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Possibility of ~5He emission in neutron induced reactions

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Science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 137-145页

作者： ZHANG Jingshang china institute of atomic energy Beijing 102413 China

The unstable nucleus5He emission has never been included in the widely used statistical model codes as the evaluation tool and interpretation experimental data. The calculated threshold energies of5He emission from light nuclei to heavy nuclei indicate that in most cases the compound nucleus induced by incident neutron would emit5He rather than3He. Since5He is unstable and can be separated into n+α spontaneously, so neutron is produced in5He emission process. The formulation of the double-differential cross section of the neutron from the two-body breakup process of emitted5He is established. Because of the strong recoil effect, the energy balance is strictly taken into account to meet the needs in nuclear engineering. Further improvement of the statistical model calculation codes on this respect is proposed. It is expected that the correlative measurement will be available to account the outgoing neutron and alpha particle simultaneously and to test and verify the existence of5He emission.

关键词： 5He emission, threshold energies, double-differential cross section.

Two-body and three-body halo nuclei

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Science china(Physics,Mechanics & Astronomy) 2003年第4期46卷 441-448页

作者：刘祖华张焕乔 china institute of atomic energy Beijing 102413China

We have extracted the nuclear asymptotic normalization coefficients (ANC) for the virtual transitions B→A+N via some transfer reactions and the radioactive nuclear beam experiments. With these coefficients, root-mean-square (rms) radii for the valence particle in some possible halo nuclei have been calculated. The values of rms radii extracted with ANC approach are nearly model-independent, hence are a good quantity for the investigation of nuclear halo. In addition, we have also calculated the rms radii for the two valence neutrons in some three-body systems in terms of the relationship between the radii of valence particle, core nucleus and nuclear matter. With two conditions for nuclear halo formation, we have examined these extracted rms radii. The results show that 11Be(1/2+, g.s), 12B(1-, 2.621 MeV), 13C(1/2+, 3.089 MeV), 14C(0-, 6.903 MeV), 14C(1-, 6.094 MeV), 15C(1/2+, g.s) and 19C(1/2+, g.s) with the valence particle in the 2s ground or excited state are the neutron halo nuclei, whereas 17F(1/2+, 0.495 MeV) and 21Na(1/2+, 2.423 MeV) are the proton halo nuclei in the excited state. For three-body systems, except the well-established two-neutron halo nuclei 6He and 11Li, 14Be and 17B might be the two-neutron halo nuclei as well.

关键词： nuclear ANC, rms radii, nuclear halo

The isotopic abundance and atomic weight of natural uranium

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Chinese Science Bulletin 1997年第10期42卷 814-817页

作者： Liu, YF Fu, SC china institute of atomic energy Beijing China

THERE are three radioactive nuclides of uranium in nature,234U,235U and 238*** isotopicabundance and atomic weight of unanium was reported *** 1983,the International U-nion of Pure and Applied Chemistry（IUPAC）gave a review of the published *** resultsof the review showed the abundance of uraniums,234U:0.000 055（5）;235U:0.007 200（12）;238U:0.992 745（60）,the atomic weight of uranium,A,（U）=238.028 9（1）.

关键词： isotopic abundance of uranium atomic weight of uranium mass spectrometric measurement.

INAA OF RM IAEA-155 WHEY POWDER

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Nuclear Science and Techniques 1993年第2期4卷 108-113页

作者：彭立新田伟之 china institute of atomic energy Beijing 102413 China

An IAEA biological RM IAEA-155 whey powder was analysed for phosphorus, as well as other 24 elements by INAA. The bremsstrahlung photons produced by P is measured by a HpGe spectrometer. The interferences involved in P determination were comprehensively studied and this method was also applied to the determinations of P in several established biological NBS SRMs and proved to be reliable for a wide range of P contents in biological samples.

关键词： Bremsstrahlung measurement Phosphorus determination NAA Biological samples Standard reference materials

Physics design of CYCAIE-100

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Chinese Physics C 2009年第S2期33卷 33-38页

作者：张天爵李振国钟俊晴安世忠姚红娟纪彬魏素敏管峰平杨建俊毕远杰贾先禄王川 china institute of atomic energy Tsinghua University

The design and construction of Beijing Radioactive Ion-beam Facility (BRIF) was started at china institute of atomic energy -CIAE) in 2004. In this project, a 100 MeV high intensity cyclotron, CYCIAE100, is selected as a driving accelerator for radioactive ion beam production. It will provide a proton beam of 75—100 MeV with an intensity of 200—500 μA. The scheme adopted in this design, i.e., stripping the accelerated H-, makes the structure more compact and construction cost much lower. At present, the design for each system has been accomplished. This paper depicts the basic physics design of the machine, including its major structure and parameters, beam dynamics and each relevant system, e.g. basic structure of the main magnet, numerical simulation of the RF resonant cavity, axial injection system, central region, and study on crucial physics problems concerning the extraction and beam lines. The major problems encountered during the design of CYCIAE-100 are also summarized in this paper.

关键词： cyclotron main magnet RF cavity axial injection extraction imperfection field

Microscopic Effective Charges and the B(E2) Values of Terminating States in Mirror Nuclei (51)～Mn and (51)～Fe

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Plasma Science and Technology 2012年第7期14卷 603-606页

作者：马海亮董保国闫玉良 Department of Nuclear Physics China Institute of Atomic Energy

The microscopic effective charges in mirror nuclei 51Mn and 51Fe are investigated with the particle-vibration coupling model based on the self-consistent Skyrme-Hartree-Fock and continuum random-phase-approximation approaches. The isovector parts are predicted to be around 0.15, and the proton effective charges are around 1.25 e, which is less than the empirical value of epff p = 1.5 e. The microscopic effective charges in neutron rich 51Mn are about 10% less than its proton rich mirror. These effective charges are combined with the shell model to calculate the reduced electric quadrupole transition probability B（E2） values in 51Mn and 51Fe. It turns out that the microscopic effective charges have well reproduced the B（E2） values and its ratio in the terminating states.

关键词： shell model effective charge particle-vibration coupling electric quadrupoletransition

Developing anti-metallic contamination polyester membranes with nuclear pore technique

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Nuclear Science and Techniques 2010年第5期21卷 285-288页

作者： LIU Cunxiong NI Bangfa TIAN Weizhi XIAO Caijing HUANG Donghui ZHANG Guiying china institute of atomic energy Beijing 102413 China

Surface contamination by conducting materials,metals in particular,is one of the important causes for electric breakdown of insulators under high *** order to explore the feasibility of nuclear track modification for anti-metallic contamination,polyester membranes with different thickness were bombarded by 32S ions from the HI-13 tandem accelerator of *** tracks formed on the surface of the membranes were etched under different *** insulating capability of the treated membranes was evaluated by using silver coatings to simulate the surface metallic *** results indicated insulators with the surface modified by nuclear pore technique have an improved capability of anti-contamination of *** sample with 144 nm Ag coating is not breakdown under 1000 V.

关键词：抗金属污染表面改性技术聚酯膜核孔原子能科学研究院涂料表面串列加速器计算模拟

Model Calculation of n + 6Li Reactions Below 20 MeV

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Communications in Theoretical Physics 2001年第10期36卷 437-442页

作者： ZHANG Jing-Shang HAN Yin-Lu china Nuclear Data Center China Institute of Atomic Energy Beijing 102413 China China Nuclear Data Center China Institute of Atomic Energy Beijing 102413 China

Based on the unified Hauser-Feshbach and exciton model for light nuclei, the calculations of reaction cross sections and the double-differential cross sections for n + 6Li are performed. Since all of the first-particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism must be taken into account. The fitting of the measured data indicates that the three-body break-up process needs to be involved, and the pre-equilibrium reaction mechanism dominates the reaction processes. In light nucleus reactions the recoil effect must be taken into account.

关键词： pre-equilibrium emission, discrete levels, three-body break-up process

A new method for analyzing the collimation angle of a neutron Soller collimator

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Chinese Physics C 2016年第1期40卷 75-78页

作者：高建波刘蕴韬陈东风 china institute of atomic energy Beijing 102413China

A new method for analyzing the collimation angle of a neutron Soller collimator is described. A Gaus- sian distribution formula is used to define the angular distribution function of the neutron source and the neutron transmission function of the Soller collimator. A relationship between the FWHM of the collimator rocking curve and the collimation angle is derived. Using this method, some rocking curve experiment results are analyzed. The results show that the new function can be a good theoretical model for fitting the experimental data, especially for the data of two collimators with different collimation angles.

关键词： Soller collimator collimation angle neutron beam