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A Bayesian-neural-network prediction for fragment production in proton induced spallation reaction

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Chinese Physics C 2020年第12期44卷 163-170页

作者：马春旺彭丹魏慧玲王玉廷普洁 Institute of Particle and Nuclear Physics Henan Normal UniversityXinxiang 453007China School of Physics Henan Normal UniversityXinxiang 453007China

Fragment production in spallation reactions yields key infrastructure data for various *** on the empirical SPACS parameterizations,a Bayesian-neural-network(BNN)approach is established to predict the fragment cross sections in proton-induced spallation reactions.A systematic investigation has been performed for the measured proton-induced spallation reactions of systems ranging from intermediate to heavy nuclei systems and incident energies ranging from 168 MeV/u to 1500 MeV/*** learning the residuals between the experimental measurements and SPACS predictions,it is found that the BNN-predicted results are in good agreement with the measured *** established method is suggested to benefit the related research on nuclear astrophysics,nuclear radioactive beam sources,accelerator driven systems,proton therapy,etc.

关键词： Bayesian neural network(BNN) spallation reaction cross sections

Nucleon stripping in deuteron-induced spallation reactions at hundreds MeV/nucleon

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Chinese Physics C 2021年第4期45卷 256-264页

作者：宋去非徐苏扬苏军 Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China

A nucleon-nucleus dynamics model was developed to investigate the proton-,neutron-,and deuteron-induced reactions at hundreds of MeV/*** this model,the trajectory of incident nucleon is described by classical mechanics,and the probability of reaction between the nucleon and nucleus is calculated by exponential *** is shown that the total reaction cross sections calculated by the model agree in general with the predictions by the CDCC and the experimental *** model was applied to investigate the nucleon stripping in deuteron-induced reactions and its symmetry energy dependence.

关键词： nucleon stripping spallation reaction deuteron-induced spallation symmetry energy

Light fragment and neutron emission in high-energy proton induced spallation reactions

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Chinese Physics C 2021年第8期45卷 119-131页

作者：程辉淦冯兆庆 School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The dynamics of high-energy proton-induced spallation reactions on target nuclides of 56Fe,58Ni,107Ag,112d,184W,181Ta,197Au,and 208Pb are investigated with the quantum molecular dynamics transport model motivated by the China initiative Accelerator Driven System(CiADS)in Huizhou and the China spallation Neutron Source(CSNS)in *** production mechanism of light nuclides and fission fragments is thoroughly analyzed,and the results obtained thereby are compared with available experimental *** statistical code GEMINI is employed in conjunction with a transport model for describing the decay of primary *** the treatment of cluster emission during the preequilibrium stage,a surface coalescence model is implemented into the *** is found that the available data in terms of total fragment yields are well reproduced in the combined approach for spallation reactions both on the heavy and light *** energetic light nuclides(deuteron,triton,helium isotopes etc)mainly created during the preequilibrium stage are treated within the framework of surface coalescence,whereas their evaporation is described in the conventional manner by the GEMINI *** this combined approach,a good overall description of light clusters and neutron emission is obtained,and some discrepancies with the experimental data are *** production of radioactive isotopes in the spallation reactions is also analyzed,i.e.,the 6.8He energy spectra.

关键词： spallation reaction LQMD transport model light charged particle neutron double differential cross section

Pairing-energy coefficients of neutron-rich fragments in spallation reactions

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Chinese Physics C 2018年第3期42卷 62-68页

作者：牛菲马春旺 Institute of Particle and Nuclear Physics Henan Normal University Institute of Modern Physics Chinese Academy of Sciences

The ratio of pairing-energy coefficient to temperature （ap/T） of neutron-rich fragments produced in spallation reactions has been investigated by adopting an isobaric yield ratio method deduced in the framework of a modified Fisher model. A series of spallation reactions, 0.5A and 1A GeV 208Pb ＋ p, 1A GeV 238U ＋ p, 0.5A GeV 136Xe ＋ d, 0.2A, 0.5A and 1A GeV 136Xe ＋ p, and 56Fe ＋ p with incident energy ranging from 0.3A to 1.5A GeV, has been analysed. An obvious odd-even staggering is shown in the fragments with small neutron excess （I=N-Z）, and in the relatively small-A fragments which have large I. The values of ap/T for the fragments, with I from 0 to 36, have been found to be in a range from -4 to 4, and most values of ap/T fall in the range from -1 to 1. It is suggested that a small pairing-energy coefficient should be considered in predicting the cross sections of fragments in spallation reactions. It is also concluded that the method proposed in this article is not good for fragments with A/As〉 85% （where As is the mass number of the spallation system）.

关键词： pairing energy neutron-rich isotope spallation reaction asymmetric muclear matter

SPAGINS:semiempirical parameterization for fragments in gamma-induced nuclear spallation

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Nuclear Science and Techniques 2023年第12期34卷 112-122页

作者： Hui‑Ling Wei Meng‑Die Zhou Pu Jiao Yu‑Ting Wang Jie Pu Kai‑Xuan Cheng Ya‑Fei Guo Chun‑Yuan Qiao Gong‑Tao Fan Hong‑Wei Wang Chun‑Wang Ma Institute of Particle and Nuclear Physics College of PhysicsHenan Normal UniversityXinxiang 453007China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China Institute of Nuclear Science and Technology Henan Academy of ScienceZhengzhou 450046China

From the empirical phenomena of fragment distributions in nuclear spallation reactions,semiempirical formulas named SPAGINS were constructed to predict fragment cross-sections in high-energyγ-induced nuclear spallation reactions(PNSR).In constructing the SPAGINS formulas,theoretical models,including the TALYS toolkit,SPACS,and Rudstam formulas,were employed to study the general phenomenon of fragment distributions in PNSR with incident energies ranging from 100 to 1000 *** the primary characteristics of PNSR,the SPAGINS formulas modify the EPAX and SPACS formulas and efficiently reproduce the measured *** SPAGINS formulas provide a new and effective tool for predicting fragment production in PNSR.

关键词： High-energy gamma-rays spallation reaction Fragment cross-section Empirical formula EPAX SPACS TALYS

Isotopic cross-sections in proton induced spallation reactions based on the Bayesian neural network method

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Chinese Physics C 2020年第1期44卷 111-122页

作者：马春旺彭丹魏慧玲牛中明王玉廷 RWada Institute of Particle and Nuclear Physics Henan Normal UniversityXinxiang 453007China School of Physics Henan Normal UniversityXinxiang 453007China School of Physics and Materials Science Anhui UniversityHefei 230601China Institute of Cyclotron Texas A&M UnivCollege StnTX 77843USA

The Bayesian neural network(BNN)method is proposed to predict the isotopic cross-sections in proton induced spallation *** from more than 4000 data sets of isotopic cross-sections from 19 experimental measurements and 5 theoretical predictions with the SPACS parametrization,in which the mass of the spallation system ranges from 36 to 238,and the incident energy from 200 MeV/u to 1500 MeV/u,it is demonstrated that the BNN method can provide good predictions of the residue fragment cross-sections in spallation reactions.

关键词： BNN method spallation reaction p+A SPACS parametrization cross-section prediction

Production rates of cosmogenic nuclei on the lunar surface

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Chinese Physics C 2014年第7期38卷 63-68页

作者：董铁矿贠素君马涛常进董武东张小平李国龙任中洲 Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryCAS Nanjing XiaoZhuang University Space Science Institute Macao University of Science and Technology Avenida Wai Long Taipa Macao China Department of Physics Nanjing University Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator

A physical model for Geant4-based simulation of the galactic cosmic ray （GCR） particles＇ interaction with the lunar surface matter has been developed to investigate the production rates of cosmogenic nuclei. In this model the GCRs, mainly very high energy protons and 0c particles, bombard the surface of the Moon and produce many secondary particles, such as protons and neutrons. The energies of protons and neutrons at different depths are recorded and saved as ROOT files, and the analytical expressions for the differential proton and neutron fluxes are obtained through the best-fit procedure using ROOT software. To test the validity of this model, we calculate the production rates of the long-lived nuclei 10Be and 26Al in the Apollo 15 long drill core by combining the above differential fluxes and the newly evaluated spallation reaction cross sections. Our numerical results show that the theoretical production rates agree quite well with the measured data, which means that this model works well. Therefore, it can be expected that this model can be used to investigate the cosmogenic nuclei in future lunar samples returned by the Chinese lunar exploration program and can be extended to study other objects, such as meteorites and the Earth＇s atmosphere.

关键词： cosmogenic nuclei Geant4 spallation reaction

Study of neutron spectra in a water bath from a Pb target irradiated by 250 MeV protons

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Chinese Physics C 2015年第4期39卷 31-36页

作者：李严严张雪荧鞠永琴马飞张宏斌陈亮葛红林万波骆鹏周斌张艳斌李建阳徐俊奎王松林杨永伟杨磊 Institute of Modern Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of High Energy Physics Chinese Academy of Sciences

spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with a cadmium （Cd） cover. According to the measured activities of the foils, the neutron flux at different resonance energies were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code. The comparison showed that the simulation could give a good prediction for the neutron spectra above 50 eV, while the finite thickness of the foils greatly effected the experimental data in low energy. It was also found that the resonance detectors themselves had great impact on the simulated energy spectra.

关键词： spallation reaction bath activation method neutron spectrum MCNPX simulation

Study on intermediate energy nucleon-nuclei reaction

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Study on intermediate energy nucleon-nuclei reaction