Institutional Repository of Institute of Modern Physics, CAS
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Effect of entrance-channel asymmetry on the isospin dependence of nucleon emission in heavy ion collisions
No full textUsing the isospin- and momentum-dependent hadronic transport model 1BUU04, we have investigated the influence of the entrance-channel isospin asymmetry on the sensitivity of the pre-equilibrium neutron/proton ratio to symmetry energy in central heavy-ion collisions induced by high-energy radioactive beams. Our analysis and discussion are based on the dynamical simulations of the three isotopic reaction Systems Sn-132+Sn-124, Sn-124+Sn-112 and Sn-112+(112)Su which are of the same total proton number but, different isospin asymmetry. We find that, the kinetic-energy distributions of the pre-equilibrium neutron/proton ratio are quite sensitive to the density-dependence of symmetry energy at incident beam energy E/A = 400 MeV, and the sensitivity increases as the isospin asymmetry of the reaction system increases.National Natural Science Foundation of China 10575119
10775061
Knowledge Innovation Project of Chinese Academy of Sciences KJCX3-SYW-N2
Major State Basic Research Developing Program of China 2007CB815004
CAS/SAFEA International Partnership Program for Creative Research Teams CXTD-J2005-1
Asia-Link Project of the European Commission CN/ASIA-LINK/008(94791
Production cross-section of Ra-230 in the reaction of 60 MeV/u O-18 ions with U-238
No full textA thick natural uranium target was bombarded with a 60 MeV/u O-18 beam. The neutron-rich isotope Ra-230 as the target residue was produced through the multinucleon transfer reaction (U-238-4p-4n). The barium and radium fraction as BaCl2 precipitate were radiochemically separated first from the mixture of uranium and reaction products. Then, the radium fraction was separated from BaCl2 precipitate by using cation exchange technique. The gamma-ray spectra of the Ra fraction were measured using an HPGe detector. The production cross sections of Ra-230 were obtained by a combination of the radiochemical separation technique and off-line gamma-ray spectroscopy. The cross section of Ra-230 has been determined to be 66 +/- 20 mu b.National Natural Science Foumdation of China 1057511
Controlled synthesis and diameter-dependent optical properties of Cu nanowire arrays
No full textUsing electrochemical deposition, Cu nanowire arrays have been successfully fabricated by home-made polycarbonate ion-track templates. The diameters were well controlled by etching time of templates. The minimum diameter is 15 nm. The morphologies and structures were analyzed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The wires prefer [1 1 0] growth direction due to H ions absorption. The optical properties of Cu nanowire arrays are studied by an ultraviolet/visible/near-infrared spectrophotometer. Two extinction peaks were observed in spectra. The optical mechanism is discussed based on surface plasmon resonanc
84.5MeV~(12)C~(4+)离子诱发金属靶原子发射的Kβ与Kα-X射线强度比值的研究
No full text本实验是在中国科学院兰州近代物理研究所,国家实验室的重离子加速器上完成的.实验用OR-TEC公司生产的HPGe X射线探测器测量了84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的K壳层特征X射线谱,计算了Kβ与Kα-X射线强度的比值,并将结果与Scofield用Hartree-Fock-Slater模型计算出的理论值与用其它方法(如:衰变幅射,用光子,电子,质子等粒子与靶相互作用)得到的实验值进行了比较.比较结果表明用84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的Kβ与K-αX射线强度比值比理论值和其它实验值要大许多
SFC引出静电偏转板高压放电的研究
No full text根据SFC引出静电偏转板的特殊工作环境和运行中发生的现象,对其高压放电机理进行了深入的研究和大量的电磁场计算。计算结果表明,在电场和磁场的共同作用下,盖板损伤的发生部位与实际运行中的打火痕迹完全符合。最后阐述了SFC引出偏转板的高压放电过程,并对其改进措施进行了研究
CSR外靶实验终端大型探测器读出电子学研制
No full text兰州重离子加速器-冷却储存环外靶实验终端大型探测器中子墙和TOF墙分别共有504个和360个通道用于测量中子和带电粒子的飞行时间,需要高精度时间测量的读出电子学系统。研制的8通道读出电子学模块采用了前沿定时的时间测量方法、基于TOT技术的电荷测量方法和PXI总线平台,电子学测试结果显示时间测量精度好于25ps
CSRe团簇内靶的真空与分子泵监测系统的设计
No full text介绍了国家重大科学工程项目——兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环(CSRe)团簇内靶真空与分子泵监测系统。该系统主要通过一个应用程序获取各真空规及分子泵的状态值,并存入、更新Oracle数据库。浏览器上的ActiveX从Oracle中读取各设备状态值进行显示,如果状态值在警戒范围,则做出相应的控制操作。该系统在实验测试中运行良好,能满足实验的要求
RIBLL终端大面积光纤阵列探测器研制
No full text描述了RIBLL终端大型探测器之一的大面积闪烁光纤阵列探测器(LASFA)的工作原理和结构特点,报道了LASFA的研制以及单元性能的改进与测试。LASFA具有很高的时间分辨和空间分辨能力,可以很好地测量RIBLL终端各种轻带电粒子的信息
用于加速器电源的数字调节器的状态矩阵参数分析与实现
No full text介绍了在基于CycloneII芯片,采用状态空间方程所实现的数字调节器系统中,必不可少的状态矩阵参数分析与实现的软件平台。通过对算法优化和对MATLAB自带函数的调用,实现了针对被控对象具体需求,精度范围在1064以内的参数获取。同时还加入了极点选取规则,使最终得到的参数更符合实际需求,为实现精确、实时的数字调节器系统提供了必要的保证
