共查询到19条相似文献,搜索用时 59 毫秒
1.
假定11Li,14Be和17B是由N=2Z核芯和两个外层中子组成的三体系统,核芯-中子和中子-中子间的作用为弱吸引指数势,不足以形成核芯-中子和中子-中子二体束缚态.本文的计算表明,核芯-中子-中子三体系统可形成束缚态,计算结果基本上解释了11Li,14Be,17B的基态能量和异常大核半径的实验结果. 相似文献
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在三体模型的基础上,采用汤川作用势,进行变分计算,进一步研究了晕核11Li,14Be和17B的基态性质,给出了晕中子密度分布的一个解析表达式.理论计算结果与最新的实验数据一致. 相似文献
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胡正国 王猛 徐瑚珊 孙志宇 王建松 肖国青 詹文龙 肖志刚 毛瑞士 张宏斌 赵铁成 徐治国 王玥 陈若富 黄天衡 高辉 贾飞 付芬 高启 韩建龙 章学恒 郑川 余玉洪 樊瑞睿 李波 郭忠言 《物理学报》2008,57(5):2866-2870
在兰州重离子加速器国家实验室(HIRFL)放射性次级束流线(RIBLL)上,用束流透射法测量了丰中子奇异核17B与C靶反应的总截面.假定17B具有15B(核芯)+2n结构,采用Gauss+HO形式的密度分布和零力程Glauber模型进行计算的结果可以很好地拟合实验数据,并得出17B的密度分布有一个很大的弥散,表明17B是双中子晕核.
关键词:
丰中子奇异核
反应总截面
Glauber模型
密度分布 相似文献
5.
在微观Vlasov方程的框架下,研究了11Li核的巨偶极共振.正常的及软巨偶极共振的计算结果都与实验值较好地符合.这两种模式对平均场自旋-轨道耦合力的依赖都十分敏感.而11Li中子晕的分布仅对软巨偶极共振有着十分重要的效应.同时也讨论了中子分离能的影响. 相似文献
6.
将丰中子素11Li视为两个价中子和9Li核芯组成的三体系统,采用吸引指数势作为粒子间的两体相互作用,在简谐振子形式下完成了该系统的变分计算.利用形状密度研究了其基态的结构,并给出了关于中子晕的理论解释. 相似文献
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用α-α-Λ三集团模型和谐振子乘积态为基的展开方法,计算了9Be直到15MeV激发能的能谱.通过计算Lπ=0+,2+,1-三个态的形状密度,确定了9Be处于上述三个态时的几何结构.并根据能谱的耦合特征和几何结构对能谱进行了K分类. 相似文献
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测量了8.17MeV与10.27MeV中子与9Be和6,7Li作用的次级中子双微分截面. 对于10.27MeV, 为了消除从D(d,np)破裂反应来的源破裂中子对双微分截面测量结果的影响, 采用了常规多探测器快中子飞行时间谱仪和非常规多探测器快中子飞行时间谱仪相结合的办法. 用Monte-Carlo方法对实验测量得到的飞行时间谱进行了详细的模拟, 通过测量谱与模拟谱的比较, 得到了实验测量的次级中子双微分截面. 实验测量结果以n-p(常规谱仪)和n-C(非常规谱仪)弹性散射微分截面作为归一. 测量结果与评价数据以及其他测量数据进行了比较. 用一个基于Hauser-Feshbach和激子模型的轻核核反应理论模型对6,7Li的次级中子双微分截面进行了计算, 理论计算结果与实验结果符合得较好. 相似文献
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The nucleus 11B has been studied over the excitation energy range from 8.5 MeV to 21.5 MeV with the 9Be(3He, p)11B / reaction at / E3He = 38 MeV. The analogs of the parent states in 11Be have been located at 12.56, 12.92, 14.40, 16.44, 17.69, 18.0, 19.15 and 21.27 MeV. A complementary measurement with the 9Be(α, d)11B reaction at Eα = 48 MeV demonstrates that the 16.44, 17.69, 18.0 and 19.15 MeV resonances have rather pure isospin . The 14.40 MeV state is a strongly isospin-mixed analog of the state in 11Be. It is argued that spin S = 1 transfer is involved in the excitation of the 16.44 MeV state and its 3.887 MeV parent in 11Be in a two-step stripping process. The states and the lowest three states are compared with the predictions of DWBA utilizing shell-model form factors. It is concluded that the strength is more strongly fragmented than is implied by the calculations of Teeters and Kurath. 相似文献
12.
Excitation functions for the (α, γ) and (p, γ) reactions leading to 10B have been measured at θ = 0° in the energy range from Ex = 6.7 to 7.6 MeV. Two resonances corresponding to levels at 6.88 and 7.44 MeV are observed. Branching ratios extracted from γ-ray spectra are the same in both reactions for the 6.88 MeV (1?, T = 0 + 1) level, but different at 7.44 MeV. The T = 0 + 1 level at 7.44 MeV (Γ = 90±10keV) is assigned 2? or 2+ from its strong branch to the 3+ ground state. We find no evidence for a second isospin mixed 1? state. 相似文献
13.
A.F. Zeller G.T. Hickey D.C. Weisser D.F. Hebbard B.A. Robson 《Nuclear Physics A》1978,301(1):130-140
Reactions induced by 14N on 26Mg at bombarding energies of 60–95 MeV have been studied. Angular distributions for states populated in 29Si by the (14N, 11B) reaction and in 30Si by the (14N, 10B) reaction have been compared with Hauser-Feshbach and DWBA calculations to determine the reaction mechanism and to deduce spectroscopic information. The cross sections for the states populated in 29Si and 30Si are in poor agreement with statistical model calculations, indicating a non-compound nucleus mechanism. 相似文献
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Angular distributions of tritons from the 6Li(n, t)4He reaction were measured at En = 7.25, 6.77, 6.57, 5.24 and 4.71 MeV. Angular distributions of douterons from respectively, the 6Li(n, d)5He two-body breakup reaction were measured at En = 6.77 and 6.57 MeV, and of protons from the 6Li(n, p)6He reaction at En = 6.77, 5.24 and 4.71 MeV. All these reactions in 6Li were analyzed as direct interaction in the formalism of the distorted wave Born approximation. The optical model for the nuclear interaction was found to apply reasonably well to nuclei as light as 4He, 5He, 6He and 6Li. In addition, 6Li as an alpha-deuteron cluster gives the best bound-state wave function to describe the experimental angular distribution of tritons. The excitation functions at forward angles of the 6Li(n, t)4He, 6Li(n, d)5He and 6Li(n, p)6He reactions were measured for incident neutron energies between 4.4 and 7.3 MeV. It is found that the 6Li(n, d)5He two-body breakup reaction has a threshold at about En = 5.3 MeV. Angular distributions at En = 18.3 MeV for tritons and protons from the 9Be(n, t)7Li and 9Be(n, p)9Li, respectively, were also measured. 相似文献
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The charged-particle reaction channels accessible in the bombardment of 10B targets by 7Li nuclei of 24 MeV incident energy are investigated by measuring all ejectiles up to Be. Except for tritons, the reactions with light ejectiles proceed mainly via the formation of a compound nucleus, whereas some of the reactions with ejectiles heavier than the α-particle can be described by a direct mechanism. 相似文献
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M. Langevin C. Détraz D. Guillemaud F. Naulin M. Epherre R. Klapisch S.K.T. Mark M. De Saint Simon C. Thibault F. Touchard 《Nuclear Physics A》1981,366(3):449-460
β-delayed emission of α-particles from 9Li and of both α and 6He particles from 11Li is observed. Singles energy spectra and two-dimensional energy spectra of coincident particles are measured. A time-of-flight versus energy measurement is used to identify the mass of the particle. New β-branches are observed which populate high-energy levels in the daughter nuclei. The branching ratios are measured and the β-delayed neutron emission probabilities are deduced. 相似文献
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Based on a refined resonating group method a microscopic multi-channel calculation for the reactions 7Li(p, p)7Li and 7Li(p, n)7Be has been performed. Diagonal S-matrix elements and differential cross sections are presented from the 7Li-p threshold up to E = 2.5 MeV c.m. and compared with experimental data. 相似文献
18.
Cross sections were determined for the 6Li(d, n)7Be reaction between 100 and 180 keV deuteron energy using the activation method. Different methods of extrapolation were employed and compared down to the energy region of astrophysical interest. 相似文献
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P. Fintz G. Guillaume F. Jundt I. Ordóñez A. Gallmann D.E. Alburger 《Nuclear Physics A》1976,259(3):493-495
The decay of delayed neutrons following the bombardment of a 10BeO target with 30–40 MeV 11B ions exhibits half-life components consistent with the production of the known activities 9Li, 16C and 17N. A previous suggestion that 19N was formed in the 10Be(11B, 2p)19N reaction and decayed with s is therefore not confirmed. Evaporation-type calculations show a low cross section for the formation of 19N. 相似文献