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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

Ground-state mass of ^(22)Al and test of state-of-the-art ab initio calculations

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Chinese physics C 2024年第3期48卷 72-78页

作者：孙铭泽于越王新鹏王猛李健国张玉虎 K.Blaum 陈祖毅陈瑞九邓涵宇付超义葛文文黄文嘉焦红扬李红蕙李宏福罗胤芳廖挺 YuALitvinov 司敏帅鹏史金阳王茜邢元明徐星徐瑚珊许甫荣袁琪 T.Yamaguchi 颜鑫亮杨建成原有进周小红周旭张敏曾奇 CAS Key Laboratory of High Precision nuclear Spectroscopy Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China max-planck-Institut für Kernphysik Saupfercheckweg 169117 HeidelbergGermany GSI Helmholtzzentrum für Schwerionenforschung Planckstraße 164291 DarmstadtGermany Advanced Energy Science and Technology Guangdong Laboratory Huizhou516007China State Key Laboratory of nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China Department of physics Saitama UniversitySaitama 338-8570Japan School of nuclear Science and Engineering East China University of TechnologyNanchang 330013China

The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in *** new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 *** compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)*** excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field *** mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.

关键词： nuclear mass Bρ-defined IMS mirror energy difference ab initio VS-IMSRG calculations chiral interactions

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

Simulation of nuclear isomer production in laser-induced plasma

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Matter and Radiation at Extremes 2024年第5期9卷 1-9页

作者： Zhiguo Ma Yumiao Wang Yi Yang Youjing Wang Kai Zhao Yixin Li Changbo Fu Wanbing He Yugang Ma Key Laboratory of nuclear physics and Ion-Beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

nuclear isomers play essential roles in various fields,including stellar nucleosynthesis,nuclear clocks,nuclear batteries,clean nuclear energy,and-ray *** technological advances in high-intensity lasers have made it possible to excite or de-excite nuclear isomers using table-top laser *** a particle-in-cell code,we investigate the interaction of a laser with a nanowire array and calculate the production rates of the^(73m)Ge(E_(1)=13.3 keV)and^(107m)Ag(E_(1)=93.1 keV)***^(73m1)Ge,production by Coulomb excitation is found to contribute a peak efficiency of 1.0×10^(19) particles s^(−1)J^(−1),while nuclear excitation by electron capture(NEEC)contributes a peak of 1.65×10^(11)particles s^(−1)J^(−1).These results indicate a high isomeric production ratio,as well as demonstrating the potential for confirming the existence of NEEC,a long-expected but so far experimentally unobserved fundamental process.

关键词： process. isomers excitation

Comparison of thermal shock resistance capabilities of the rotary swaged pure tungsten,potassium-doped tungsten,and W-La2O3 alloys

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Tungsten 2024年第4期6卷 759-766页

作者： Tao Yang Hao Wang Fan Feng Xiang Liu Xue-Yu Gong You-Yun Lian Jian-Bao Wang School of nuclear Science and Technology University of South China Southwestern institute of physics

Tungsten-based materials are one of the most important candidates for the plasma facing materials（PFMs） of future fusion reactors,and it is necessary to study the properties of tungsten-based materials under the service conditions of fusion devices to ensure the long-term steady-state operation of future fusion *** this paper,different tungsten-based materials made by the same rotary swaging process are selected to simulate the transient thermal loads on the PFMs of a fusion reactor using an electron beam,and thermal load experiments are carried out by changing the power density of a loading pulse and the pulse *** is found that different tungsten-based materials made by the same process have large differences in thermal shock resistance,and the doped tungsten materials（W-K and W-La2O3） are significantly better than the pure tungsten materials with the increase in thermal shock power density and the number of cycles,especially the W-K materials,which have excellent performance.

关键词： Electron beam Rotary swaging Thermal shock Tungsten materials

An effective gauge field theory of the nucleon interactions

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Communications in Theoretical physics 2024年第10期76卷 78-86页

作者： Eduard Boos Skobeltsyn institute of nuclear physics Lomonosov Moscow State University Faculty of physics Lomonosov Moscow State University

We discuss the possibility of constructing an effective gauge field theory of the nucleon interactions based on the ideas of isotopic invariance as well as hypercharge invariance as a local gauge symmetry and spontaneous breaking of this symmetry. The constructed effective field theory predicts the structure of interactions of protons and neutrons with ρ- and σ-mesons, and with pi-mesons and photons, as well as interactions of these particles with each other. The Lagrangian of the theory consists of several parts involving dimension 4 and 5 gauge invariant operators. Feynman rules for physical degrees of freedom that follow on from the Lagrangian define the structure of diagrams for one-boson exchanges between nucleons, predicting the internucleon one-boson-exchange potential as well as nucleon scattering amplitudes. The range of applicability of the effective theory is discussed and estimates are made of the resulting coupling constants. The theory predicts the mass of the neutral ρ0-meson to be about 1 MeV larger than the mass of the charged mesons ρ±. The vector ω-meson, which is a sterile particle with respect to the considered gauge group SUI（2） × UY（1）, can be added to the scheme via a gauge-invariant operator of dimension 5, as shown in the appendix.

关键词： gauge invariance nucleon interactions spontaneous symmetry breaking

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

Measurement of yields and angular distributions ofγ-quanta from the interaction of 14.1 MeV neutrons with oxygen,phosphorus,and sulfur

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Chinese physics C 2024年第3期48卷 79-92页

作者： D.N.Grozdanov N.A.Fedorov S.B.Dabylova Yu.N.Kopatch I.N.Ruskov V.R.Skoy T.Yu.Tretyakova C.Hramco P.I.Kharlamov G.V.Pampushik P.G.Filonchik A.V.Andreev Joint institute for nuclear Research(JINR) DubnaRussia institute for nuclear Research and nuclear Energy Bulgarian Academy of SciencesSofiaBulgaria Faculty of physics Lomonosov Moscow State UniversityMoscowRussia L.N.Gumilyov Eurasian National University AstanaKazakhstan Skobeltsyn institute of nuclear physics Moscow State UniversityMoscowRussia institute of Chemistry of Moldova ChisinauRepublic of Moldova Moscow institute of physics and Technology MoscowRussia

A study of the inelastic scattering of neutrons with an energy of 14.1 MeV on the nuclei of oxygen,phosphorus,and sulfur was performed at the TANGRA facility at JINR(Dubna).The experiment aimed to refine existing data and obtain new data on the yields and angular distributions ofγ-quanta emitted by the studied nuclei due to neutron-induced nuclear reactions using the tagged neutron *** types of detector systems were used to registerγ-***γ-ray yields were measured using a high-purity germanium(HPGe)*** angular distributions ofγ-rays were obtained using a system of 18 scintillation detectors based on bismuth germanite Bi_(4)Ge_(3)O_(12)(BGO)located around the *** performed experiments measured the yields of two transitions for the reaction of tagged neutrons with 16O,nine transitions for the reaction with ^(31)P,and nine transitions for the reaction with ^(32)S for the first *** angular anisotropy of theγ-radiation accompanying the inelastic scattering of neutrons with an energy of 14.1 MeV on ^(31)P nuclei was also measured for the first time.

关键词： tagged neutron method yields of gamma-quanta high-resolution gamma-spectrometry neutron-nuclear reactions neutron scattering

Unbound^(28)O,the heaviest oxygen isotope observed:a cutting-edge probe for testing nuclear models

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nuclear Science and Techniques 2024年第2期35卷 1-2页

作者： Jian-Guo Li Bai-Shan Hu Shuang Zhang Fu-Rong Xu School of physics and State Key Laboratory of Nuclear Physics and TechnologyPeking UniversityBeijing 100871China institute of Modern physics Chinese Academy of SciencesLanzhou 730000China Southern Center for nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

The beyond-dripline oxygen isotopes^(27,28)O were recently observed at RIKEN,and were found to be unbound decaying into^(24)O by emitting *** unbound feature of the heaviest oxygen isotope,^(28)O,provides an excellent test for stateof-the-art nuclear *** atomic nucleus is a self-organized quantum manybody system comprising specific numbers of protons Z and neutrons N.

关键词： testing quantum system