基于数字延迟线的高分辨率TDC系统

介绍了采用数字延迟线集成电路芯片和微控制器结合组成的高性价比的时间数字化测量系统。在单通道工作模式下,系统的分辨率达到125ps,动态量程达到7．2μs。该系统被用于浅水环境的机载激光测深系统。     

A low dead time vernier delay line TDC implemented in an actel flash-based FPGA

In this paper,a high precision vernier delay line(VDL) TDC(Time-to-Digital Convertor) in an actel flash-based Field-Programmable-Gate-Arrays A3PE1500 is implemented,achieving a resolution of 16.4-ps root mean square value or 42-ps averaged bin size.The TDC has a dead time of about 200 ns while the dynamic range is 655.36 μs.The double delay lines method is employed to cut the dead time in half to improve its performance.As the bin size of the TDC is dependent on temperature,a compensation algorithm is adopted as temperature drift correction,and the TDC shows satisfying performance in a temperature range from –5℃ to +55℃.     

The clock system for LHAASO WCDA based on reduced White Rabbit

Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchronous clock signals with low jitter to the frontend electronics distributed in the field of 90 000 m~2.The White Rabbit protocol provides an option,which has been approved to achieve sub-ns accuracy and ps jitter in the synchronization of around 1 000 nodes in the order of 10 km.But the hierarchy of the original is too complex for Large High Altitude Air Shower Observatory application.Thus we proposed a reduced scheme based on the White Rabbit protocol.The validation circuit shows that the clock skew due to the fiber length difference can be adjusted to less than 25 ps and the clock jitter is less than 62 ps.     

A QTC-based signal readout for position-sensitive multi-output detectors

A new signal readout method for position-sensitive multi-output detectors,such as those in high-energy spectroscopy measurement and nuclear imaging,was developed by combining the charge division circuit,summing circuit and charge-to-time conversion(QTC) circuit.The 64 outputs of a Hamamatsu H8500 position-sensitive photomultiplier tube were processed,and three digital pulses were generated.The widths of digital pulses were determined using the time-to-digital converter in an field programmable gate array.The energy and position information of incident y-rays is estimated based on the proportionality between the width of digital pulses and input charge created by y-photons.A prototype was built using discrete components and tested,and the energy and position resolutions were improved compared with that obtained with standard ADCs.This method greatly simplifies the front-end electronics and the digital interface.It enables a compact electronics system and an easy integration into an ASIC.     

分布式加速器控制系统时间同步系统的研究

现代大型加速器控制系统大都采用分布式控制系统,系统使用网络交换各类数据.各种控制动作及数据获取要求各智能控制器的CPU基于时间进行调度,因此时标系统在分布式控制系统中具有极其重要的作用.本文论述了采用软件实现的时间同步系统及其所采用的时间协议和原理以及达到的精度等.     

A time and charge measurement board for muon tomography of high-Z materials

In this paper,a versatile time and charge measurement (MQT) board for muon tomography is described in detail.For time measurement,the general-purpose timeto-digital converter (TDC) chip TDC-GP2 is employed,while for charge measurement,digitization plus numerical integration in field programmable gate array is employed.Electronic tests demonstrate that the total 32 channels of two MQT boards have a time resolution of superior than 100 ps,with excellent linearity for time and charge measurement.     

A time and charge measurement board for muon tomography of high-Z materials

In this paper,a versatile time and charge measurement (MQT) board for muon tomography is described in detail.For time measurement,the general-purpose time-to-digital converter (TDC) chip TDC-GP2 is employed,while for charge measurement,digitization plus numerical integration in field programmable gate array is employed.Electronic tests demonstrate that the total 32 channels of two MQT boards have a time resolution of superior than 100 ps,with excellent linearity for time and charge measurement.     

八路时间测量系统

一、引言随着科学技术的发展,需要测时的领域愈来愈多。如在核物理实验中用飞行时间法测中子能谱、甄别带电粒子和测核激发态的时间关联及加速器的性能研究和激光测量等。核爆试验中的参数测量,也需要精确为测时技术。本文所述为八路时间测量系统是为研究强流相对论性电子束加速器的强流二极管放电时,它的各种电压和电流脉冲之间的肘间关联     

An USB-based time measurement system

<正>In this paper,we report the electronics of a timing measurement system of PTB(portable TDC board), which is a handy tool based on USB interface,customized for high precision time measurements without any crates. The time digitization is based on the High Performance TDC Chip(HPTDC).The real-time compensation for HPTDC outputs and the USB master logic are implemented in an ALTERA's Cyclone FPGA.The architecture design and logic design are described in detail.Test of the system showed a time resolution of 13.3 ps.     

A precise time measurement evaluation board for a radiography system of high-Z materials

The time resolution of a radiography system for high-Z materials shall be at least 1 ns, hence the need of a time measurement system with a resolution of about 100 ps. In this paper, a Time Measurement Evaluation Board (TMEB) is developed to meet the need. It is based on the time-to-digital converter of ACAM TDC-GP2. Test results show an overall time resolution of 81 ps in detecting cosmic-rays with a plastic scintillator.     

粒子物理实验中的精密时间间隔测量

本文是关于粒子物理实验中精密时间间隔测量的电子学方法和技术的一个综述.描述了精密时间间隔测量在粒子物理实验中的作用,以及粒子物理实验对时间间隔测量系统的性能指标需求.讨论了时间间隔测量的基本电子学手段,并着重分析了时间内插技术的分类和实现方法.     

BaF2 TIME DIFFERENTIAL PERTURBED ANGULAR DISTRIBUTION SPECTROMETER

A BaF2 time differential perturbed angular distribution spectrometer has been established at the HI-13 tandem accelerator in CIAE.The time resolution of the spectrometer is 195ps and the nonlinearity is less than 2%.The spectrometer works very stably and no time drift is found over a period of experimental runs.This spectrometer has been successfully used in the g-factor measurement of 43Sc(19/2^-,3.1232MeV).     

A digitalizing board for the prototype array of LHAASO WCDA

In this paper,a digitalizing board for readout of PMT signals in the prototype array of WCDA(water Cerenkov detector array)for LHAASO(Large high altitude air shower observatory)is designed.The prototype array is composed of 9 PMTs,including the pulse time and charge measurement from the PMTs,and clock generation and trigger decision.In the digitalizing board,FPGA reconfiguration and data readout via VME bus are implemented.Test results show that the performances meet well with the requirements of readout electronics.It has been installed in Yangbajing and tests with the prototype array and DAQ is ongoing.     

A time-over-threshold technique for PMT signals processing

A novel front-end circuit designed for PMT signals processing considering the solution of ＂Time Walk＂ correction is discussed in this paper. We are trying to apply the TOT （Time over Threshold） technique to our research. Different from traditional ways, where amplitude is measured, time width is measured for slew correction here, which takes the advantage of TDC. Expensive fast ADCs are abandoned and the whole time measurement electronics design becomes more effective and economical. Test boards have been developed and a convenient method is introduced to evaluate our TOT technique. Results have shown that a 10ps slew correction resolution is achieved throughout the amplitude range from -108mV to -2000mV for negative signals of both 5 ns leading and trailing edge with 10 ns 50%-50% pulse width.     

用于多丝漂移室读出的扇入延迟前端电子学

多丝漂移室阵列是设计中的低温高密核物质测量谱仪(Cooling storage ring External-target Experiment,CEE)上的前角带电粒子径迹探测器,信号读出的一种备选方案是采用传统前置放大器和采样幅度数字转换器(Analog-to-Digital Converter,ADC)来完成信号的放大和获取,该方案结构较简单,成本适中,而且可以处理单根丝上的多重点火信号。为了进一步降低电子学的通道数目,而又不显著影响探测器的性能,研制了一种扇入延迟电路,将漂移室上不同的多根丝信号进行扇入延迟处理,合成为一路信号后再输入到采样ADC的单个通道进行波形采样和数字化。实际的测试结果表明,该电路对信号处理产生的信号能量展宽好于1%,时间晃动好于500 ps,对应的位置分辨好于25?m,满足漂移室径迹探测器阵列对位置分辨小于300?m的要求。     

和平堆重水泄漏到二次冷却剂监测系统的改造方案

针对阿尔及利亚比林核研究中心和平堆现有重水泄漏到二次冷却剂监测系统存在的响应时间慢且无法给出重水泄漏量的问题,提出了该系统的改造方案。对于¹⁶N监测系统用MCNP程序对探测器效率进行了模拟计算。该改造方案具有响应速度快,能有效判断重水泄漏量等优点,可提升和平堆的安全性。     

A new TOF system for target recoil-ion momentum spectroscopy at IMP

A high resolution time measurement system with high data transfer rate was designed for the COLTRIMS (Cold Target Recoil-Ion Momentum Spectroscopy) system in Institute of Modern Physics,Chinese Academy of Sciences.It is used to measure the Time of Flight(TOF) with a high resolution for all 20 channels.Based on the PCI Extensions for Instrumentation(PXI) standard,the readout electronics system consists of one Clock-Trigger fan-out module and four TOF modules.Test results show that the system meets the demands of COLTRIMS,with a time resolution of better than 25 ps and a data transfer rate over 20 MB/s.     

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.     

大面积位置灵敏中低能中子谱仪的时间刻度系统的研究

在利用飞行时间法测量中子位置和能量的大面积位置灵敏中子谱仪的研制过程中,提出了利用“绝对时间差”刻度的方法来测量各个电子学的相对时间,系统研究了对光电倍增管时间分辨影响的因素,其中包括光源的种类、光源的发光时间等,并得到使光电倍增管的时间分辨达到最佳60ps的实验条件。     

锑钾铯光阴极制备系统

双碱金属锑化物光阴极在可见光下有高量子效率(QE)、低发射度和强射(RF)频电场,实用真空下寿命较长,产生的高亮度电子束团满足能量回收型直线加速器要求。此类光阴极都含有元素Cs,需在超高真空(UHV)下制备、转移及工作。本文简述了SINAP的双碱金属锑化物光阴极制备装置及各种仪器功能,提出了UHV获得、光阴极基底清洗和K-Cs-Sb光阴极制备过程的方案。通过实验测量了K-Cs-Sb光阴极QE与激光入射功率密度和波长的关系,并构想了基于此制备装置的K-Cs-Sb光阴极的其它性能测试实验。