共查询到20条相似文献,搜索用时 15 毫秒
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第一讲中子散射与散裂中子源 总被引:1,自引:0,他引:1
中子散射是研究物质微观结构和动态的理想工具之一,广泛地应用于凝聚态物质研究和应用的众多学科领域.散裂中子源能是新一代的加速器基脉冲中子源,能为中子散射提供高通量的脉冲中子.文章简明地介绍了中子散射的特点和它作为物质结构和动态探针的优越性,以及散裂中子源的基本原理、发展状况和多学科的应用优势.我国计划建设的散裂中子源CSNS中,靶站将由多片钨靶、铍/铁反射体和铁/重混凝土生物屏蔽体组成.质子束功率100kW下,脉冲中子通量约为2.4×1016n/cm2/s.第一期将设计建造高通量粉末衍射仪、高分辨粉末衍射仪、小角散射仪、多功能反射仪和直接几何非弹性散射仪等五台典型的中子散射谱仪,以覆盖大部分的中子散射研究领域. 相似文献
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Ming-Yang Huang 《中国物理C(英文版)》2016,40(6):063002-063002
We study the detection of accelerator neutrinos produced at the China Spallation Neutron Source(CSNS).Using the code FLUKA,we have simulated the production of neutrinos in a proton beam on a tungsten target and obtained the yield efficiency,numerical flux,and average energy of different flavors of neutrinos.Furthermore,detection of these accelerator neutrinos is investigated in two reaction channels:neutrino-electron reactions and neutrino-carbon reactions.The expected numbers of different flavors of neutrinos have also been calculated. 相似文献
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Neutronics studies of solid targets for spallation neutron source using Monte Carlo simulation 下载免费PDF全文
Neutronics studies for a solid target have been done with Monte Carlo high-energy particle transport code NMTC/JAM,when the proton beam with high kinetic energy bombards the target.The effect of the main parameters of the target on the neutron flux is discussed to optimize the target,which will be used for the concept design of the target of spallation neutron source.A target with its aspect ratio 1.5:1 or 2:1 gives the highest neutron flux.Tungsten is the most acceptable material from the technical and economical points of view.Beryllium as a moderating reflector can increase the neutron flux effectively. 相似文献
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Kurt N. Clausen 《Pramana》2008,71(4):623-628
In this paper the most promising technology for high power neutron sources is briefly discussed. The conclusion is that the
route to high power neutron sources in the foreseeable future is spallation — short or long pulse or even CW — all of these
sources will have areas in which they excel.
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由于缺少可用的散裂中子源,多年来我国在大气中子单粒子效应方面主要依靠模拟仿真和单能中子试验的方式开展研究.随着中国散裂中子源(CSNS)通过国家验收,基于CSNS开展大气中子单粒子效应研究成为可能.本文利用CSNS反角白光中子源开展多款静态随机存取存储器器件的中子单粒子效应试验,并与早期开展的高原大气试验结果进行对比,对CSNS在大气中子单粒子效应研究中的应用进行评估.结果表明,相同器件在CSNS反角白光中子源测得的单粒子翻转截面小于大气试验的结果,且不同器件的翻转截面与特征尺寸没有明显的单调关系.分析得到前者由于CSNS反角白光中子谱偏软;后者由于特征尺寸降低导致的临界电荷变小和灵敏体积变小对截面的贡献是竞争关系.针对截面偏小的问题,根据能谱差异分析了中子能量阈值对器件翻转截面的影响,发现能量阈值取12MeV进行计算时,器件在CSNS反角白光中子源和高原大气中子环境中能够得到较一致的截面.研究结果表明CSNS反角白光中子源能够用于加速大气中子单粒子效应试验.考虑到CSNS的运行功率正在逐步提高,且多条规划中的白光中子束线与大气中子能谱更为接近,预期未来CSNS将能更好地应用于大气中子单粒子效应研究. 相似文献
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鲍杰 陈永浩 张显鹏 栾广源 任杰 王琦 阮锡超 张凯 安琪 白怀勇 曹平 陈琪萍 程品晶 崔增琪 樊瑞睿 封常青 顾旻皓 郭凤琴 韩长材 韩子杰 贺国珠 何泳成 何越峰 黄翰雄 黄蔚玲 黄锡汝 季筱路 吉旭阳 江浩雨 蒋伟 敬罕涛 康玲 康明涛 兰长林 李波 李论 李强 李晓 李阳 李样 刘荣 刘树彬 刘星言 马应林 宁常军 聂阳波 齐斌斌 宋朝晖 孙虹 孙晓阳 孙志嘉 谭志新 唐洪庆 唐靖宇 王鹏程 王涛峰 王艳凤 王朝辉 王征 文杰 温中伟 吴青彪 吴晓光 吴煊 解立坤 羊奕伟 杨毅 易晗 于莉 余滔 于永积 张国辉 张旌 张林浩 张利英 张清民 张奇伟 张玉亮 张志永 赵映潭 周良 周祖英 朱丹阳 朱科军 朱鹏 《物理学报》2019,68(8):80101-080101
中国散裂中子源(CSNS)已于2018年5月建设完工,随后进行了试运行.其中的反角白光中子束线(Back-n)可用于中子核数据测量、中子物理研究和核技术应用等多方面的实验.本文报道对该中子束的品质参数测量实验过程以及最终实验结果.实验主要采用中子飞行时间法,利用~(235)U,~(238)U裂变室和~6Li-Si探测器测量了中子能谱和中子注量率,又利用闪烁体-互补金属氧化物半导体探测系统测量了中子束斑的剖面,得到了该束线的初步实验测量结果.其中白光中子的全能谱测量范围eV—100 MeV,给出了不确定度分析;给出了中子注量率两个实验厅位置的满功率值;给出了白光中子在直径60 mm情况下的全能区束斑.通过与模拟结果的比较探讨了以上结果的合理性,并提出了改进计划.这些实验结果为以后该束线的核数据测量和探测器标定实验奠定了基础. 相似文献
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Manish Sharma V. Kumar H. Kumawat J. Adam V. S. Barashenkov S. Ganesan S. Golovatiouk S. K. Gupta S. Kailas M. I. Krivopustov H. S. Palsania V. Pronskikh V. M. Tsoupko-Sitnikov N. Vladimirova H. Westmeier W. Westmeier 《Pramana》2007,68(2):307-313
A beam of 1 GeV proton coming from Dubna Nuclotron colliding with a lead target surrounded by 6 cm paraffin produces spallation
neutrons. A Th-foil was kept on lead target (neutron spallation source) in a direct stream of neutrons for activation and
other samples of 197Au, 209Bi, 59Co, 115In and 181Ta were irradiated by moderated beam of neutrons passing through 6 cm paraffin moderator. The gamma spectra of irradiated
samples were analyzed using gamma spectrometry and DEIMOS software to measure the neutron cross-section. For this purpose
neutron fluence at the positions of samples is also estimated using PREPRO software. The results of cross-sections for reactions
232Th(n, γ), 232Th(n, 2n), 197Au(n, γ), 197Au(n, α), 197Au(n, xn), 59Co(n, α), 59Co(n, xn), 181Ta(n, γ) and 181Ta(n, xn) are given in this paper. Neutronics validation of the Dubna Cascade Code is also done using cross-section data by other
experiments.
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Neutron beam monitor based on a boron-coated GEM 总被引:1,自引:0,他引:1
A new thermal neutron beam monitor with a Gas Electron Multiplier (GEM) is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm GEM foils. Enriched boron-10 is coated on one surface of the aluminum cathode plate as the neutron convertor. 96 channel pads with an area of 8 mm×8 mm each are used for fast signal readout. In order to study the basic characteristics of a boron-coated GEM, several irradiation tests were carried out with α source 239Pu and neutron source 241Am(Be). The signal induced by the neutron source has a high signal-to-noise ratio. A clear image obtained from α source 239Pu is presented, which shows that the neutron beam monitor based on a boron-coated GEM has a good two-dimensional imaging ability. 相似文献
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Dubna Cascade Code (version-2004) has been used for the Monte Carlo simulation of the 1500 MWt accelerator driven sub-critical system (ADS) with 233U + 232Th fuel using the IAEA benchmark. Neutron spectrum, cross-section of (n, xn) reactions, isotopic yield, heat spectra etc. are simulated. Many of these results that help in understanding the IAEA benchmark
are presented. It is revealed that the code predicts the proton beam current required for the 1500 MWt ADS for K
eff = 0.98 to be 11.6 mA. Radial distribution of heat is fairly in agreement with other codes like the EA-MC and it needs nearly
1% less enrichment than given by other codes. This may be because the code takes care of the role of larger order of the (n, xn) reactions. It is emphasized that there is a strong need to study (n, xn) reactions both theoretically and experimentally for better design.
This talk is dedicated to the fond memory of late Professor V S Barashenkov, JINR, Dubna 相似文献
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The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper.The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed. 相似文献
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I. Altarev M. Daum A. Frei E. Gutsmiedl G. Hampel F. J. Hartmann W. Heil A. Knecht J. V. Kratz T. Lauer M. Meier S. Paul U. Schmidt Y. Sobolev N. Wiehl G. Zsigmond 《The European Physical Journal A - Hadrons and Nuclei》2008,37(1):9-14
We have determined for the first time the velocity distribution of neutrons from a solid 2H2 ultracold neutron (UCN) source. The spectrum rises sharply above 4.5m/s and has a maximum around 7m/s after transport in
an 8m long guide. The number of neutrons in the UCN velocity range (< 7m/s) may be increased by a factor of two by placing
the experiment 1m above the UCN source level. 相似文献
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The spallation cross-section data for the long-lived fission products(LLFPs) are scarce but required for the design of accelerator driven systems. In this paper, the isospin dependent quantum molecular dynamics model and the statistical code GEMINI are applied to simulate deuteron-induced spallation in the energy region of GeV/nucleon. By comparing the calculations with the experimental data, the applicability of the model is verified. The model is then applied to simulate the spallation of 90 Sr, 93 Zr, 107 Pd, and 137 Cs induced by deuterons at 200, 500 and 1000 MeV/nucleon. The cross-sections of isotopes, the cross-sections of long-lived nuclei, and the reaction energy are presented.Using the above observables, the feasibility of LLFP transmutation by spallation is discussed. 相似文献
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Abstract High-pressure neutron-diffraction experiments using the time-of-flight (TOF) method are presented. We first introduce the helium-gas pressure system at Argonne's Intense Pulsed Neutron Source (IPNS) with the Special Environment Powder Diffractometer (SEPD). The results for TIBa2CuO6+8, and La2?x, Srx, CuO4–8 are briefly reviewed. We then introduce the present situation in Japan. We have been developing a high-pressure system on high-resolution powder diffractometer (HRP) which was much improved recently and renamed VEGA at KEK. The best resolution of 0.45% was obtained at VEGA. The preliminary results for YBa2, Cu4O8, and HgBa2, CuO4+8, are presented and compared with the SEPD data. 相似文献
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Shuang Hong Yong-Wei Yang Hu-Shan Xu Hai-Yan Meng Lu Zhang Zhao-Qing Liu Yu-Cui Gao Kang Chen 《中国物理C(英文版)》2016,40(11):114102-114102
Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactors. To calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by the FLUKA Monte Carlo code. All the data used to make the Origen2.1 libraries are obtained from Nuclear structure & decay Data (NuDat2.6). The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper. 相似文献
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采用速度干涉(VISAR)测试技术,对强激光辐照下纯铝的动态力学响应和层裂特性进行了实验测量和分析。样品厚度分别为200 μm 和485 μm,激光脉冲的半高宽约为10 ns,功率密度变化范围为1010~1011 W·cm-2。实测了样品自由面速度波形,反映了强激光加载作用下材料损伤演化过程以及损伤对材料动态响应的影响。计算得到了冲击波强度(2.0~13.4 GPa) 和不同拉伸应变率下铝的层裂强度(1.6~2.3 GPa)。在所采用的实验条件和1维近似下,激光辐照产生的冲击波强度与激光功率密度之间成线性关系。最后讨论了层裂强度与拉伸应变率之间的关系,显示层裂强度随着拉伸应变率的增加而增大。 相似文献