共查询到20条相似文献,搜索用时 31 毫秒
1.
Li Zuyu Wang Hongwei He Zhiyong Duan Limin Zhang Baoguo Dai Guangxi Fu Yanbiao Jin Genming Wu Heyu 《中国物理C(英文版)》1999,23(8):753-759
The energy spectra of intermediate-mass fragments (IMF) (3≤Z≤16) have been measured from 6° to 110° for 40Ar+natAg reachon at 30 MeV/u. The energy spectra were analyzed by the moving source model. The natUres of the projechle-like source, target-like source and mid-rapidity source as well as the evolution with angle and nuclear charge were discussed. Two intermediate mass fragments, measured by correlation method in forward angles, come from two sources. One comes from projectile-like source, and other one mainly comes from intermediate source respectively. 相似文献
2.
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
3.
Temperatures and Excitation Energies of Hot Nuclei in Reactions of 40Ar+natAg,209Bi at MeV/u
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Yin Shuzhi Jin Weiyang Zhang Chun Jin Genming Zheng Jiwen Wu Enjiu Tan Jilian Li Zuyu Wang Sufang Song Mingtao Wu Heyu He Zhiyong Jiang Dongxing Qian Xing 《中国物理C(英文版)》1997,21(8):680-685
Coincidence measurements of fission fragment and light charged particle have been perfotrmed for the reactions of 40Ar+natAg,209Bi at E/A=25MeV using 4 PPAC and 11 sets of ΔE-E telescopes.Angular correlations of fission fragment were ploted as a function of the folding angle between the two detected fission fragments.The linear momentum transfer distributions were derived by measuring angular correlations.The backward spectra of light particles detected in coincidence with fission fragments having different average〈LMT〉are analyzed with Maxwell distribution.After some corrections the initial temperatures of the hot nuclei are determined from the energy spectra.The excitation energies corresponding to the different average〈LMT〉are obtained considering the reaction Q values and pre-equilibrum emission.In the central collision of the 40Ar+natAg,209Bi reactions,excitation energies are measured to be about 4.2MeV/u,2.4MeV/u and temperatures about 6.1MeV,5.5MeV,respecdvely.In semi-central collision,excitaionen energies are measured to be about 3.5MeV/u,1.9MeV/u and temperatures about 5.8MeV,4.8MeV respectively. 相似文献
4.
Light Particle and Complex Fragments Emission from 12C Induced Reactions on 58Ni,64Ni at E/A=46.2MeV
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YIN Shu-Zhi ZHAN Wen-Long ZHU Yong-Tai GUO Zhong-Yan FENG En-Pu XI Hong-Fei ZHOU Jian-Qun LIU Guan-Hua 《中国物理C(英文版)》1992,16(4):364-369
Energy spectra of light charged particles and complex fragments emitted in the interaction of 46.2MeV/u 12C with different target 58Ni,64Ni,12C,197Au and 209Bi have been measured by telescopes,consisting of CsI(Tl) and surface barrier detector stacks.These telescopes for light charged particles and complex fragments have good energy resolution and mass identification.The inclusive data have been analysed within a moving source parametrization.The complex fragment yields from different targets have been compared at several angles.The systematic variation of deduced isotope yields ratios with different reaction systems is used to detemine the N/Z degree of freedom equilibration of the system achieved. 相似文献
5.
THE MEASUREMENT OF COMPLETE FUSION CROSS-SECTIONS FOR THE REACTIONS 12C+27Al, 12C+209Bi AND 14N+Pb
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Mica track detectors were used for the measurement of evaporation residues and fission fragments of compound nuclei formed in 12C+27Al, 12C+209Bi and 14N+Pb reactions. The complete fusion cross-sections and excitation functions were then obtained. By using the sharp cut-off model approximation, the values of the critical angular momenta were extracted from the complete fusion cross-sections. The results obtained were compared with the calculations based on current theories for critical angular momentum; they were found to agree within experimental uncertainties. 相似文献
6.
Angular and Z Distributions of the Fragments at Forward and Intermediate Angles in the Reaction of 25MeV/u 40Ar+115In,58Ni,27Al
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WANG JinChuan ZHAN WenLong GUO ZhongYan XI HongFei LIU Hang ZHOU JianQun ZHAO YouXiong 《中国物理C(英文版)》2000,24(1):41-48
The angular & Z distributions of foe fragments emitted in the forward and intermediary angles are measured at the reaction of 25 MeV/u 40Ar+115In,58Ni,27Al. Their characteristics are investigated based on the model of Modified Qantum Molecular Dynamics (MQMD). Generally, the theoretical calculations are in good agreement with the experiment data. But in the forward angles the yield of the fragments is underestimated by MQMD model while in the case of the intermediate angle region, the calculation is higher than the experiment data in some degree for the fragments whose charge numbers are in the vicinity of the proiectile. The angular & charge distributions of the fragments are also compared with the statistical model of GEMINI. The results turn out to be that a small proportion of the statistical evaporation component exists in the forward angles while in the intermediate angle region, this component increases to some extent. However, its ratio is still small. It is found that the equilibrium evaporation component decreases gradually when the Z of the fragments becomes smaller. 相似文献
7.
ZHANG Dong-Hai 《中国物理C(英文版)》2002,26(1):40-45
Production of helium projectile fragments in 16O-emulsion interactions at 60 A GeV is investigated. The total charge changing and partial production cross-sections are measured experimentally on the basis of helium multiplicity. The multiplicity distribution of helium projectile fragments obeys a KNO scaling. In the peripheral collision of 16O at 60 A GeV in nuclear emulsion, the production of target fragments depends on the multiplicity of helium projectile fragments linearly. The averge multiplicity of target fragments decreases with the increasing of the number of helium projectile fragments which can be well expliained by the model of participant-spectator (the nuclear geometric model) of nucleus-nucleus interactions. 相似文献
8.
Energy Correlations between Fragments and Light Charged Particles in Reaction of 25MeV/u 40Ar+115In
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WANG Jin-Chuan ZHAN Wen-Long GUO Zhong-Yan XI Hong-Fei ZHOU Jian-Qun ZHAO You-Xiong 《中国物理C(英文版)》2001,25(2):115-120
The correlations between the emitted fragments at θlab=15°and the light charged particles(LCPs) at the close geometry configuration in the reaction of 25MeV/u 40Ar+115In were measured. The energy correlations between fragments (4≤Zf≤14) and the LCPs including proton, deuterium, tritium and a particle as well as the energy spectra of the LCPs were obtained. The result shows the existence of sequential decay mechanism. It is found that the peak position of angular correlation is at the small angles and the most probable correlation angle is at 2°or so; The peak positions of the two components in the energy spectra of LCPs increase gradually with the mass of correlated partner; The lighter primaly products are more easier to be excited and decay to IMFs and the LCPs. In the Sequential decay, the yield of the LCPs with more heavier mass is higher than that of the lighter LCPs. The result reveals that the total correlation yield ratios summed over the fragments of Zf=4—14 are 1: 1. 3: 1. 78: 7. 57 for proton, deuterium, tritium and a particles, respectively. 相似文献
9.
YAN De-Hong GUO Zhong-Yan WU En-Jiu YIN Shu-Zhi FAN En-Jie XI Hong-Fei LIU Guan-Hua ZHANG Qing-Li FENG En-Pu LU Xiu-Qin ZHAO Kui CHENG Ye-Hao LI Qing-Li LI Min JIANG Cheng-Lie 《中国物理C(英文版)》1991,15(2):158-164
The angular distributions and Wilczynski plots of emitted fragments from He to O in reaction of 16O+64Ni at 96MeV have been measured.The DIC cross section and intereaction time were obtained.DIC character of the reaction was discussed.The trace which shows that the emitted fragments of He and Li mainly come from the evaporation process of compound nuclei emerged. 相似文献
10.
RADIOCHEMICAL INVESTIGATION OF MASS DISTRIBUTIONS IN 12C-INDUCED FISSION OF 209Bi AND 238U
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The yields of 15 and 17 fission, products have been obtained by radiochemical determinations in 12C-induced fission of 209Bi and 238U respectively. From these data, the mass distributions of fission fragments are calculated based on three different hypotheses for the charge distribution. The results seem to indicate that the hypothesis of equal charge displacement gives the best fit to the Gaussian distribution for the masses of the fission fragments. By comparison with the mass distributions for 209Bi (12C, f), 238U(12C, f) and 197Au(12C, f) in our early measurement, we find that for fission parameter Z2/A>37, the width of the mass distributions increases with Z2/A rapidly. 相似文献
11.
Interaction time ~4.3×10-21s of the dissipative products in the collision 27Al+27Al is extracted from the measurement of excitation functions by using the developed Ericson statistical theory. 相似文献
12.
FENG En-Pu WANG Qi ZHU Yong-Tai YIN Xu MIAO He-Bin SUN Shu-Ming LI Song-Lin WU Zhong-Li FAN Guo-Ying XIE Yuan-Xiang ZHAN Wen-Long 《中国物理C(英文版)》1986,10(3):323-329
By using ΔE-E telescope and the time of flight detector, the energy spectra of products between 6Li and 16O were measured for the reaction 12C+27Al, at 61.8MeV. The contour plots of differential cross section in c.m. system and the angular distributions of emitted fragments were obtained. The calculated values of fully relaxed energies in deep inelastic collistions agree with the experimental values. The mean interaction time of di-nuclear system was estimated as from 1×10-21s to 1.4×10-22s 相似文献
13.
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
14.
By means of using an isospin-dependent Boltzmann-Langevin equation which includes isospin-dependent symmetry energy, Coulomb energy, isospin-dependent nucleon-nucleon cross sections, Pauli blocking, and initialization, the radial expansion flow of reaction systems 40Ca+58Ni and 40Ca+58Fe at 53, 100, 150, and 200 MeV/u in the central collisions were studied. It has shown that the more neutron rich system exhibits smaller radial expansion flow. It was found that the neutron rich system had smaller threshold energy which may provide a new method to determine the isospin dependent nuclear equation of state from calculated result and linear fitting result. 相似文献
15.
This work is concerned with the analyses of the shower and gray particle production in 4.5 A GeV/c 24Mg collision with emulsion nuclei. The highest particle production occurs in the region of the low impact parameters. While the multiplicity of the shower particles emitted in the forward direction depends on the projectile mass number and energy, the multiplicity of the backward ones shows a limiting behaviour. The source of the emission of the forward shower particles is completely different from that of the backward ones. The target fragments are produced in a thermalized system of emission. 相似文献
16.
XIAO Zhi-Gang WU He-Yu LI Zu-Yu JIN Gen-Ming WANG Hong-Wei DUAN Li-Min ZHANG Bao-Guo HU Rong-Jiang WEI Zhi-Yong LIU Yong-Ying WANG Su-Fang LU Zhao-Hui ZHU Yong-Tai ZHU Hai-Dong 《中国物理C(英文版)》2001,25(6):494-499
Isotope ratios,defined as the yield ratio of two isotopes with the same charge,were analyzed as a function of kinetic energy of outgoing particles at 20° in the reactions of 40Ar+112,124Sn and 5°in36Ar+112,124Sn at incident energy of 35MeV/u. Isotope ratios between the neutron-deficient isotopes and stable isotope increase with kinetic energy,while those between the neutron rich isotopes and stable isotope decrease. This different behavior was observed similar for both 112Sn and 124Sn targets. The isotope ratios show rather obvious target dependence at 20° and little target dependence at 5°. As the outgoing energy getting down,the N/Z ratio of the fragmentation products at 5° diverts gradually from the N/Z ratio of the projectile to that of the system. These observations indicate that the isospin degree of freedom does not reach complete equilibrium in the peripheral or semi-peripheral collision at this bombarding energy. 相似文献
17.
Intermediate mass fragments(2Z≤11) emitted from 294 MeV 20Ne+159Tb reaction have been measured by △E-E telescope counters at the angle of 10°—150°region.The energy spectra of the fragments at back angle(>90°) have bell shape,and their peaks locate near the Coulomb barrier of exit channel.The analysis of the energy spectra has been done in terms of moving source and indicate that all the fragments are emitted from a common source,the compound nuclei formed in incomplete fusion process.The charge and angular distributions of the fragments originated from the asymmetric binary decay of the formed compound nuclei have been calculated based on statistical GEMINI code,and the results are in well agreement with the experimental data. 相似文献
18.
Measurement of Angular Cross Correlation of the Cross Section Fluctuation in Dissipative Collision 27Al+27Al
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The excitation function was measured from θlab=10.4° to 57.4° in dissipative collision 27Al+27Al with incident energy ranging from 114 to 123 MeV in step of 200 keV. The Angular-cross Correlation Functions (ACFs) of cross section fluctuation within large angle region were obtained through experiment for the first time. It is found that the angular coherent width is at least 40°. It is interesting that the ACFs is not simple bell shape but shows strong asymmetry. The over-all behavior is that ACF varies more quickly for the backward angles. Itis also noticed that the cross section fluctuation in the forward angle region (θcm<70°) shows much stronger angular coherence than in the backward angle region (θcm>70°). This angular dependence may be attributed to the coherent rotation effect of intermediate dinuclear system. 相似文献
19.
20.
Azimuthal Distribution and Azimuthal Correlation of the Particles in 10.6MeV/u 84Kr+27Al Collision
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The light charged particle emission in coincidence with fragmemts in 10.6MeV/u 84Kr+27Al collision is studied.Emphasis is laid on the characters of two-order anisotropy coefficient of Fourier expansion up to two order from fitting particle azimuthal distribution and particle-particle azimuthal correlation.The derived results prove that particle emission is statistically independent with the same azimuthal distribution in each event.It is found that two-order anisotropic coefficient depends weakly on the fragment mass and increases with increasing emitted particle mass. 相似文献