3)*** have developed cell fabrication capabilities at the CMRR,and cells at various pressures ranging from 100 to 1000 Pa have been fabricated and *** a typical borosilicate cell with 100 Pa pressure,the absolute polarization is measured as Pn≈70%,and the transverse relaxation time is estimated as t2≈0.5 ***,we constructed a few aluminosilicate cells,each carefully filled with pure^(3)He at a pressure of 100 ***,we conducted a comprehensive evaluation of their performance in the context of MEOP.

关键词： metastability exchange optical pumping polarized^(3)He magnetic resonance

the biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of Environmental sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key laboratory of Radiation physics and technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated *** reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron *** anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by *** was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction *** of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NAdH)from enzymatic reaction of sodium lactate with various *** transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NAdH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

Principal components of nuclear mass models

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science China(physics,Mechanics & Astronomy) 2024年第7期67卷 65-71页

作者： Xin-Hui Wu Pengwei Zhao department of physics Fuzhou UniversityFuzhou 350108China State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China

Principal component analysis(PCA)is employed to extract the principal components(PCs)present in nuclear mass models for the first *** effects from different nuclear mass models are reintegrated and reorganized in the extracted *** PCs are recombined to build new mass models,which achieve better accuracy than the original theoretical mass *** comparison indicates that using the PCA approach,the effects contained in different mass models can be collaborated to improve nuclear mass predictions.

关键词： nuclear mass principal component analysis nuclear models statistical methods

Structure and 2p decay mechanism of^(18)Mg

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nuclear science and techniques 2024年第6期35卷 145-154页

作者： Long Zhou de-Qing Fang Si-Min Wang Hui Hua Key laboratory of nuclear physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for theoretical nuclear physics NSFC and Fudan UniversityShanghai 200438China School of physics and State Key laboratory of nuclear physics and technology Peking UniversityBeijing 100871China

the recently discovered,extremely proton-rich nuclide 18 Mg exhibits ground-state decay via two sequential two-proton(2p)emissions through the intermediate nucleus,*** study investigates the structure and the initial 2p decay mechanism of^(18)Mgby examining the density and correlations of the valence protons using a three-body Gamow coupled-channel *** results show that the ground state of^(18)Mgis significantly influenced by the continuum,resulting in a significant s-wave ***,based on the current framework,this does not lead to a significant deviation in mirror symmetry in either the structure or spectroscopy of the 18Mg-18C ***,the time evolution analysis of the^(18)Mgground state suggests a simultaneous 2p emission during the first step of *** observed nucleon-nucleon correlations align with those of the light-mass 2p emitters,indicating a consistent decay behavior within this nuclear region.

关键词： Structure of^(18)Mg two-proton decay Proton-proton correlation

Generalized time-dependent generator coordinate method for induced fission dynamics

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Frontiers of physics 2024年第4期19卷 1-12页

作者： B.Li d.Vretenar t.Nikšić J.Zhao P.W.Zhao J.Meng State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China physics department Faculty of ScienceUniversity of Zagreb10000 ZagrebCroatia Center for Circuits and Systems Peng Cheng LaboratoryShenzhen 518055China

the generalized time-dependent generator coordinate method(td-GCM)is extended to include pairing *** correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight *** particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional,while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation *** the inclusion of pairing correlations,various time-dependent phenomena in open-shell nuclei can be described more *** model is applied to the description of saddle-to-scission dynamics of induced *** generalized td-GCM charge yields and total kinetic energy distribution for the fission of 240Pu,are compared to those obtained using the standard time-dependent density functional theory(td-dFt)approach,and with available data.

关键词： nuclear density functional theory generator coordinate method fission dynamics

Implications of neutron skin measurements on Skyrme equations of state

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Chinese physics C 2024年第6期48卷 155-161页

作者：管大为裴俊琛蒋崇基 State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China Southern Center for nuclear-science theory(SCNt) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

the recent measurements of neutron skins via parity violation in electron scattering have extracted an abnormally thick neutron skin for 208 Pb,which has significant consequences in nuclear equation of state(EoS)and neutron star *** this study,we perform optimizations of extended Skyrme forces in a consistent manner by including neutron skin thicknesses from PREX-Ⅱand CREX experiments and investigate nuclear EoSs and neutron stars in the GW170817 event By varying the fitting weights of neutron skins,several new Skyrme parameterizations are *** results show the competition in the fitting procedure to simultaneously describe neutron skins,other properties of finite nuclei,and neutron star *** prospects of resolving neutron skin issues are also discussed.

关键词： neutron skin equation of state neutron star Skyrme force

Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

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nuclear science and techniques 2024年第1期35卷 178-187页

作者： Sheng-da tang Yong-Hao Chen Jing-Yu tang Rui-Rui Fan Qiang Li Gong Li dong Liu Zheng-Yao Jin Xing-Zhu Cui tian-Xiang Chen Yi-Wei Yang Rong Liu Han Yi Yang Li Zhen Yang Qi An Hao-Fan Bai Jiang-Bo Bai Jie Bao Ping Cao Qi-Ping Chen Zhen Chen Zeng-Qi Cui An-Chuan Fan Chang-Qing Feng Fan-Zhen Feng Ke-Qing Gao Min-Hao Gu Chang-Cai Han Zi-Jie Han Guo-Zhu He Yong-Cheng He Yang Hong Yi-Wei Hu Han-Xiong Huang Wei-Hua Jia Hao-yu Jiang Wei Jiang Zhi-jie Jiang Ling Kang Bo Li Chao Li Jia-Wen Li Xiao Li Jie Liu Shu-Bin Liu Guang-Yuan Luan Chang-Jun Ning Bin-Bin Qi Jie Ren Zhi-Zhou Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-Xin tan Li-Jiao Wang Peng-Cheng Wang Zhao-Hui Wang Zhong-Wei Wen Xiao-Guang Wu Xuan Wu Li-Kun Xie Yong-Ji Yu Guo-Hui Zhang Lin-Hao Zhang Mo-Han Zhang Qi-Wei Zhang Xian-Peng Zhang Yu-Liang Zhang Yue Zhang Zhi-Yong Zhang Mao-Yuan Zhao Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu Sino-French Institute of nuclear Engineering and technology Sun Yat-sen UniversityZhuhai 519082China Institute of High-Energy physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source science Center Dongguan 523803China School of nuclear science and technology University of Science and Technology of ChinaHefei 230026China State Key laboratory of Particle detection and Electronics University of Science and Technology of ChinaHefei 230026China State Key laboratory of Particle detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China UStC Archaeometry laboratory University of Science and Technology of ChinaHefei 230026China Institute of nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China department of Modern physics University of Science and Technology of ChinaHefei 230026China State Key laboratory of nuclear physics and technology School of PhysicsPeking UniversityBeijing 100871China Key laboratory of nuclear data China Institute of Atomic EnergyBeijing 102413China Northwest Institute of nuclear technology Xi’an 710024China University of Chinese Academy of sciences Beijing 100049China

Nondestructive and noninvasive neutron assays are essential applications of neutron *** resonance transmission analysis(NRtA)is a powerful nondestructive method for investigating the elemental composition of an *** back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRtA method for nuclide identification was conducted at the CSNS Back-n via two test *** results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRtA method at *** study reveals its potential future applications.

关键词： CSNS White neutron beam NRtA Nuclide identification Nondestructive method

Benchmark experiment on slab^(238)U with d-t neutrons for validation of evaluated nuclear data

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nuclear science and techniques 2024年第2期35卷 145-159页

作者： Yan-Yan ding Yang-Bo Nie Yue Zhang Zhi-Jie Hu Qi Zhao Huan-Yu Zhang Kuo-Zhi Xu Shi-Yu Zhang Xin-Yi Pan Chang-Lin Lan Jie Ren Xi-Chao Ruan Key laboratory of nuclear data China Institute of Atomic EnergyBeijing 102413China School of nuclear science and technology Lanzhou UniversityLanzhou 730000China Institute of Fluid physics China Academy of Engineering PhysicsMianyang 62100China

A benchmark experiment on^(238)U slab samples was conducted using a deuterium-tritium neutron source at the China Institute of Atomic *** leakage neutron spectra within energy levels of 0.8-16 MeV at 60°and 120°were measured using the time-of-flight *** samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3,6,and 9 *** leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of^(238)U evaluated neutron data from CENdL-3.2,ENdF/B-Ⅷ.0,JENdL-5.0,and *** on the comparison,the deficiencies and improvements in^(238)U evaluated nuclear data were *** results showed the following.(1)the calculated results for CENdL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60°and 120°.(2)the calculated results of CENdL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 120°.(3)the calculated results for CENdL-3.2 significantly overestimated the measurements in the 3-8.5 MeV energy interval at 60°and 120°.(4)the calculated results with JENdL-5.0 were generally consistent with the measurement results.

关键词： Leakage neutron spectra Uranium d-t neutron source Evaluated nuclear data