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Investigation ofβ—‑decay half‑life and delayed neutron emission with uncertainty analysis

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Nuclear Science and Techniques 2023年第1期34卷 111-123页

作者： Yu‑Feng Gao Bo‑Shuai Cai cen‑xi yuan Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Sino‑French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

β-decay half-life and β-delayed neutron emission(βn) are of great importance in the development of basic science and industrial applications, such as nuclear physics and nuclear energy, where β--decay plays an important role. Many theoretical models have been proposed to describe β-decay half-lives, whereas the systematic study of βn is still rare. This study aimed to investigate β--decay half-lives and βn probabilities through analytical formulas and by comparing them with experimental data. Analytical formulas for β--decay properties have been proposed by considering prominent factors, that is, decay energy,odevity, and the shell effect. The bootstrap method was used to simultaneously evaluate the total uncertainty on calculations,which was composed of statistic and systematic uncertainties. β--decay half-lives, βn probabilities, and the corresponding uncertainties were evaluated for the neutron-rich region. The experimental half-lives were well reproduced. Additional predictions are also presented with theoretical uncertainties, which helps to better understand the disparity between the experimental and theoretical results.

关键词： Neutron-rich nucleus -delayed neutron emissions Bootstrap method

Recent studies on potential accident-tolerant fuel-cladding systems in light water reactors

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Nuclear Science and Techniques 2020年第3期31卷 94-123页

作者： Sheng-Li Chen xiu-Jie He cen-xi yuan Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Universite Grenoble Alpes I-MEP238402 Saint Martin d’HeresFrance

Accident-tolerant fuel(ATF)has attracted considerable research attention since the 2011 Fukushima nuclear *** improve the accident tolerance of the fuel-cladding systems in the current light-water reactors,it is proposed to develop and deploy(1)an enhanced Zrbased alloy or coated zircaloy for the fuel cladding,(2)alternative cladding materials with better accident tolerance,and(3)alternative fuels with enhanced accident tolerance and/or a higher U *** review presents the features of the current UO2-zircaloy *** techniques and characters to develop coating materials and enhanced Zr-based alloys are *** features of several selected alternative fuels and cladding materials are reviewed and *** neutronic evaluations of alternative fuel-cladding systems are *** is expected that one or more types of ATF-cladding systems discussed in the present review will be implemented in commercial reactors.

关键词： Accident-tolerant fuel Accident-tolerant cladding Light-water reactor Neutronic evaluation

Shell-model study on properties of proton dripline nuclides with Z,N=30-50 including uncertainty analysis

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Chinese Physics C 2022年第8期46卷 196-210页

作者： Bo-Shuai Cai Guang-Shang Chen cen-xi yuan Jian-Jun He Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China Key Laboratory of Beam Technology and Materials Modification of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Beijing Radiation center Beijing 100875China

The binding and proton separation energies of nuclides with Z,N=30-50 are investigated based on the shell model,with an uncertainty analysis via statistical *** formulas are used to obtain the binding and proton separation energies according to shell-model *** non-parametric bootstrap method is applied to establish an uncertainty decomposition and recomposition ***,this is used to estimate the stability of proton(s) emission for each *** formulas for calculating the binding energies with a systematic uncertainty of~0.3 Me V are proposed,and a reliable extrapolation ability is *** binding energy formulas deduce similar forms for their respective S_(p) and S_(2 p) energies,which predict the extension of the nuclear boundary of this region.A good description of the binding and proton separation energies is *** one-and twoproton separation energies and partial half-lives of proton emission are predicted,thus revealing a new ***,there are 30 unstable nuclides predicted to be bound against proton(s)-*** nuclear properties will be useful in nuclear astrophysics.

关键词： shell model proton dripline uncertainty analysis

Quenching of single-particle strengths of carbon isotopes 9-12,14-20C with knockout reactions for incident energies 43–2100 MeV/nucleon

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Chinese Physics C 2022年第6期46卷 147-153页

作者： Yi-Ping Xu Dan-Yang Pang cen-xi yuan xiao-Yan Yun School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China School of Physics Beihang UniversityBeijing 100191China Sino-French Institute ofNuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China College of Physics and Optoelectronics Taiyuan University of TechnologyTaiyuan 030024China

To study the quenching of single-particle strengths of carbon isotopes,a systematic analysis is performed for ^(9-12,14-20) C,with single neutron knockout reactions on Be/C targets,within an energy range from approximately 43 to 2100 MeV/nucleon,using the Glauber *** energies do not show any obvious effect on the resulting values across this wide energy *** extracted quenching factors are found to be strongly dependent on the proton-neutron asymmetry,which is consistent with the recent analysis of knockout reactions but is inconsistent with the systematics of transfer and quasi-free knockout reactions.

关键词： spectroscopic factors knockout reactions reduced single-particle strength one-neutron removal

Many-body correlations in shell model effective interactions derived by ab initio methods and the V_(low-k) approach

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Chinese Physics C 2018年第11期42卷 78-84页

作者： xiao-Bao Wang Guo-xiang Dong Hua-Lei Wang cen-xi yuan Yong-Jing Chen Ya Tu School of Science Huzhou UniversityHuzhou 313000China School of Physics and Engineering Zhengzhou UniversityZhengzhou 450001China Sino-Prench Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China Key Laboratory of Science and Technology on Nuclear Data China Institute of Atomic EnergyBeijing 102413China School of Physics Science and Technology Shenyang Normal UniversityShenyang 110034China

We investigate many-body correlations caused by two- and three-body （2-, 3bd） forces. Shell-model effective interactions derived from ab initio methods （coupled-cluster method, no-core shell model） are adopted. Vlow-k potentials, based on many-body perturbation theory, are also tested, especially for their cut-off dependence. We compare the central, tensor and spin-orbit interactions from microscopic theory to the fitted interactions. After the inclusion of the three-body force, the matrix elements become fairly close to those fitted directly to experimental data. Calculations of neutron-rich oxygen isotopes are performed, to clarify the effects of 3bd forces, tensor, and spin-orbit interactions on the nuclear binding and excitation energies. We find that the 3bd force can influence the binding energies greatly, which also determines the drip line position, while its effect on excitation energies is not very pronounced. The spin-orbit force, which is part of the 2bd force, can affect the shell structure explicitly, at least for neutron-rich systems.

关键词： shell model effective interactions tensor force three-body force

Monopole effects, core excitations, and β decay in the A = 130 hole nuclei near ^(132)Sn

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Chinese Physics C 2019年第5期43卷 35-40页

作者： Han-Kui Wang Zhi-Hong Li cen-xi yuan Zhi-Qiang Chen Ning Wang Wei Qin Yi-Qi He College of Physics and Telecommunication Engineering Zhoukou Normal University China Institute of Atomic Energy Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University College of mathematics and statistics Zhoukou Normal University

The proton and neutron cross-shell excitations across the Z = 50 shell are investigated in the southwest quadrant of ^(132) Sn by large-scale shell-model calculations with extended pairing and multipole-multipole force. The model space allows proton(neutron) core excitations, and both the low-and high-energy states for ^(130) In are well described, as found by comparison with the experimental data. The monopole effects between the proton orbit and neutron orbit are studied as the new monopole correction that perfectly reproduces the first 1^+ level in ^(130) In. The energy interval of proton(neutron) core excitations in ^(130) In lies in the range of 4.5-6.5(2.0-4.1) MeV, and the high energy yrast states are predicted as neutron core excitations. The decays are calculated among the A=130 nuclei of ^(130) In, ^(130) Sn and ^(130) Cd.

关键词： monopole effects core-excitations β decay hole nuclei

Fusion reactions around the barrier for Be+^(238)U

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Chinese Physics C 2021年第5期45卷 100-104页

作者： Bo Mei Dimiter L.Balabanski Wei Hua Yu-Hu Zhang xiao-Hong Zhou cen-xi yuan Jun Su Sino-French Institute of Nuclear Engineering and Technology Sun Y at-sen UniversityZhuhai 519082China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Extreme Light Infrastructure Nuclear Physics “Horia Hulubei”National R&D Institute for Physics and Nuclear EngineeringStrada Reactorului 30077125 Bucharest MagureleRomania

Fusion-evaporation cross sections of^(238)U(^(9)Be,5n)^(242)Cm are measured over a wide energy range around the Coulomb *** measured cross sections are compared with model calculations using two codes,namely HIVAP2 and KE ***2 calculations overestimate the measured fusion-evaporation cross sections by a factor of approximately *** KEWPIE2 calculations,two approaches,namely the Wentzel-Kramers-Brillouin(WKB)approximation and the empirical barrier-distribution(EBD)method,are used for the capture probability;both of them properly describe the measured cross ***,fusion cross sections of^(7.9)Be+^(238)Umeas-ured in two experiments are applied to constrain model calculations further through three codes,i.e,HIVAP2,KEWPIE2,and *** in these codes are also examined by comparison with measured fusion cross *** the comparisons indicate that the K EWPIE2 calculations using the WKB approximation agree well with the measured cross sections of both fusion reactions 7.9 Be+^(238)U and the fusion-evaporation reaction 238U(9 Be,5n)242 *** using the fusion code CCFULL are also in good agreement with the measured fusion cross sections of 7.9 Be+^(238)U.

关键词： fusion-evaporation reaction ^(238)U fusion cross sections near barrier energies

Negative Parity States in ^(39)Cl Configured by Crossing Major Shell Orbits

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Chinese Physics Letters 2019年第6期36卷 17-20页

作者： Long-Chun Tao cen-xi yuan Jian-Ling Lou xiao-Fei Yan Yan-Lin Ye School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University RIKEN Nishina center Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University Department of Physics University of Tsukuba Department of Physics Kyungpook National University Department of Physics Osaka University Department of Physics Tokyo Institute of Technology Department of Advanced Sciences Hosei University Department of Physics Meiji University

Traditional "magic numbers" were once regarded as immutable throughout the nuclear chart. However, unexpected changes were found for unstable nuclei around N = 20. With both proton and neutron numbers around the magic number of 20, the neutron-rich ^(39)Cl isotope provides a good test case for the study of the quantumstate evolution across the major shell. In the present work, the negative parity states in ^(39)Cl are investigated through the β decay spectroscopy of 39 S. Newly observed γ transitions together with a new state are assigned into the level scheme of ^(39)Cl. The spin parity of 5/2^- for the lowest negative parity state in ^(39)Cl is reconfirmed using the combined γ transition information. These systematic observations of the negative parity states in ^(39)Cl allow a comprehensive comparison with the theoretical descriptions. The lowest 5/2^- state in ^(39)Cl remains exotic in terms of comparisons with existing theoretical calculations and with the neighboring isotopes having similar single-particle configurations. Further experimental and theoretical investigations are suggested.

关键词： Negative Parity States Crossing Major Shell Orbits immutable throughout

Low-lying states of 92,93Nb excited in the reactions induced by the weakly-bound nucleus 6Li near the Coulomb barrier

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Chinese Physics C 2019年第10期43卷 69-77页

作者： Yi-Feng Lv Jing-Bin Lu Gao-Long Zhang Yi-Heng Wu cen-xi yuan Guan-Jian Fu Guang-xin Zhang Zhen Huang Ming-Li Wang Shi-Peng Hu Hui-Bin Sun Huan-Qiao Zhang Cheng-Qian Li Ke-Yan Ma Ying-Jun Ma Yun-Zuo Liu College of physics Jilin UniversityChangChun 130012China INFN Laboratori Nazionali di LegnaroLegnaro (Padova)Italy Irfu/CEA Universite de Paris-SaclayGif-sur-YvetteFrance School of Physics and Nuclear Energy Engineering Beihang UniversityBeijing 100191China Beijing Advanced Innovation center for Big Data-Based Precision Medicine Beihang UniversityBeijing 100083China School of Physics and Electronic Engineering An Qing Normal UniversityAn qing246133China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Physics Science and Engineering Tongji UniversityShanghai 200092China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China China Institute of Atomic Energy Beijing 102413China Dipartimento di Fisica and INFN Sezione di PadovaPadovaItaly

Excited states of odd-odd nucleus 92Nb and odd-A nucleus 93Nb were populated in the 6 Li+ 89 Y reaction with an incident energy of 34 MeV. The processes that produce 92,93Nb and can be measured by a combination of light charged particle and gamma ray measurements are discussed. Twenty new transitions are observed and eight new levels are constructed in 92Nb, and in addition two new transitions are added to the level scheme of 93Nb. Using shell2 model calculations, the low-lying structure of 9 Nb is investigated and compared with the experimental results.

关键词： weakly-bound projectile coincidence measurement level structure odd-odd nucleus 92Nb odd-A nucleus 93Nb.