CSNS四极陶瓷真空盒磁控溅射镀TiN膜研究

介绍了中国散裂中子源（CSNS）快循环同步加速器（RCS）中四极陶瓷真空盒内表面镀TiN膜技术与成膜系统装置。采用磁控溅射法,通过在绝缘体长直管道外表面安装金属屏幕罩来提供同轴电场的方法,解决了镀膜均匀性的问题。镀膜样品Ti、N比在0.9~1.1范围内,膜厚为100nm左右,附着力达到要求,总体满足设计指标,完成了CSNS四极陶瓷真空盒样机的镀膜。     

中国散裂中子源快循环同步加速器注入系统水平涂抹凸轨磁铁样机的设计

阐述了中国散裂中子源（CSNS）快循环同步加速器（RCS）注入系统水平涂抹凸轨磁铁样机的设计。为满足设计要求和空间位置关系的需要，提出一种不对称窗框型铁芯结构，同时针对样机研制中存在的技术难题提出相应的解决方案。磁场模拟计算和试验的结果表明，该结构设计合理。     

壁电流探测器在中国散裂中子源快循环同步加速器调束中的应用

快循环同步加速器（RCS）是中国散裂中子源（CSNS）的重要组成部分。负氢粒子束经直线加速器加速至80 MeV，剥离成质子束注入至RCS环并加速累积至1.6 GeV引出打靶。束流通过安装在RCS环的壁电流探测器（WCM）感应得到束流的强度信息，环高频与环主二极磁铁的失配会导致束流的实际振荡偏离理论预测。本文通过对WCM的数据进行分析得到了纵向工作点、束流的实际振荡频率、束团的电荷量、束团的形状变化等信息，方便了加速器的调束，并对参数测量中的测量误差进行了分析。     

基于EPICS的注入凸轨脉冲电源控制样机研制

中国散裂中子源（CSNS）快循环同步加速器（RCS）是一台高束流功率质子加速器,凸轨磁铁脉冲（BUMP）电源是CSNS注入系统的重要设备。根据CSNS工程建设的要求,需在预研阶段研制一套凸轨电源控制样机,用于研究和解决控制系统建造中的一些关键技术。注入凸轨电源样机通过横河公司生产的WE7000测量系统实现对脉冲电源的控制,根据物理设计需要可完成对电源的任意波形给定输出并实现对电源输出波形的回采显示。本文主要介绍了基于EPICS系统的WE7000设备驱动的开发,以及在此基础上研制的注入凸轨脉冲电源控制样机的应用。通过联机测试的结果表明,该样机满足对注入凸轨脉冲电源的控制要求,达到了预研目的。     

CSNS/RCS中主要阻抗元件的仿真计算研究

中国散裂中子源（CSNS）快循环同步加速器（RCS）是强流质子加速器,对环中真空元件的阻抗研究是判断束流能否稳定运行的重要依据。通过正确估算环中元件阻抗,可及时对元件的阻抗进行有效控制和防止束流不稳定性发生,从而减小束流损失。本文利用CST电磁场仿真软件给出了RCS环中高频腔及准直器的耦合阻抗,并探讨了bus-bar结构对高频腔本身及束流稳定的影响,发现需重新设计bus-bar结构使腔固有频率大于10 MHz才能彻底解决因共振可能引起的丢束。此外,计算表明,主准直器屏蔽有利于减小耦合阻抗及损失功率,在安装代价较小的情况下需对主准直器进行屏蔽。     

中国散裂中子源漂移管直线加速器研制进展

漂移管直线加速器(DTL)是中国散裂中子源(CSNS)直线加速器的主要部分,负责将脉冲流强为15mA的负氢离子从3 MeV加速到80 MeV,再注入到快循环同步加速器(RCS)中实现进一步加速。CSNS DTL由4节长度约9m的RF腔体组成,单节RF腔体由1台3MW的速调管提供功率。每节腔体又分为3段长约3m的机械腔体以便于加工和安装。DTL腔体和漂移管的研制是整个CSNS直线加速器的关键。本文介绍了CSNS DTL研制过程,包括国内首次在强流质子加速器RF腔内表面进行高导无氧铜电镀、新型磁铁线圈的研制、小孔径磁铁的高精度测量等。加工及测试结果均满足CSNS的设计要求。     

CSNS/RCS四极磁铁样机磁场仿真计算和谐波分析

中国散裂中子源快循环同步加速器(CSNS/RCS)的四极磁铁共48台,分为4种孔径,每种孔径磁铁制作1台样机。目前4台样机磁铁已完成加工制造并进行了直流旋转线圈磁场测量。初步直流磁场测量结果显示,3台样机的部分磁场谐波分量超过了设计要求,需进行补偿。采用三维仿真软件OPERA进行建模,并进行磁场计算,分析了谐波超差的原因,确定了磁场补偿方案,最终样机磁铁的磁场质量满足设计要求。     

CSNS/RCS粒子散射束流损失研究

在中国散裂中子源快循环同步加速器（CSNS/RCS）中,质子束流在加速过程中会与一些器件（如剥离膜、准直器、散射引出膜等）相互作用,产生粒子散射并导致束流损失。本工作首先利用ORBIT模拟RCS束流注入过程,并用FLUKA模拟注入束流穿过剥离膜的粒子散射过程,计算剥离膜散射所造成的束流损失。其次,模拟质子束流与准直器相互作用的粒子散射,计算质子束流与不同尺寸的次级准直器相互作用的吸收效率,作为对次级准直器优化的依据。最后,研究CSNS/RCS膜散射引出方案,利用FLUKA对不同引出方案进行模拟并比较,得到最佳的可行性方案。     

基于Modbus/RS232的数字电源控制器的远控设计与实现

中国散裂中子源(CSNS)的磁铁电源全面采用数字化技术。磁铁电源是由电源内部的数字电源控制器DPSCM来进行电压电流回路的调节,其主要是由CYCLONE Core+NIOS-II系统组成,它具有RS-232通信(MODBUS协议)接口。为此,远程控制系统制定了基于Modbus/RS232的DPSCM的通讯规约,并使用MOXA嵌入式串口设备DA682开发了基于Modbus/RS232的EPICS IOC和实时数据库,并与DPSCM及RCS动态电源进行了现场联调。调试结果表明,使用DA682完全能够实现对RCS磁铁电源的远程控制,系统稳定可靠易扩展,满足物理要求。     

基于ANSYS和Matlab的CSNS/RCS主准直器的运输振动分析

以中国散裂中子源(China Spallation Neutron Source,CSNS)/快循环同步加速器(Rapid Cycling Synchrotron,RCS)主准直器为对象,研究从合肥某工厂通过公路运输到位于东莞的CSNS装置地运输过程中的振动情况。整个主准直器装置中,最薄弱的部位是刮束器的薄钨片,其质地硬而脆,运输途中的振动可能导致其发生破坏。考虑到装置造价高,制造周期长,现场无条件修复,对运输过程的安全进行评估很有必要。文中运用Matlab/Simulink建立卡车模型,仿真运输过程得到振动信号,通过试验测得实际运输过程的振动信号,将两种情况下获得的振动激励加载到ANSYS中的主准直器模型中,由此获得薄钨片在虚拟运输过程中因振动而产生的应力。通过仿真和试验,验证了仿真模型的有效性,得到了安全运输的指导车速。对加速器设备的运输振动安全评估具有实际意义。     

Development of Thin-wall Vacuum Chamber for Heavy Ion Medical Accelerator

Heavy Ion Medical Machine (HIMM), developed by the Institute of Modern Physics, Chinese Academy of Sciences, is the first medical heavy ion accelerator with independent intellectual property rights in China. Because the RAMPING mode was used for high frequency pulse dipole magnets of HIMM and the rising rate of magnetic field is 1.6 T/s, the vacuum chamber installed in the high frequency pulsed magnet is a thin-wall stainless vacuum chamber with reinforcing ribs to reduce the influence of eddy current on the ion beam stability. However, the gap size of magnet occupied by thin-wall stainless vacuum chamber with reinforcing ribs is too large, and it not only causes the high cost of magnets, but also greatly improves the maintenance cost. Based on these reasons, a new thin-wall vacuum chamber (0.3 mm) with ceramic lining was put forward and the prototype was designed and manufactured. The test results show that the obtained pressure of the prototype is in the order magnitude of 10^-10 Pa, and the magnet gap can be effectively reduced. And it is the development direction of thin-wall vacuum chamber of accelerator in the future.     

医用重离子加速器薄壁真空室研制

中国科学院近代物理研究所研制的医用重离子加速器装置是我国第1台拥有自主知识产权的医用重离子加速器，其高频脉冲二极磁铁使用RAMPING工作模式且磁场上升速率为1.6 T/s，所以安装在高频脉冲磁铁内的真空室采用一种薄壁加筋结构不锈钢真空室以减少涡流对离子束稳定性的影响。然而由于薄壁加筋不锈钢真空室占用磁铁气隙尺寸偏大，不仅造成了磁铁造价成本偏高，更是提高了运维成本。基于以上原因，本文提出陶瓷内衬薄壁（0.3 mm）真空室，并研制了原理样机。测试结果表明：样机真空度进入了10^-10 Pa量级范围，并可有效减小磁铁气隙，是未来加速器薄壁真空室的发展方向。     

陶瓷真空室研制及其阻抗的研究

介绍了电子储存环注入凸轨击磁铁及春真空室常采用的几种技术方案。合肥电子储存环新凸轨注入系统选择了铁氧体磁铁内置陶瓷真空室的方式。为了同时满足脉冲磁场穿透性能及束流耦合阻抗的要求,陶瓷真空室的内壁须镀１层金属薄膜。     

Patterned metallic coating of a ceramic chamber in storage ringbump magnets

To permit the pulsed field of a bump magnet to penetrate the vacuum chamber of a particle storage ring, a section of ceramic chamber is used. A thin metal coating on the inner surface is usually employed to prevent the static charge build-up on the surface of the ceramic chamber, as well as to reduce the coupling impedance. The metal coating, however, can lead to heating of the chamber walls due to eddy current. To avoid such an unwanted effect, a patterned coating is employed. In this paper, we discuss the electrical power and the field distortion due to the eddy current and the effect of various patterned metallic coatings on the motion of a circulating beam. The results are applied to the storage ring of the Pohang Light Source     

Vacuum Poloidal Magnetic Field of Tokamak in Alternating-Current Operation

Vacuum poloidal magnetic field of tokamak in alternating-current (AC) operation is investigated. It is found that the vacuum magnetic field in AC operation is qualitatively different from that in direct-current (DC) operation. In the DC case, the vacuum magnetic field varies along the poloidal direction with one period, while in the AC case, the vacuum magnetic field varies along the poloidal direction with two periods. This implies that two sets of vertical field coil may be needed for the AC operation.     

超重元素合成实验靶室及转靶装置

文章介绍兰州重离子加速器放射性次级束流线（RIBLL）的超重元素合成实验靶室和转靶系统，并对改进的真空密封磁耦合传动机械作简单描述。转靶系统采用可程序控制的无级变速电机、真空密[JP2]封磁流体耦合和特殊皮带传动机构，使得靶盘转速在0~600r/min范围内可调，靶盘边缘摆幅＜0.2mm。     

3D-simulation studies of the modified magnetic multipole structure for an electron cyclotron resonance ion source

Experiments have shown that efficient operation of an electron cyclotron resonance ion source requires that the magnetic field fulfills the so-called scaling laws. In most cases the requirements for the radial magnetic field, i.e. the strength of the magnetic multipole are the most difficult to satisfy. This is due to the fact that the multipole is usually produced from permanent magnets, which makes a value of 1.3 T feasible. One possible solution to increase the multipole field is the so-called Modified MultiPole Structure (JYFL-MMPS). This new idea makes it possible to increase the magnetic field at the places where the plasma flux is in contact with the plasma chamber wall. In this article we will present detailed three-dimensional magnetic field simulations of the JYFL-MMPS.     

Maintenance Method for Tokamak Fusion Reactors with Downward Access to Torus Inboard Structures

A concept of tokamak fusion reactor maintenance is presented. Reactor structures and maintenance machines are arranged so that the component inside a shielding structure can be replaced through the hatches located on the upper side of the torus shielding structure. The plasma vacuum boundary is constituted by the inside wall of the shielding structure. The magnet vacuum chamber contains two toroidal magnets in a single room, so that strong support structures can be placed between these toroidal magnets. A merit of this reactor is that the inboard reactor structures are accessible with keeping the magnet cryogenic condition and without disassembling any major reactor components. The practicability of this method will depend on the time required to move the blanket segments in the toroidal direction and to weld pipes by remote handling. A number of ideas for reducing this time are presented.     

Neutronics Analysis of Water-Cooled Ceramic Breeder Blanket for CFETR

In order to investigate the nuclear response to the water-cooled ceramic breeder blanket models for CFETR, a detailed 3D neutronics model with 22.5otorus sector was developed based on the integrated geometry of CFETR, including heterogeneous WCCB blanket models,shield, divertor, vacuum vessel, toroidal and poloidal magnets, and ports. Using the Monte Carlo N-Particle Transport Code MCNP5 and IAEA Fusion Evaluated Nuclear Data Library FENDL2.1,the neutronics analyses were performed. The neutron wall loading, tritium breeding ratio, the nuclear heating, neutron-induced atomic displacement damage, and gas production were determined.The results indicate that the global TBR of no less than 1.2 will be a big challenge for the watercooled ceramic breeder blanket for CFETR.