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determination of the neutron skin thickness from interaction cross section and charge-changing cross section for B,C,N,O,F isotopes

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Nuclear Science and Techniques 2016年第3期27卷 153-158页

作者： Xiu-fang Li de-qing fang Yu-Gang Ma Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The effective neutron and proton root-meansquare radius of stable and unstable nuclei(^(12-15,17)B,^(12-20)C,^(14-21)N,^(16-24)O and ^(18-21,23-26)F) were deduced from the charge-changing cross section,σ_(cc),and the interaction cross sections,σ_I,by using a statistical abrasion-ablation model *** extracted proton radii are in good agreement with the data from the Atomic Data and Nuclear Data Tables within the ***,we can observe that the neutron skin thickness increases monotonously with the increasing neutron number in these isotopes,which is consistent with the systematical trend of theoretical calculations.

关键词：中子皮厚度作用截面同位素变化截面电荷均方根半径测定不稳定核

Neutron skin and its effects in heavy-ion collisions

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Nuclear Science and Techniques 2024年第12期35卷 217-238页

作者： Meng‑Qi Ding de‑qing fang Yu‑Gang Ma Key Laboratory of Nuclear Physics and Ion‑Beam Application(MOE) Institute of Modern PhysicsFudan University200433 ShanghaiChina Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan University200438 ShanghaiChina

Neutron skin is an exotic phenomenon that occurs in unstable *** this study,the various efects of the neutron skin on nuclear reactions and their relationship with the properties of nuclear structures are *** on numerous studies using theoretical models,strong correlations have been found between the neutron skin thickness and the neutron removal cross section,neutron/proton yield ratio,t∕3He yield ratio,neutron-proton momentum diference,isoscaling parameter,photon production,reaction cross sections for neutron-induced reactions,charge-changing cross-sectional diferences of mirror nuclei,astrophysical S-factor,and other quantities in nuclear reactions induced by neutron-rich ***,the relationships between the neutron skin thickness and certain properties of the nuclear structure,such asα-cluster formation,αdecay,nuclear surface,nuclear temperature,and proton radii diference of mirror nuclei,have also been ***,it has also been shown that the neutron skin plays a crucial role in relativistic heavy-ion ***,an unstable nucleus with a neutron skin can be generated by radioactive nuclear beam facilities,and the thickness of the neutron skin can be extracted by measuring the sensitive probes,which further helps impose stringent constraints on the equation of state of asymmetric nuclear matter and the properties of neutron stars.

关键词： Neutron skin Radioactive nuclear beam Equation of state of asymmetric nuclear matter

decay modes of highly excited nuclei

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Nuclear Science and Techniques 2018年第6期29卷 9-18页

作者： Zhen-fang Zhang de-qing fang Yu-Gang Ma Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The deexcitation of single excited ^(112) Sn nuclei at T = 1–30 MeV is simulated using the isospin-dependent quantum molecular dynamics(IQMD) model and GEMINI model. The fragmentation mechanism, critical behavior,and kinematic characteristics are investigated within these two models. The results show that the IQMD model can be applied to the analysis of fragmentation processes, critical points, and slope temperature extraction. The results of IQMD are generally consistent with experimental - Z_(bound) data. However, GEMINI can reproduce the experimental data better than IQMD for isotopic distributions.

关键词：原子核腐烂 IQMD 破碎过程双子座试验性动力学模型

Study on the performance of a large-size CsI detector for high energy γ-rays

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Nuclear Science and Techniques 2018年第1期29卷 58-64页

作者： He Dong de-qing fang Chen Li Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The measurement of high-energy γ-rays is an important experimental method to study the giant resonance in a nucleus, c reaction in nuclear astrophysics, and so on. The performance of a large-size Cs I detector for crays detection is studied by comparison between the experimental measurements and GEANT4 simulation. The reliability of the simulated efficiency for low-energy γ-rays is verified by comparing with the experimental data. The efficiency of the Cs I detector for high-energy γ-rays was obtained by the GEANT4 simulation. The simulation shows that the detection efficiency of 20 Me V γ-rays can reach 3.8%.

关键词： CsI:Tl Scintillation detector Full absorption efficiency Energy resolution GEANT4 simulation

Investigation of the symmetry energy of nuclear matter using isospin-dependent quantum molecular dynamics

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Nuclear Science and Techniques 2020年第6期31卷 83-89页

作者： Hao Yu de-qing fang Yu-Gang Ma Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of the Chinese Academy of Sciences Beijing 100080China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

Simulations of infinite nuclear matter at different densities,isospin asymmetries and temperatures are performed using the isospin-dependent quantum molecular dynamics(IQMD)model to study the equation of state and symmetry energy.A rigorous periodic boundary condition is used in the *** energies are extracted from the binding energies under different conditions and compared to the classical molecular dynamics(CMD)model using the same *** results show that both models can reproduce the experimental results for the symmetry energies at low densities,but IQMD is more appropriate than CMD for nuclear matter above the saturation *** indicates that IQMD may be a reliable model for the study of the properties of infinite nuclear matter.

关键词： Infinite nuclear matter Symmetry energy IQMD model

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

Recent progress in two-proton radioactivity

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Nuclear Science and Techniques 2022年第8期33卷 118-146页

作者： Long Zhou Si-Min Wang de-qing fang Yu-Gang Ma 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

During the last few decades,rare isotope beam facilities have provided unique data for studying the properties of nuclides located far from the beta-stability *** nuclei are often accompanied by exotic structures and radioactive modes,which represent the forefront of nuclear *** them,two-proton(2p)radioactivity is a rare decay mode found in a few highly proton-rich *** 2p decay lifetimes and properties of emitted protons hold invaluable information regarding the nuclear structures in the presence of a low-lying proton continuum;as such,they have attracted considerable research *** this review,we present some of the recent experimental and theoretical progress regarding the 2p decay,including technical innovations for measuring nucleon-nucleon correlations and developments in the models that connect their structural aspects with their decay *** impressive progress should play a significant role in elucidating the mechanism of these exotic decays,probing the corresponding components inside nuclei,and providing deep insights into the open quantum nature of dripline systems.

关键词： Exotic decay Two-proton radioactivity Nucleon-nucleon correlation Experimental and theoretical development

Preface to special issue:dedicated to Professor Wenqing Shen in honor of his 80th birthday

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Nuclear Science and Techniques 2024年第12期35卷 209-216页

作者： de-qing fang Xiang-Zhou Cai Hong-Wei Wang Yu-Gang Ma Key Laboratory of Nuclear Physics and Ion-Beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai200438China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China

We are honored to dedicate this issue to Professor Wenqing Shen to celebrate his 80th birthday,along with his distinguished career,great achievements in nuclear science,and fruitful contributions to science and technology *** Wenqing Shen was born in Shanghai on August 21,*** graduating from middle school with outstanding grades,he was admitted to the preparatory program of Fudan University;this marked the frst turning point in his life.

关键词： admitted turning birthday

design and performance of a high-speed and low-noise preamplifier for SiPM

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Nuclear Science and Techniques 2023年第11期34卷 93-102页

作者： Xi‑Yang Wang Hong‑Yu Zhang de‑qing fang Wan‑Bing He Xiao‑Long Wang Qi‑Bin Zheng Shi‑Ming Zou Key Laboratory of Nuclear Physics and Ion‑beam Application(MOE)and Institute of Modern Physics Fudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China Laboratory of Radiation detection and Medical Imaging and School of Health Science and Engineering University of Shanghai for Science and TechnologyShanghai 200093China

Considering the R&D for upgrading the K^(0)_(L) andμdetectors in the Belle II experiment using a scintillator and silicon pho-tomultiplier(SiPM),we designed a compact high-speed and low-noise *** preamplifier demonstrated a good gain stability,bandwidth of 426 MHz,baseline noise level ofσ≈0.6 mV,dynamic range of up to170 mV of the input signal amplitude,good time resolution of 20 ps,and it can be comprehensively applied to *** pole-zero-cancelation in the preamplifier reduces both the rise and fall times of the SiPM signal,which can significantly improve the time resolution and reduce the pile-up when using a large SiPM or an array of *** combinations of the preamplifier and several types of SiPMs demonstrated time resolutions better than 50 ps for most cases;when the number of detected photons was larger than 60,a time resolution of approximately 25 ps was achieved.

关键词： Silicon photomultiplier High-speed amplifier Low noise High time resolution