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     

Design of 150kV bouncer modulator

The 150 kV bouncer modulator is designed to drive the 10 MW multi-beam klystron for the DESY TESLA Test Facility. The modulator is different from the 10 kV modulators previously built at Fermilab. First, the new 150 kV bouncer modulator has no transformer, so the modulator circuit is simplified and the output waveform is improved well. Second, the bouncer circuit has been changed to fit the output need, which is the most significant challenge. This paper gives the design of the 150 kV long pulse bouncer modulator.     

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…     

BEI-1电子直线加速器定时触发系统

本文介绍了一个完整的全集成电路化的定时触发系统,用于双功率源馈送功率BEI-1电子直线加速器中。它是由七个专用NIM标准插件组成,即:同步、异步基准脉冲发生器,用于电子枪、行波管、速调管调制器、能量倍增器的延迟放大电路以及快速保护电路。这套系统在BEI-1电子直线加速器上能正常运行,证明它的各项性能达到了设计指标。     

9MeV行波电子直线加速器加速管的物理设计

海关大型货物在线检测用加速器采用４ＭＷ速调管作为微波功率源,保证加速管入口功率可达３．５ＭＷ、工作频率为２８５６ＭＨｚ;以行波方式加速电子,聚束器俘获效率大于８０％;加速管全长约２２０ｃｍ;电子能量设置９、６ＭｅＶ两档,对应的额定脉冲束流强度理论设计值分别为１７０和３００ｍＡ。本文给出了纵向粒子动力学、盘荷波导的尺寸及加速管的工作特性等方面的计算结果。     

Lifetime estimation of IGBT module using square-wave loss discretization and power cycling test

The Shanghai advanced proton therapy facility is a proton cancer treatment device designed and built by the Shanghai Institute of applied physics at the Chinese academy of sciences. The accelerator part comprises a proton linear accelerator (linac) injector and a circular synchrotron. An alternating current current transformer (ACCT) is used for non-intercepting beam current measurement at the drift tube linac exit. According to the beam characteristics, the ACCT is required to complete real-time beam current and pulse width measurements at currents of 3–30 mA, frequencies of 1–10 Hz, and pulse widths of 40–400 μs. In this paper, we report the design and development of an ACCT. The designed ACCT was simulated using CST Microwave Studio, and calibrated using an oscilloscope and signal generator. Variations in the output signal of the ACCT were investigated as a function of ceramic gap size, number of coil turns, and resistance. According to the simulation and experimental results, the optimal number of coil turns was found to be 30. In addition, a low-pass filter was adopted to filter the noise introduced during long-distance signal transmission using a coaxial cable with the length of 20 m. The calibration results show that the corresponding rise time of the ACCT is 800 ns with the sensitivity of 8.2 V/A and a droop of less than 1%, meeting the design requirements.

     

电子直线加速器串联谐振充电电源的设计与实现

电子直线加速器一般使用线型脉冲调制器作为脉冲电源。在脉冲调制器充电系统中,使用LC串联谐振充电技术为脉冲形成网络（PFN）充电可提高效率并减小体积,是大功率线型脉冲调制器的发展方向之一。本工作基于串联谐振充电技术的基本原理,设计并制造了1台脉冲调制器样机,结合实测波形和工程应用,提出了改善稳定度的方法。测量结果表明,脉冲调制器样机的设计方案正确,实现了设计指标。     

Research of a fractional-turn ratio saturable pulse transformer and its application in a microsecond-range pulse modulator

As a combination device for a step-up pulse transformer and a magnetic switch,the saturable pulse transformer is widely used in pulsed-power and plasma technology.A fractional-turn ratio saturable pulse transformer is constructed and analyzed in this paper.Preliminary experimental results show that if the primary energy storage capacitors are charged to 300 V,an output voltage of about 19 kV can be obtained across the capacitor connected to the secondary windings of a fractional-tum ratio saturable pulse transformer.Theoretical and experimental results reveal that this kind of pulse transformer is not only able to integrate a step-up transformer and a magnetic switch into one device,but can also lower the saturable inductance of its secondary windings,thus leading to the relatively high step-up ratio of the pulse transformer.Meanwhile,the application of the fractional-turn ratio saturable pulse transformer in a μs range pulse modulator as a voltage step-up device and main switch is also included in this paper.The demonstrated experiments display that an output voltage with an amplitude of about 29 kV,and a 1.6 μs pulse width can be obtained across a 3500 Ω resistive load,based on a pulse modulator,if the primary energy storage capacitors are charged to 300 V.This compact fractional-turn ratio saturable pulse transformer can be applied in many other fields such as surface treatment,corona plasma generation and dielectric barrier discharge.     

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。     

A distributed control system for picosecond accelerator at SINAP

The picosecond accelerator （PA） is a low energy electron linear accelerator facility under commissioning, which is built for the experiment of ps level pulse radiolysis in Shanghai Institute of Applied Physics （SINAP）. A practical distributed DA＆C system for this facility has been developed. In view of the upgrading-ability and maintainability of the control system and controlled devices, Advantech distributed intelligent DA＆C products are adopted into the control system. ADAM 5000/TCPs with the protocol of Modbus/TCP are employed to accomplish data acquisition and device control. The PC-compatible programmable logic controller, ADAM-5511. is also adopted to handle the interlocks and the emergency events. On the software side, the integrated software package Kingview V6.5, which fi＇iendly supports all Advantech products, has been used to develop the upper layer control logic and process the data. This paper describes the control system design and system architecture, The intelligent ADAM controllers and the software platform are also discussed in detail.     

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。     

Characteristics of the beam injection system in an electron LINAC

The main characteristics of an electron beam injection system are described; the system is used for injecting and focusing electron beams into the acceleration structure of an 10 MeV linear electron accelerator. The beam injection system consists of a Pierce convergent diode-type electron gun with pulse modulator for power supply and a thin axially symmetric lens. The perveance and the capture coefficient were optimized by the analogical resistors network. This type of injection system was used in the linear electron accelerators: ALIN - 3 MeV, ALIN - 10 MeV and ALID − 8 MeV, performed at NILPRP^∗ Bucharest, Romania.     

Proposed high voltage power supply for the ITER relevant lower hybrid current drive system

In the framework of the EFDA task HCD-08-03-01, the ITER lower hybrid current drive (LHCD) system design has been reviewed. The system aims to generate 24 MW of RF power at 5 GHz, of which 20 MW would be coupled to the plasmas. The present state of the art does not allow envisaging a unitary output of the klystrons exceeding 500 kW, so the project is based on 48 klystron units, leaving some margin when the transmission lines losses are taken into account. A high voltage power supply (HVPS), required to operate the klystrons, is proposed. A single HVPS would be used to feed and operate four klystrons in parallel configuration. Based on the above considerations, it is proposed to design and develop twelve HVPS, based on pulse step modulator (PSM) technology, each rated for 90 kV/90 A. This paper describes in details, the typical electrical requirements and the conceptual design of the proposed HVPS for the ITER LHCD system.     

影响De-Qing线路稳压效果的因素分析

一、影响De-Qing线路工作的几种因素在电子直线加速器中,脉冲调制器输出脉冲电压的稳定度会影响速调管的相位调制,从而影响束流能散度。北京正负电子对撞机(BEPC)对电子直线段的能散度要求相当高,为±0.6%。因此,提高电压稳定度成为脉冲调制器研制工作中的一个重要方面。     

Precision Phase Adjustment of a Linear Accelerator High Power Waveguide Feed Network

Each klystron of the SLAC accelerator feeds four consecutive 10-foot accelerator sections through approximately 25 feet of earth shielding. The high power waveguide network which divides and guides the power to the four sections is adjusted so that the rf waves traveling within the accelerator sections are, at the end of each section, phased within ± two degrees of an ideal wave traveling at the velocity of light. A modulated reflection technique is used to compare the electrical phase length from a single input port through the four arms of the network during adjustment. The inclusion of the previously tuned accelerator sections in the network allows the total phase error to be minimized if careful control is exercised over the section terperatures. The measuring system, the reflection modulators, and the possible errors involved are discussed.     

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.     

110MW脉冲调制器控制器设计

为确保110MW脉冲调制器运行稳定可靠、维修安全和人员安全,同时满足中国科学院上海应用物理研究所100MeV直线加速器总体控制对调制器的要求,通过分析110MW脉冲调制器设备电路、工作原理和元器件特性,结合其硬件电路设计特点,描述了110MW脉冲调制器的设备控制器的监控方法和设计。通过调试、模拟运行和测试,控制器设计达到对调制器进行安全可靠的控制和保护的要求。     

The VEBA Relativistic Electron Accelerator

The VEBA high-current, relativistic electron accelerator has been designed and constructed at NRL for application in the study of high-power microwave sources. To meet the requirements of this study, the accelerator was designed for operation in either a short (60 nsec) or long (2.2 ?sec) pulse mode. The short-pulse mode has been in operation for nearly two years and has proven to be an extremely reliable design. The design of the long-pulse mode is now complete and component fabrication will soon be underway. The pulse-forming network in the short-pulse mode is an unbalanced, water Blumlein with an output impedance of 9.2? The Blumlein is pulse charged by a 17 stage Marx generator which has a series capacitance of 29.4 nF. By transmission along a tapered coaxial line, the output pulse is transformed to 20 ? and the voltage developed across a matched load increased to a maximum of 2.5 MV. The proposed conversion to the long-pulse mode will require that the Blumlein and transformer sections be removed and the diode assembly be attached directly to the oversized Marx tank. The direct coupling between the Marx and the Blumlein will then be replaced by two, nested, water capacitors which are shunted by spiral inductors. When coupled in series with the Marx, this output filter will form a three-section, voltage-fed, Guillemin (type A), pulse-forming network with a characteristic impedance of 40 ? and a maximum output voltage of 0.9 MV.     

压电变压器原理研究及特性测试

研究了一种可用于粒子加速器的压电变压器结构及工作原理，并采用等效电路和实验相结合的方法测试了压电变压器的若干工作特性。