最新刊期
      卷 0 ， 期 0 ， 2020
      • LU Jie ZHOU Qiaogen WANG Hongfei
        Vol. 33, Issue 8, (2010)
        摘要：The in-vacuum undulator(IVU-25) with hybrid magnet structure in SSRF(Shanghai Synchrotron Radiation Facility) is the first one developed in China.Major parameters of IVU-25 are:minimum operation gap,7 mm;peak field,0.94 T;period length,25 mm;period number,80,and total length,2 m.The field integral errors,caused by unavoidable remanence divergence of the magnets,position errors of magnets and poles,etc.,would badly affect the beam orbit in the storage ring,hence the need of corrections of the integrated multipoles using the magic fingers technique.In this paper,we present the integrated multipoles correction methods by reducing the normal and skew first field integral errors based on the simulated-annealing algorithm.The results show that the final values of the integrated multipoles are all better than the required ones.  
        关键词：In-vacuum undulator;Integrated multipoles;Simulated-annealing algorithm;First field integral errors   
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        发布时间：2021-03-05
      • WANG Xiaolong DONG Lan LI Bo MEN Lingling LUO Tao
        Vol. 33, Issue 8, (2010)
        摘要：BEPCII storage rings are built in the existing tunnel of BEPC.This needs disassembling the old accelerator,rebuilding the floor,and installing new water tubes,cables and equipment.In order to improve working efficiency,we extracted the installation and alignment work of the eighty-four standard cells,which constituted the main part of the storage rings,as a pre-alignment task.In this paper,we present a general report on the pre-alignment of the BEPCII storage rings.Detail descriptions are given to the magnet fiducialization method,fiducialization accuracy analysis,equipment installation and adjustment method,the nominal coordinate calculation,and the survey apparatus and the survey accuracy of the primary equipments in the cell.The BEPCII project has been checked and accepted in July 2009.  
        关键词：BEPCII;Pre-alignment;Magnet fiducialization;Error analysis   
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        发布时间：2021-03-05
      • ZHANG Rui1,2 ZHAO Yubin1 FU Zechuan1,2 LIU Jianfei1 1
        Vol. 33, Issue 8, (2010)
        摘要：In this paper,an algorithm with the function of automatic interlock and protection for 2-phase stepper motor control is described.The algorithm is used in the frequency tuning loop of superconductivity RF cavity.The design mainly uses FPGA to constitute the pulse distributor and ascends frequency step by step to make the stepper motor have a smooth transition from low frequency startup station to the stable working state.Also,it has the function of automatic interlocking and protection to prevent the stepper motor from going beyond the limit,by setting additive interlocking signals.Test results show that by optimizing and setting different startup frequency and different ascending frequency speed,the stepper motor works stably in the superconductivity RF cavity of SSRF.  
        关键词：Tuning loop;Stepper motor;FPGA;Ascending frequency   
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        发布时间：2021-03-05
      • GAO Yi1,2 QIU Aici2 LV Min1 YANG Hailiang2 ZHANG Zhong2 ZHANG Pengfei2 1
        Vol. 33, Issue 8, (2010)
        摘要：The UNIPIC code is used to simulate working process of a rod-pinch diode.The influences of anode plasmas and diode structural parameters on electron pinching are investigated.The electron beams don’t pinch to the rod tip at 1-2 MV without the ion effect.When the ions emitted from the anode surface reach a current of certain value,further increase of the ion current does not have a significant influence on the diode total current and the current density at the rod tip.With all the three surfaces of the cathode emitting electrons,the pinching quality of the electron beam emitted from the upstream surface is the best of all surfaces.Increasing the cathode length does not have an obvious effect in accelerating the process to achieve strong pinching.Influence of the distance from the anode tip to the cathode surface is analyzed,too.The differences between numerical simulations and experimental results are explained.  
        关键词：Rod-pinch diode;Pinching characteristics;Electron beam;Ion current;Plasma   
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        发布时间：2021-03-05
      • ZHANG Yu1,2 LUO Peng1,2 YAO Zeen1,2 YANG Qiaoyun1 LIU Yang1 1
        Vol. 33, Issue 8, (2010)
        摘要：A beam-shaping-assembly(BSA) of D-T neutron source for the fast neutron therapy was presented.The shielding effects of the BSA were evaluated by MCNP simulation and the calculation of the absorbed dose in water.The neutron energy spectrum and the gamma energy spectrum from the BSA beam at SSD=100 cm were simulated using MCNP code.The gamma contamination level in the BSA beam was analyzed by comparing the neutron dose and the gamma dose.The simulation of the BSA neutron beam transportation in a water phantom was carried out.The absorbed doses in the water phantom were calculated.Dose distribution along the axis,dose mapping of various depths and iso-dose contour in the water phantom were presented.  
        关键词：Beam-shaping-assembly;D-T neutron source;Fast neutron therapy;Source-skin-distance;Absorbed dose   
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        发布时间：2021-03-05
      • LIU Weixin XU Daojin WU Qinzhi
        Vol. 33, Issue 8, (2010)
        摘要：Irradiation test of GaAlAs heterojunction infrared emitting diode OP224 and NPN-silicon phototransistor OP604 were performed by using 60Co γ-rays.The cumulative effect of oxide-trap charge and interface-trap charge under 60Co γ-rays irradiation were analyzed.The results showed that as the irradiation dose increased,the maximum forward current and the infrared light intensity of GaAlAs heterojunction infrared emitting diode OP224 gradually decreased;the dark current of NPN-silicon phototransistor OP604 gradually increased,and the photocurrent decreased.  
        关键词：Optoelectrical device;Ionizing irradiation effect;Oxide-trap charge;Interface-trap charge   
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        发布时间：2021-03-05
      • HE Jiaheng JIANG Lin ZHONG Wenbin MA Zongping WANG Jing LI Xingliang JIAN Yuan
        Vol. 33, Issue 8, (2010)
        摘要：By fixing 125I onto a silver wire and sealing it into titanium capsules,a radioactive seed source can be made for brachytherapy of intraocular and brain tumors,or as permanent implants for prostate cancer.In this paper,aimed at optimizing procedures to prepare the 125I seeds,131I was used as a substitution of 125I to study the iodine adsorption onto silver wires coated with palladium.Effects of the carrier concentration,adsorption time,temperature and palladium-coating of the silver wires on the iodine adsorption were investigated.With the optimized procedures of iodine adsorption on the Pd-coated silver wires,the adsorbing efficiency can reach 90%.  
        关键词：131I;Brachytherapy;Seed;Adsorption;Silver wire coated with palladium   
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        发布时间：2021-03-05
      • ZHANG Guopeng LAN Xiaoli CHEN Quan CAO Wei HE Yong ZHANG Yongxue
        Vol. 33, Issue 8, (2010)
        摘要：A recombinant adenovirus Ad5-sr39tk-IRES-VEGF165(Ad5-SIV) was constructed in our lab,using mutant simplex herpes viral thymidine kinase reporter gene(HSV1-sr39tk) as a report gene,and human vascular endothelial growth factor 165(VEGF165) as a therapeutic gene.A replication-defective adenovirus carrying the enhanced green fluorescent protein gene(Ad5-EGFP) was used as a control.MSCs were infected with Ad5-SIV at different multiplicity of infection(MOI = 0,10,25,50,75 and 100).The expression of HSV1-sr39tk and VEGF165 was detected by immunofluorescence,and the secretion of VEGF was detected by enzyme-linked immunosorbent assay(ELISA).The cellular uptake of 131I-FIAU was performed to detect the expression of HSV1-sr39tk.The immunofluorescence showed HSV1-sr39tk and VEGF165 protein could express successfully at Ad5-SIV-infected MSCs.The cellular uptake of 131I-FIAU increased with the virus titer(P<0.05).The time dependent uptake showed uptake rates increased rapidly from 30 min to 150 min,with a plateau after 150 min.ELISA results showed VEGF165 protein secretion increased with the titer(P<0.05).The VEGF165 protein secretion correlated highly with the uptake rate of 131I-FIAU(P<0.05).In conclusion,HSV1-sr39tk and VEGF165 could express successfully after MSCs were infected with Ad5-SIV.The expression of therapy gene correlated significantly with the reporter gene.This provides a theoretical basis for in vitro nuclear reporter gene imaging with this system.  
        关键词：Vascular endothelial growth factor;Mesenchymal stem cells;Report gene;Gene therapy;HSV1-sr39tk   
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        发布时间：2021-03-05
      • WEN Fuhua DENG Huaifu TANG Ganghua YI Chang WU Kening
        Vol. 33, Issue 8, (2010)
        摘要：A fully automated synthesis of 18F-flurorthymidine(18F-FLT) was performed on PET-MF-2V-IT-I system.18F-FLT was obtained via two-step reactions,including nucleophilic fluorination of 3-N-t-butoxycarbonyl-1-[5’-O-(4,4’-di-methoxytriphenylmethyl)-2’-deoxy-3’-O-(4-nitrobenzenesulfonyl)-β-D-threopentofuranosy]thymine with fluoride,and subsequent hydrolysis of the protecting group with HCl in the same reaction vessel and purification with three Sep-Paks.18F-FLT PET/CT images were performed on mice models bearing hepatocellular carcinoma.Fully automated synthesis of 18F-FLT was completed within the total synthesis time of about 35 min.The uncorrected radiochemical yield was between 12% and 15%,the radiochemical purity was over 95%.The quality control indexes of 18F-FLT injection met the requirements of radiopharmaceuticals quality.18F-FLT PEC/CT imaging showed high uptake in the tumors.This method provides simple and rapid synthesis of 18F-FLT with short radiosynthesis time and a high radiochemical yield for clinical need.  
        关键词：18F-FLT;Sep-Pak purification;Automated synthesis   
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        发布时间：2021-03-05
      • YIN Chunyan AN Qi ZHOU Jiawen DU Zhongwei LIU Shubin
        Vol. 33, Issue 8, (2010)
        摘要：This paper describes two clock modules in the time-of-flight readout systems,which are applied in the Cold Target Recoil Ion Momentum Spectrometer(COLTRIMS) system and the Cooler Storage Ring(CSRm) at Institute of Modern Physics,Chinese Academy of Sciences.The two clock modules are designed on 3U PXI module and 6U PXI module.With high precision crystal oscillators and clock distribution,these two modules offer clock signal to the TOF readout electronics modules with low jitter less than 11 ps(RMS) and 12 ps(RMS).  
        关键词：Cycle-to-cycle jitter;Skew;RMS;LVDS;Clock system   
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        发布时间：2021-03-05
      • YANG Litao LI Dongcang YANG Lei MENG Xiangting YANG Yang
        Vol. 33, Issue 8, (2010)
        摘要：Based on application requirements,an χ-γ dosimeter has been developed in our laboratory.The new method of voltage-to-frequency conversion is adopted in the design,and this enables long-distance transmission of analog signals in the form of frequency,with improved ability of interference resistance and dosimetry accuracy.Combining FPGA with SOPC technology,with embed equal precision measurement module and MC8051 IP core,data acquisition,computation and display of the χ-γ dosimeter are realized,with improved performance in terms of measurement speed,precision and system flexibility.Principles of the circuit modules and design methodology are given in detail in this paper.Test results proved that the design is of advantages.  
        关键词：χ-γ Dosimeter;FPGA;MC8051 IP core;V/F;Equal precision measurement   
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        发布时间：2021-03-05
      • LIU Meng QI Yujin ZHAO Cuilan ZHANG Xuezhu
        Vol. 33, Issue 8, (2010)
        摘要：This work is aimed at developing a novel simplified readout circuit for 2×2 H8500 multi-anode PSPMT array.The readout scheme is based on two-stage resistive networks with truncated center of gravity(TCOG) positioning method to optimize the detector performance.Test results showed that the readout circuit,which reduces the readout channels from 256 to 4,could well resolve the 1.2 mm crystal elements of the NaI(Tl) crystal array,with maximized effective field-of-view(FOV) of the detector,covering the entire active area of the detector.However,the optical coupling measures in the gap regions between the PSPMTs are necessary,so as to improve image distortion in the gap regions.The results indicate that our design is effective and can be adopted for high-resolution gamma camera with even larger FOV.  
        关键词：Positioning readout electronics;Multi-anode position-sensitive photomultiplier tubes;High resolution gamma camera   
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        发布时间：2021-03-05
      • WU Wensheng XIAO Lizhi
        Vol. 33, Issue 8, (2010)
        摘要：In this paper,the MCNP code is used to calculate responses to detector counting rate and formation sensitivity in oil-well logging with different opening shapes and angles of the γ-ray source aperture and detector collimator.The results show that the opening shape and angle of the source aperture affect the measurement precision far more than the opening shape and angle of the detector collimator,and the influences are greater than that of the formation sensitivity.A logging system that is equipped with a γ-ray source having a cuniform aperture of 45° opening angle,and a window aperture of 0°opening angle for a long-spacing detector or a short-spacing detector,and 5°-15° opening angle for a middle-spacing detector,will improve the measurement precision.  
        关键词：High-resolution density logging;Collimation aperture;Opening angle;Measurement precision   
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        发布时间：2021-03-05
      • SHEN Tianjian LIANG Daihua CAI Jianhua DAI Zhimin XIA Huihao WANG Jianhua SUN Sen YU Guojun WANG Xiao WANG Dongxing LIU Xin
        Vol. 33, Issue 8, (2010)
        摘要：Radioisotope battery,as a new type of power source,was developed in 1960s.It is advantageous in terms of long working life,high reliability,flexibility to rugged environment,maintenance free,and high capacity rate,hence its unique applications in space,isolated terrestrial or ocean spots,deep waters,and medicine.In this paper,we analysz the primary performances and classification of radioisotope thermoelectric generator,as well as characteristic,basic principle,and structure of radioisotope thermoelectric generator(RTG),which is the most popular in application of radioisotope battery in space,undersea,terrestrial and medicine.A prospect for development and application of radioisotope battery in the 21st century is given,too.  
        关键词：Radioisotope battery;Thermoelectric generator;Thermo source;Radiation damage   
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        发布时间：2021-03-05
      • HOU Jingwei LUO Yangming CHEN Xiaojun
        Vol. 33, Issue 8, (2010)
        摘要：Several powder preparation methods,fabrication processes and tritium release performance of candidate lithium ceramic breeder materials are reviewed in this paper.The influencing factors of tritium release performance are discussed,and the fabrication processes and tritium release performance of candidate lithium ceramic breeder materials in different countries are compared.Finally,the development of internal study of lithium ceramics is prospected.  
        关键词：Lithium ceramics;Fabrication;Releasing tritium   
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        发布时间：2021-03-05
      • LI Piyi1 HUANG Pinwen1 FU Zaiwei1 XU Bin1 HUANG Aizhong2 HU Pengcheng2 QI Ming1 1
        Vol. 33, Issue 8, (2010)
        摘要：Linear alkyl benzene(LAB) has many advantages of appreciable light yield,relatively long light attenuation length and environment friendly,etc.It is selected as the LS solvent in the Daya Bay Reactor Neutrino Experiment.To make sure that LAB can meet the experimental requirements on light attenuation length in the 350-450 nm wavelength rang,we developed an improved system to measure,in a faster and more accurate way,light attenuation length of the LAB liquid samples.LAB samples before and after purification by filtration with β-Al2O3 and silica gel powders were measured,and composition analyses of the LAB samples were performed.In the experiments we found the chemical impurities that reduced the light attenuation length of the LAB product,and based on the findings the producer optimized the production process to reduce the impurity concentration.The LAB product is qualified for its application in the Daya Bay Reactor Neutrino Experiment.  
        关键词：LAB;Light attenuation length;Impurity composition;Neutrino experiment;Daya Bay   
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        发布时间：2021-03-05
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