基于VME总线的嵌入式Linux应用的研究

介绍了在高能物理实验的数据获取读出系统中应用嵌入式Linux的可行性分析与关键技术。首先介绍测试系统的硬件平台与软件框架。重点介绍在读出系统中实现嵌入式Linux应用的关键技术—寄存器读写、CBLT传输、中断处理、多线程技术、cache相关的处理等。系统开发基于VME总线,通过修改Linux内核与vme_universe驱动,解决了开发过程中的相关问题。最后给出系统测试运行结果,基于Linux的读出系统已经可以配合在线软件较为稳定地运行,系统性能达到预期效果,验证了在高能物理实验中采用基于Linux的读出系统的可行性。     

A shared memory based interface of MARTe with EPICS for real-time applications

The Multithreaded Application Real-Time executor (MARTe) is a multi-platform C++ middleware designed for the implementation of real-time control systems. It currently supports the Linux, Linux + RTAI, VxWorks, Solaris and MS Windows platforms. In the fusion community MARTe is being used at JET, COMPASS, ISTTOK, FTU and RFX in fusion [1].The Experimental Physics and Industrial Control System (EPICS), a standard framework for the control systems in KSTAR and ITER, is a set of software tools and applications which provide a software infrastructure for use in building distributed control systems to operate devices.For a MARTe based application to cooperate with an EPICS based application, an interface layer between MARTe and EPICS is required. To solve this issue, a number of interfacing solutions have been proposed and some of them have been implemented. Nevertheless, a new approach is required to mitigate the functional limitations of existing solutions and to improve their performance for real-time applications.This paper describes the design and implementation of a shared memory based interface between MARTe and EPICS.     

IR-FEL装置数据存档和查询系统

IR-FEL装置控制系统是基于EPICS的分布式控制系统,装置运行过程中产生的历史数据可用于装置的性能分析和故障诊断,对装置的性能提升和运行维护具有重要意义。本文以Archiver Appliance作为历史数据存档工具,采用前、后端分离的软件架构,设计和开发了IR-FEL装置数据存档和查询系统。系统后端包含历史数据查询和实时数据推送两种服务端程序,使用Nginx反向代理服务器提供了统一的数据查询接口;前端是基于Vue.js的单页应用,提供了历史数据定制查询、自由查询和运行状态显示页面。系统自投入运行以来,性能稳定、功能完善,满足了IR-FEL调试和运行的需求。     

The data-acquisition system for the CMS tracker beam tests

This paper describes the conception and the development of a real-time data-acquisition system for prototype detectors of the Tracker being designed for the compact muon solenoid (CMS) experiment at the Large Hadron Collider of CERN, European Laboratory for Particle Physics, Geneva, Switzerland. The rationale for the development of a dedicated data-acquisition system was the need to perform two fundamental beam tests (the “Milestone Barrel 1” and “Milestone Forward 1”), with large-scale prototypes of the detectors planned as the baseline design. The number of readout channels, the complexity of the readout electronics, and the stringent requirements of the milestone tests mandated that a thorough understanding of the issues related to the physics of the detectors themselves be coupled with the application of leading-edge electronic and software engineering technologies. The implementation described in this paper is based on a distributed architecture. An event builder CPU handles the two main tasks of synchronizing a variable number of front-end processors and formatting the data in preparation for the transfer to a dedicated high-performance storage system, while the front-end processors handle the hardware and the real-time readout. Additional workstations are used to decouple the actual task of transferring the data files and monitoring the detector performance on-line from the readout farm. The system has been successfully operated during the two aforementioned Milestone tests, allowing the CMS Tracker collaboration to pass them, with the simultaneous readout of up to 40000 detector channels. The results of the two Milestones have led to the compilation of the “Tracker Technical Design Report”. Subsequently, the same readout system has been used for a number of other beam tests, and it has formed the basis for the development of further, more advanced data-acquisition systems for the new readout electronic of the CMS Tracker     

Upgrade issues in FTU control,data acquisition and management

FTU is operating since 1989, thus its hardware and software infrastructure must be continuously updated to preserve its efficiency and reliability. This issue can be addressed by means of two distinct approaches: (i) the migration to an emulated environment enabling the use of modern hardware on virtualized standard servers to keep the operating systems full functionality and the application environment; (ii) the porting of the complete system architecture to new hardware, new operating systems, and new programming languages. This paper reports on the upgrades implemented on FTU in the last two years using both these approaches including the new system to acquire and store the image frames of FTU plasma discharges through a Photron FASTCAM SA4 camera. Regarding data handling, a small Linux high performance computing system (1TFlops) with a high performance data storage system (100 TB) in InfiniBand DDR infrastructure has been installed as data analysis, modelling and archive cluster for the next three years of FTU experimental activities.     

Progress in control and data acquisition for the ITER neutral beam test facility

SPIDER, the ion source test bed in the ITER neutral beam test facility, is under construction and its operation is expected to start in 2014. Control and data acquisition for SPIDER are undergoing final design. SPIDER CODAS, as the control and data acquisition system is referred to, is requested to manage 25 plant units, to acquire 1000 analogue signals with sampling rates ranging from a few S/s to 10 MS/s, to acquire images with up to 100 frames per second, to operate with long pulses lasting up to 1 h, and to sustain 200 MB/s data throughput into the data archive with an annual data storage amount of up to 50 TB. SPIDER CODAS software architecture integrates three open-source software frameworks each addressing specific system requirements. Slow control exploits the synergy among EPICS and Siemens S7 programmable controllers. Data handling is by MDSplus a data-centric framework that is geared towards the collection and organization of scientific data. Diagnostics based on imaging drive the design of data throughput and archive size. Fast control is implemented by using MARTe, a data-driven, object-oriented, real-time environment. The paper will describe in detail the progress of the system hardware and software architecture and will show how the software frameworks interact to provide the functions requested by SPIDER CODAS. The paper will focus on how the performance requirements can be met with the described SPIDER CODAS architecture, describing the progress achieved by carrying out prototyping activities.     

A Prototype of the Read-out Subsystem of the BESIII DAQ Based on PowerPC

1 Overview of the data acquisi-tion system for BES IIIAfter having run successfully for more than tenyears, the BEPC e+ e- collider will be upgradedfor higher luminosity, which will be increased to1033 cm-2 ·sec-1 [1]. Therefore, its detector BESII willbe upgraded to BESIII in order to take advantage ofthis increased luminosity, named BESIII.Trigger rate and event size define the performance re-quirements for the data acquisition (DAQ) system. Forpeak luminosity, we expect a L1 t…     

A Prototype of the Read-out Subsystem of the BESⅢ DAQ Based on PowerPC

This article describes the prototype of the read-out subsystem which will be subject to the BESⅢ data acquisition system. According to the purpose of the BESⅢ, the event rate will be about 4000 Hz and the data rate up to 50 Mbytes/sec after Level 1 trigger. The read-out subsystem consists of some read-out crates and a read-out computer whose function is to initialize the hardware, to collect the event data from the front-end electronics after Level 1 trigger, to transfer data fragments to the computer in online form through two levels of computer pre-processing and high-speed network transmission. In this model, the crate level read-out implementation is based on the commercial single board computer MVME5100 running the VxWorks operating system.The article outlines the structure of the crate level testing platform of hardware and software. It puts emphasis on the framework of the read-out test model, data process flow and test method at crate level. Especially, it enumerates the key technologies in the process of design and analyses the test results. In addition, results which summarize the performance of the single board computer from the data transferring aspects will be presented.     

基于APV25芯片的GEM探测器读出电子学系统的测试与改进

气体电子倍增器(GEM)是目前最具发展前景的位置灵敏气体探测器。其新一代读出电子学系统包括APV25前端卡、多用途数字转换器（MPD)、VME控制器及基于Linux的采集软件DAQ。本工作完成了读出系统的调试,获得了系统在40 MHz和20 MHz工作频率下的理想数据。在长时间测试中,系统运行稳定。通过对软件配置的优化和对硬件的改进,降低了噪声水平,提高了信噪比。     

Integrating knowledge-based systems into operations at the McMasterUniversity FN Tandem Accelerator Laboratory

The development of an accelerator operators' companion, which incorporates a knowledge-based front-end that is tuned to user operational expertise is described. The front-end also provides connections to traditional software packages such as database and spreadsheet programs. Two prototype implementations are presented. The importance of modifying expert procedures when a multitasking environment is involved, as discovered during work on the back-end (that is, during real-time expert system control development), is discussed     

DAMPE-PSD读出电子学研制

暗物质粒子探测卫星(dark matter particle explorer, DAMPE)是我国空间科学卫星系列的首发星,用于找出可能的暗物质粒子信号。塑料闪烁体阵列探测器(plastic scintillator detector, PSD)分系统作为卫星有效载荷的主体部件之一,参与承担高能粒子电荷测量和电子/γ射线鉴别任务。PSD由82根塑料闪烁体条和164个光电倍增管（photomultiplier tube, PMT)组成,有328个输出通道,每根塑料闪烁体条的动态范围为2×103,需配备1套完备的读出电子学系统。该电子学系统由4块前端电子学（front-end electronics, FEE）板构成,共具有360个信号处理通道,总功耗6 W。电路主要包括电荷测量电路、模拟调理电路、模数变换电路、刻度电路、环境监测电路、FPGA电路、电源管理电路以及接口电路等,其主要功能是基于32路模拟信号将PMT的电荷信号输入VA160 ASIC芯片,考虑了抗辐照加固、温度设计等一系列关键问题,以确保在严酷的太空中具有长期的可靠性。测试结果表明,该FEE系统工作稳定、性能良好,具有较好的技术指标,每个电子学通道实现了0～12.5 pC的动态范围,通道的随机噪声水平好于2 fC,积分非线性好于0.6%。FEE能适应恶劣的空间环境,具有很高的可靠性。FEE配合PSD样机还分别于2014年和2015年在欧洲核子中心（CERN）的PS和SPS终端成功完成了2次束流试验,验证了PSD的探测能力完全满足任务书中提出的功能和指标要求,能很好实现实际科学任务需求。     

Design of FPGA based high-speed data acquisition and real-time data processing system on J-TEXT tokamak

Tokamak experiment requires high-speed data acquisition and processing systems. In traditional data acquisition system, the sampling rate, channel numbers and processing speed are limited by bus throughput and CPU speed. This paper presents a data acquisition and processing system based on FPGA. The data can be processed in real-time before it is passed to the CPU. It provides processing ability for more channels with higher sampling rates than the traditional data acquisition system while ensuring deterministic real-time performance. A working prototype is developed for the newly built polarimeter–interferometer diagnostic system on the Joint Texas Experimental Tokamak (J-TEXT). It provides 16 channels with 120 MHz maximum sampling rate and 16 bit resolution. The onboard FPGA is able to calculate the plasma electron density and Faraday rotation angel. A RAID 5 storage device is adopted providing 700 MB/s read–write speed to buffer the data to the hard disk continuously for better performance.     

A new long-pulse data system for EAST experiments

A long pulse discharge requires high throughput data acquisition. As more physics diagnostics with high sampling rate are applied and the pulse length becomes longer, the original EAST (Experimental Advanced Superconducting Tokamak) data system no longer satisfies the requirements of real-time data storage and quick data access. A new system was established to integrate various data acquisition hardware and software for easy expansion and management of the system. Slice storage mechanism in MDSplus is now being used for the continuous and quasi real-time data storage. For every data acquisition thread and process, sufficient network bandwidth is ensured. Moreover, temporal digitized data is cached in computer memory in doubly linked circular lists to avoid the possible data loss by the occasional temporal storage or transfer jam. These data are in turn archived in MDSplus format by using slice storage mechanism called “segments”. For the quick access of the archived data to the users, multiple data servers are used. These data servers are linked using LVS (Linux Virtual server) load balance technology to provide a safe, highly scalable and available data service.     

用于CBM-TOF超级模块探测器质量控制的分布式数据读出方法

高压缩重子物质(Compressed Baryonic Matter,CBM)实验装置飞行时间谱仪利用由多气隙电阻板室(Multi-gap Resistive Plate Chamber,MRPC)探测器构建的超级模块实现高密度、高精度的粒子飞行时间测量,该超级模块可支持高达320通道的高精度时间测量能力,数据率高达6 Gbit·s~(-1)。为实现超级模块探测器的性能评估,提出一种基于千兆以太网的分布式数据读出方法,利用片上系统技术实现读出节点的千兆网络传输能力。测试结果表明,针对单条数据传输路径,原型读出模块在全链路情况下,能实现约467 Mbit·s-1的综合数据传输速率。读出方案中事例组装、命令发送、状态显示等功能均运行正常。     

Cluster storage for COMPASS tokamak

The COMPASS tokamak is expected to produce several gigabytes of data per shot in near future. A new storage system is needed to accommodate and access all the data. It should be scalable, fault-tolerant, and parallel. It should not be based on proprietary solutions to maintain independence from hardware and software manufacturers and preferably it should be built on inexpensive commodity hardware. One of the promising distributed parallel fault-tolerant file systems, GlusterFS, was selected for testing. The aim of the work was to make initial tests of a particular small GlusterFS setup to confirm its aptitude for the COMPASS storage system. Aggregated reading throughput from multiple NFS clients was one of the most important figures that were benchmarked, it scaled well with the number of clients, starting just above 60 MiB/s¹ for 1 client and going slightly over 300 MiB/s for 6 clients.     

From distributed to multicore architecture in the RFX-mod real time control system

The real-time control system of RFX has been operating since 2004 providing effective control of the plasma position and of the MagnetoHydroDynamic (MHD) modes. The demand for new and more computing-intensive control algorithms and the need for shorter latency pushed the system to its limits and, thus, a complete re-design was carried out in 2012. The new system adopts radically different solutions in hardware, operating system and software management. The VME PowerPC CPUs communicating over Ethernet have been now replaced by a single multicore server. VxWorks, previously used in the VME CPUs has now been replaced by Linux, which can be currently considered a real-time system provided an accurate tuning of the Linux scheduler and interrupt configuration.The previous framework for control and communication has been replaced by MARTe, a modern framework for real-time control gaining interest in the fusion community. The usage of MARTe allowed a rapid development of the control system and, in particular, its intrinsic simulation ability gave us the possibility of carrying out most debugging in simulation, without affecting machine operation. As a result the whole system has been finally commissioned in RFX in only two weeks.     

FPGA-based embedded Linux technology in fusion: The MAST microwave imaging system

A cutting-edge standalone data acquisition system has been developed using Field Programmable Gate Arrays (FPGAs). It has 16 ADC channels operating at 250 MSPS, at 14-bit resolution acquiring continuously at 8 GB/s for 0.5 s. The system uses the Virtex 6 FPGA running embedded Linux on the MicroBlaze^TM soft processor. We propose the development of a standard FPGA architecture, based on a methodology which has enabled us to develop this system using commercial-off-the-shelf (COTS) components. This architecture can easily be modified for a variety of applications, both high and low performance at a competitive cost in terms of hardware, engineering and development.     

Test system of the front-end readout for an application-specific integrated circuit for the water Cherenkov detector array at the large high-altitude air shower observatory

The water Cherenkov detector array (WCDA) is an important part of the large high-altitude air shower observatory (LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit (ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range [1-4000 photoelectrons (P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30％root mean square (RMS) at 1 P.E.and 3％ RMS at 4000 P.E.,which are beyond the application requirements.     

高密度塑料闪烁体探测器的数据获取系统设计

由中国科学院近代物理研究所承担的塑料闪烁体探测器研究项目,其目标是开展空间粒子探测、重构入射电子轨迹、区分电子和光子、鉴别重离子。为配合该探测器测试工作,设计了一套完备的数据获取电路(DAQ)与上位机软件。DAQ接收4块前端电子学(FEE)板的数据,可完成360路电子学通道的数据读出;接收上位机的控制命令并分发给各FEE;接收探测器的击中信息并产生触发信号;接收FEE的遥测数据并传给上位机。该DAQ与上位机通过USB总线和RS232总线实现实时通信。上位机软件基于LabWindows/CVI软件平台开发,实现对FEE电子学系统的控制、数据读取与保存,以及FEE系统运行状态参数信息的实时显示。该数据获取系统电路结构紧凑、功能完善,上位机软件具有良好的人机交互界面。经现场实际运行,DAQ与上位机软件满足设计要求,目前已成功应用于塑料闪烁体探测器读出电子学测试系统。