基于SOPC技术的EAST定时与同步系统

定时与同步系统是托卡马克装置实现等离子体放电流程实时控制的基础。基于SOPC技术研制的EAST分布式定时与同步系统可为各子系统提供精确时钟和同步触发信号,使装置各子系统按照预先设定好的流程运行,实现EAST等离子体放电实验时序的精确控制。EAST定时与同步系统的时序精度高于1μs,可以满足当前EAST实验的需要。     

EAST托卡马克中央定时系统的实现

中央定时系统是EAST托卡马克装置总控系统的重要组成部分,是总控系统对各子系统进行时序和触发控制的基础.本工作建立的EAST中央定时系统采用分布式的系统结构,可对32 MHz的系统时钟信号进行0-65535的任意整数分频;能对系统触发进行延迟输出,最大的延迟时间为4294s、延迟的分辨率为1 μs.该系统性能稳定,并已成功地投入到2006年9月EAST托卡马克装置的首轮正式物理放电实验中.     

上海光源线站ps精度定时系统设计

为满足上海光源线站工程ps时间分辨科学研究需求,设计了ps精度定时系统。定时系统采用事件定时原理产生与射频时钟信号共相位的时钟信号、光纤传输网络用于时钟信号传输,并在EPICS软件控制架构下,产生高精度可控时钟同步信号序列,根据不同的同步控制需求,为激光器、探测器等被同步设备提供触发信号。研究结果表明:定时系统的硬件同步触发抖动为3.360 ps、延迟步长精度为3.703 ps,可实现10 ps时间分辨实验的同步控制。     

BEPCⅡ直线定时系统光信号收发器的研制

定时系统为BEPCⅡ直线电子枪、调制器和正电子源等设备提供精确的同步触发信号.因光纤介质的传输损耗低,使用光纤收发器传输同步触发脉冲信号,不但可以实现信号的远距离传输,同时保障了信号的电气隔离,增强了系统抗噪声能力.目前,自主研发的OTB插件已经投入了BEPCⅡ的直线定时系统的运行,结果表明系统性能达到并优于定时系统的设计指标.     

BEPCII直线定时系统光信号收发器的研制

定时系统为BEPCII直线电子枪、调制器和正电子源等设备提供精确的同步触发信号。因光纤介质的传输损耗低，使用光纤收发器传输同步触发脉冲信号，不但可以实现信号的远距离传输，同时保障了信号的电气隔离，增强了系统抗噪声能力。目前，自主研发的OTB件已经投入了BEPCII的直线定时系统的运行，结果表明系统性能达到并优于定时系统的设计指标。     

EAST托卡马克激光吹气杂质注入系统控制系统设计及测试

开展托卡马克等离子体中杂质输运与杂质控制研究对于提升等离子体约束性能与保障装置安全有重要意义。为了在EAST(Experimental Advanced Superconducting Tokamak)托卡马克装置上开展杂质输运研究,需要发展一套用于注入示踪杂质粒子的激光吹气（Laser Blow-off,LBO）微量杂质注入系统。本文描述了一种用于EAST托卡马克装置上LBO系统的控制系统设计过程与测试结果。该系统采用了全新的自动控制流程,使得系统可以重复、定量地向EAST等离子体注入不同元素的示踪杂质粒子。该设计通过STM32单片机系统实现对聚焦透镜位移、激光器被触发时刻的准确控制,且激光光斑直径可调,以改变杂质注入量。测试结果显示,系统能快速检测到外触发信号并实现精确定时,激光光斑聚焦位置误差小于0.40 mm,达到激光吹气杂质注入实验要求。本研究对在EAST装置上开展等离子体杂质输运研究具有重要意义。     

射频负离子源分布式定时同步系统设计

为满足负离子源中性束注入系统对定时同步的功能需求,设计了射频负离子源分布式定时同步系统.通过精密时钟同步协议对中性束系统中的各子系统进行同步控制,建立统一的时钟基准.实现精准控制各子系统的投入时序以及运行时间,有效提高定时精准度,保证每炮实验完整有序进行.实验测试结果表明:目前同步控制精度控制在1 μs以下,满足时序控...     

基于FPGA的同步触发时序系统设计

<正>时序系统中同步触发输出多道相互独立可调的脉冲信号,用于驱动触发加速器的电子枪、调制器、微波功率放大器等,使其工作同步。传统触发多由信号源和分离元件的模拟电路组成,存在精度低、可调性差和易受干扰等缺点。为使系统具有良好的可控性和高精度控制效果,采用可编程片上系统实现一种可编程硬件的同步定时触发系统。利用FPGA并发特性提高系统的速度,各I/O     

基于高精度脉冲发生器的定时系统设计

为满足自由电子激光装置的正常运行需求,需要向加速器设备提供精确的定时触发信号。依据上海软X射线自由电子激光装置(Soft X-ray Free-Electron Laser Facility,SXFEL)的物理需求和系统分配,基于高精度脉冲发生器,结合具有联锁接口的光电转换器,实现了SXFEL定时系统的硬件设计。系统的软件部分使用实验物理与工业控制系统(Experimental Physics and Industrial Control Systems,EPICS)完成基于网络的分布式远程控制。通过在线测试,该系统运行稳定可靠,抖动时间小于150 ps,满足加速器对定时系统的要求。     

高分辨小型伽玛相机的数据采集触发电路

本文设计了一个数据采集触发电路,把伽玛相机位置读出信号的峰位检测转化为精度高的过零定时测量.该采集触发电路将输入信号全通滤波成形为一个有过零点的双极性信号,检测其过零点的位置检测峰位,产生触发脉冲,由单稳态触发器调节脉冲的脉宽和延时,用于后端数据采集系统的启动信号.实验证明:该触发电路性能稳定,对信号峰位的定时精度高,适用于高分辨小型伽玛相机的模块化开发.     

A distributed timing and synchronization system for EAST

The distributed timing and synchronization system (DTSS) plays an important role in Experimental Advanced Superconducting Tokamak (EAST), which is one of the national key fusion research facilities in China. This system synchronizes each subsystem of EAST by using reference clock and trigger. A prototype DTSS module has been developed based on PXI bus and RIO (reconfigurable I/O) devices. The DTSS can provide reference clock in frequency up to 80 MHz. The trigger can be pre-defined from 1 ms to 6872 s with 10 ns accuracy. In addition, this system can acquire, process signals, and send output or command to other systems. The DTSS has been successfully applied to 2010 fall EAST experiment, and the results confirmed its accuracy and reliability. After the analysis of system requirement, the architecture of the DTSS and the technical implementation based on PXI are presented in this paper.     

Upgrade of the Distributed Time-Keeping and Synchronization System for EAST

The distributed time-keeping and synchronization system(DTSS)underwent an upgrade for EAST during the last shutdown.The upgraded DTSS,designed based on PXI bus and reconfigurable I/O devices,synchronizes all other sub-systems by using a reference clock and trigger.It can produce a uniform clock up to 80 MHz,provide a delayed trigger from 1 ms to6872 s in 1 ms steps with 10 ns accuracy,and acquire the outputs of itself for self-inspection.The new DTSS was successfully applied in the 2012 spring EAST campaign,and has proven to be stable and reliable,giving an effective performance.The system structure and software development will be illustrated in detail in this paper.     

Data Acquisition System of Neutral Beam Injector on EAST

In order to supervise the elements of the neutral beam injector (NBI) spatially located at several places, a distributed NBI data acquisition system (NBIDAS) on experimental advanced superconducting tokamak (EAST) is developed in this paper. NBIDAS consists of field instrument and measurement devices, servers and remote data processing terminals. In order to remotely manage and monitor the field devices of the NBI system, a device management client software is also developed as the human–machine interfaces between the field devices and remote system administrators. A control signal acquisition system is developed for diagnosing these generated analog and digital signals from the NBI control system. NBIDAS based on network technologies is capable of extending system functions and upgrading devices. The detail of the architecture and implementation of the NBIDAS on EAST is discussed in the paper.     

EAST积分器系统的设计

在核聚变实验中,积分器是还原微分信号的基本手段。长时间低漂移积分器系统的研制是托卡马克实验中的重要环节。以差分式积分器为核心,结合线性隔离技术、程控放大器技术和嵌入式以太网通信技术,设计实现了EAST（ExperimentAdvanceSuperconductorTokamak）积分器系统。提出的系统整体标定方法进一步提高了该积分器系统的精度。性能测试表明,在增益为1时,该积分器在100s内的积分漂移小于10mV,满足了当前EAST实验的需求。该积分器系统已投入EAST的实验中,并取得了良好的运行效果。     

Technical diagnosis system for EAST tokamak

Technical diagnosis system (TDS) is one of the important subsystems of EAST (experimental advanced superconducting tokamak) device, main function of which is to monitor status parameters in EAST device. Those status parameters include temperature of different positions of main components, resistance of each superconducting (SC) coils, joint resistance of SC coils and high-temperature superconducting (HTS) current leads, strain of cold-quality components endured force, and displacement and current of toroidal field (TF) coils in EAST device, which are analog input signals. In addition there are still some analog and digital output signals. The TDS monitors all of those signals in the period of EAST experiments. TDS data monitoring is described in detail for it plays important role during EAST campaign. And how to protect the SC magnet system during each plasma discharging is presented with data of temperature of coolant inlet and outlet of SC coils and feeders and cases of the TF coils and temperature in the upper and middle and bottom of the TF coil case.During construction of the TDS primary difficulties come from installation of Lakeshore Cernox temperature sensors, strain measurement of central solenoid coils support legs and installation of co-wound voltage sensors for quench detection. While during operation since the first commissioning big challenges are from temperature measurement changes in current leads and quench detection of PF coils. Those difficulties in both stages are introduced which are key to make the TDS reliable. Meanwhile analysis of experimental data like temperature as a back up to testify quench occurrence and stress on vacuum vessel thermal shield and vacuum vessel have also been discussed.     

The Development of Data Acquisition and Remote Real-Time Display System for EAST NBI

The data acquisition and remote real-time display system for the neutral beam injectors (NBI) on experimental advanced superconducting tokamak (EAST) are described in this paper. Distributed computer systems including local data acquisition (DAQ) facility, remote data server (DS), real-time display terminal are adopted with Linux and Windows operating system. Experimental signals are gathered by DAQ device at local working field. On the one hand, these gathered data will be sent to DS which runs on remote server main control layer on EAST NBI control network for saving and processing; on the other hand, these data will be sent to real-time display terminal which runs on remote monitoring layer on EAST NBI for displaying and monitoring experimental signals real-timely. Another point needs to be mentioned is that the real-time display software can call back historical data from DS for querying. The software of data acquisition and DS are programmed by C language while the real-time display software is programmed by Labview flow chart. The hardware mainly includes DAQ cards, server, industrial personal computer and others auxiliary hardware. Now the system proved to be performed well through experiments on NBI testing bed.     

Spatial Resolution Measurements of C,Si and Mo Using LIBS for Diagnostics of Plasma Facing Materials in a Fusion Device

Recently,a laser-induced breakdown spectroscopic(LIBS) system has been developed for in situ measurements of the chemical compositions of plasma facing materials(PFMs)in the Experimental Advanced Superconducting Tokamak(EAST).In this study,a LIBS system,which was used in a similar optical configuration to the in situ LIBS system in EAST,has been developed to investigate the spatial distribution of PFM elements at 1CP4 Pa.The aim of this study was to understand the nature of the spatial distribution of atoms or ions of different elements in the plasma plume and optimize the signal to background ratio for the in situ LIBS diagnosis in EAST.The spatial profiles of the LIBS signals of C,Si,Mo and the continuous background were measured.Moreover,the influence of laser spot size and laser energy density on the LIBS signals of C,Si,Mo and H was also investigated.The results show that the distribution of the C,Si and Mo peaks' intensities first increased and then decreased from the center to the edge of the plasma plume.There was a maximum value at R≈1.5 mm from the center of the plasma plume.This work aims to improve the understanding of ablating plasma dynamics in very low pressure environments and give guidance to optimize the LIBS system in the EAST device.     

The EAST distributed data system

In this year, Experimental Advanced Superconducting Tokamak (EAST) has undergone the first tests successfully, and the EAST distributed data system has been reliably operated in the EAST experimental campaigns. This paper gives an overview of this system.The EAST distributed data system is based on the design of, and the experiences with the HT-7 data system; it is aimed to be a distributed, real-time and scalable system. The EAST distributed data system includes control subsystem, data acquisition subsystem and data service subsystem. Control subsystem provides remote control of the all data acquisition units, full information management and state monitoring; data acquisition subsystem that provide real-time and quasi-real-time data support for long-pulse operation consists of a set of autonomous data acquisition units which support autonomous operating and remote control. Data service subsystem is responsible for storing and publishing data.     

EAST低温系统主运行模式的控制流程设计与分析

EAST托卡马克核聚变实验装置是世界上从事核聚变研究的先进科学设备。EAST低温系统是该装置的主要子系统之一,其相应DCS控制系统具有很高的稳定性和可扩展性,各部分的控制相互独立、并行执行。本文详细介绍和分析了EAST低温控制系统及在正常降温、稳态和失超模式下的控制流程设计。     

Electron Cyclotron Emission Imaging on the EAST Tokamak

An upgraded electron cyclotron emission imaging (ECEI) system consisting of new optics lenses with necessary electronics for receiving and processing signals for two dimension (2D) ECEI diagnostics was installed on EAST. Hyperboloid lens were adopted in the new system to optimize the spatial resolutions. The mixers array of sixteen elements measured the plasma electron cyclotron emission at eight frequencies simultaneously, and the profiles of the electron temperature and its fluctuation in an area of 20 cm (vertical) × 6 cm (horizontal) could then be analyzed. Eevolution of sawtooth precursor and crash in EAST was observed.