注入聚束腔的离子束的能量分散对直线加速器输出束流波形的影响

一、理论分析众所周知,在质子直线加速器前常用聚束腔来提高加速器的捕获效率。从聚束腔至加速器入口有一段聚束漂移空间,如图1所示。     

国产45MW速调管实验研究

对45MW实验速调管的电子枪、谐振腔和聚焦磁场结构设计进行了优化研究与测试分析,并对实验管进行了高功率测试分析,以检验设计方案的可行性与合理性。在300kV高压下,输出脉冲功率达45MW,其重复频率12.5Hz,脉宽为2μs,效率约42%,增益约49dB。速调管电子枪导流系数约为2.05μp,与电子枪的理论设计基本吻合。从输出功率与电压的关系来看,速调管谐振腔与聚焦磁场的设计与优化可满足国产45MW速调管的需要。     

聚束系统设计与计算程序

LMOVE程序是一个模拟粒子纵向运动的FORTRAN语言程序。它可以计算由三电极双间隙聚束器(或这种聚束器的组合)、单狭缝谐波聚束器、静电加速管和自由飘浮空间组成的束流脉冲化系统。程序采用大量粒子模拟束团在纵向相空间内的运动,并用Monte-Carlo方法随机产生相空间内各代表点的初始条件。因此,较为适合模拟粒子在配有聚束器件的静电加速器中的纵向运动。本程序不考虑粒子的空间电荷效应。     

电子直线加速器束截面测量系统及其应用

用于北京自由电子激光30MeV电子直线加速器的注入及输出束的截面监测系统,由可伸缩荧光屏束截面探头、摄象取样装置及图象采集卡和计算机处理系统构成。用此系统测量加速器注入(≤1.2MeV)和输出(≥20MeV)电子束的截面宽度、密度分布、发射度等参量。其硬件的空间分辨率好于110μm,束宽测量精度好于50μm。经加速器在线使用2年以上考验,性能可靠,得到了满意结果。     

单漂移聚束器的非标准聚束模式

单漂移聚束器标准聚束模式要求粒子注入能量和聚束器漂移管的几何尺寸之间必须满足严格的条件,严重地限制了可聚束粒子的种类。文章论述了采用非标准聚束模式的方法,计算不同粒子在HI-13串列加速器上实现脉冲聚束的可行性。     

NSRL 200MeV电子直线加速器的速调管真空保护装置

报道了一种能保护高功能速调管安全的速调管真空保护装置。该装置保护动作时间≤１５ｍｓ，在强电磁干扰速调管走廓中能稳定可靠地工作。     

单漂移聚束腔的改进

为扩展中国原子能科学研究院高压倍加器的ns脉冲束的能区范围,研制了一种新的聚束装置,使该加速器从仅能提供300keVns脉冲束,扩展到能提供100～400keV整个能区的ns脉冲束。     

S波段D4009大功率速调管相位稳定性测试

本文介绍D4009脉冲大功率速调管电压-相位调制灵敏度测试原理及线路,并对测试结果进行了分析。在注电压～200 kV时,D 4009管的电压-相位调制灵敏度～6°。     

Analysis of the measurement field of the optical klystron

The measured fields of the optical klystron in NSRL (National Sychrotron Radiation Laboratory)are, given, incluing the distribution on the axis,and the integrated filed distribution.the harmonic magnet fild and the spectra of the spontaneous emission are analyzed,and the multiple fild is presented by fitting the diagram.The influence of the integrated fild on the colse orbit of the beam and on the operation parameters of the storage ring ,and the compensation in the oexperiment are also discussed.     

HLS单束团时序系统的参数测试及在线实验

为实现合肥同步辐射光源（ＨＬＳ）单束团注入,研制出一套单束团时序系统＾「１、２」。其主要特点是系统输出各时序信号与贮存环高频信号保持同步以及时序信号时间抖动小。实验结果显示,快速通道时序信号的时间抖动小于２００ｐｓ。该系统在线实验获得成功。     

基于相干渡越辐射的束团长度测量研究

电子束团长度是束流诊断中的重要参数,基于相干渡越辐射(Coherent Transition Radiation,CTR)的测量方法是一种简单易行的高时间分辨率测量方法。本文调研并分析了不同电子束团长度测量方法的优缺点,选择基于CTR方法作为主要研究方向,主要针对上海深紫外自由电子激光实验装置(Shanghai Deep Ultra-Violet Free Electron Laser,SDUV-FEL)和X射线自由电子激光试验装置(Shanghai X-ray Free Electron Laser,SXFEL)进行了实验方案设计和模拟分析。结果表明,通过合理的参数选择和方案优化,用该方法可对飞秒至皮秒范围内的束团长度进行测量,时间分辨率能到达飞秒量级,满足SDUV-FEL的实验需求和SXFEL的工程需求。     

加速器束团长度频谱法测量系统设计

主要介绍一种基于束流频谱的柬团长度测量系统的设计,它通过拾取条带上的束流频谱,分析得到束团频谱中的两个频率成分的幅度比,从而求出束团长度.整个系统结构类似数字位置探测器(DBPM),采用软件无线电的技术,利用高速高精度ADC直接中频带通采样,以省掉一部分模拟器件,减少模拟部分带来的误差.这种柬团长度测量系统最大的好处就是可以在线实时的测量束团长度,为加速器研究提供重要的参考.     

基于PC的光学速调管磁间隙控制系统

描述了合肥国家同步辐射实验室(NSRL)储存环自由电子激光(SRFEL)光学速调管(TOK)磁极间隙控制系统的原理和结构，给出了系统硬件结构、软件流程图及其工程实现。该调节系统可以独立或同时调节TOK调制段、色散段、辐射段三部分磁极间隙的大小，精度达到0.01mm；多重安全保护能确保储存环真空室不被破坏。     

Velocity bunching for the linac of Shanghai Deep UV FEL facility

High brightness electron beam is one of the main goals of the research and development effort in RF photo-injectors.Compared with the normally used magnetic chicane,an alternative scheme,commonly known as 'velocity bunching',has been proposed as a tool to compress electron beam pulses in modern high brightness photo-injector sources.This paper presents numerical optimization systematically and the first attempt to demonstrate the velocity bunching scheme on SDUV-FEL linac experimentally.The relationship between the degree of bunching and the off-crest phase of the accelerating structure is explored experimentally.Velocity bunching operating mode illustrates flexible performances with an intrinsic machine jitter,which agrees well with the theoretical prediction.     

Evaluation of mean time between accidental interruptions for accelerator klystron systems based on the reliability engineering method

Frequent beam trips as experienced in existing high-power proton accelerators may cause thermal fatigue in Accelerator-Driven System components. In order to overcome the beam-trip problem, the beam-trip frequencies were estimated based on operational data on existing accelerators. However, there are at least three methods to calculate the mean time between accidental interruptions (MTBI) for one of the accelerator components, the klystron system. In this study, the four types of MTBI for the klystron systems of an electron/positron injector linear accelerator at the High Energy Accelerator Research Organization were compared based on the same operational data. In the analysis, the stop events of the klystron systems were classified, and the MTBI for the klystron systems was calculated using the Kaplan–Meier (KM) estimation, which is a representative non-parametric reliability method. As a result, the mean value of the MTBI found by the KM estimation was 57.3 ± 6.5 hours. On the other hand, the mean values of the MTBI found by the three traditional methods were 30.9 ± 2.4, 32.0 ± 2.3, and 50.4 ± 5.9 hours. The mean values for the ratios of the MTBI found by the KM estimation, to the MTBI found by the traditional estimation, were 1.67 ± 0.07, 1.58 ± 0.06, and 1.14 ± 0.01, respectively. Although these results are obviously different from traditional results, it appears that the present estimation is suitable for the MTBI for accelerator components.     

基于PC的光学速调管色散段磁极间隙调节系统

描述了合肥国家同步辐射实验室（ＮＳＲＬ）光学速调管色散段磁极间隙调节系统的原理和结构。该调节系统已应用在ＮＳＲＬ的储存环自由电子激光实验中,效果良好,调节精度可高达１０－３ｍｍ。     

大型加速器控制中模式管理器的开发及应用

本工作从加速器控制系统的软件设计角度提出并开发了一种管理加速器运行模式和数据的方法,即加速器模式管理器(model manager)。该软件利用Oracle数据库作为加速器运行模式及数据的存储平台,能够绘制和比较加速器各种模式的多种函数曲线,且提供在线模拟运行加速器的功能,为大型加速器的调试提供方便。该系统已成功用于LCLS加速器。