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Fission Properties of Neutron-Rich Nuclei around the End Point of r-Process

Chinese physics Letters 2023年第1期40卷 23-27页

作者：陈佳炜裴俊琛强雨迟济怀 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

We studied the fission properties of neutron-rich nuclei278,286Cf around the end point of r-process by microscopic self-consistent approaches. The fission barriers and potential energy surfaces are obtained by constrained static Skyrme Hartree–Fock-BCS calculations. Fission fragments are studied by dynamical time-dependent Hartree–Fock+BCS calculations. Results show that286Cf has an octupole deformation at ground state, which can increase the fission barrier height by 1.1 Me V and enhance significantly the spontaneous fission half-life. To search possible fission channels, dynamical calculations with a broad coverage of initial deformations result in two slightly asymmetric peaks around A=128 and 150 for278Cf, and A=133 and 153 for286Cf. Very asymmetric fission channels as given by semi-empirical models are not found in our results.

关键词： Hartree dynamical asymmetric

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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

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Examination of machine learning for assessing physical effects:Learning the relativistic continuum mass table with kernel ridge regression

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Chinese physics C 2023年第7期47卷 138-150页

作者：杜晓凯郭鹏吴鑫辉张双全 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

The kernel ridge regression(KRR)method and its extension with odd-even effects(KRRoe)are used to learn the nuclear mass table obtained by the relativistic continuum Hartree-Bogoliubov *** respect to the binding energies of 9035 nuclei,the KRR method achieves a root-mean-square deviation of 0.96 MeV,and the KRRoe method remarkably reduces the deviation to 0.17 *** investigating the shell effects,one-nucleon and twonucleon separation energies,odd-even mass differences,and empirical proton-neutron interactions extracted from the learned binding energies,the ability of the machine learning tool to grasp the known physics is *** is found that the shell effects,evolutions of nucleon separation energies,and empirical proton-neutron interactions are well reproduced by both the KRR and KRRoe methods,although the odd-even mass differences can only be reproduced by the KRRoe method.

关键词： machine learning kernel ridge regression relativistic continuum Hartree-Bogoliubov theory nuclear mass table

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Vector-like lepton searches at a muon collider in the context of the 4321 model

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Chinese physics C 2023年第10期47卷 99-106页

作者：郭启隆高乐耘冒亚军李强 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

A feasibility study is performed on the search for vector-like leptons(VLLs)at a muon collider in the context of the"4321 model",an ultraviolet-complete model with rich collider phenomenology and the potential to explain several recent existing B physics measurements or *** production and decays of VLLs lead to an interesting final state topology with multi-jets and multi-tau *** this study,we perform a Monte Carlo investigation with various machine learning techniques and examine the projected sensitivity on VLLs over a wide mass range at a TeV-scale muon *** find that a 3 TeV muon collider with only 10 fb^(−1) of data can be sensitive over the mass range of a VLL up to 1450 GeV in the"4321 model."

关键词： vector-like lepton machine learning muon collider

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laboratory observation of electron energy distribution near three-dimensional magnetic nulls

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Plasma Science and technology 2024年第3期26卷 46-52页

作者：何任川徐田超杨肖易肖池阶张祖煜袁瑞鑫王晓钢郭志彬余修铭盖跃 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China Department of Physics Harbin Institute of TechnologyHarbin 150001People's Republic of China

The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection *** explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic *** study measured the plasma floating potential and ion density profiles around the 3D magnetic *** potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial *** axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic *** scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null *** kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.

关键词： electron acceleration EEDF 3D magnetic null magnetic reconnection

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Comparison of displacement damage effects on the dark signal in CMOS image sensors induced by CSNS back-n and XAPR neutrons

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nuclear Science and Techniques 2024年第10期35卷 29-40页

作者： Yuan-Yuan Xue Zu-Jun Wang Wu-Ying Ma Min-Bo Liu Bao-Ping He Shi-Long Gou State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China State Key Laboratory of Artificial Microstructure and Microscopic Physics School of Physics Peking UniversityBeijing 100871China

This study investigates the effects of displacement damage on the dark signal of a pinned photodiode CMOS image sensor(CIS)following irradiation with back-streaming white neutrons from white neutron sources at the China spallation neutron source(CSNS)and Xi'an pulsed reactor(XAPR).The mean dark signal,dark signal non-uniformity(DSNU),dark signal distribution,and hot pixels of the CIS were compared between the CSNS back-n and XAPR neutron *** nonionizing energy loss and energy distribution of primary knock-on atoms in silicon,induced by neutrons,were calculated using the open-source package *** analysis combining experimental and simulation results showed a noticeable proportionality between the increase in the mean dark signal and the displacement damage dose(DDD).Additionally,neutron energies influence DSNU,dark signal distribution,and hot *** neutron energies at the same DDD level may lead to pronounced dark signal non-uniformity and elevated hot pixel values.

关键词： Displacement damage effects CMOS image sensor(CIS) CSNS back-n XAPR neutrons Geant4 Dark signal non-uniformity(DSNU)

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Generation of medical isotopes ^(47)Sc,^(67)Cu through laser-induced(γ,p)reaction

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nuclear Science and Techniques 2024年第11期35卷 219-227页

作者： Jian-Yao Zhang Di Wu Hao-Yang Lan Huan-Gang Lu Jia-Xin Liu Jian-Feng Lv Mei-Zhi Wang Xue-Qing Yan State Key Laboratory of Nuclear Physics and Technology School of PhysicsCAPTPeking UniversityBeijing 100871China Beijing Laser Acceleration Innovation Center Beijing 101407China

Short-lived medical isotopes and their generators are typically produced in nuclear reactors and cyclotrons that require extensive ***,considering the environmental concerns and economic costs of these traditional approaches,modern laser technology,which provides extremely strong electric fields within tabletop-sized areas,can serve as a potential supplementary *** specifically on the(γ,p)generation of the vital medical isotopes^(47)Sc and^(67)Cu,we used both experimental results and PIC-GEANT4 simulations to demonstrate that laser-induced photonuclear reaction is a promising method for isotope *** developed a model capable of calculating isotope yields under various laser conditions and acceleration *** findings revealed that a 200 TW laser can sufficiently produce diagnostic amounts of^(47)Sc and^(67)Cu,while simultaneously providing high specific activity,which is significant in medical applications for improving treatment efficacy,enhancing image resolution,and reducing side effects.

关键词： Photonuclear reaction Laser-drivenγ-Ray Medical isotope

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Reconstruction of poloidal magnetic field profiles in field-reversed configurations with machine learning in laser-driven ion-beam trace probe

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Plasma Science and technology 2024年第3期26卷 83-87页

作者：徐栩涛徐田超肖池阶张祖煜何任川袁瑞鑫许平 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China School of Physics Xihua UniversityChengdu 610039People's Republic of China

The diagnostic of poloidal magnetic field(B_(p))in field-reversed configuration(FRC),promising for achieving efficient plasma confinement due to its highβ,is a huge challenge because B_(p)is small and reverses around the core *** laser-driven ion-beam trace probe(LITP)has been proven to diagnose the B_(p)profile in FRCs recently,whereas the existing iterative reconstruction approach cannot handle the measurement errors *** this work,the machine learning approach,a fast-growing and powerful technology in automation and control,is applied to B_(p)reconstruction in FRCs based on LITP principles and it has a better performance than the previous *** machine learning approach achieves a more accurate reconstruction of B_(p)profile when 20%detector errors are considered,15%B_(p)fluctuation is introduced and the size of the detector is remarkably ***,machine learning could be a powerful support for LITP diagnosis of the magnetic field in magnetic confinement fusion devices.

关键词： FRC LITP poloidal magnetic field diagnostics machine learning

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Inward particle transport driven by biased endplate in a cylindrical magnetized plasma

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Plasma Science and technology 2024年第3期26卷 126-130页

作者：盖跃徐田超肖池阶郭志彬王晓钢何任川杨肖易张祖煜袁瑞鑫 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China Department of Physics Harbin Institute of TechnologyHarbin 150001People's Republic of China

The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state *** active control of inward particle transport is considered as one of the most critical issues of magnetic confinement ***,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)*** results reveal that the inward particle flux increases with the bias voltage of the *** is also found that the profile of radial electric field(Er)shear is flattened by the increased bias *** velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the *** experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.

关键词： inward particle transport biased endplate turbulent transport

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Detector array with digital data acquisition system for charged-particle decay studies

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nuclear Science and Techniques 2025年第4期36卷 140-150页

作者： Hao Jian Xin-Xing Xu Kai-Long Wang Jia-Jian Liu Chao-Yi Fu Peng-Jie Li Yan-Yun Yang Guang-Xin Zhang Kang Wang Fang-Fang Duan Long-Hui Ru Guang-Shun Li Bing Ding Yun-Hua Qiang Cen-Xi Yuan Jun-Bing Ma Shi-Wei Xu Yu-Feng Gao Rui Fan Fan-Chao Dai Si-Xian Zha Hao-Fan Zhu Jin-Hai Li Shu-Lian Qin Zhi-Fang Chang Cheng Kong He-Xuan Yan Hao-Wei Xu Jia-Long Ning Bo-Ren Liu Jie Zhou Yu-Dong Chen Bo-Shuai Cai Yu-Ting Wang Hong-Yi Wu Zhi-Xuan Wang Dong-Sheng Hou Hu-Shan Xu Xiao-Hong Zhou Yu-Hu Zhang Meng Wang Zheng-Guo Hu Jenny Lee State Key Laboratory of Heavy Ion Science and Technology Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy Science and Technology Guangdong Laboratory Huizhou 516003China Department of Physics The University of Hong KongHong KongChina Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Institute of Particle and Nuclear Physics Henan Normal UniversityXinxiang 453007China Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich *** digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγ*** system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for *** the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time *** detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.

关键词： β-delayed proton decay Double-sided silicon strip detector High-purity germanium detector Digital data acquisition system Implantation–decay correlation

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