HLS-Ⅱ储存环工作点测量系统的开发（英）

介绍了在合肥光源重大维修改造工程期间,开发的一套基于扫频激励法的工作点测量系统。测量系统硬件包括基于条带BPM的信号拾取电极、前端信号调理模块、一台带跟踪输出的信号分析仪N9000AEP、功率放大器以及用于激励束流的条带激励器。系统控制软件采用EPICS开发,基于EPICS Stream Device设计的输入输出控制器(soft IOC)运行在服务器虚拟机中,通过VXI11协议进行通信实现对信号分析仪的控制和数据获取;用户操作界面采用EPICS平台下的EDM开发,通过Channel Access与IOC通信。在HLS-II储存环上对工作点测量系统进行了在线的调试。调试结果说明,在扫频范围为2.1 MHz到4.1 MHz时,工作点测量系统的统计分辨率在水平方向上好于0.000 3,在垂直方向上好于0.000 2。     

HEPS在轴注入冲击器系统及快脉冲电源样机研制

高能同步辐射光源(HEPS)是我国计划建造的下一代基于储存环的高亮度光源,束流自然发射度已经接近衍射极限。作为典型的低发射度储存环(LER),HEPS的动力学孔径远小于物理孔径,传统的离轴累积注入已经无法满足要求,只能采用基于strip-line kicker的在轴注入方案。为了实现逐束团操控,HEPS要求注入kicker脉冲电源底宽(3%~3%) < 10 ns,半高宽(50%~50%)>4.5 ns,幅度>±17.5 kV(50 Ω负载),重复频率>50 Hz。高能同步辐射光源验证装置(HEPS-TF)工程研制了一台基于DSRD的双极性快脉冲电源性能样机,在50 Ω负载上可以获得上升时间(10%~90%) < 2.6 ns,下降时间(90%~10%) < 3.2 ns,半高宽(50%~50%)>5 ns,底宽(3%~3%) < 10 ns,幅度>±18 kV的脉冲高压,可以满足HEPS注入基准方案——在轴置换注入的要求。     

CSNS引出冲击磁铁脉冲电源设计

从脉冲电源参数计算, 电源整体设计, 脉冲形成网络(PFN)设计和优化等方面介绍了中国散裂中子源快循环同步加速器引出Kicker磁铁脉冲电源的初步设计情况, 提出一种新型的低阻抗PFN设计方法, 给出了脉冲电源和PFN的参数, 利用PSPICE程序仿真了充电电压为36.5kV情况下磁铁的励磁脉冲电流波形, 励磁电流脉冲幅值达到5.8kA. 结合仿真结果, 分析了不同PFN节数和传输电缆长度对磁铁电流波形的影响.     

Beam stability in synchrotrons with digital transverse feedback systems in dependence on beam tunes

The beam stability problem in synchrotrons with a digital transverse feedback system (TFS) is studied. The TFS damper kicker (DK) corrects the transverse momentum of a bunch in proportion to its displacement from the closed orbit measured at the location of the beam position monitor (BPM). It is shown that the area and configuration of the beam stability separatrix depend on the beam tune, the feedback gain, the phase balance between the phase advance from BPM to DK and the phase response of the feedback chain at the betatron frequency.     

Development of tools for real-time betatron tune measurements at the Nuclotron

A betatron tune measurement system was developed and tested at the Nuclotron. A white noise and chirp signals were used for transverse beam motion excitation. A custom FlexRIO digitizer module was developed which provides excitation signal generation for kicker electrodes and real-time signal acquisition from pickup electrodes. A high resolution FFT algorithm was implemented inside a NI PXI FPGA module, connected to digitizer. The measurement system is integrated with the NICA control system based on the TANGO Controls. Results and tests performed with the Nuclotron beam are presented.     

低能质子束脉冲踢束器的物理设计

电子回旋共振(ECR)质子源产生的脉冲质子束脉宽通常在ms或亚ms量级,高梯度加速结构要求注入的质子束脉宽为100 ns或更短,需要一个脉冲踢束器将大部分不需要的束流踢开,留下所需的短脉冲质子束。设计的踢束器采用静电偏转方法,针对在研ECR质子源的束流参数,设计了脉冲踢束器的结构尺寸,使用ANSYS软件计算了踢束器的静电场分布情况,利用软件内置的CMATRIX宏提取了结构电容的数据,给出了对脉冲踢束电源的参数要求,讨论了踢束脉冲上升沿和产生的束流脉冲上升沿的对应关系。     

Study on the effects of chromaticity and magnetic field tracking errors at CSNS/RCS

The Rapid Cycling Synchrotron (RCS) is a key component of the China Spallation Neutron Source (CSNS). For this type of high intensity proton synchrotron, the chromaticity, space charge effects, and magnetic field tracking errors between the quadrupoles and the dipoles can induce beta function distortion and tune shift, and induce resonances. In this paper, the combined effects of chromaticity, magnetic field tracking errors and space charge on beam dynamics at CSNS/RCS are studied systemically. 3-D simulations with different magnetic field tracking errors are performed by using the code ORBIT, and the simulation results are compared with the case without tracking errors.     

Design and Construction of a New Type Kicker Magnet for Injection of BEPCⅡ Storage Ring

For the severe requirements of BEPCⅡ injecting kicker magnets, the two schemes of low impedance kicker magnets used in other accelerator labs in the world are not adaptive to the BEPCII storage ring. A new scheme of kicker magnets proposed in this article solves the difficult problem of BEPCII kicker magnet design. And the successful construction of a prototype has demonstrated that the new scheme of kicker magnets is viable and the design of the kicker magnet structure is reasonable.     

Longitudinal RF capture and acceleration simulation in CSNS RCS

China Spallation Neutron Source (CSNS) is a high power proton accelerator-based facility. Uncontrolled beam loss is a major concern in designing the CSNS to control the radioactivation level. For the Rapid Cycling Synchrotron (RCS) of the CSNS, the repetition frequency is too high for the longitudinal motion to be fully adiabatic. Significant beam loss happens during the RF capture and initial acceleration of the injection period. To reduce the longitudinal beam loss, beam chopping and momentum offset painting methods are used in the RCS injection. This paper presents detailed studies on the longitudinal motion in the RCS by using the ORBIT simulations, which include different beam chopping factors, momentum offsets and RF voltage optimization. With a trade-off between the longitudinal beam loss and transverse incoherent tune shift that will also result in beam losses, optimized longitudinal painting schemes are obtained.     

CSNS\RCS引出系统快脉冲冲击磁铁样机的设计

 设计了中国散裂中子源(CSNS)快循环同步加速器(RCS)引出系统快脉冲冲击磁铁样机。为降低磁铁和其电源的研制难度,保证运行的可靠性,决定采用美国散裂中子源(SNS)的Single-turn结构。根据磁铁的设计指标,给出了磁铁设计要求铁芯材料选择方法、整体的结构设计以及如何对磁铁进行定位和准直,并采用Opera程序进行模拟计算,结果表明：当铁芯长度为220 mm时,磁有效长度大约为302 mm;磁感应密度最大的地方在4个内角上,约为0.215 T;在133 mm×200 mm的平面范围内,磁场均匀性优于±0.8%。理论分析和Opera程序模拟均验证了磁铁结构方案的可行性。     

Kicker magnet modulator in the 2-GeV Pohang light source

The 2.0-GeV Pohang light source (PLS) is a third-generation synchrotron light source that is the first such facility in Korea and the fifth in the world. The PLS mainly consisted of a full-energy injection linac and a storage ring. Four kicker magnets are installed in the storage ring tunnel to move the stored beam orbit in the storage ring closer to the injected beam from the beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. A kicker magnet modulator drives all four kicker magnets to maintain field balance and synchronized kick of the beam. Specification of the kicker magnet modulator is ~6.0-μs-full width, 200-ns flattop width with ±0.2% regulation, ~24-kA peak current, and 10-Hz repetition rate. Two thyratron switches (EEV CX-1536AX) are used in the system. As the inverse voltage is dangerous to thyratron operation, a new surge suppression circuit was developed. The kicker modulator has been operated very reliably since its installation in August 1995. In this article, design, simulation, and experimental results of the kicker magnet modulator are discussed. In addition, measurement result of spatial B-field distribution in the kicker magnet and maximum operating range of kicker magnet are discussed     

环形正负电子对撞机注入引出分布参数型冲击磁铁设计

环形正负电子对撞机（CEPC）是一台周长100 km,最高能量为120 GeV的双环对撞机。为了满足不同能量粒子从增强器注入到对撞环,针对W和Z能量模式设计了对撞环离轴注入系统,用于实现束流的累积。为了提高注入效率,兼容不同注入能量,不同束流填充模式,同时尽可能减少注入过程中冲击磁铁对其它束团的扰动,要求对撞环离轴注入冲击磁铁系统是一个上升时间和下降时间小于200 ns,脉冲底宽调节范围为440～2420 ns的梯形波脉冲放电系统。和常见的集中参数型冲击磁铁相比,分布参数型冲击磁铁具有更优越的动态响应特性,适合产生一个前沿更加陡峭、波形更为理想的梯形波脉冲。根据CEPC的束流注入物理需求,完成了一台分布参数型冲击磁铁的物理设计和结构设计,并采用了PSpice和Opera程序进行模拟仿真。设计结果表明：冲击磁铁由26级LC单元结构叠装而成,磁铁总长为1018 mm,磁有效长度为942 mm;在[-20,20] mm磁铁孔径内,磁场强度为0.042 1 T,磁场均匀性优于±0.2%;冲击磁铁系统总上升时间（10%～90%）为193 ns,下降时间（90%～10%）为191 ns。理论分析、...     

Impedance measurements of the extraction kicker system for the rapid cycling synchrotron of China Spallation Neutron Source

The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to understand the kicker impedance before its installation into the tunnel. Conventional and improved wire methods are employed in the impedance measurement. The experimental results for the kicker impedance are explained by comparison with simulation using CST PARTICLE STUDIO. The simulation and measurement results confirm that the window-frame ferrite geometry and the end plate are the important structures causing coupling impedance. It is proved in the measurements that the mismatching from the power form network to the kicker leads to a serious oscillation sideband of the longitudinal and vertical impedance and the oscillation can be reduced by ferrite absorbing material.     

兰州重离子冷却储存环束流踢轨控制系统

 踢轨系统是一种以快速脉冲方式工作的以高压大电流驱动的特殊二极磁铁系统,用于环形加速器的束流注入和引出。简要介绍了在兰州重离子加速器冷却储存环上采用ARM+DSP+FPGA技术实现踢轨控制时序的方法,时间控制精度达ns量级。ARM主要控制信号的网络通讯,踢轨系统的时序精度控制主要由DSP结合FPGA技术完成。远程时序控制信号均通过光纤传输,同时对踢轨电源的电压给定采用信号隔离器及铁氧体以抑制脉冲干扰。经现场测试,系统可以安全稳定地实现束流踢轨的控制要求。     

Beam transport experiment with a new kicker control system on the HIRFL

A kicker control system is used for beam extraction and injection between two cooling storage rings(CSRs) at the Heavy Ion Research Facility in Lanzhou(HIRFL). To meet the requirements of special physics experiments, the kicker controller has been upgraded, with a new controller designed based on ARM+DSP+FPGA technology and monolithic circuit architecture, which can achieve a precision time delay of 2.5 ns. In September2014, the new kicker control system was installed in the kicker field, and the test experiment using the system was completed. In addition, a pre-trigger signal was provided by the controller, which was designed to synchronize the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of "missed kick"and "inefficient kick" were not observed, and the multichannel trigger signal delay could be adjusted individually for kick power supplies in digitization; thus, the beam transport efficiency was improved compared with that of the original system. The fast extraction and injection experiment was successfully completed based on the new kicker control systems for HIRFL.     

Design and results for a 345 GHz sis focal plane array using planar technology

We describe a focal plane array using antenna elements and SIS junctions photo-etched on a quartz substrate. The etched antenna is of a new strip-line type in which a two-dimensional corrugated horn is phase-corrected with a strip-line lens. Good beam efficiency is indicated by the measured antenna patterns. A DSB receiver temperature of 225 K was obtained with a number of imperfections still present.     

中国散裂中子源磁铁系统和样机研制

中国散裂中子源(China Spallation Neutron Source, CSNS)快循环同步加速器(Rapid Cycling Synchrotron, RCS)磁铁由24块二极磁铁、48块四极磁铁、16块六极磁铁和若干斜四极磁铁以及校正磁铁组成, 其中二极磁铁和四极磁铁是带直流偏置的25Hz正弦交流励磁, 铁芯和线圈导体将产生不可忽视的涡流效应. 为了积累批量生产磁铁的制造经验, 探索磁铁后期处理和磁场测量方法, 已完成了中空水冷铝绞线试样线圈的研制, 启动了二极磁铁和四极磁铁样机的研制. 本文将对相关进展进行介绍.     

BEPCⅡ横向束流反馈系统条带电极的设计及模拟计算

 用高频结构模拟程序HFSS优化设计条带电极kicker并计算了它的反射参数和横向分流阻抗。从模拟得到的反射参数可以看出，在要求的250MHz带宽范围内, 反射的功率小于7%，说明了条带与功率传输线是阻抗匹配的；模拟得到的横向分流阻抗与公式计算得到的结果基本上一致。当频率250MHz时，得到了1 300Ω的分流阻抗，在此种条件下，需要反馈功率为123W方能抑制束流不稳定性，这为电极的机械设计和在反馈系统中选择功率放大器提供了最基本的依据。     

上海同步辐射装置储存环注入冲击磁铁的设计

 开展了上海同步辐射装置储存环注入冲击磁铁的结构和脉冲电源的技术设计,并进行了磁场分布和励磁电流波形的模拟计算。还给出了陶瓷真空盒镀膜的设计参数,提出了计算陶瓷真空盒镀膜接受同步光功率的公式,研究了防止镀膜和波纹管受到同步光照射的机械布局设计。     

p-PbTe的strip-line透射光谱研究

报道p-PbTe在深低温、强磁场下,不同远红外波长和晶体取向条件下的strip-line透射光谱。观察到一种新的对透射光谱的模式耦合影响。基于对这一复杂的模式耦合问题数学处理的解决,从实验光谱的拟合计算中得到p-PbTe的能带参量,进一步应用6能带的k·p模型解释了能带参量的光谱特性。 关键词：