共查询到20条相似文献,搜索用时 78 毫秒
1.
Li Zuyu Wang Hongwei He Zhiyong Dun Limin Zhang Baoguo Dai Guangxi Fu Yanbiao Jin Genming 《中国物理C(英文版)》1998,22(8):684-689
Fragment-fragment conelation functions have been measured in E/A=30 MeV 40Ar+natAg reaction via the technique of intensity interferometry. Emission times of intermediate mass fragments have been extracted from reduced velocity correlation functions by using the threebody trajectory model. The average emission time of intermediate mass fragments varies with the energy of fragments. It decreases from about 300fm/c for low energy fragments to about 80fm/c for energetic fragments. After subtmcting the contribution of projectile-like fragments, average emission times of mid-rapidity fragments are of the order of 250fm/c for this reaction.It indicates that intermediate mass fragments emitted in this reaction mainly come from sequential binary decays. 相似文献
2.
Fission Fragment Angular Correlation in the Reaction Induced by 84.0MeV 16O Bombarded 238U
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QIAN Xing ZHANG Huan-Qiao LIU Zu-Hua XU Jin-Cheng CHEN Shao-Lin XU Kan LU Li-Xin 《中国物理C(英文版)》1993,17(2):173-178
Fission fragment angular distribution and angular correlation in the reaction induced by 84.0MeV 16O bombarded 238U have been measured by using two position-sensitive PPAC with large area.Transfer fission has been removed from total fission using fission fragment angular correlation technique.The contribution to the total fission cross section arising from transfer is about 10%.The anisotropy of fission fragment for transfer-fission is rather small,thus the removal of the transfer fission has little effect on the total fragment angular distribution.Indeed the anisotropy becomes larger by about 5% and anomalously anisotropies still persist. 相似文献
3.
The pre-equilibrium correction for the nuclear reactions induced by fast neutron is considered as follows: the nuclear reaction processes with the exciton number equal to or larger than five can still be described by the statistical theory of the nuclear reaction. The particle emission processes, in which less than five excitons are involved, are calculated by means of the exciton model and the γ emission of one exciton state is calculated by the direct capture mechanism. For the three-exciton state, only the semidirect capture mechanism, which plays the main role in the researched energy region, is taken into account. The interference effect between the direct and semidirect capture is also considered. The radiative capture cross sections for 40Ca and 208Pb in the neutron incident energy region from 3 MeV to 20 MeV are calculated and a better coincidence with the experimental values is obtained. At the same time, the contribution to the (n, γ) reaction cross sections of the γ emissions before and after statistical equilibriums as well as the characteristics of the direct capture, semidirect capture and their interferece terms are discussed. 相似文献
4.
ZHAO Kai LI Zhu-Xia WU Xi-Zhen WANG Ning ZHANG Ying-Xun TIAN Jun-Long ZHANG Huan-Qiao LIU Zu-Hua 《中国物理C(英文版)》2006,30(1):26-31
Based on the Improved Quantum Molecular Dynamics Model the fusion reactions of 40,48Ca+90,96Zr are studied by making a more rigorous treatment of the initial condition. The study shows that:(1) the calculated fusion cross sections for all four reactions of 40,48Ca+90,96Zr are in good agreement with experiment data; (2) the sub-barrier fusion for the neutron-rich reaction 40Ca+96Zr is ubstantially enhanced as compared with the other three reactions. In order to understand the reason why the sub-barrier fusion of the neutron-rich reaction 40Ca+96Zr is enhanced as compared with the non-neutron-rich reaction 40Ca+96Zr and that of the neutron-rich reaction 48Ca+96Zr is not enhanced, the further investigations are carried out, those are: the dynamic fusion barriers for four reactions, the relation between dynamic fusion barrier and nucleon transfer and the relation between nucleon transfer and corresponding reaction Q value. It has been found that positive Q value leads to the strong nucleon transfer which reduces the dynamic fusion barrier and enhances the sub-barrier fusion cross section. 相似文献
5.
庞丹阳叶沿林 郑涛李智焕 李湘庆葛愉成 华辉吴翠娥 楼建玲卢飞 范凤英A. Ozawa Y. Yamaguchi R. Kanungo D. Fang I.Tanihata 《中国物理快报》2007,24(10):2785-2788
The inclusive differential cross sections of the ^7 Li nucleus in a reaction induced by ^6He on a ^9Be target are measured at an incident energy of 25 MeV/nucleon. Finite-range distorted-wave Born approximation calculations suggest that these ^7 Li particles are formed in a direct single-proton pickup reaction ^9Be(^6He,^7 Li)^8Li. The experimental data can be well reproduced by taking into account of the contributions of both the ground states and the first excited states of ^7Li and ^8Li. 相似文献
6.
MEASUREMENT AND ANALYSIS OF EMITTED α PARTICLES IN REACTIONS OF 12C BOMBARDING 12C,27Al AND natCa
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XIE Yuan-Xiang WU Guo-Hua ZHU Yong-Tai MIAO Rong-Zhi FENG En-Pu YIN Xu MIAO He-Bin CAI Jing-Xiang SHEN Wen-Qing SUN Shu-MiNG WEI Jian-Jun LI Song-Lin 《中国物理C(英文版)》1985,9(1):71-76
The energy spectra and angular distributions of the emitted α particles in the reactions of the 69.5MeV 12C bombarding 12C,27Al and natCa have been measured and analysed using the fast particle exciton model. The contribution from the equilibrium and preequilibrium α-emissions is calculated to be 89%, 81% and 83% of the total α yields for the three reactions respectively, where the preequilibrium α emissions are 11%, 14% and 16% respectively. A small contribution comes from the other reaction mechanism. 相似文献
7.
LI Er-Tao LI Zhi-Hong LI Yun-Ju YAN Sheng-Quan BAI Xi-Xiang GUOBing SU Jun WANG You-Bao WANG Bao-Xiang LIAN Gang ZENGSheng FANG Xiao ZHAO Wei-Juan LIU Wei-Ping 《中国物理快报》2009,26(7)
Angular distribution of the 12C(6He,7Li)11B transfer reaction is measured with a secondary 6He beam of 36.4MeV for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approximation (DWBA) calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), Beijing. 相似文献
8.
Angular distributions and differential range distributions have been measured with nuclear chemistry techniques for 20 target residues from the reactions of 115In with 92 and 71MeV 16O ions.In terms of the increase of impact parameter,the results indicate continuous evolution of the reaction mechanisms from complete fusion,incomplete fusion to direct reaction involving steadily decreasing transfer of mass and momentum.Contribution of incomplete fusion in 16O+115In reaction is significantly larger than that in 16O+65Cu reaction. 相似文献
9.
Three-body exit channel in the reaction 12C+16O at 56MeV has been studied by using measurement of the coincidence between the two changed particles.The projected spectra of the coinsidence between the two α-particles shows that the channel α+24Mg is the main intermediate process of three-body exit channel α1+α2+20Ne in the reaction 12C+16O at 56MeV.The analysis of theoretical calculation showed that the sum of sequential decay and statistical break-up fit the experimental spectra satisfactorily. 相似文献
10.
The reaction of 139La(82Se, x)136Ba was used in this experiment. The nuclide 136Ba was produced via the transfer reaction channel. Some new γ rays of 136Ba were measured and a new isomer state at 10+ was observed. The half life of this isomer is 94ns based on its time spectrum. According to the intensities of gamma transition and gamma-gamma coincidence relationship, the scheme of 136Ba is suggested. 相似文献
11.
HUA Hui JIANG DongXing LI XiangQing QIAN Tao WU HeYu JIN GenMing ZHAN WenLong DUAN LiMin GUO ZhongYan XIAO ZhiGang LI ZuYu WANG ShuFang ZHANG BaoGuo 《中国物理C(英文版)》2000,24(6):512-517
In the reaction of 33.4MeV/u 17N on a target 9Be,the measured neutron spectra at different angles exhibit a complex pattern and vary regularly as a function of the detected angle. The detected neutrons probably come from the three origins:nucleon-nucleon collisions between the projectile and target,break-up of 17N and statistical evaporations from the hot nuclei. By analyzing the measured neutron angular distribution and calculating with QMD and GEMINI for the reaction concerned, 4.49,0.44 and 5.5barns were obtained for neutron emission cross sections due to the three origins mentioned above,respectively. 相似文献
12.
WANG DA-YAN LI ZU-YU YUAN SHUANG-GUI GUO ZHONG-YAN JIN GEN-MING XU GUO-JUN YUE HAI-KUI WANG XI-MING CHEN JU-SHENG ZENG WEN-BING XIE HONG-MEI QIAN ZHENG-GUANG ZHANG LI DAI GUANG-XI 《中国物理C(英文版)》1982,6(5):609-615
In this paper, we present energy spectra and angular distributions for the α-par-ticles emitted in the reaction of 12C+197Au at 64 and 67 MeV and for α, Be and B emittedin the reaction at 71.5 MeV. The most-probable energles of the variousproducts emittedin this reaction decrease.with decreasing incident energy. The angular distributions peak near grazing angle.The peak position of the angular distributions shift from--80°to--120°while the projec-tile energy decreases from 71.5 MeV to 64 MeV. These all show the features of the transferreaction. The 6Li product also has been measured and the 8Be particle emitted from thisreaction was detected at 90°to the beam direction using α-α coincident technique at 71.5MeV. The coross section of the 3Be is only few percent at the same angle. 相似文献
13.
The oscillatory structure appeared in the differential cross section of the reaction for 16O(16O, 12C)20Ne may be explained by particle transfer from covalent channel to ionic channel in the nuclear molecular orbital theory. 相似文献
14.
Ultrafast third-order optical nonlinearities of the as-deposited and annealed Au:Bi2O3 nanocomposite films deposited by magnetron cosputtering are investigated by using femtosecond time-resolved optical Kerr effect (OKE) and pump probe techniques. The third-order optical nonlinear susceptibility is estimated to be 2.6Ф×10^- 10 esu and 1.8 × 10.9 esu at wavelength of 800nm, for the as-deposited and the annealed film, respectively. The OKE signal of the as-deposited film is nearly temporally symmetrical with a peak centred at zero delay time, which indicates the dominant contribution from intraband transition of conduction electrons. For the annealed film, the existence of a decay process in OKE signal implies the important contribution of hot electrons. These characteristics are in agreement with the hot electron dynamics observed in pump probe measurement. 相似文献
15.
ZHU Sheng-Jiang 《中国物理C(英文版)》1992,16(6):539-545
The high spin states in 68Ge,65Ga and 67Ga were studied through in-beam gamma-ray spectroscopy experiment.The reaction 46Ti(25Mg,xpxn) was used with beam energy 68MeV.In 68Ge the new multiplicity of band structures,the crossing transitions among the bands and a new band with possible big diformation were observed.The experiment results agree with a new microscopic model calculation (EXCITED FED VAMPIR).In 65Ga and 67Ga a few band structures with strong collectivity were observed and the new level schemes were given. 相似文献
16.
Optical Potential Parameters for Halo Nucleus System ^6He+^12C from Transfer Reaction ^11B(^7Li, ^6He)^12C
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The optical potential parameters for the halo nucleus system ^6He+^12C are extracted from fits to the measured angular distributions of ^11B(^7Li, ^6He)12C reaction at energies of 18.3 and 28.3MeV with distorted-wave Born approximation analysis. The characters of the obtained optical potentiM parameters are basically consistent with the results extracted from the fits to the elastic-scattering angular distributions in the literature. 相似文献
17.
LIU Shao-Xiang 《中国物理C(英文版)》1985,9(3):321-326
The angular distribution has been measured for elastic scattering on 40Ar with 11B and for the single proton transfer reaction 40Ar(11B, 10Be)41K at the incident beam energy of 50 MeV. The elastic scattering cross section has been fitted in terms of the optical model. The EFR-DWBA aproach with recoil effect has been used to analyze the differential cross section. The spectroscopic factor was extracted. 相似文献
18.
Elastic scattering angular distributions of the 14^N+16^O system and the angular distributions of transfer reaction 16^O(14^N,13^C)17^F at ELab=76.2 MeV and 57 MeV have been measured and calculated by means of the exact finiterange distorted-wave Born approximation with the PTOLEMY code. The optical potential parameters for the weakly bound nuclear system 17^F+13^C have been deduced and applied to analyse the elastic scattering angular distributions of the similar systems 17^F+12^C and 17^F+14^N which are taken from literature. The result shows that the transfer reaction with stable projectile and target combination can be used as an alternative method to extract the optical potential parameters for the weakly bound nuclear system. 相似文献
19.
The dynamical calculation of quasi-fission reaction induced by 10.6MeV/u 84Kr on 27Al is performed using one-body dissipation model.The calculation suggests a fission time larger than 200×10-22 sec.It is found that the threshold for emergence of quasi-fission in the reactoin system is 8MeV/u. 相似文献
20.
GAO Bing-Shui ZHOU Xiao-Hong FANG Yong-De ZHANG Yu-Hu LIU Min-Liang WANG Si-Cheng WANG Jian-Guo MA Fei GUO Ying-Xiang WU Xiao-Guang HE Chuang-Ye ZHENG Yun WANG Zhi-Min YAN Xin-Liang WANG Zhi-Gang FANG Fang 《中国物理C(英文版)》2014,38(6):064001-064001
The neutron rich nucleus 193Os was produced in the 192Os(7Li, 6Li)193Os reaction. An isomeric state based on the 9/2-[505] Nilsson orbital was identified in the present work. The half-life of the isomeric state was extracted and discussed in terms of the K quantum number. A level scheme built on the isomeric state was proposed based on the experimental data. 相似文献