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1.
Angular distributions of fragments B, C, N, O, F, Ne, Na, Mg and Al induced by the collision of ^19F ^27Al at 114 MeV have been measured. Angular dispersion parameters are extracted from the experimental data and compared with the theoretical ones. The dynamic dispersions for dissipative products depend strongly on the charge number Z of the fragments. 相似文献
2.
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
3.
重离子核反应中的碎片发射机制是近年来人们十分关注的研究课题。利用ΔE-E 探测器,测量了~6 MeV/u 的19F+27Al 反应中核电荷数Z = 2 ~13 的出射碎片。对产物的能谱、角分布、激发函数及能量自关联函数的分析表明,出射产物主要来自弹靶核深部非弹性碰撞所形成的转动的双核系统。In recent years, extensive studies have been made to understand the fragment emission mechanisms in low energy light heavy-ion reactions. These fragments are found to be emitted from quasielastic/projectile breakup, deep-inelastic and fusion-fission processes. Fragments of Z = 2~13 induced by the collision of 19F+27Al have been measured by ΔE-E telescope. The analysis of the energy spectra, angular distributions, excitation functions and energy auto-correlation functions of these fragments shows that the emission of fragments is coming from a rotational dinuclear system formed in the dissipative collision of the projectile and target nuclei. 相似文献
4.
韩建龙 王琦 白真 董玉川 李松林 段利敏 徐瑚珊 徐华根 陈若富 吴和宇 李志常 路秀琴 赵葵 周平 刘建成 许国基 Sergey Yu Kun 《原子核物理评论》2008,25(4):322-326
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19F+27Al耗散反应产物的激发函数测量。 束流19F的入射能量从110.25 MeV到118.75 MeV, 步长250 keV, 测量了实验室系+57°, +31°, -15°和-29°出射的类弹产物B, C, N, O, F和Ne的激发函数。 观测到激发函数具有耗散反应的特征涨落结构, 分析了激发函数之间的长程角度关联以及强烈的电荷数关联。 Excitation functions have been measured for the projectile like fragments of B, C, N, O, F and Ne in the 27Al(19F,x)y reactions at incident energies from 110.25 MeV to 118.75 MeV in 250 keV steps. Strong cross section fluctuations in the excitation functions has been observed. The cross correlation coefficients of the excitation functions for different atomic number Z and for different scattering angle θ cm have been deduced. These coefficients are much larger than the statistical theoretical calculated ones. This indicates that there are strong correlations between different exit channels in the dissipative heavy ion collision of 27Al(19F, x)y. 相似文献
5.
TOGANO Y AOI N BABA H HONDA T OKADA K HARA Y IEKI K ISHIBASHI Y ITOU Y IWASA N KANNO S KAWABATA T KIMURA H KONDO Y KURITA K KUROKAWA M MORIGUCHI T MURAKAMI H OISHI H OTA S OZAWA A SAKURAI H SHIMOURA S SHIODA R TAKESHITA E TAKEUCHI S YAMADA K YAMADA Y YASUDA Y YONEDA K MOTOBAYASHI T 《中国科学:物理学 力学 天文学(英文版)》2011,(Z1)
Two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg. 相似文献
6.
The radionuclide ~(22)Na generates the emission of a characteristic 1.275 MeV γ-ray. This is a potential astronomical observable, whose occurrence is suspected in classical novae. The ~(22)Mg(p, γ)~(23)Al reaction is relevant to the nucleosynthesis of ~(22)Na in Ne-rich novae. In this study, employing the adiabatic distorted wave approximation and continuum discretized coupled channel methods, the squared neutron asymptotic normalization coefficients(ANCs)231 for the virtual decay of Ne → ~(22)Ne + n were extracted, and determined as(0.483 ± 0.060) fm~(-1) and(9.7 ± 2.3) fm~(-1) for the ground state and the first excited state from the experimental angular distributions of ~(22)Ne(d, p)~(23)Ne populating the ground state and the first excited state of ~(23)Ne, respectively. Then, the squared proton ANC of ~(23)Al_(g.s.) was obtained as C_(d5/2)~(2)(~(23)Al)(2.65 ± 0.33) × 10~3 fm~(-1) according to the charge symmetry of the strong interaction. The astrophysical S-factors and reaction rates for the direct capture contribution in ~(22)Mg(p, γ)~(23)Al were also presented. Furthermore, the proton width of the first excited state of ~(23)Al was derived to be(57 ± 14) eV from the neutron ANC of its mirror state in ~(23)Ne and used to compute the contribution from the first resonance of ~(23)Al. This result demonstrates that the direct capture dominates the ~(22)Mg(p, γ)~(23)Al reaction at most temperatures of astrophysical relevance for 0.33 T_9 0.64. 相似文献
7.
We present an analysis of π-20Ne elastic scattering at intermediate energy basing on the α+16O model of the20Ne nucleus and in the framework of Glauber multiple scattering theory. Satisfactory agreement with the general features of the experimental data of pion elastic scattering on the neighboring 4N-type nuclei is obtained without any free parameters. Compared with the experimental angular distributions of pion elastic scattering on12C,16O,24Mg,and28Si nuclei, the difractive patterns and the positions of the dips and peaks in the angular distributions of π-20Ne elastic scattering are reasonably predicted by the calculations. 相似文献
8.
重离子耗散反应产物激发函数研究的新进展 总被引:1,自引:1,他引:0
评述了近两年多来在重离子耗散反应激发函数研究中新的实验结果与理论进展.重点介绍27Al+2 7Al耗散反应产物的长程角度关联以及19F+93Nb耗散反应中截面及其涨落测量的不可重复性. The experimental study and the theoretical development on the structures of excitation functions in dissipative heavy ion collisions last years were reviewed. Especially the long range angular correlation in the reaction of 27Al+ 27Al and the non reproducibility of the cross sections measured in the reaction of 19F+ 93Nb were introduced. The experimental results indicate that the angular coherent width in the dissipative... 相似文献
9.
《中国科学:物理学 力学 天文学(英文版)》2015,(11)
Understanding the properties of nuclei inside "island of inversion" is still an interesting issue. Based on a simple Nilsson model with a new set of isospin-dependent parameters, and with non-axial deformations considered, we have performed three-dimensional potential-energy-surface calculations for Ne, Na, Mg and Al isotopes that are claimed to be in or nearby the A~30 island of inversion". It is found that shape coexistence and triaxial deformation(or softness) exist in these nuclei. Large deformations are obtained by the improved Nilsson parameters, which explains the observed large electric quadrupole transition probabilities. The large deformations happening in30 Ne,31Na,32 Mg and33Al indicate the quenching of the spherical N = 20 neutron shell gap. The calculations of nuclear binding and two-neutron separation energies have been also improved with the isospin-dependent parameters and the inclusion of the non-axial deformation degree of freedom. 相似文献
10.
An experiment aimed to investigate the two-proton (2p) decay of the previously unknown nucleus 30Ar was performed at GSI: By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of 30Ar were observed for the first time. For the calibration purpose, 2p decays of 19Mg were also remeasured by tracking the coincident 17Ne+p+p trajectories. By comparing the measured angular p-17Ne correlations with those obtained from the corresponding Monte Carlo simulations, the simultaneous 2p decay of 19Mg ground state and the sequential 2p emission of several known excited states of 19Mg were confirmed. One new excited state in 19Mg and two new excited states in 18Na were observed. 相似文献
11.
Angular Distributions and Angular Dispersions of the Dissipative Products in19F+27Al Reaction
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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
12.
A. A. Rollefson C. P. Browne M. A. Gummin L. O. Lamm M. Wiescher V. Wijekumar 《Zeitschrift für Physik A Hadrons and Nuclei》1988,331(1):101-102
The27Al(3He,α)26Al reaction has been used to determine 1-transfers for states in26Al between 6.3- and 6.5- MeV excitation. Angular distributions of α-particles between 5° and 15°, when added to our previously published results confirm a strong 1=0 component for a state at 6363 keV but indicate pure 1=2 for states at 6410 and 6498 keV. We discuss implications for nucleosynthesis. 相似文献
13.
Angular Distributions of Projectile Fragments Produced in Collisions of 200A GeV 32S Beam with Cu
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Angular distributions of projectile fragments P,Si,Al and Mg produced in collisions of 200A GeV 32S beam with Cu are measured.The range of σpt deduced is within 130—270MeV/c. 相似文献
14.
《Radiation measurements》1997,28(1-6):245-248
Angular distribution of positive particles emitted from deuterium plasma focus device was determined using LR-115 detectors. Discrimination of positive particles was achieved by varying the widths of Al or macrofol layers. The angular distributions of different positive particles were compared, also. Corresponding distribution of soft X-ray was analyzed using the X-ray Kodak Industrial film. 相似文献
15.
J.C. Vermeulen A.G. Drentje L.W. Put R.R. De Ruyter Van Steveninck R.H. Siemssen J.F.A. Van Hienen H. Hasper H.T. Fortune 《Nuclear Physics A》1981,369(1):82-108
The 25Mg(d, 6Li)21Ne and 27Al(d, 6Li)23Na reactions were studied with a broad-range magnetic spectrograph at Ed = 55 MeV with an energy resolution of ~ 40 keV. Angular distributions were obtained from θlab = 10°–37° for some eighty transitions to states up to Ex ? 9.5 MeV. The data were analyzed with zero-range and finite-range DWBA. Experimental spectroscopic factors are compared with those predicted by the SU(3) model and by microscopic shell-model calculations made with the Chung-Wildenthal interaction in the full (1sd)n space. 相似文献
16.
The 26Mg(d, n)27Al reaction has been studied at 6 and 8 MeV deuteron bombarding energies using the time-of-flight technique for neutron detection. The good neutron energy resolution of the present work permitted the determination of the excitation energy of 70 states populated by the reaction. Angular distributions of neutrons leading to 50 levels in 27Al were measured between 0° and 100°. The experimental cross sections were analysed in the framework of the DWBA and Hauser-Feshbach theories to deduce lp values and transition strengths. New spin and parity assignments were obtained for 11 levels. The agreement between the DWBA predictions and some of the measured angular distributions was improved by modifying the optical-model radii in both incoming and outgoing channels. The experimental results are compared with the corresponding data from previous studies and with Nilsson-model and recent shell-model calculations. 相似文献
17.
C. T. Coburn J. F. Shriner Jr. C. R. Westerfeldt 《Zeitschrift für Physik A Hadrons and Nuclei》1992,343(2):185-189
Angular distributions for27Al(p, α 0) and excitation functions for27Al(p, p 0) and27Al(p, α 0) have been measured for 2+ resonances in thep+27Al system. For 10 of these resonances, partial widths have been determined for three proton channels, and the relative sign between the reduced width amplitudes in two of these channels has been deduced. Linear correlation coefficients between reduced widths and between reduced width amplitudes in different channels have been calculated. The amplitudes appear consistent with the expected Gaussian distribution. 相似文献
18.
19.
M. Wery 《Nuclear Physics A》1973,210(2):329-340
Angular distributions and excitation functions have been measured for the 16O(t, t) reaction from 1.4 to 3.7 MeV triton energy using a differentially pumped gas target. The observed resonances have been analysed with the Humblet-Rosenfeld theory. It appears that the 13–15 MeV excitation range of the compound system of 19F is dominated by several levels of large triton partial width. Levels populated in the three-particle transfer reaction (7Li, α) on 16O are compared with the resonances. 相似文献