Design and commissioning of a high magnetic field muon spin relaxation spectrometer at the ISIS pulsed neutron and muon source

The high magnetic field (HiFi) muon instrument at the ISIS pulsed neutron and muon source is a state-of-the-art spectrometer designed to provide applied magnetic fields up to 5 T for muon studies of condensed matter and molecular systems. The spectrometer is optimised for time-differential muon spin relaxation studies at a pulsed muon source. We describe the challenges involved in its design and construction, detailing, in particular, the magnet and detector performance. Commissioning experiments have been conducted and the results are presented to demonstrate the scientific capabilities of the new instrument.     

A controllable voltage divider for Hamamatsu R11410-20 photomultipliers for use in the RED 100 emission detector

A control circuit for the operation of Hamamatsu R11410-20 photomultiplier tubes (PMTs), which is intended for use in the RED 100 liquid-xenon emission detector, was developed. To prevent the photocathode degradation due to intense flashes that are associated with signals from high-energy cosmic-ray muons, the circuit forms a voltage pulse that is fed to the PMT photocathode and “blocks” the interelectrode gap between the photocathode and the first dynode. Thus, electron current through this gap is stopped for some time, which suffices for the complete collection of ionization electrons in the RED 100 detector after a cosmic muon passes its sensitive volume. The parameters of the circuit are selected such that the PMT relaxation time after the termination of a blocking pulse, which is determined by the transient processes in the divider, is ～200 μs for a divider with a total resistance of 20 MΩ. This is acceptable for the intended application of the RED 100 detector in an experiment on the search for coherent neutrino scattering off xenon nuclei.     

A Plane Parallel Chamber Used as a Stopped Muon Detector for the Active Target of the FAMILON Project

The performance characteristics of a plane parallel chamber were investigated on beams of slow muons and positrons, as well as on an electron beam from a ¹⁰⁶Ru β source. The chamber was filled with CO₂ or a gas mixture of Ar (30%) + CO₂(70%) at atmospheric pressure. The amplitude spectra of charged particles and the efficiency of their detection were measured. The muon and positron momenta were ∼27 MeV/c. It was shown that the muon detection efficiency of the plane parallel chamber with a 1-mm gas gap and CO₂ (100%) used as a working gas was as high as 99%, while that of the chamber with a 0.4-mm gas gap and a working gas mixture of Ar(30%) + CO₂(70%) was 88%. This result, along with the detector's high response speed, allows the plane parallel chamber to be used as an active target being developed for a future experiment (FAMILON) on searching for neutrinoless muon decay with the release of a scalar Goldstone's boson (μ → eα). __________ Translated from Pribory i Tekhnika Eksperimenta, No. 5, 2005, pp. 29–35. Original Russian Text Copyright ? 2005 by Vorobyev, Gordeev, Zhdanov, Elkin, Ivochkin, Komarov, Kosianenko, Scheglov, Scherbakov.     

基于SOC-FPSLIC的无人机舵机控制系统

介绍了无人驾驶飞机系统级集成电路舵机的操控原理,阐述了用单片现场可编程的系统级集成电路实现的PWM信号控制舵机系统的结构.利用FPSLIC中集成的、基于双端口,SRAM的AT40K FPGA和高性能的嵌入式RISC AVR内核,实现高分辨率的PWM的发送和接收,从而方便地完成了手/自动的切换.通过串口实现了上位机的控制和双向通讯.     

Robust Optimal Estimates of the Parameters of Muon Track Segments in Cathode Strip Chambers for CMS Experiments

Cathode strip chambers are designed for the muon system of the compact muon solenoid under construction at CERN. These chambers must ensure a high accuracy (100 m) of measurements of muon coordinates under heavy background conditions, when 20% of measured muon coordinates are contaminated by a secondary electromagnetic accompaniment and it is often impossible to separate overlapping hits. As a result of this contamination, the distribution of measurement errors differs substantially from a normal (Gaussian) distribution. In these cases, the traditional least squares method is inapplicable. For this reason, a robust (stable against noise) iteration procedure is proposed for fitting track segments in cathode strip chambers. The optimal weight function is derived in an explicit form with allowance for actual contamination introduced by the electromagnetic accompaniment. A comparative analysis is carried out for simulated and experimental data from the chamber prototype. The results conclusively indicate that the robust approach must be applied to fit tracks in cathode strip chambers when data are heavily contaminated.     

基于SA4828的三相SPWM变频电源设计

介绍了以8051为控制器,结合专用的SPWM集成电路SA4828的三相SPWM变频电源的设计。系统主电路采用AC-DC-AC结构,控制电路由8051单片机最小系统和SA4828三相SPWM产生器及少量的扩展外围芯片构成,实现了变频电源的全数字化控制。     

Eddy current measurement of the thickness of top Cu film of the multilayer interconnects in the integrated circuit (IC) manufacturing process

This paper proposes a new eddy current method, named equivalent unit method (EUM), for the thickness measurement of the top copper film of multilayer interconnects in the chemical mechanical polishing (CMP) process, which is an important step in the integrated circuit (IC) manufacturing. The influence of the underneath circuit layers on the eddy current is modeled and treated as an equivalent film thickness. By subtracting this equivalent film component, the accuracy of the thickness measurement of the top copper layer with an eddy current sensor is improved and the absolute error is 3 nm for sampler measurement.     

一种新型仪器用液晶显示控制器芯片的设计

针对液晶显示控制器SED1335的局限提出一种新的仪器用液晶控制器芯片的设计.该显示控制器内置双显示缓冲设计,显示缓冲采用双层映射,显著提高了显示数据的更新率,增加了显示数据的更新量.新型液晶控制器芯片逻辑用VHDL语言设计,编译形成IP核后,配置下载到低功耗FPGA芯片XC3S400中.这种液晶控制器芯片应用在手持数字存储示波器的显示模块中解决了液晶显示内容闪烁和波形更新率低的问题.     

An integrated circuit for silicon photomultipliers tubes

A two-channel integrated circuit for processing current pulses of silicon photomultiplier is based on an АБМК-1.3 analog basic array. Each channel of the integrated circuit contains a transresistance amplifier with a maximal conversion coefficient of about 5 mV/μA, regulated in a ?70 dB range, and a discriminator with a threshold changeable within ±500 mV. The circuit designs of separate stages of the integrated circuit and experimental characteristics are given.     

Estimation of the muon range with low efficiency hodoscopic counters

The influence of the efficiency of muon detection by hodoscopic scintillation counters on the precision of the muon range reconstruction in a detector is analyzed. The precision and systematic bias of a range estimate do not depend on the counters efficiency starting, approximately, from 60%. Article prepared for publishing as a preprint of IHEP.     

基于声发射技术的水轮机裂纹检测系统研究

研究了利用声发射技术实时检测水轮机叶片的裂纹的检测系统。重点介绍了检测系统软、硬件设计中的关键问题,以硬件描述语言(VHDL)设计出FPGA芯片来实时接收声发射信号的特征参数,来实现对水轮机叶片进行实时动态的裂纹检测。     

集成电路芯片管脚尺寸自动检测的研究与实现

集成电路芯片管脚尺寸是否合格,是芯片自动化安装的关键,本文应用机器视觉和机械自动化技术,研制自动检测设备,实现集成电路芯片管脚尺寸检测自动化。实验测试表明,该设备具有较高的检测精度和检测速度,检测结果满足要求。     

KC05可控硅移相触发器在实际运用中的改进

KCO05集成电路是可控硅触发电路中的一种。本文针对在实际使用中遇到了一些问题,从KC05的工作原理入手,分析产生问题的原因,通过增加外围线路改进KC05的性能,解决产生的问题,不影响整个触发电路的正常工作,满足设备正常使用的要求,使KC05集成电路得到了较好的使用。     

Integrated circuit ac mutual inductance bridge for magnetic susceptibility measurements

A versatile ac mutual inductance bridge is described which uses integrated circuit operational amplifiers (op-amps) for the measurement of magnetic susceptibilities of ferro-, ferri-, and para-magnetic samples. The circuit employs op-amps both for balancing the bridge and for detecting the differential signal from the sample coil. The response of the circuit is linear over a wide range of sample susceptibilities, and is calibrated directly in absolute units (emu) using a multiturn digital potentiometer. The sensitivity of the instrument for weak paramagnetic samples (1 g) is +/-3x10(-7) emu.     

常用双积分型A/D转换器自动量程转换接口电路

设计一种简单、实用的接口电路，它与常用双积分型A／D转换器配合，可实现自动量程转换功能，扩展这类芯片的测量范围。提高其测量精度。该接口电路具有体积小、成本低、结构简单、调试容易和工作可靠的特点，可以和不同型号的双积分型A／D转换器联接。     

磁致伸缩与磁弹一体化传感器的研制

为开发具有缺陷检测与应力测量双功能的单体传感器,设计出一种包括静态偏置磁路和内、外层感应线圈的一体化传感器结构,可工作于磁致伸缩与磁弹传感器两种模式。结合磁致伸缩与磁弹基本理论,以能量转换效率和应力测量灵敏度为指标,采用有限元仿真法对一体化传感器的偏置磁场进行优化选取。一体化传感器的试验测试结果表明,传感器工作于磁致伸缩传感器模式时,可在直径6.3 mm钢杆中激励产生L(0,1)模态超声导波并有效检测出宽度和深度均为1 mm的槽型缺陷,增加外层感应线圈的驱动直流可对静态偏置磁场强度进行补偿以使接收的缺陷回波信号幅值增加,提高传感器的缺陷检测能力;工作于磁弹传感器模式时,随激励信号幅值增大,传感器的应力测量灵敏度和测量结果线性度均有提高,其中测量结果线性拟合确定系数最高达0.992 4,表明一体化传感器可用于高精度应力测量。     

高速同步数据采集卡设计

提出了一种数据采集卡的设计方案，应用maxim的A／D芯片MAX125实现了8通道高速同步采集。预处理电路、A／D转换和FIFO缓存集成在同一块电路板上，组成一个功能比较完善的模块，可方便地应用于旋转机械的状态监测和故障诊断。     

纯气动复合油雾喷射润滑集成箱开发与实现

针对商用微量润滑装置无法满足战场环境修理工作要求的问题,设计开发了基于纯气体驱动的复合油雾喷射(Combined Mist-jet, CMJ)润滑集成箱。为获得稳定的微小流量发生量,采用气动频率发生器、脉冲式微量泵等构建的供油回路和基于固定节流孔的节流特性的供水回路,实现微小润滑介质的稳定发生、喷射用量的快速调节和精确显示,并通过微小流量标定试验提高喷射参数精度。该集成箱开发与实现为CMJ技术在飞机钛合金结构修理中的应用奠定了基础。     

一种准正弦波逆变电源的设计

采用高频多级逆变方案设计的一款准正弦逆变电源.此电源以12V直流电输入,经过高频逆变整流环节(DC-DC)和PWM逆变环节(DC-AC),在输出终端得到高质量的准正弦交流电.并对遇到的电磁干扰问题进行分析和排除.由于采用集成逻辑芯片和高频变压器,使得电源体积小,成本低,转换率高.     

集成电路的再生供电与新型地址选通电路

根据CMOS数字集成电路中的基本反向器在基本逻辑状态之下的静态工作电流IDD=0的原理,在输入端,用峰值检波法从时钟脉冲电压形VCP中检出的再生电压V′DD,来顶替常规电源电压VDD,完成向CMOS数字集成电路供电的物理任务。为了使再生供电在工程设计中发挥重要作用。本文介绍了在二总线式多路（N选1）操作系统中,用再生供电而产生的新型地址选通电路,从而有力支持了新型二总线式看动巡回检测系统的设计概念。