为了保证324 MHz超导腔高功率输入耦合器测试平台的安全可靠运行,基于PLC和FPGA控制器设计了联锁保护系统.整机系统主要包括速调管功率源部分和耦合器部分,联锁保护系统全面监测所有设备的工作状态,同时执行正常的时序逻辑和异常情况下的联锁保护逻辑及故障定位,确保整机系统运行的安全性.文章主要介绍联锁保护系统软硬件设计及运行情况,其长期运行测试结果表明:联锁保护系统保障了耦合器测试台系统的正常运行,满足设备状态监测显示、联锁保护及故障锁存等功能要求.

低电平射频控制系统主要用于对加速腔的高频场和谐振频率的控制,保证加速器的稳定运行并输出高品质的束流.低电平控制系统软件提供可视化操作界面,实现数据显示和存储、自动化算法等功能,提高了低电平系统的可操作性,减少了人工作业量和故障率.软件开发具有灵活性强、开发周期短的特点,适合控制速度要求相对不高而逻辑较为复杂的功能开发.本文介绍中国散裂中子源直线加速器射频低电平控制系统软件的开发设计,重点介绍前馈自动计算、加速腔的频率自动控制、频率失谐算法、一键升功率、界面优化等相关内容.最终低电平控制系统幅度相位稳定度指标优于要求的设计指标,且达到长时间稳定运行的要求.

为了保证BNCT速调管功率源系统安全稳定运行,并满足系统实时监测、快速响应、故障定位、易维护等要求,开发设计一套基于西门子PLC的联锁保护系统.该系统实时监测水冷、高压电源、撬棒等所有设备工作状态,同时根据速调管要求执行加电、故障联锁逻辑程序,并实现故障定位、状态显示.本文主要介绍控制系统总体方案设计、软硬件设计以及后期的联调测试情况.

RF breakdown is a common phenomenon in high-power RF devices. It may make irreversible damage to physical structure. Finding a sensitive method to detect the phenomenon and to cut-off RF power as quickly as possible is a good way to prevent the RF breakdown damage. This paper presents a digital and multi-function high-power RF protection system based on VSWR (Voltage Standing Wave Ratio) measurement. The response time of this system is about 700 ns, which includes 300 ns for klystron delay and path delay. The system provides a series of functions that meet the requirements of pulsed and long running accelerators. It also supports real-time graphical display and data recording, which is useful for fault analysis.

中国科学院高能物理研究所建造了一台基于加速器的硼中子俘获治疗(BNCT)实验装置.射频功率源系统为352.2 MHz射频四极加速器(RFQ)提供高频功率,使束流离开RFQ时,其能量达到3.5 MeV.BNCT射频功率源系统主要包括速调管功率源、数字低电平控制系统、射频传输系统.本文介绍了BNCT射频功率源系统,主要包括物理需求、系统组成、关键设备、安装和调试.目前该装置已进行动物实验,加速器打靶束流功率4.3 kW,加速器射频功率源系统运行稳定.

本文研制了中国散裂中子源(CSNS)直线加速器高功率自动老炼平台,该平台集成了驻波比保护、真空检测、弧光打火探测器、腔体谐振频率计算和变频等功能,可根据腔体的打火情况自适应调节功率进行腔体老炼,通过软件界面对相关参数进行修改即可适应不同腔体的需求.该平台具有高安全性、高智能化、灵活性强的特点,其已在CSNS直线加速器8套功率源系统上使用,在保证腔体和功率源安全的前提下,大幅提高了老炼效率和降低值班人员的劳动量.

The China spallation neutron source (CSNS) linac is designed with beam energy of 81MeV and a peak current of 15mA in the first phase. The RF power system for the 81 MeV Linac requires 8 units of RF power sources, each unit has one independent digital low level RF (LLRF) control system which is used to stabilize the amplitude and phase of the RF accelerating field along the linac, and to minimize beam loss. During beam commissioning, all of 8 on-line units of LLRF control system were operating stably and reliable, the control precision of accelerating fields met requirement of beam commissioning. The amplitude and phase variations of the linac fields are less than $\pm$0.2% and $\pm$0.2$^\circ$ without beam loading, or $\pm$0.5% and $\pm$0.5$^\circ$ with 10mA beam loading, much better than the design requirements of $\pm$1% in amplitude and $\pm$1$^\circ$ in phase.

China Spallation Neutron Source (CSNS) is the first neutron source facility in developing countries. it includes a powerful linear proton accelerator, a rapid circling synchrotron, a target station and three neutron instruments [1] . As one of the largest science and technology infrastructure projects in China, CSNS is expected to have positive effects in promoting the sciences, high-tech development and national security. Klystron power supply of CSNS is an important part of linac. High-voltage pulse generator is used for the mod_anode of Klystron. High-voltage pulse generator is composed of 400Hz series-resonant DC high-voltage power supply and solid state modulator. it includes variable frequency power supply (50Hz converted to 400Hz), step-up transformer (0.5kV-6kV), 400Hz series-resonant L/C, energy storage capacitor bank and high-voltage pulse modulator. This paper introduces the structure and principle of the high-voltage pulse generator, Focusing on the introduction of high-voltage pulse generator control system, test and operation of high-voltage pulse generator.

中国散裂中子源加速器质子束流加速能量为1.6 GeV,重复频率为25 Hz,撞击固体金属靶产生散射中子,一期工程的打靶束流功率为100 kW.直线加速器的设计束流流强为15 mA,输出能量为81MeV.射频加速和聚束系统包括一台射频四极场加速器、中能束流传输线的两个聚束器、四节漂移管直线加速器加速腔和直线-环束流传输线的一个散束器,与之相对应,共有8个单元在线运行的射频功率源为其提供所需的射频功率.目前,直线射频功率源系统预研项目已全部完成,各项性能参数均已达到设计指标,当前正处在批产安装调试阶段.

A beam line is built after the IHEP RFQ for halo study. To determine transverse emittance and ellipse parameters of the RFQ output beam, beam size data obtained from the first two of 14 wire scanners are employed. By using the transfer matrix method and the least square method, a set of linear equations were set up and solved. The solutions were then applied as initial beam parameters in multi-particle simulations to check the method of calculation. It is shown that difference between the simulated RMS beam size and the measured one at the measurement location is less than 7 experiments.

In beam halo experiments, it is very important to correctly characterize the RFQ output proton beam. In order to simulate the beam dynamics properly, we must first know the correct initial beam parameters. We have used two different methods, quadrupole scans and multi-wire scanners to determine the transverse phase-space properties of the proton beam. The experimental data were analyzed by fitting to the 3-D nonlinear simulation code IMPACT. For the quadrupole scan method, we found that the RMS beam radius and the measured beam-core profiles agreed very well with the simulations. For the multi-wire scanner method, we choose the case of a matched beam. By fitting the IMPACT simulation results to the measured data, we obtained the Courant-Snyder parameters and the emittance of the beam. The difference between the two methods is about eight percent, which is acceptable in our experiments.

The China Spallation Neutron Source (CSNS) project is currently under construction in Dongguan city, in the Guangdong province of southern China. The CSNS accelerator consists of an H - linac and a proton rapid cycling synchrotron. The 324MHz RF linac is designed with a beam energy of 81MeV and a peak current of 30mA, which mainly includes one RF Quadrupole (RFQ) accelerator and four Drift Tube Linac (DTL) accelerators. Each DTL accelerator is driven by a klystron RF system that consists of a pulse klystron, a new -120kV High Voltage power supply, and a solid state modulator, crowbar and low level RF control system. The new high voltage 400Hz ac series resonance high voltage power supply (HVPS) passed acceptance tests with good results. Predevelopment for the prototyping of the modulator and crowbar were also completed, and batch production is ongoing. This paper describes the R&D activities of the high voltage power supply and the modulator.

Space-charge forces acting in mismatched beams have been identified as a major cause of beam halo. In this paper, we describe the beam halo experimental results in a FODO beam line at IHEP. With this beam transport line, experiments are carried out to compare the measured data with the multi-particle simulations and to study the formation of a beam halo. The maximum measured amplitudes of the matched and mismatched beam profiles agree well with simulations. Details of the experiment are presented.

强流质子RFQ加速器加速场的频率为352.2 MHz,加速场幅度和相位的精度分别要求控制在±1%和±1°的范围,为了达到这一要求,设计了一套数字低电平控制系统,该系统包括加速场的幅度和相位控制、腔体的谐振频率控制和高功率射频连锁保护3个部分。腔体采样信号的下变频及反馈激励信号的上变频由模拟器件来完成。幅相实时反馈处理过程采用数字I/Q解调的方法,在1块stratixⅡ的FPGA板上实现,板上另有3块DSP用于通信和协助FPGA进行数据处理。系统完成后与RFQ加速器进行联机调试,测试结果基本满足控制精度的要求。

ADS technology is under study in China for the purpose to provide a new option for the development of nuclear power station, which is going to play a more important role in our newly increased power resources to meet the demand of the rapid economy growth. In an ADS basic research program supported by Chinese government, a long-pulse intense-beam RFQ accelerator will be built at IHEP, Beijing, as the means to master the key technology in a CW RFQ. At present we have finished the design of the RFQ with pulse beam current of 50mA, output energy of 3.5MeV and length of 4.7m with two segments coupled by a resonant coupling cell. A technological copper model cavity of 1.2m long has been machined. The RF power supply of 352.2MHz, 1.2 MW has been installed. In this paper, we will report the R&D activities on the RFQ, including the beam dynamic design, the copper model manufacture and measurement and the RF power supply.