The Linux Based Distributed Data Acquisition System for the ISTRA＋ Experiment

The DAQ hardware of the ISTRA experiment consists of the VME system crate that contains two PCI-VME bridges interfacing two PC‘s with VME,external interrupts receiver,the readout controller for dedicated front-end electronics,the read-out controller buffer memory module,the VME-CAMAC interface,and additional control modules,The DAQ computing consist of 6 PC‘s running the Linux operating system and linked into LAN.The first PC serves the external interrupts and acquires the data from front-end electronics,The second one is the slow control computer.The remaining PC‘s host the monitoring and data analysis software.The Linux based DAQ software provides the external interrupts procssing,the data acquisition,recording,and distribution between monitoring and data analysis tasks running at DAQ PC‘s.The monitoring programs are based on two packages for data visualization:home-written on and the ROOT system.My SQl is used as a DAQ database.     

Design and development of the CSNS ion source control system

Now that the CSNS ion source test stand has been stably working for years, an online control system for the CSNS ion source which aims to be more stable and reliable is now under development. F3RP61-2L, a new PLC CPU module running an embedded Linux system, is introduced to the system as an IOC, to function together with the I/O modules of FA-M3 PLC on the PLC-bus. The adoption of the new IOC not only simplifies the architecture of the control system, but also improves the data transmission speed. In this paper, the design and development of the supervisory and control system for the CSNS ion source are described.     

A Multi Purpose DAQ System Developed for the nTOF Commissioning

The neutron Time Of Flight (nTOF) facility at CERN is a high flux spallation neutron source commissioned in Nov 2000 and APr 2001.For the commissioning phases an innovative multipurpose DAQ system was developed and used.This system is capable of handling high data rated(10Mb/s) with the use of the National Instruments PCI-VXI interface board to communicate with the VME crates.The graphical user interface is based on Java^TM and ROOT allowing immediate visualization of the data and providing a flexible way of creating configurations for various experimental setups.     

Dedicated 4πβ(LS)-γ(HPGe) digital coincidence system based on synchronous high-speed multichannel data acquisition

A dedicated 4πβ(LS)-γ(HPGe) digital coincidence system with five acquisition channels has been developed. Three ADC acquisition channels with an acquisition resolution of 8 bits and acquisition rate of 1 GSPS are utilized to collect the signals from three PMTs which are used to detect β decay, and two acquisition channels with an acquisition resolution of 16 bits and acquisition rate of 50 MSPS are utilized to collect the signals from high-purity germanium(HPGe), which is used to detect γ decay. In order to increase the accuracy of the coincidence system, all five acquisition channels are synchronous within 500 ps. The data collected by the five acquisition channels will be transmitted to the host PC through a PCI bus and saved as a file. Off-line software is utilized for the 4πβ(LS)-γ(HPGe) coincidence and data analysis as needed in practical applications. Tests of the system show that system can record pulse signals from 4πβ(LS)-γ(HPGe) synchronously for further coincidence calculation and the highest coincidence rate of the system is 20 K/s, which is sufficient for most applications. Compared with traditional coincidence modules like MAC3, the digital coincidence system has a higher flexibility of coincidence algorithm. In addition, due to the use of ADC, the structure of the coincidence system is simplified. This paper introduces the design of the hardware, the synchronization method and the test results of this system.     

ISSDE: A Monte Carlo implicit simulation code based on Stratonovich SDE approach of Coulomb collision

A Monte Carlo implicit simulation program, Implicit Stratonovich Stochastic Differential Equations(ISSDE), is developed for solving stochastic differential equations(SDEs) that describe plasmas with Coulomb collision. The basic idea of the program is the stochastic equivalence between the Fokker–Planck equation and the Stratonovich SDEs. The splitting method is used to increase the numerical stability of the algorithm for dynamics of charged particles with Coulomb collision. The cases of Lorentzian plasma, Maxwellian plasma and arbitrary distribution function of background plasma have been considered. The adoption of the implicit midpoint method guarantees exactly the energy conservation for the diffusion term and thus improves the numerical stability compared with conventional Runge–Kutta methods. ISSDE is built with C++ and has standard interfaces and extensible modules. The slowing down processes of electron beams in unmagnetized plasma and relaxation process in magnetized plasma are studied using the ISSDE, which shows its correctness and reliability.     

Development of 0.5-V Josephson junction array devices for quantum voltage standards

The design, fabrication, and the characterization of a 0.5-V Josephson junction array device are presented for the quantum voltage standards in the National Institute of Metrology(NIM) of China. The device consists of four junction arrays, each of which has 1200 3-stacked Nb/Nb_xSi_(1-x)/Nb junctions and an on-chip superconducting microwave circuit which is mainly a power divider enabling each Josephson array being loaded with an equal amount of microwave power. A direct current(dc) quantum voltage of about 0.5 V with a ～1-mA current margin of the 1 st quantum voltage step is obtained.To further prove the quality of NIM device, a comparison between the NIM device with the National Institute of Standards and Technology(NIST) programmable Josephson voltage standard(PJVS) system device is conducted. The difference of the reproduced 0.5-V quantum voltage between the two devices is about 0.55 nV, which indicates good agreement between the two devices. With the homemade device, we have realized a precise and applicable 0.5-V applicable-level quantum voltage.     

Quality of Service on Linux for the Atlas TDAQ Event Building Network

Congestion control for packets sent on a network is important for DAQ systems that contain an event builder using switching network technologies.Quality of Service(QoS) is a technique for congestion control.Recent Linux releases provide QoS in the kernel to manage network traffic.We have analyzed the packet-loss and packet distribution for the event builder prototype of the Atlas TDAQ system.We used PC/Linux with Gigabit Ethernet network as the testbed.The result showed that QoS using CBQ and TBF eliminated packet loss on UDP/IP transfer while the UDP/IP transfer in best effort made lots of packet loss.The result also showed that the QoS overhead was small.We concluded that QoS on Linux performed efficiently in TCP/IP and UDP/IP and will have an important role of the Atlas TDAQ system.     

Configuration of an optical waveguide interconnect mesh network based on EOPCB

<正>An optical waveguide interconnect mesh network scheme for parallel multiprocessor systems based on an electro-optical printed circuit board(EOPCB) with multimode polymer waveguide is proposed.The system consists of 2×2 processor element chips interconnected in a mesh network configuration.An additional layer with optical waveguide structure is embedded in a conventional printed circuit board to construct the EOPCB.Vertical cavity surface emitting laser(VCSEL)/positive intrinsic-negative(PIN) arrays are applied as the optical transmitters/receivers.Three 1×12 VCSEL/PIN parallel optical transmitting/receiving modules are used to provide 32 input/output optical channels required by the 2×2 chip-to-chip optical mesh interconnect system.The data rate in each optical channel is 3.125 Gbps and thus 10 Gbps parallel optical interconnect link for each direction of a chip is obtained.The optical signals from a processor element chip can be transmitted to another chip through optical waveguide interconnect embedded in the board.Thus the optical interconnect mesh network for parallel multiprocessor system can be implemented.     

Trigger design for a gamma ray detector of HIRFL-ETF

The Gamma Ray Array Detector (GRAD) is one subsystem of HIRFL-ETF (the External Target Facility (ETF) of the Heavy Ion Research Facility in Lanzhou (HIRFL)). It is capable of measuring the energy of gamma-rays with 1024 CsI scintillators in in-beam nuclear experiments. The GRAD trigger should select the valid events and reject the data from the scintillators which are not hit by the gamma-ray. The GRAD trigger has been developed based on the Field Programmable Gate Array (FPGAs) and PXI interface. It makes prompt trigger decisions to select valid events by processing the hit signals from the 1024 CsI scintillators. According to the physical requirements, the GRAD trigger module supplies 12-bit trigger information for the global trigger system of ETF and supplies a trigger signal for data acquisition (DAQ) system of GRAD. In addition, the GRAD trigger generates trigger data that are packed and transmitted to the host computer via PXI bus to be saved for off-line analysis. The trigger processing is implemented in the front-end electronics of GRAD and one FPGA of the GRAD trigger module. The logic of PXI transmission and reconfiguration is implemented in another FPGA of the GRAD trigger module. During the gamma-ray experiments, the GRAD trigger performs reliably and efficiently. The function of GRAD trigger is capable of satisfying the physical requirements.     

Development of front-end readout electronics for silicon strip detectors

Front-end readout electronics have been developed for silicon strip detectors at our institute. In this system an Application Specific Integrated Circuit (ASIC) ATHED is used to realize multi-channel energy and time measurements. The slow control of ASIC chips is achieved by parallel port and the timing control signals of ASIC chips are implemented with the CPLD. The data acquisition is carried out with a PXI-DAQ card. The software has a user-friendly GUI developed with LabWindows/CVI in the Windows XP operating system. The test results show that the energy resolution is about 1.14% for alpha at 5.48 MeV and the maximum channel crosstalk of the system is 4.60%. The performance of the system is very reliable and is suitable for nuclear physics experiments.     

机载网络数据实时处理系统设计

推进剂补加飞控模拟器是飞控中心用来验证推进补加程序和地面测控方案、训练操作人员的模拟仿真系统,为系统演练构造一个尽量逼真的任务环境。提出了一种用于推进剂在轨补加任务准备的飞控模拟器设计,详细介绍了系统结构和原理, 给出了系统信息流向、软件设计,最后对主要技术难点及解决措施进行了说明,该模拟器具有真实性高、通用性高及灵活性高的特点,可以实现对推进剂在轨补加过程的动态模拟,在我国首次推进剂补加任务准备中得到了充分的应用和验证,取得了较好的效果。     

基于FPGA的FSO准同步数字复接器的实现

为了实现多路信号在同一大气信道中的传输,提出一种适用于自由空间光通信(FSO)系统的准同步数字复接方案.该方案利用数字复接扩大传输容量,通过加入滤波模块和采用择多判决的方法,提高系统的抗干扰能力.整个系统采用自顶向下模块化的方法进行设计,所有功能模块均用VHDL语言进行描述,并用现场可编程门阵列(FPGA)芯片EP1C3T100C6对整个系统进行硬件实现.以三路准同步数字信号的复接分接为例,给出了软件仿真和硬件实验结果.结果表明系统可以准确、可靠地实现三路准同步信号的复接分接.     

工作气体对MRPC性能影响的研究

多气隙电阻板室(MRPC)飞行时间探测器模型从2003年2月开始在美国布鲁克海文国家实验室(BNL)的AGS束流上顺利完成了为期10周的测试(共28个MRPC模块168路读出,其中12个模块即72个读出道配置了读出电子学).实验表明工作气体的选择对MRPC的工作性能有很大影响.测量了几种不同成分的混合气体(A)90%C₂H₂F₄+5%iso-C₄H₁₀+5%SF6、(B)95.3%C₂H₂F₄+47%iso-C₄H₁₀及(C)100%C₂H₂F₄下MRPC探测效率和时间分辨等特性的变化,并给出了相应条件下的流光信号几率     

发动机气门尺寸计算机视觉检测软件系统的设计

介绍了一种基于Visual C#的发动机气门尺寸计算机视觉检测软件系统。根据发动机气门尺寸计算机视觉检测的功能需求,采用Visual C#开发平台,设计开发了检测软件整体结构。通过调用运动控制卡中的运动函数库,在闭环控制状态下实现对伺服电机的控制。设计了控制线阵CCD进行图像采集程序和检测结果输出控制程序。实现了对各软件功能模块的调用与管理,并已实际应用于汽车发动机气门尺寸自动光电检测系统中,取得了良好的应用效果。     

ER-200D-SRC型EPR谱仪微机系统的改造

详细叙述了德国BRUKER分析仪器公司ER-200D-SRC型EPR谱仪与IBM PC/386微机联机的软硬件系统,该系统综合了仪器的自动磁场扫描控制,数据采集累加和数据分析处理及数据绘图、打印等各项功能。其硬件由IBMPC/386微机及二大接口模块组成。一块为商品化的12位A/D、D/A接口卡,另一块为自行设计的以INTEL-8255可编程通用接口电路为主体的数字量输入输出控制接口卡,可分别独立地插入PC机的扩展槽中,其软件采用C语言编写,具有菜单式、结构化、模块化、汉字工作提示、实验数据实时屏幕绘图、实验参数实时显示等特点,用户界面良好,该系统恢复并提高了原谱仪的整体性能,具有一定的推广价值。     

Integrated,reliable laser system for an 87Rb cold atom fountain clock

We designed, assembled, and tested a reliable laser system for ⁸⁷Rb cold atom fountain clocks. The laser system is divided into four modules according to function, which are convenient for installing, adjusting, maintaining, and replacing of the modules. In each functional module, all optical components are fixed on a baseplate with glue and screws, ensuring the system's structural stability. Mechanical stability was verified in a 6.11g RMS randomvibration test, where the change in output power before and after vibration was less than 5%. Thermal stability was realized by optimizing of the structure and appropriate selection of component materials of the modules through thermal simulation. In the laser splitting and output module, the change in laser power was less than 20% for each fiber in thermal cycles from 5 ℃ to 43 ℃. Finally, the functionality of the laser system was verified for a rubidium fountain clock.     

Readout electronics testing of the CMS Tracker modules with LT setup

The tracking part of the CMS detector will be built with ∼16000 silicon detector modules, and kept at −10°C for the ten years of the operation of the LHC. All the model materials need to be verified of having a good performance at this low temperature, before their installation into the CMS Tracker. In order to track performance quality, assurance tests are done with two different systems. Of the two setups used, the LT system module is the one that is used to identify whether the performance of readout electronics and leakage current flowing on the silicon sensors is affected by low temperature. In this paper a detailed layout of the CMS TOB modules and their front-end hybrids are presented. In addition, the LT testing results of the 190 TOB modules that were produced and tested in 2004 by the FNAL-CMS group are given. The text was submitted by the author in English.     

边界扫描测试在数字电路自动测试系统中的研究与应用[BT)]

边界扫描测试是当前数字电路模块故障隔离的主要手段,但测试能力受到模块可测试性设计限制,其它方面作用也被忽略。文中对数字电路自动测试系统设计提出了边界扫描测试应用技术,包括系统自检测试,模块功能测试和模块故障隔离。在系统自检测试中应用边界扫描,提高了设备自检故障隔离精度;而对于模块功能测试,边界扫描测试技术提供了一种新的选择;在故障隔离中扩展和延伸应用边界扫描技术,突破了模块自身测试性的限制,提高了边界扫描测试的故障覆盖率和故障隔离精度。通过实际测试验证表明,该设计方法稳定可靠,同时提升了测试系统自身和模块的测试能力和隔离精度。     

Parameter optimization of solar modules based on lens concentrators of radiation and cascade photovoltaic converters

Two main issues governing the design of a solar concentrator module with triple-junction nano-heterostructure photovoltaic converters (PVCs) are considered: the effective concentration of radiation using Fresnel lenses and effective heat removal from PVCs. By theoretically and experimentally simulating these processes, the design parameters of module’ s elements are determined. A test batch of full-size modules has been fabricated. Each module consists of a front panel of small-size Fresnel lenses (a total of 144 lenses arranged as a 12 × 12 array) and the corresponding number of multilayer InGaP/GaAs/Ge PVCs. The PVCs are mounted on heat-distributing plates and are also integrated into a panel. The efficiency of the concentrator module with a 0.5 × 0.5-m entrance aperture measured under outdoor conditions is 24.3%, which is more than twice as high as the efficiency of standard (concentrator-free) silicon modules. In smaller test modules, the efficiency corrected for the PVC standard temperature (25° C) reaches 26.5%.     

Design and electrical characteristics of a modular plasma torch

A modular system for constructing an atmospheric pressure plasma source is presented and studied. The design and construction of the plasma torch module by modifying and reassembling the structural components of two different models of spark plugs are first described. Each module can produce a torch plasma of 1 cm radius and 6 cm height and having a peak density exceeding 10¹³ cm^-3. A set of modules, each connected in series with a ballasting capacitor in the circuit, can be operated as an array sharing a common power source to produce a dense and large-volume plasma. The electrical characteristics of the module are studied for the case of a single module and two capacitively coupled modules. The discharge can be maintained, with the aid of ballasting capacitors, in a stable diffuse arc. Furthermore, the coupled discharges in an array of modules are operated with the maximum power efficiency as indicated by a near one power factor seen by the power line