ns-200中子发生器束流脉冲化技术研究及束流传输模拟计算

在ns-200中子发生器上开展了束流脉冲化技术研究工作,采用正弦波速调管聚束方法设计了束流脉冲化系统,研制了高频电源系统、脉冲测量系统和远程自动控制系统.运用LEADS软件,进行了束流传输的模拟计算,并显示了束流传输包络曲线.整机安装调试获得了半高宽小于3.5ns、峰值电流大于1mA的聚束脉冲,束流稳定,各项指标达到技术要求.目前,已长期投入脉冲运行,完成了多个物理实验.     

一种高频加热装置

【《日本的科学和技术》1984年1—2月号第16页报道】1980年以来,日本原子能研究所就一直在研究等离子体试验装置(JT-60)的加热装置。最近,在原子能研究所的指导下,东芝电气公司和日本电气公司共同试制成功了用于高频加热装置的大功率速调管(一大功率电子管),经试验,输出功率达1兆瓦,脉冲宽度为10秒,是目前世界上最强的高频输出速调管。使用装备了该速调管的高频加热装置和中性束注入加热     

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。     

考虑纵向与横向耦合效应的束流传输

束流的纵向压缩,也即聚束,是强流加速器所必需的。但是,有关聚束过程的物理机制,目前尚未十分清楚。作者推导得出了计入聚束过程中束流强度变化的纵向与横向耦合的包络线方程,为研究考虑聚束效应的束流传输提供了工具,并实际应用于马里兰大学的电子束脉冲压缩实验的物理设计中。     

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。     

571.2 MHz次谐波聚束腔结构的物理设计

文章给出了北京正负电子对撞机二期工程(BEPCⅡ)未来预注入器中571.2 MHz次谐波聚束腔结构的物理设计步骤和方法。分别使用二维有限差分法分析软件Superfish和三维有限积分法分析软件MAFIA对优化后的聚束腔结构进行了计算,得到了比较一致的结果。另外,对Superfish和MAFIA在设计聚束腔结构上的优缺点进行了比较。     

SFC轴向注入线上的线性聚束器

ＳＦＣ轴向注入线采用了一个双间隙漂移管式聚束器和一个单间隙栅网型聚束器，分别采用三角波和锯齿波的聚束波形。采用充放电式的高频电压发生器可以得到要求的聚束电压。     

宽脉冲高功率速调管快速保护系统

介绍了一种用于射频电子直线加速器型FEL注入器的宽脉冲高功率速调管快速保护系统。首先简要地讨论了这种宽脉冲高功率速调管快速保护系统的要求,综述了目前仍在使用的几种保护方法,然后给出了本系统的基本原理、理论计算和电路设计。对于速调管输出功率的变化和一对检波器的不完全匹配对快速保护系统的影响,可以采取使用检波特性几乎线性的热载流子二极管及监控聚束器的驻波比的办法来解决。最后,给出了一些测试结果,表明该系统具有响应时间快(<2μs)、驻波比可调(1.5～2.0)、结构简单、抗干扰性能好的特点。该系统已成功地工作了两年多。     

速调管管体温差保护装置的研制与应用

速调管是直线加速器系统重要的分系统之一。它是加速器的功率源,加速器的微波功率就是通过速调管放大输出的,因此,速调管的工作状态直接影响加速器的正常运行。速调管工作时,良好的束流聚焦状态非常重要,否则,会引起速调管输出功率下降,甚至会损坏速调管。为了间接判断速调管的     

微秒矩形脉冲顶部抖动测量

一、导言速调管电压脉冲顶部的变化会引起微波输出相移,影响束特性。因此,电子直线加速器对调制器输出脉冲顶部平坦度提出严格要求。测量脉冲顶部特性的方法有多种。例如利用场致发射二极管测量高压矩形脉冲顶部电压的微小变化;利用Kerr效应测量高压脉冲绝对值及确定脉冲形状等。但这些方     

200MeV电子直线加速器隧道内及速调管走廊内的瞬发辐射场

直线加速器隧道内存在着一个具有特定时间结构和空间分布的强瞬发辐射场,它主要由轫致辐射和中子组成。用丙氨酸剂量计和电子自旋共振（ＥＳＲ）方法进行测量,得到隧道内关键位置的三维空间辐射场分布。这对于了解加速器的运行状态和射线积累剂量对各种有机材料的损伤程度是有意义的。速调管走廊内的辐射场主要是由于大功率速调管的运行造成的,因各个速调管参数不一致而使各点的辐射剂量呈现出较大的差异。但速调管走廊内的辐射水平不太高,故允许人员有条件地进入其中工作,因此在辐射安全联锁系统中将其定为可绕过的联锁点。本文简单介绍国家同步辐射实验室这两处辐射场的特点,并对其测量的方法和结果进行了叙述和讨论     

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。     

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.     

SXFEL装置上速调管输入输出特性曲线的线性化

在上海软X射线自由电子激光(Soft X-ray Free-electron Laser,SXFEL)中的微波低电平控制系统中,通过对各速调管的输出信号进行测量和控制,保证加速器的稳定运行并且达到技术指标。另一方面,SXFEL中的脉冲速调管的输入输出特性存在非线性的关系,这种电子管放大器不理想的非线性特性会导致微波低电平(Low Level Radio Frequency,LLRF)控制系统调节的效率降低。基于SXFEL装置,采用基于现场可编程门阵列(Field Programmable Gate Array,FPGA)的数字预失真方法,在LLRF控制系统中设计了一套实现高功率速调管放大器线性化的在线系统。S波段加速装置和其相应的东芝E3730A速调管及高压调制器和低电平系统实地测试结果表明,在LLRF控制系统中建立的在线系统能够有效补偿速调管带来的非线性问题,提高微波低电平控制系统的精度及准确性。     

100MeV电子直线加速器激励系统

文章描述了100MeV电子直线加速器激励系统的原理、结构、调试结果和主要技术性能。该系统的中功率速调管放大器能够输出15kW的脉冲功率,经微波输出部分分别激励6只高功率速调管。结果表明,系统结构简单,性能良好,完全满足加速器的使用要求。     

Results of a modulator pulse top ripple reduction study

The design of a modulator that can produce high-voltage klystron drive pulses with minimal ripple on the top is described. The design study focused on ways to reduce ripple and adjust the shape of the pulse to minimize variations in the final output of the klystron. Comparisons of the pulse performance for a range of possible loads were done to determine the sensitivity of the design to load characteristics. The resulting modulator design incorporates dual pulse forming networks, and uses a cancellation scheme to reduce ripple. The basic design, simulations and the performance of a low-power prototype are discussed. A high-power klystron modulator design is summarized     

相干谐波辐射实验的测量和控制系统

电子束和种子激光一同通过光学速调管时,产生相干谐波辐射,这是获得短长波相干光的一种很有希望的途径。为产生相干辐射,光学速调管波荡器磁极间隙,种子激光波长和电子能量三者必须满足共振条件,电子束团和种子激光脉冲在时间上必须严格同步。为使某次相干谐波辐射达到极大值,光学速调色散段磁极间隙必须调节,介绍了相干谐波辐射的测量、种子激光与电子束的同步和光学速调管极间隙调节系统。     

Analysis and optimization of high-power pulse transformer for SXFEL

A C-band accelerator structure was used to accelerate electrons at the Shanghai soft X-ray free-electron laser test facility(SXFEL-TF) in Shanghai Institute of Applied Physics(SINAP). The microwave system of this accelerator structure used a 110 MW pulse modulator and a klystron(PV-5050) to provide the power supply. A pulse transformer is a crucial device in a modulator klystron system and plays significant roles in voltage level transformation, matching impedances, and polarity inversion.This study presents the optimization of a high-voltage pulse transformer. The design considerations of reducingflattop ringing and flattop droop, and shortening leading edge are provided. The model simulation, mechanical design, and the relevant experimental results are also presented.     

Simulation study of transverse optical klystron radiation

The radiation from a transverse optical klystron(TOK) is calculated by far field approximation and numerical integration,in which the effects of electron-beam emittance and energy spread are considered.Accurate electron-beam profiles have been experimentally determined and modeled by the Monte Carlo method.The calculated spectra illustrate the emittance of Hefei storage ring imposes on the spontaneous radiation of TOK.     

Simulation calculation of 24kV long pulse TESLA modulator

1 Introduction output pulse is designed to meet the following speci- fications: The 24 kV long pulse modulator converts AC line Output voltage: 120 kVvoltage to pulsed high voltage in the 120 kV range to Output current: 138 Abe applied to the Thomson TH1801 multibeam kly- Pulse width: 1.7 msstron catho…