共查询到17条相似文献,搜索用时 242 毫秒
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测量了19F+27Al耗散反应产物B,C,N,O,F和Ne的激发函数, 入射束流的能量从110.25MeV到118.75MeV,能量步长为250keV. 用能量自关联函数方法从激发函数中提取了各反应产物的平均衰变宽度, 利用同时考虑反应中所形成的中间双核系统的转动特性和衰变特性而发展了的Ericson核反应统计理论, 讨论了19F+27Al耗散反应中双核系统随时间的演化过程. 相似文献
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完成了19F+93Nb耗散反应产物激发函数的两次独立测量,入射束流的能量从102MeV到108MeV,步长250keV.实验结果在一些相同能量点两次测量的截面不能重复.分析表明:能量自关联函数的离散程度大约相当于随机计数率引起的离散程度的3倍;激发函数曲线相对于能量平均本底的几率分布,有大约21髎超出了标准高斯分布宽度的3倍;两次测量得到的截面之差的几率分布大约有18髎也超出了标准高斯分布宽度的3倍.可见,两次测量的19F+93Nb耗散反应产物激发函数的截面不重复性具有明确的统计意义,其来源不是计数率的随机涨落. 相似文献
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在中国原子能科学研究院的HI-13串列静电加速器上完成了114MeV和118.75MeV的19F+27Al耗散反应产物B, C, N, O, F, Ne, Na和Mg的微分截面测量. 条形27Al同位素靶的大小尺寸为10mm×50mm, 平均
厚度约67μg/cm2. 固定入射束流19F的能量, 通过移动靶位, 先后轰击了靶上20个不同的位置.实验结果表明, 在弹靶系统、入射能量以及探测系统都相同的多次独立的微分截面测量中, 截面的涨落不呈现高斯型几率分布. 截面测量的这种不重复现象难以用有限计数率的统计性质来解释. 相似文献
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完成了114MeV19F+27Al深部非弹性碰撞产物的角分布测量.分析了反应产物B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,讨论了反应形成的中间双核系统随时间演化过程中角分布所表现出的耗散特点.从实验上提取了反应产物各元素的角分散参数并作了角分散参数的理论拟合,讨论了角分散参数的物理意义以及角分散参数与耗散反应产物的电荷数Z之间的依赖关系. 相似文献
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完成了19F+27Al深部非弹性碰撞产物的角分布测量.初步分析了反应产B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,展现出深部非弹性反应机制的特点,显示了反应系统随时间的演化过程. Angular distributions of fragments produced in the deep inelastic collision of~(19)F+~(27)Al have been measured for incident energy of 114 MeV at θ_(lab)= 9~(o), 24~(o), 40~(o), 55~(o), 70~(o) and 85~(o). Angular distributions of dissipative products B, C, N, O, F, Ne, Na, Mg and Al are analyzed to provide an evolution process of the intermediate dinuclear system formed in the reaction. 相似文献
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Analysis of the Energy Autocorrelation Functions in Dissipative Heavy Ion Collision of 27Al+27Al 下载免费PDF全文
The excitation functions of the dissipative fragments emitted from the reaction of 27Al+27Al have been measured in the energy region from 114MeV to 127MeV in steps of 200keV. The detection system covered continuous angles from 10° to 57° in laboratory system. The energy autocorrelation functions of the dissipative fragments have been analyzed by using different approaches,especially using the statistical nuclear reaction model with memory. The results indicate that the intermediate dinuclear system formed in the dissipative process is set in a damped coherent nuclear rotation which causes the nonself averaging oscillation structure in the excitation functions and originates from a typical quantum chaotic motion. 相似文献
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A. K. Nasirov A. I. Muminov R. K. Utamuratov G. Fazio G. Giardina F. Hanappe G. Mandaglio M. Manganaro W. Scheid 《The European Physical Journal A - Hadrons and Nuclei》2007,34(3):325-339
The anisotropy in the angular distribution of the fusion-fission and quasifission fragments for the 16O + 238U , 19F + 208Pb and 32S + 208Pb reactions is studied by analyzing the angular-momentum distributions of the dinuclear system and compound nucleus which
are formed after capture and complete fusion, respectively. The orientation angles of the axial symmetry axes of the colliding
nuclei relative to the beam direction are taken into account for the calculation of the variance of the projection of the
total spin onto the fission axis. It is shown that there is a large contribution of the quasifission fragments in the 32S + 208Pb reaction to the deviation of the experimental angular anisotropy from the statistical model results. Enhancement of anisotropy
at low energies in the 16O + 238U reaction is connected with the quasifission of the dinuclear system having low temperature and relatively small effective
moment of inertia. 相似文献
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《Nuclear Physics A》1997,624(4):755-772
Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100A MeV to 800A MeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z ⩾ 2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces. 相似文献
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Energy coherence widths of the dissipative products in the collision 27Al+27Al are extracted from measurement of the excitation functions. Then, the nuclear temperature T of the intermediate dinuclear system are determined, and discussed by using a concept of coherence rotation. 相似文献
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J.C. Steckmeyer F. Lefebvres C. Le Brun J.F. Lecolley M. lHaridon A. Osmont J.P. Patry 《Nuclear Physics A》1984,427(2):357-396
The angular momentum transferred to fragment spins has been studied in the damped nuclear reactions Ar+Bi at 255 MeV and 295 MeV and Ni+Pb at 435 MeV from measurement of the angular distribution of the fission fragments of the heavy-recoil nucleus in coincidence with the projectile-like fragment. The heavy-fragment spin is strongly aligned along the normal to the reaction plane and the rigid-rotation limit of the dinuclear system is attained. The dealignment mechanisms produce spin components mainly located in a plane approximately perpendicular to the heavy-recoil lab direction. They are well described by a dynamical model based on the nucleon exchange between the two ions during the collision. The spin-component fluctuations reach high values. In the heavy-recoil direction, these fluctuations are increasing with the total kinetic energy loss and the charge transfer from the projectile to the target. The spin values extracted from both the angular distributions and the fission probabilities are seen to be compatible. 相似文献
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Angular Distributions and Angular Dispersions of the Dissipative Products in19F+27Al Reaction 下载免费PDF全文
DONG Yu-Chuan WANG Qi LI Song-Lin DUAN Li-Min WU He-Yu XU Hua-Gen CHEN Ruo-Fu XU Hu-Shan HAN Jian-Long LI Zhi-Chang LU Xiu-Qin ZHAO Kui ZHOU Ping 《中国物理C(英文版)》2005,29(2):147-151
Angular distributions of fragments b,c,n,o,f,ne,na,mg and al induced from the reaction of 19F+27Al have been measured at the beam incident energy of 114mev. the angular distributions and the element distributions at different angles were analyzed to provide an evolution process of the intermediate dinuclear system. the angular dispersion parameters were extracted from the experimental data and compared with the theoretical results. the dynamic dispersions for the dissipative products are not negligible and depend strongly on the charge number Z of the fragments,the deeper dissipation the more dynamic dispersion. 相似文献