A 20 kV, 5 A, 1 ns Risetime Pulsed Electron Beam Source

A 20 kV, 1 ns risetime pulsed electron beam source was developed using an extremely small gap （0.1 mm） diode driven by a sub-nanosecond risetime, 10 kV rectangular pulse generator. A beam current of 5 A was detected by using a fast response Faraday cup at a distance of 2 cm away from a grid anode. The shot to shot variation of the electron beam pulse was less than 10%.     

Measurement of the Beam Position in the Extraction System of the ILU-10 Linear Electron Accelerator

A system for measuring beam position for a ILU-10 pulsed linear electron accelerator is described. The accelerator generates an electron beam with energy up to 5 MeV. The rf generator operates at 115 MHz in the pulsed mode with pulse duration of about 500 sec and pulse repetition frequency up to 50 Hz. The average beam power can reach 60 kW. Two electrostatic sensors (pickups) are used to measure the position of the beam. The principle of operation of the measurement apparatus is based on homodyne detection of the signals from the pickups. The second harmonic of the frequency of the accelerating voltage of the accelerator power supply (230 MHz) is chosen as the working frequency. The detected signal is fed from each pickup plate into an integrator and then a ADC. The beam position is calculated on a computer. The resulting error in the beam coordinates is about 0.5 mm with a 110 mm in diameter position sensor.     

Electron Linac Design for Pion Radiotherapy

The electron linac provides a straightforward, state-of-the-art method of producing the primary beam required for a hospital-based multiport pion radiotherapy facility for cancer treatment. The accelerator and associated beam transport system described in this paper are capable of generating an electron beam of about 250 kW and delivering it alternately to one of several pion generators and treatment areas. Each pion generator, a prototype of which now exists at the Stanford W. W. Hansen Laboratory, would contain a target for the electron beam and sixty separate superconducting magnet channels which focus the pions in the patient. The considerations which enter the design of a practical linac are presented together with a possible layout of a flexible beam transport system.     

200keV直流/脉冲中子发生器束流输运模拟计算

计算机模拟计算在各种类型加速器的设计中起着很重要的作用。例如,计算机模拟很快就可以确定加速器各部件的最佳工作参数和所需要的光学条件,使一台加速器复杂的束流输运系统设计变成简单的工作。TRANSPORT程序是当今世界上关于束流输运计算的最优秀程序之一。但是,该程序不能进行静电加速器离子光学系统的计算,也不能作直线加速器的粒子动力学计算。为此从北京大学引进了LEADS程序,它不仅具有TRANSPORT程序的优点,还克服了其不足。对含有聚束(脉冲束流)系统的加速器粒子动力学进行模拟是LEADS程序的新特色。实验中用LEADS程序模拟了200keV直流/脉冲中子发生器束流输运过程,得到了横向相图、纵向相图和束包络图。还用LMOV程序计算和验证了聚束系统,束流脉冲波形图和实验结果比较接近。     

Modification of a pulsed 14-MeV fast neutron generator to a medium-energy ion accelerator for TOF-RBS application

The first drift-tube neutron generator in Thailand, developed during 1980s under the support by the International Atomic Energy Agency (IAEA), was a 150 kV deuteron accelerator-based 14 MeV fast neutron generator. The accelerator was featured by a nanosecond pulsing system consisting of a beam chopper in combination with a beam buncher. Following the rapid development of ion beam technology and increasing needs for materials applications in the laboratory, the accelerator has been upgraded and modified to a large extent into a medium-energy ion-accelerator for time-of-flight Rutherford backscattering spectrometry (TOF-RBS) applications. The modification of the accelerator included the changing of the ion source, the accelerating tube and the mass-analyzing magnet, the upgrading of the pulsing system, and the installation of a TOF-RBS detecting system. The new accelerator is capable of supplying a 400-keV He-ion beam with ns-pulses for nano-layered materials analysis. This paper provides technical details of the modification.     

350keV电子高压加速器研制

加速器辐照装置用于辐照生产医用输液塑料袋原膜材。所研制的350keV电子高压加速器具有以下特点：在静电加速器中采用高压倍压电源代替输电带，此新型结构加速器可输出低能大功率电子束，且体积小、自屏蔽，适于在线辐照加工；一般高压倍压电源采用50Hz供电，而在此装置中由14kHz中频电源供电，高压电源体积小。加速器空载高压达370kV，电子束350keV/20mA，扫描宽度70cm，辐照剂量不均匀性好于7%。该加速器辐照装置已投入运行，并已生产出合格医用输液袋膜材投放市场，产品填补了国内医用输液袋膜材市场的空白。     

纵向多灯丝电子帘加速器的束流不均匀度

束流不均匀度是电子帘加速器束流性能的一重要指标。影响束流不均匀度的主要因素是加速器结构中各电极（阴极、反射极、栅极、阳极）的电位、形状及其相对位置。本工作针对1台纵向多灯丝电子帘加速器的实际结构参数,计算其束流不均匀度,通过分析和比较,讨论了进一步改善束流不均匀度的可能途径,为改进电子帘加速器的设计提供了参考。     

Status of Work on the VÉPP-5 Injection Complex

The VÉPP-5 injection complex under construction at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences is a powerful source of intense electron and positron bunches at 510 MeV, which covers all needs of the electron–positron colliding beam setups currently operating and under construction at the Institute of Nuclear Physics. The complex includes a 285 MeV linear electron accelerator, a 510 MeV linear positron accelerator, and an accumulator–cooler with beam injection and ejection channels. Intense work on the design, assembly, and tuning of the linear electron accelerator has been conducted in the last 2 yr. As a result, by August 2002 the linear electron accelerator was put into operation with all standard subsystems. By this time, the isochronous achromatic turning of the electron beam, a system for converting electrons into positrons, and the first accelerating structure of the linear positron accelerator were assembled and put into operation. All this made it possible to accelerate the positron beam up to 75 MeV. Preliminary results of tests of the linear accelerators are presented.     

The New 5 MeV Electrostatic Ion Accelerator at the Central Research Institute for Physics, Budapest, Hungary

The new 5 MeV electrostatic ion accelerator, projected, built, and tested at the Central Research Institute for Physics in Budapest, with some necessary aid from Hungarian industry /pressure vessel etc./ is described. The accelerator's main specifications are detailed and an account is given of the experiences with glass and porcelain accelerating tubes. By careful design, the intensity of radiation in the range of 4-5 MV has been reduced by 2-3 orders of magnitude. Without an ion beam there was only 3-5 times the intensity of the natural radiation background /i.e. less than 0.5 mR/h/ on the outer surface of the generator vessel when operated at 4-5 MV. The radiation level with the accelerated ion beam is accordingly also very low. During a 7-month period in 1970 the generator ran for 3,250 hours of measurements in nuclear physics.     

NDZ-20医用电子直线加速器的注入系统

文章介绍了NDZ-20医用电子直线加速器的束流注入系统的结构和特性。电子枪为轰击型的皮尔斯电子枪。漂移管上的预聚焦线圈、偏掉线圈、导向线圈和束流前沿切割线圈用来实现对电子束的多种控制,实现加速器的ARC,ADC和BLC运用,以保证加速器运行的稳定性和可靠性,改善反馈加速器的能谱。     

衰减法测量静电加速器电子束能量

研制了薄壁平行板透射电离室,研究了透射电离室的特性。用透射电离室测量静电加速器电子束在铝中的透射分布,得到不同高压下电子束在铝中的外推射程,进而确定电子束能量。     

强聚焦圆柱形四极电透镜

在JM-400静电脉冲加速器中,安装在大三通闸阀后面的圆柱形四极电透镜具有强聚焦的功能,可以将φ30 mm平行离子束会聚成φ5 mm以下的束径。双元四极电透镜的透镜见图1。八个电极用1Cr 18 Ni 9 Ti制成,每个电极长60 mm,宽28 mm,用螺栓均匀地固定在绝缘壳体上。两组电极边缘相距24 mm。透镜绝缘壳体用螺栓同轴安装在铝合金外壳内,使其工作时保持真空。绝缘壳体是四极电透镜的关键零件,它要支撑八个电极构成内径φ40_0~(+1.0)mm的同轴     

DZ-12/4多能量档电子直线加速器辐照关键参数测试

中国原子能科学研究院建立了一台DZ-12/4多能量档电子直线加速器,该装置主要用作辐射加工级电子束辐照实验平台。为了检测该电子束辐照实验平台辐照工艺控制参数,本文利用中国原子能科学研究院FJL-02型辐射变色薄膜剂量计对DZ-12/4多能量档电子直线加速器关键参数能量进行了测量,并对研制的束流监测系统法拉第筒的可靠性进行了验证。结果表明,DZ-12/4多能量档电子直线加速器能量在4~12 MeV范围可调,运行参数准确可靠;日常运行中,加速器运行人员通过监测设备和调节加速器参数可有效控制并估计辐照剂量,具有非常好的实用性和简便性。     

Design of a Shuttle Microtron for Radiation Therapy

A design proposal for a new type of electron accelerator for radiotherapy applications is presented. The three-pass, fixed-magnet shuttle microtron is designed to allow continuous variation of electron beam energy from 4 to 24 MeV, while providing maximum current levels for x-ray treatment at 6, 12, and 20 MeV. The reflector magnets are structured for both axial and radial beam focusing and the entire accelerator fits into the horizontal arm of a rotatable therapy gantry.     

Technological Electron Accelerator with Beam Power up to 25 kW

A technological electron accelerator with beam power up to 25 kW is described. Cost and reliability criteria are used to justify the choice of microwave power supply and accelerator structure. The high average beam power and low cost of the setup put it on par with best foreign analogues. The high readiness factor and large decrease of the scheduled preventative maintenance time make it possible to use the accelerator as a multipurpose source of ionizing radiation in industrial radiation-technological processes and in scientific research.     

射频反馈电子直线加速器的稳态特性

本文讨论了含聚束器的射频反馈电子直线加速器基于耗散方程的稳态束负载理论,导出了加速器稳态特性的解析关系,最后计算了桥比n=1和n=n_(opt)加速器的负载特性。     

硼中子俘获治疗加速器ECR质子源电磁场仿真设计

电子回旋共振(ECR)质子源具有可给流强高、亮度高、可靠性高、使用频率高、易维护、小型化等优点,因而被硼中子俘获治疗(BNCT)装置的直线加速器所采用。本文利用CST软件对2.45 GHz ECR质子源进行优化设计。优化后ECR质子源的等离子体发生器腔体的尺寸为101.12 mm×45.00 mm,给出了脊波导耦合器的最优尺寸参数,使等离子体发生器腔体内电场强度提高为普通波导的4.5倍。通过Opera-3D对ECR质子源的引出电极结构进行了仿真计算,并给出了优化参数。另外,初步设计了质子源的线圈磁铁系统,优化了磁场分布。本文结果为质子源的研制提供了数据。     

中国散裂中子源快循环同步加速器束团长度研究

束团长度是中国散裂中子源（CSNS）快循环同步加速器（RCS）束流动力学的关键参数,通过对束团长度的研究,可了解RCS的机器性能并进一步指导机器优化研究。本文对RCS 100 kW时的束团长度进行精确测量,100 kW引出时的束团长度为105 ns。RCS 500 kW时束团长度可能超过无损引出允许值,需压缩束团长度。理论上提高腔压可压缩束团长度,本文模拟研究500 kW时束团长度随腔压曲线的变化规律,模拟结果表明提高加速后半阶段的腔压可压缩束团长度,给出了500 kW时无束流损失引出的腔压曲线。基于100 kW束流条件实验验证了通过提高加速后半阶段腔压来压缩束团长度的有效性和可行性,实验测量结果与模拟结果一致。因此,提高加速后半阶段腔压是500 kW时无损引出束流的有效方法。     

微波零相位法测量超导加速器ps级电子束纵向长度

本文基于微波零相位法,将中国工程物理研究院太赫兹自由电子激光(CTFEL)2×4-cell超导加速器的下游腔作为零相位腔,测量了上游腔增能后的电子束纵向长度,并通过束流动力学模拟证明,当两个超导腔正常工作时,上游腔出口处的电子束纵向长度与下游腔出口处的接近。实验结果表明,CTFEL 2×4-cell超导加速器能实现半高宽小于6.8 ps的电子束,满足装置出光要求。