Physics design of CYCAIE-100

The design and construction of Beijing Radioactive Ion-beam Facility (BRIF) was started at China Institute of Atomic Energy -CIAE) in 2004. In this project, a 100 MeV high intensity cyclotron, CYCIAE100, is selected as a driving accelerator for radioactive ion beam production. It will provide a proton beam of 75—100 MeV with an intensity of 200—500 μA. The scheme adopted in this design, i.e., stripping the accelerated H-, makes the structure more compact and construction cost much lower. At present, the design for each system has been accomplished. This paper depicts the basic physics design of the machine, including its major structure and parameters, beam dynamics and each relevant system, e.g. basic structure of the main magnet, numerical simulation of the RF resonant cavity, axial injection system, central region, and study on crucial physics problems concerning the extraction and beam lines. The major problems encountered during the design of CYCIAE-100 are also summarized in this paper.     

Determination of the nucleon-nucleon interaction in the ImQMD model by nuclear reactions at the Fermi energy region

The nucleon-nucleon interaction is investigated by using the improved quantum molecular dynamic （ImQMD） model with three sets of parameters IQ1, IQ2 and IQ3, in which the corresponding incompressibility coefficients of nuclear matter are different. The charge distributions of fragments are calculated for various reaction systems at different incident energies. The parameters strongly affect the charge distributions and the fragment multiplicity spectrum below the threshold energy of nuclear multifragmentation. The fragment multiplicity spectrum for 238U＋197Au at 15 A MeV and the charge distributions for 129Xe＋12~Sn at 32 and 45 A MeV, and 197Au＋197Au at 35 A MeV are reproduced by the ImQMD model with the set of parameter IQ3. It is found that： 1） The charge distribution of the fragments and the fragment multiplicity spectrum are good observables for testing the model and the parameters. 2） The Fermi energy region is a sensitive energy region for studying nucleon-nucleon interaction.     

Determination of the nucleon-nucleon interaction in the ImQMD model by nuclear reactions at the Fermi energy region

The nucleon-nucleon interaction is investigated by using the improved quantum molecular dynamic (ImQMD) model with three sets of parameters IQ1,IQ2 and IQ3,in which the corresponding incompressibility coefficients of nuclear matter are different. The charge distributions of fragments are calculated for various reaction systems at different incident energies. The parameters strongly affect the charge distributions and the fragment multiplicity spectrum below the threshold energy of nuclear multifragmentation. The fragment multiplicity spectrum for ²³⁸U+¹⁹⁷Au at 15 A MeV and the charge distributions for ¹²⁹Xe+¹²⁰Sn at 32 and 45 A MeV,and ¹⁹⁷Au+¹⁹⁷Au at 35 A MeV are reproduced by the ImQMD model with the set of parameter IQ3. It is found that: 1) The charge distribution of the fragments and the fragment multiplicity spectrum are good observables for testing the model and the parameters. 2) The Fermi energy region is a sensitive energy region for studying nucleon-nucleon interaction.     

Beam Energy Dependence of the π-/π+ Ratio

Using the isospin- and momentum-dependent hadronic transport model IBUU04, the effects of symmetry energy on the π^-/π^＋ ratio are studied. Our investigations are based on the calculations of the ^132 Sn＋^124Sn semi-central collisions at beam energies of 400/AMeV, 600/A MeV and 800/A MeV. It is found that both the transverse momentum and kinetic energy distributions of the π^-/π^＋ ratio are rather sensitive to the symmetry energy, especially around the Coulomb peaks. The position of the Coulomb peak is shown to be nearly independent of beam energy. The sensitivity of the π^-/π^＋ ratio to the symmetry energy decreases as the beam energy increases from 600/A MeV to 800/A MeV.     

A three-dimensional Eulerian method for the numerical simulation of high-velocity impact problems

In the present paper, a three-dimensional （3D） Eulerian technique for the 3D numerical simulation of high-velocity impact problems is proposed. In the Eulerian framework, a complete 3D conservation element and solution element scheme for conservative hyperbolic governing equations with source terms is given. A modified ghost fluid method is proposed for the treatment of the boundary conditions. Numerical simulations of the Taylor bar problem and the ricochet phenomenon of a sphere impacting a plate target at an angle of 60~ are carried out. The numerical results are in good agreement with the corresponding experimental observations. It is proved that our computational technique is feasible for analyzing 3D high-velocity impact problems.     

Forward-backward multiplicity correlations of target fragments in nucleus-emulsion collisions at a few hundred MeV/u

The forward-backward multiplicity and correlations of a target evaporated fragment (black track particle) and target recoiled proton (grey track particle) emitted from 150 A MeV ⁴He, 290 A MeV ¹²C, 400 A MeV ¹²C, 400 A MeV ²⁰Ne and 500 A MeV ⁵⁶Fe induced different types of nuclear emulsion target interactions are investigated. It is found that the forward and backward averaged multiplicity of a grey, black and heavily ionized track particle increases with the increase of the target size. The averaged multiplicity of a forward black track particle, backward black track particle, and backward grey track particle do not depend on the projectile size and energy, but the averaged multiplicity of a forward grey track particle increases with an increase of projectile size and energy. The backward grey track particle multiplicity distribution follows an exponential decay law and the decay constant decreases with an increase of target size. The backward-forward multiplicity correlations follow linear law which is independent of the projectile size and energy, and the saturation effect is observed in some heavy target data sets.     

Stripping extraction calculation and simulation for CYCIAE-100

A 100 MeV H- compact cyclotron is under construction at China Institute of Atomic Energy (CYCIAE-100). The proton beams of 75 MeV-100 MeV at an intensity of 200 μA will be extracted in dual opposite directions by charge exchange stripping devices. The crossing point at the switching magnet center is fixed inside the magnet yoke and the stripping points for various extraction energies are calculated by the code CYCTRS. With the code GOBLIN, we can calculate the transfer matrix including the dispersion effects from the stripping point to the switch magnet. The beam distribution just after stripping foil can be obtained from the multi-particle tracking code COMA and the extracted beam parameters after the switch magnet such as emittance, envelope, dispersion, energy spread, bunch length, etc. are given by the extraction orbit simulations.     

Meshless analysis of three-dimensional steady-state heat conduction problems

Steady-state heat conduction problems arisen in connection with various physical and engineering problems where the functions satisfy a given partial differential equation and particular boundary conditions, have attracted much attention and research recently. These problems are independent of time and involve only space coordinates, as in Poisson’s equation or the Laplace equation with Dirichlet, Neuman, or mixed conditions. When the problems are too complex, it is difficult to find an analytical solution, the only choice left is an approximate numerical solution. This paper deals with the numerical solution of three-dimensional steady-state heat conduction problems using the meshless reproducing kernel particle method (RKPM). A variational method is used to obtain the discrete equations. The essential boundary conditions are enforced by the penalty method. The effectiveness of RKPM for three-dimensional steady-state heat conduction problems is investigated by two numerical examples.     

Stripping extraction calculation and simulation for CYCIAE-100

A 100 MeV H- compact cyclotron is under construction at China Institute of Atomic Energy (CYCIAE-100). The proton beams of 75 MeV-100 MeV at an intensity of 200 μA will be extracted in dual opposite directions by charge exchange stripping devices. The crossing point at the switching magnet center is fixed inside the magnet yoke and the stripping points for various extraction energies are calculated by the code CYCTRS. With the code GOBLIN, we can calculate the transfer matrix including the dispersion effects from the stripping point to the switch magnet. The beam distribution just after stripping foil can be obtained from the multi-particle tracking code COMA and the extracted beam parameters after the switch magnet such as emittance, envelope, dispersion, energy spread, bunch length, etc. are given by the extraction orbit simulations.     

Design and gamma sensitivity measurement of a novel dual-emitter vacuum Compton detector

A novel dual-emitter vacuum Compton detector (D-VCD) with higher gamma ray detecting efficiency is proposed. The emitters are made of Ta--Al clad metal. The gamma ray sensitivity is studied by Monte Carlo simulation using the MCNP code. A comparison between calculations and results measured by using the 1.25~MeV gamma ray of Co-60 is also performed. Experimental sensitivities for two sample D-VCDs with the same materials and structures are 1.92×10^ - 20 and 2.02×10^ - 20~C.cm²/MeV separately, which are consistent with the simulation result of 1.98×10^ - 20~C.cm²/MeV and are 4 times higher than that of VCD with a single Fe emitter. According to the simulation results, in a gamma energy range from 0.5 to 3~MeV, the maximum sensitivity variance for the D-VCD is less than 15%, and less than 5% in a range from 1 to 2~MeV in particular. The novel D-VCD is applicable to the detection of intense pulse gamma rays.     

锂离子电池中的物理问题及其研究进展

锂离子电池作为一种性能优越的新型可充放电池已经或将要在移动通信、手提式计算机和电动汽车等诸多领域获得广泛的应用 .然而与锂离子电池相关的物理问题却往往被人们忽视 .例如 ,如何从本质上来提高正极材料的体相电子电导率 ,而不是在正极活性物质中添加炭黑之类的电子导电材料 .文章将着重针对与锂离子电池相关的物理问题 ,介绍近年来的主要进展 ,以期待对锂离子电池有更深入的了解 .     

对称能密度依赖的输运理论模型研究中的一些问题的讨论

本文非常简要地介绍了目前通过重离子碰撞中的对称能敏感观测量获取对称能密度依赖的研究现状,讨论了在输运理论模型计算中可能引起计算结果的不确定性的几个问题。特别与目前广泛采用的输运理论模型计算相关的3个方面的问题,即对称势动量依赖项和中子、质子有效质量劈裂;不同电荷态△产生的阈能和相关截面的介质修正;输运理论模型中的多体关联和涨落等的处理等问题。     

Recent progress in solid oxide and lithium ion conducting electrolytes research

Recent material developments of fast solid oxide and lithium ion conductors are reviewed. Special emphasis is placed on the correlation between the composition, structure, and electrical transport properties of perovskite-type, perovskite-related, and other inorganic crystalline materials in terms of the required functional properties for practical applications, such as fuel or hydrolysis cells and batteries. The discussed materials include Sr- and Mg-doped LaGaO₃, Ba₂In₂O₅, Bi₄V₂O₁₁, RE-doped CeO₂, (Li,La,)TiO₃, Li₃La₃La₃Nb₂O₁₂ (M=Nb, Ta), and Na super-ionic conductor-type phosphate. Critical problems with regard to the development of practically useful devices are discussed.     

锂离子电池中的物理问题

锂离子电池是一种性能优越的新型可充放电池．文章在简述了它的原理和特性之后，着重介绍了所涉及的一些物理问题，诸如嵌入物理、载流子输运、渗流、分形和相变等，以期对锂离子电池有更深入的理解     

Simulation of induced radioactivity for a heavy ion medical machine

The radioactivity induced by carbon ions of the Heavy Ion Medical Machine (HIMM) was studied to asses its radiation protection and environmental impact. Radionuclides in the accelerator component, and in the cooling water and air at the target area, which are induced from primary beam and secondary particles, are simulated by FLUKA Monte Carlo code. It is found that radioactivity in the cooling water and air is not very important at the required beam intensity and energy that is needed for treatment, while radionuclides in the accelerator component may cause some problems for maintenance work and, therefore, a suitable cooling time is needed after the machine is shut down.     

中能重离子碰撞过程中的同位旋分馏

本文主要在我们近几年来对中能重离子碰撞中同位旋分馏研究工作的基础上,结合国际上对这个问题研究的进展。对同位旋分馏动力学,产生同位旋分馏的机制,入射道效应,特别是建议将同位旋分馏强度作为提取同位旋相关平均场和建立同位旋不对称核物质状态方程的可能性进行了讨论和分析。并进一步对该问题的深入研究进行了讨论。     

几个量子力学问题的统一解法

通过变换求得连带Laguerre方程的变通形式，它包括了量子力学中-维谐振子、三维谐振子和类氢离子所满足的径向薛定谔方程，因此可用统一的方法对这三个问题的能级和波函数求解。     

Ionenstrahlätzen – Verfahren und Ausrüstungen für die Mikrostrukturierung

Ion beam techniques are widely used jur modification as well us analysis of materials in development and production of VLSI circuits and their importance is continuously increased in course of the reduction of structure dimensions. Some possibilities and problems connected with the application of ion beams of low energy in the pattern transfer are- described and the stage of development achieved in the Central Institute of Isotope and Radiation Research is outlined.     

氢化氙离子XeH+基态X1S+解析势能函数的变分研究

采用双原子分子离子XY+的能量自洽法(Energy-consistent -method for ion XY+, ECMI)研究了氢化氙离子XeH+基态X1S+的解析势能函数,并与解析形式的Morse势和Huxley- Murrell-Sorbie（HMS）势、耦合电子对方法(coupled electron pair approximation method, CEPA)的结果和基于实验的Rydberg-Klein-Ress（RKR）数据进行了比较。结果表明,由ECMI方法得到的解析势能函数ECMI势明显优于Morse势和HMS势,与理论方法的结果和RKR数据符合得很好,并能得到CEPA和RKR非法缺乏的离解区和渐近区的势能数据以及正确的离解极限,而正确的全程势能数据对研究各种散射问题都是非常必要的。     

电子束离子阱及高电荷态离子相关物理

文章简要介绍了电子束离子阱（EBIT）的发展背景及其在国际上的状况，较详细地解释了它的结构和工作原理，介绍了它在分解研究等离子体方面的特别优势以及在EBIT上能够实现的高电荷态离子相关的前沿物理学问题研究。