Physical design of a 10 MeV LINAC for polymer radiation processing

In China, polymer radiation processing has become one of the most important     

C波段2 MeV驻波加速管物理设计

为了发展结构紧凑、小束斑加速器,进行了C波段驻波电子直线加速器加速管的物理设计和研究。利用多级聚束和大孔径注入方法,抑制空间电荷效应。加速管由3个聚束腔和4个加速腔组成,长约163 mm,馈入微波功率源1 MW。在最终的数值模拟中,得到脉冲电流约150 mA,俘获效率优于30％,在加速管出口外约14 mm处,对电子的横向分布进行非线性Gauss拟合,得到束斑直径（FWHM）约为0.55 mm。     

用于合肥光源200 MeV直线加速器束流位置测量的信号处理系统

合肥光源(Hefei Light Source,HLS)200 MeV直线加速器的束流横向位置是一个重要的运行参数,直接决定注入的效率,为此新开发了一种非拦截型、高精度、易于将测量结果数字化的条带电极束流位置测量系统（beam position monitor, BPM）,该系统由条带电极和信号处理系统组成。信号处理系统选用对数比的信号处理方法,由带通滤波器（BPF）、对数检波模块、信号放大器、模数转换模块和上位机组成。带通滤波器选用中心频率为2.856 GHz、带宽为10 MHz的腔体滤波器,对数检波模块采用对数放大器AD8313芯片,模数转换模块采用NI公司的PXI-5102,上位机的数据采集程序采用Labview编写。本系统有效地采用了虚拟仪器（VI）的技术,具有模块化、开放性、易于交互、可扩展的特点,测试结果表明,其分辨率达到0.1 mm,符合设计要求。     

100 MeV电子直线加速器的物理设计

能量为100 MeV左右的高性能电子直线加速器是第三代同步辐射光源注入器和自由电子激光注入器的重要组成部分,采用热阴极栅控电子枪、聚束系统和4根SLAC型加速管作为加速器主体结构,一套45 MW的速调管调制器系统和波导系统作为微波功率源系统。设计中,使用了国际通用的模拟软件对加速器的动力学特性进行了数值模拟和参数优化,电子束能量达到100 MeV以上,能散小于1%,归一化发射度小于30 mm·mrad。     

C波段2 MeV驻波加速管物理设计

 为了发展结构紧凑、小束斑加速器,进行了C波段驻波电子直线加速器加速管的物理设计和研究。利用多级聚束和大孔径注入方法,抑制空间电荷效应。加速管由3个聚束腔和4个加速腔组成,长约163 mm,馈入微波功率源1 MW。在最终的数值模拟中,得到脉冲电流约150 mA,俘获效率优于30％,在加速管出口外约14 mm处,对电子的横向分布进行非线性Gauss拟合,得到束斑直径（FWHM）约为0.55 mm。     

在速调管中空间电荷波对辐射波引起的电子束群聚的修正

在相对论情况下,导出了速调管(klystron)和契伦柯夫(Cherenkov)器件中考虑空间电荷波影响的被调制电子束的谐波电流公式;并且分析了空间电荷波对电子束群聚的影响：在小信号时使群聚减小;在大信号时使群聚增强。     

Physical design and cooling test of C-band standing wave accelerating tube

The physical design and cooling test of a C-band 2MeV standing wave (SW) accelerating tube are described in this paper. The designed accelerating structure consists of 3-cell buncher and 4-cell accelerating section with a total length of about 163mm,excited with 1MW magnetron. Dynamic simulation presents that about 150mA beam pulse current and 30{\%} capture efficiency can be achieved. By means of nonlinear Gauss fit on electron transverse distribution, the diameter of beam spot FWHM (full width at half maximum of density distribution) is about 0.55mm. Cooling test results of the accelerating tube show that frequencies of cavities are tuned to 5527MHz and the field distribution of bunching section is about 3:9:10.     

Central region design for a 10 MeV internal ion source cyclotron

Internal ion sources are widely adopted in commercial cyclotrons used for short-life isotopes produc-tion. Without beam manipulation provided by the external beam injection line, the central region of this type of cyclotron is more sensitive and should be carefully designed. A design study and beam dynamics simulation for the central region of a 10 MeV compact cyclotron is presented. The OPERA3D/TOSCA code was used to calculate the electric field from a parameterized three dimensional (3D) central region model. With iterative structure optimizations of the central region, the beam centering and vertical focusing is well controlled, and the RF phase acceptance is around 25° A c++ code for beam simulation in the central region was developed and tested.     

Central region design for a 10 MeV internal ion source cyclotron

Internal ion sources are widely adopted in commercial cyclotrons used for short-life isotopes production. Without beam manipulation provided by the external beam injection line, the central region of this type of cyclotron is more sensitive and should be carefully designed. A design study and beam dynamics simulation for the central region of a 10 MeV compact cyclotron is presented. The OPERA3D/TOSCA code was used to calculate the electric field from a parameterized three dimensional （3D） central region model. With iterative structure optimizations of the central region, the beam centering and vertical focusing is well controlled, and the RF phase acceptance is around 25°. A c＋＋ code for beam simulation in the central region was developed and tested.     

紧凑型回旋加速器物理问题及调束技术

介绍了紧凑型回旋加速器CYCIAE-100的特点及设计过程中重点考虑的一些物理问题,如紧凑型直边扇磁铁结构的轴向聚焦、异性高频谐振腔的设计、空间电荷效应等。研究了该加速器的调束技术,包括调束方案、诊断设备布局及径向靶测量的束流信息、物理图像。CYCIAE-100的主磁铁设计中,为降低磁铁和高频腔的加工难度而采用直边扇形磁极,为解决直边扇形磁极在大半径处的轴向聚焦力下降的问题,采用变气隙技术,从而有效提高轴向聚焦力。采用自行开发的基于PIC技术的宏离子模拟程序OPAL-CYCL进行了空间电荷效应的研究,结果表明,CYCIAE-100的极限流强为10 mA。     

紧凑型回旋加速器物理问题及调束技术

介绍了紧凑型回旋加速器CYCIAE-100的特点及设计过程中重点考虑的一些物理问题,如紧凑型直边扇磁铁结构的轴向聚焦、异性高频谐振腔的设计、空间电荷效应等。研究了该加速器的调束技术,包括调束方案、诊断设备布局及径向靶测量的束流信息、物理图像。CYCIAE-100的主磁铁设计中,为降低磁铁和高频腔的加工难度而采用直边扇形磁极,为解决直边扇形磁极在大半径处的轴向聚焦力下降的问题,采用变气隙技术,从而有效提高轴向聚焦力。采用自行开发的基于PIC技术的宏离子模拟程序OPAL-CYCL进行了空间电荷效应的研究,结果表明,CYCIAE-100的极限流强为10 mA。     

Preliminary design studies of a 100 MeV H−/H+ LINAC as injector for SNS synchrotron/ADS LINAC

It is proposed to construct a spallation neutron source (SNS) at Centre for Advanced Technology (CAT) based on a 1 GeV proton synchrotron with 100 MeV H⁻ LINAC as injector. Additionally, the LINAC can form the first 100 MeV part of a 1 GeV proton LINAC to be built in future for accelerator driven system (ADS) applications. We are exploring a configuration of the 100 MeV LINAC which will consist of an H⁻ ion source, a 4–6 MeV RFQ followed either by a 20 MeV drift tube LINAC (DTL) and 100 MeV separated function drift tube LINAC (SDTL) or a coupled cavity drift tube LINAC (CCDTL) structure. In this paper, we present the results of our preliminary physics design studies of the RFQ-SDTL, RFQ-CCDTL and RFQ-DTL-SDTL configurations. The design of the 4.5 MeV RFQ is discussed along with the matching sections between the RFQ-SDTL/DTL and RFQ-CCDTL. The choice of the accelerator configuration and that of various parameters of the individual accelerator structures under consideration are discussed. The design objectives are to arrive at a configuration which eases heat removal for CW operation and which is less prone to halo formation in order to reduce the beam loss at higher energies.     

北京大学ERL装置交汇段的研究与设计

在交汇段设计理论的基础上,针对北京大学ERL的具体情况,对交汇段的束流传输结构进行了优化设计,通过模拟得到了满足要求的一组设计参数;研究了空间电荷效应以及相干同步辐射对束流发射度、能散及包络的影响。结果表明：空间电荷效应对发射度影响不大,但对束流包络影响较明显;相干同步辐射引起的发射度增长及能散较小,且不影响束流包络。     

Beam-loss driven injection optimization for CSNS/RCS

This paper summarizes the painting injection optimization for the Chinese Spallation Neutron Source (CSNS) ring. This optimization focuses on two main design goals: the lower beam loss and a space-charge tune shift low enough to avoid strong resonances. Finally, the 3-D particle tracking is performed and we get some important results about the beam properties and beam loss.     

中国加速器驱动次临界系统主加速器初步物理设计

中国加速器驱动次临界系统（C-ADS）计划采用一个平均流强为10 mA的连续波质子加速器作为次临界堆的驱动器,驱动加速器的束流功率为15 MW,最终能量1.5 GeV,其中主加速器是驱动加速器的一个重要部分,完成束流能量从10 MeV到1.5 GeV的加速,所有加速腔均采用超导结构。为了避免频繁束流中断对反应堆的损坏,设计要求驱动加速器在运行过程中束流可以中断的次数非常有限,因此加速器在设计过程植入了容错机制,尝试了各种可能的方法以最大程度地满足C-ADS加速器的高可靠性和稳定性的要求。介绍了C-ADS主加速器的基本设计: 总长度306.4 m, 束流的归一化RMS发射度增长控制在5%以内。总结了各个重要参数选择过程中的考虑以及整个加速段多粒子跟踪模拟的束流动力学结果。     

Variation of concentration of charge carriers in a diffusion-junction rectifier under the influence of radiation processing of materials

ABSTRACT

In this paper, we analyzed changing of dynamics of redistribution of dopant during the manufacturing of diffusion-junction rectifier in a heterostructure due to radiation processing. In this regard, concentration of charge carriers will also be changed. We also introduce an analytical approach to analyze mass transport with account nonlinearity, space and time variation of parameters of the transport.     

上海光源150MeV电子直线加速器的设计与调试

上海光源150MeV直线加速器由热阴极电子枪, 次谐波聚束器和聚束器, 四根S波段等梯度行波加速管及必要的磁铁等组成. 外围还有由从微波到直流的电源和功率源, 性能监测和联锁控制的硬件和软件等. 概述了150MeV直线加速器的设计, 安装, 调试和达到的结果.     

The design of a radio frequency quadrupole LINAC for the RIB project at VECC Kolkata

A radio frequency quadrupole LINAC has been designed for the VECC-RIB project for an input beam energy of 1.0 keV/u and q/A≥1/16. The output energy will be about 90 keV/u for a 3.4 m long, 35 MHz structure. A half-scale cold model of the RFQ has been fabricated and tested for rf structure design study. The beam dynamics and rf-structure design along with the results of the cold model tests will be presented.     

上海光源150 MeV直线加速器次谐波腔耦合器的设计与调试

通过将次谐波腔体等效为RLC并联回路,求得了射频功率馈入腔体的耦合度公式,分析了上海光源直线加速器次谐波腔输入耦合器的设计要点,通过3维电磁计算软件CST的数值模拟方法对耦合器结构尺寸、耦合环的深度与方位、耦合度进行了模拟计算。介绍了对次谐波腔耦合器进行小信号测试的过程、腔体安装及在线调试的方法。     

Beam-loss driven injection optimization for CSNS/RCS

This paper summarizes the painting injection optimization for the Chinese Spallation Neutron Source （CSNS） ring. This optimization focuses on two main design goals： the lower beam loss and a spacecharge tune shift low enough to avoid strong resonances. Finally, the 3-D particle tracking is performed and we get some important results about the beam properties and beam loss.