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A Simulation Study on the Flash X-Ray Spectra Spatial Distribution

Plasma Science and Technology 2013年第11期15卷 1165-1168页

作者：徐修峰李世平曹宏睿肖锐陈楠章林文阴泽杰 State Key Laboratory of Particle Detection and Electronics University of Science andTechnology of China Department of Modern Physics University of Science and Technology of China Institute of Fluid Physics CAEP

Accurate measurement of flash X-ray energy spectra plays an important role in highenergy flash radiography. In this paper, by virtue of Geant4 toolkit, we simulated the generation and transport of X-ray photons resulting from the interaction of a high-energy electron beam with a solid thin target. We obtained the flash X-ray energy spectral distribution in the plane perpendicular to the electron beam incident direction. Our results indicate that the flash X- ray spectrum is almost uniform in the azimuthal direction but is quite different in the radius direction. Specifically, as the radius increases, the incident X-ray dose decreases significantly. Our work paves a theoretical basis for selecting appropriate structures and layout of the spectrometer and facilitates the measurements of flash X-ray energy spectra.

关键词： Geant4 flash X-ray spectra spatial distribution

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Study of 2D interpolating readout for a micro-pattern gaseous detector

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Chinese Physics C 2013年第2期37卷 44-48页

作者：董明义修青磊刘荣光张建欧阳群陈元柏 State Key Laboratory of Particle Detection and Electronics Institute of High Energy Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

The two-dimensional interpolating readout, a new readout concept based on resistive anode structure, was studied for the micro-pattern gaseous detector. Within its high spatial resolution, the interpolating resistive readout structure leads to an enormous reduction of electronic channels compared with pure pixel devices, and also makes the detector more reliable and robust, which is attributed to its resistive anode relieving discharge. A GEM （gaseous electron multiplier） detector with 2D interpolating resistive readout structure was set up and the performance of the detector was studied with ^55Fe 5.9 keV X-ray. The detector worked stably at the gain up to 3.5 × 104 without any discharge. An energy resolution of about 19%, and a spatial resolution of about 219 μm （FWHM） were reached, and good imaging performance was also obtained.

关键词： interpolating readout resistive anode readout structure micro-pattern gaseous detector GEM

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A new method of waveform digitization based on time-interleaved A/D conversion

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Chinese Physics C 2013年第11期37卷 49-57页

作者：叶春逢赵雷封常青刘树彬安琪 State Key Laboratory of Particle Detection & Electronics University of Science and Technology of China Anhui Key Laboratory of Physical Electronics Department of Modern PhysicsUniversity of Science and Technology of China 705 Research Division of Electronic Engineering Institute

Time interleaved analog-to-digital conversion （TIADC） based on parallelism is an effective way to meet the requirement of the ultra-fast waveform digitizer beyond Gsps. Different methods to correct the mismatch errors among different analog-to-digital conversion channels have been developed previously. To overcome the speed limi- tation in hardware design and to implement the mismatch correction algorithm in real time, this paper proposes a fully parallel correction algorithm. A 12-bit l-Gsps waveform digitizer with ENOB around 10.5 bit from 5 MHz to 200 MHz is implemented based on the real-time correction algorithm.

关键词： waveform digitizer time-interleaved analog-to-digital conversion time-skew error digital correctionalgorithms

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A fast improved fat tree encoder for wave union TDC in an FPGA

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Chinese Physics C 2013年第10期37卷 56-62页

作者：沈奇赵雷刘树彬廖胜凯祁宾祥胡雪野彭承志安琪 State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Department of Modern Physics University of Science and Technology of China Hefei National Laboratory for Physical Sciences at Microscale

Up to now, the wave union method can achieve the best timing performance in FPGA-based TDC designs. However, it should be guaranteed in such a structure that the non-thermometer code to binary code （NTH2B） encoding process should be finished within just one system clock cycle. So the implementation of the NTH2B encoder is quite challenging considering the high speed requirement. Besides, the high resolution wave union TDC also demands that the encoder convert an ultra-wide input code to a binary code. We present a fast improved fat tree encoder （IFTE） to fulfill such requirements, in which bubble error suppression is also integrated. With this encoder scheme, a wave union TDC with 7.7 ps RMS and 3.8 ps effective bin size was implemented in an FPGA from Xilinx Virtex 5 family. An encoding time of 8.33 ns was achieved for a 276-bit non-thermometer code to a 9-bit binary code conversion. We conducted a series of tests on the oscillating period of the wave union launcher, as well as the overall performance of the TDC; test results indicate that the IFTE works well. In fact, in the implementation of this encoder, no manual routing or special constraints were required; therefore, this IFTE structure could also be further applied in other delay-chain-based FPGA TDCs.

关键词： wave union TDC FPGA binary encoder time interpolation

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Beam test of a one-dimensional position sensitive chamber on synchrotron radiation

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Chinese Physics C 2013年第10期37卷 105-109页

作者：刘梅代洪亮祁辉荣庄保安张建刘荣光朱启明欧阳群陈元柏江晓山王雅洁刘鹏常广才 State Key Laboratory of Particle Detection and Electronics Institute of High Energy Physics Chinese Academy of Sciemces University of Chinese Academy of Sciences CAS Key Laboratory for Biological Efects of Nanomaterials and Nanosafety

A one-dimensional single-wire chamber was developed to provide high position resolution for powder diffraction experiments with synchrotron radiation. A diffraction test using the sample of SiO2 has been accomplished at 1W2B laboratory of Beijing Synchrotron Radiation Source. The data of the beam test were analyzed and some diffraction angles were obtained. The experimental results were in good agreement with standard data from ICDD powder diffraction file. The precision of diffraction angles was 1% to 4.7%. Most of the relative errors between measured values of diffraction angles and existing data were less than 1%. As for the detector, the best position resolution in the test was 138 p.m （a value） with an X-ray tube. Finally, discussions of the results were given. The major factor that affected the precision of measurement was deviation from the flat structure of the detector. The effect was analyzed and the conclusion was reached that it would be the optimal measurement scheme when the distance between the powder sample and detector was from 400 mm to 600 mm.

关键词： gaseous detector synchrotron radiation powder X-ray diffraction ICDD-pdf

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Simulation and calibration of the response function of multi-sphere neutron spectrometer

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Nuclear Science and Techniques 2013年第6期24卷 105-108页

作者： JIANG Xiaofei CHEN Chao CAO Jing CAO Hongrui LI Shiping SONG Xianying YIN Zejie State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Department of Modern Physics University of Science and Technology of China Southwestern Institute of Physics

In order to realize the on-line real-time measurement of neutron spectrum of ITER fusion,this paper presents a multi-sphere spectrometer system which consists of eight thermal neutron detectors,namely SP9 3He proportional counter,embedded in eight different diameter polyethylene *** response function of eight polyethylene spheres of multi-sphere neutron spectrometer was calculated after the simulation of the neutron transport processes in multi-sphere spectrometer by adopting software *** peak of the response function is in the low energy region for smaller diameter polyethylene *** the polyethylene sphere diameter increased,the peak of the response function moves to the high energy *** experimental calibration adopts 241Am-Be neutron *** relative error between normalized data of experiment 4πsolid angle counts and normalized data of simulated detection efficiency of 4in to 8in polyethylene sphere is from 1.152%to 12.222%.The experimental results verify the response function of the *** these results provide a theoretical and experimental basis for solving the on-line real-time neutron spectrum of ITER fusion.

关键词：响应函数中子谱仪仿真在线实时测量正比计数管数据归一化校准 Geant4

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Dynamic linear calibration method for a wide range neutron flux monitor system in ITER

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Nuclear Science and Techniques 2013年第4期24卷 57-60页

作者： LI Shiping XU Xiufeng CAO Hongrui YANG Qingwei YIN Zejie State Key Laboratory of Particle Detection and Electronics University of Science andTechnology of China Department of Modern Physics University of Science and Technology of China Southwestern Institute of Physics

As a key part of the diagnosis system in the International Thermonuclear Experimental Reactor(ITER),the neutron flux monitor(NFM),which measures the neutron intensity of the fusion reaction,is a Counting-Campbelling system with a large dynamic counting range.A dynamic linear calibration method is proposed in this paper to solve the problem of cross-over between the different counting and Campbelling channels,and improve the accuracy of the cross-calibration for long-term *** experimental results show that the NFM system with the dynamic linear calibration system can obtain the neutron flux of the fusion reactor in real time and realize the seamless measurement area connection between the two channels.

关键词：动态非线性监测系统中子通量校正方法 ITER 国际热核实验反应堆聚变反应堆组成部分

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Attenuation length measurements of a liquid scintillator with LabVIEW and reliability evaluation of the device

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Chinese Physics C 2013年第7期37卷 47-51页

作者：高龙俞伯祥丁雅韵周莉温良剑谢宇广王志刚蔡啸孙希磊方建薛镇章爱武吕绮雯孙丽君葛永帅刘颖彪牛顺利胡涛曹俊吕军光 State Key Laboratory of Particle Detection and Electronics (Institute of High Energy Physics Chinese Academy of Sciences) Graduate University of Chinese Academy of Sciences Shanxi University

An attenuation length measurement device was constructed using an oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested in a variety of ways. The test results show that the set-up has a good stability and high precision （sigma/mean reached 0.4 percent）. Besides, the accuracy of the measurement system will decrease by about 17 percent if a filter is used. The attenuation length of a gadolinium-loaded liquid scintillator （Gd-LS） was measured as 15.1±0.35 m where Gd-LS was heavily used in the Daya Bay Neutrino Experiment. In addition, one method based on the Beer-Lambert law was proposed to investigate the reliability of the measurement device, the R-square reached 0.9995. Moreover, three purification methods for Linear Alkyl Benzene （LAB） production were compared in the experiment.

关键词： attenuation length liquid scintillator （LS） Beer-Lambert law LabVIEW

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Research of Power-on detection in POE Topology

Research of Power-on Detection in POE Topology

引用

The 2014 International Conference on Materials Science and Engineering Technology(MSET 2014)

作者： Zhao HAN Jie WU Qing-yun DONG Ke REN Juan DONG Modern Physics Department of University of Science and Technology of China State Key Laboratory of Particle Detection and Electronics

ISBN: (纸本)9783038351023

POE（Power Over Ethernet） realizes the multiplexing of power transmission and data transmissionTo ensure the safety of power supply process, PD（Powered Device）, when connected, must be detected by PSE（Power Sourcing Equipment）This article describes the methods of PD detection especially in the symmetrical architectureThe symmetrical architecture means that PSE and PD are connected and either of them can play a role of PSE or PDIn our new approach, signature resistance is replaced by signature capacitanceThe connection of PD changes the capacitance load of the system, so the step response can be used to detect the change of capacitance loadThis method requires zero static current, which reduces the system power consumptionThe theoretical analysis, PSPICE simulation and the experimental results are given.

关键词： POE connection detect symmetrical architecture signature resistance step response

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A GEANT4 simulation study of BESⅢ endcap TOF upgrade

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Chinese Physics C 2013年第9期37卷 30-35页

作者：张辉邵明李澄陈宏芳衡月昆孙勇杰唐泽波姬长胜陈天翔杨帅 Department of Modern Physics University of Science and Technology of China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Institute of High Energy Physics Chinese Academy of Sciences

A GEANT4-based Monte-Carlo （MC） model is developed to study the performance of endcap time- of-flight （ETOF） at BESIII. It＇s found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF＇s readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber （MRPC） with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate （per channel）, from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESIII.

关键词： BESIII multi-hit ETOF Upgrade MRPC time resolution

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