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1.
In order to improve the accuracy of accelerator mass spectrometry (AMS) measurement for 182Hf/180Hf, a series of measurements have been taken in the AMS laboratory at the China Institute of Atomic Energy (CIAE). The major ones include the instantaneous monitoring of 180HfF5- current, testing the stability of transmission, the alternate measurements of an unknown sample and standard, and the origin identification and minimization of background 182W. The experimental details and the improvement in the measurement accuracy, as well as some useful suggestions for better satisfying the requirements of certain practical applications, are presented in this paper. 相似文献
2.
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
3.
董克君 何明 李振宇 王祥高 李朝历 游曲波 包轶文 武绍勇 沈洪涛 管永精 张伟 凡金龙 杨磊 孙宏清 丁有钱 贺国珠 李世琢 龚杰 何贤文 陆丽燕 王伟 胡跃明 袁坚 张生栋 常永福 姜山 《中国物理快报》2010,27(11):27-30
Accelerator mass spectrometry (AMS) is one of the most promising methods to detect minute amounts of 182Hf. However, the sensitivity of 5×10^-11 for ^182Hf/180Hf obtained previously by the AMS method at China Institute of Atomic Energy (CIAE) cannot meet the requirement of some applications. We present some new improvements of measurement method for AMS measurement of 182Hf at the CIAE HI?13 tandem accelerator system. As a result, a sensitivity of 1.0×10^-11 for 182Hf/180Hf is achieved. 相似文献
4.
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
5.
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
6.
DETERMINATION OF THE AVERAGE NEUTRON ENERGY USING CROSS SECTION RATIO OF 58Ni(n,p)58m+gCo and 58Ni(n,2n)57Ni REACTIONS
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YUAN Jun-Qian WANG Yong-Chang QIU Jiu-Zi WANG Hua-Min REN Zhong-Liang YANG Jing-Kang 《中国物理C(英文版)》1990,14(6):569-572
The method of determination for average neutron energy from D-T reaction by using two silicon semiconductor detectors and the cross section ratios of 58Ni(n,p)58m+gCo and 58Ni(n,2n)57Ni reactions is described.The plot of the cross section ratio against the neutron energy has been obtained.The results have been compared with existing data. 相似文献
7.
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
8.
Element Distributions of Intermediate Mass Fragments Emitted in 30 MeV/u 40Ar+58,64Ni and 115In Reactions
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Gou Quanbu Zhu Yongtai Xu Hushan Wei Zhiyong Lu Jun Zhang Yuhu Wang Qi Li Songlin Wu Zhongli 《中国物理C(英文版)》1999,23(6):512-517
The element distribuhons of intermediate mass fragments (IMF) emitted over an angular region of 5°—140° have been measured in the reachons of 30MeV/u 40Ar+58,64Ni and 115In. Within 20°—80° range the IMFs with Z=3-24 were observed. The IMF production cross section changes smoothly with its charge number,and the element distribuhon changes continuously when the IMF charge number increases across the charge number of the projectile. There is no strong dependence of the element distribution on the charge number of the projectile in this angular region.The transition nature of the reaction mechanism in the intermediate energy region and the power law of the IMF element distribution,as well as the dependence of element distributions on the threshold of the detectors were discussed. 相似文献
9.
Some experimental results measured for light emission particles with Z≤2 from 12C+64Ni reaction at E(12C)=69, 56MeV are reported. A comparison between moving source model calculation and proton's spectra have been performed. Extracted parameters of the source with faster velocity are agreement with the systematic values found before. The composite particle energy spectra of α, 3He and D were analyzed by coalescence model. 相似文献
10.
Neutrino Energy Loss by Electron Capture on Nucleus ^56Mn, ^56Fe, ^56Co and ^56Ni in Strong Electron Screening
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Based on the p-f shell model, the neutrino energy loss rates for nucleus ^56Mn, ^56Fe, ^56Co and ^56Ni in the electron capture process are canvassed in and not in a strong electron screening. The results show that the neutrino energy loss rates for ^56Mn, ^56Fe, ^56Co and ^56Ni decrease about 15%, 10%, 60% and i order of magnitude correspondingly at the temperature T9 = 15 and even debase 2 orders of magnitude at the temperature T9 = 1. 相似文献
11.
The Angular Distributions of intermediate Mass Fragments Emittsd in 30 MeV/u 40Ar+58,64Ni and 115In Reactions
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Gou Quanbu Zhu Yongtai Xu Hushan Wei Zhiyong Lu Jun Zhang Yuhu Wang Qi Li Songlin Wu Zhongli 《中国物理C(英文版)》1999,23(4):328-333
The angular distributions of intermediate mass fragments with Z=3-19 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5°—140°have been measured.Exponential distribution function: dσ/dΩ=N·exp(-θ/a) was used tO fit the measured angular distributions.We have extracted the decay factor a that can be connected with the interaction time τ, and the factor N that is related to the intensity of the emission source.The relationships of a(Z) with Z and N(Z) with Z for different reaction systems and different angular ranges have been discussed. The dependence of angular distributions on isospin and the symmetry of reaction system have also been discussed. 相似文献
12.
Loess is the most important and the most typical continental classic sediments of Quaternary. So the measurement of In-situ produced cosmogenic 10Be is expected to be used for the Loess stratigraphic age. But the production rate of In-situ produced cosmogenic 10Be in Loess quartz is very low. It requires very high sensitivity and accuracy of measurement. This work has measured the concentrations of 10Be of two layers in Loess section of Luochuan including L8, L9 and the concentrations of 10Be in (of) blank sample with the HI-13 AMS system at China Insitute of Atomic Energy(CIAE), then calculated the content of 10Be in loess quartz for each layer. The ratio of 10Be/9Be was found in the range of 10-13. The background of 10Be/9Be was about 3×10-14. 相似文献
13.
HUANG Xiao-Long 《中国物理C(英文版)》2006,30(4):306-309
Based on the experimental data of the total, the nonelastic and the elastic cross sections and the elastic scattering angular distributions for n+58Ni reactions, a set of parameters for a neutron optical model potential is obtained in the incident neutron energy region from 0.8—150MeV. Then reaction cross sections, angular distributions, energy spectra, gamma-ray production cross sections and gamma-ray production energy spectra are calculated in terms of the optical model, the distorted wave Born approximation theory, the Hauser-Feshbach theory, the exciton model and the cascade mechanism inside nuclear. The results are analyzed and compared with the existing experimental data and other evaluated data from ENBF/B-6. They are in agreement with each other within error bars. 相似文献
14.
着重介绍加速器质谱计(AMS)14C断代方法,北京大学近三年来AMS14C断代工作,还介绍了夏商周断代工程及其AMS14C断代工作.The method of accelerator mass spectrometry (AMS) 14 C dating, some AMS 14 C dating work in Peking University during the recent three years and the project of Xia Shang Zhou chronology are introduced. 相似文献
15.
为满足核工程对核数据的需求,对20 MeV以下65Cu(n, p)65Ni 反应截面的实验数据进行了分析和评价,包括实验数据的收集、修正、选取、归一、误差调整和数据处理,在分析实验误差特别是关联误差的基础上构造了每家数据的协方差矩阵,最后利用样条拟合程序SPCC给出了评价截面数据和实验数据的协方差矩阵。评价不仅考虑了实验数据的误差,还考虑了数据间的相关性。To meet the needs for nuclear data engineering, the experimental data of the 65Cu(n, p)65Ni cross section below 20 MeV were analyzed and evaluated.The evaluation procedure includes the experimental data collection, correction, selection, normalization, error adjustment and data processing, especially the covariance matrix for each experimental data is constructed with the information on experimental errors and correlation errors. The evaluation cross section data and the corresponding covariance matrices were given using the spline fitting procedure SPCC. The evaluation work was done with the consideration of not only the experimental errors but also the correlation of data. 相似文献
16.
加速器质谱是近年来蓬勃发展的一种十分活跃的核分析技术,其应用涉及环境科学、地质学、核物理及天体物理、生物医学等多个领域。中国原子能科学研究院的加速器质谱装置自从1989年建立至今,已经对^36Cl,^10Be,^129I,^26Al,^79Se和^41Ca等多种核素进行了成功测量。介绍了中国原子能科学研究院的加速器质谱计系统、核素的测量原理及几种相关核素的成功应用。The Accelerator Mass Spectrometry facility at the China Institute of Atomic Energy was established in 1989. The measurement methods for interesting nuclides such as ^36Cl, ^10Be, ^129I, ^26Al, ^79Se and ^41Ca etc. have been established and studies on their applications have been carried out. The facility and some interesting applications are briefly introduced. 相似文献
17.
QIU Jiu-Zi JIANG Shan HE Ming YIN Xin-Yi DONG Ke-Jun GUAN Yong-Jing WU Shao-Yong 《中国物理C(英文版)》2007,31(8):719-723
182Hf with half-life of about (8.90±0.09) Ma is an extinct radionuclide and can only be produced by a supernova explosion in nature. Therefore 182Hf is an ideal candidate nuclide for the study on possible supernova explosions in the vicinity of the earth within the last 100 million years. In addition, 182Hf is a long-lived radionuclide of particular interest for nuclear engineering. Accurate measurement of ultra-trace 182Hf is very important for reactor design,studies on nuclear cosmo-physics and other fields. With an accelerator mass spectrometry (AMS), it is possible to detect the trace amounts of 182Hf. In this paper, the detection method of 182Hf with HI-13 AMS system at China Institute of Atomic Energy (CIAE) and the chemical procedures to reduce 182W interference are presented. The energy and TOF two-dimension spectra of 182Hf and 183W for blank and a series of standard samples have been obtained, respectively. The 182W contribution to the counts in 182Hf peak was corrected by 183W normalization. The detection sensitivity of this AMS facility for 182Hf/180Hf ratio measurement is about 4.15±10-11 at present. 相似文献
18.
A new method for measuring selenium-79 with AMS, which is based on extracting molecular negative ions, is described in this paper. According to the experimental results, the extraction ion form SeO2- could depress the interference of Bromine-79 as much as 5 order levels, that is to say, the background of 79Br can be deducted to 79Br/Se≈10-10. By the way, the chemical form of sample and preparation flow was also developed. Finally, three 79Se AMS calibration standard samples with theoretical 79Se/Se ratios of 5.06×10-7, 6.87×10-8, 5.40×10-10 were obtained and the method of 79Se measurement was set up, which actualized transmission and detection of 79Se. By using our Bragg curve detector, the two isobars 79Br and 79Se could be partly identified to a certain extent and 79Se can be identified from 79Br about 1 order level. AMS measurements of the three calibration standard samples above were performed and good linearity was obtained. The sensitivity of the measurement is (5.16±1.80)×10-11. 相似文献
19.
范凤英 郑涛 叶沿林 江栋兴 华辉 李智焕 葛愉成 李湘庆 楼建玲 史帆 吕林辉 曹中鑫 聂鹏煊 李奇特 宋玉收 卢飞 徐瑚珊 胡正国 王猛 张雪荧 李琛 陈若富 唐彬 徐治国 岳珂 张亚鹏 臧永东 章学恒 姚向武 陈金达 涂小林 张洁 武大鹏 白真 《中国物理快报》2009,26(8):74-77
Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution. 相似文献
20.
The present detection limit for 182Hf at CIAE HI-13 AMS systems could not satisfy various applications (e. g. detection of a nearby supernovae signal). Therefore, techniques were developed in this work to improve the AMS measurement of 182Hf mainly on building a new injector and using a method that based on solid-phase reaction for the preparation of HfF4 samples from HfO2. The experimental results show that mass resolution of the injector can reached 630, and the F-/O- and beam current of 180HfF5- for HfF4 samples produced by dry method is about 2—3 times and 1.5 times of that by previously method, respectively. 相似文献