最新刊期
      卷 0 ， 期 0 ， 2020
      • LI Changxing GU Ming CHEN Zhihao YUAN Qibing FAN Xuerong
        Issue 2, (2007)
        摘要：The high-power pulse modulator of LINAC will produce strong electromagnetic interference when it runs. To meet the EMC requirements for high performance LINAC operation, the pulse modulator should be shielded. This paper presents the research on electromagnetic radiation interference produced by LINAC modulators, the analysis of the possible leaky passes, the shielding efficiency and the measurement of the modulator’s EMI. The results show that the EMC design of the modulator cabinet can restrain electromagnetic interference.  
        关键词：LINAC;Pulse modulators;Shielding effectiveness;Electromagnetic interference (EMI)   
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        发布时间：2021-03-12
      • HUANG Guoqing1,2 YE Kairong1 1
        Issue 2, (2007)
        摘要：With the improvement of technology, many new accelerator bunch length measurement methods are in-vented in recent years, such as streak camera, Martin-Puplett interferometer, electro-optic detection, frequency do-main method. Each method has its respective advantages, disadvantages and applied domains. A review on various bunch-length measurement methods is given in this paper. At present many large accelerators in the world universally use streak camera to measure bunch length. For beam bunches of ultrashort duration, optic technology and frequency domain method are adopted, and the resolution of some methods can reach to the order of femtosecond.  
        关键词：Bunch length measurements;Streak camera;Martin-Puplett interferometer;Frequency domain   
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        发布时间：2021-03-12
      • LI Rui LU Songlin HU Zhimin LI Deming
        Issue 2, (2007)
        摘要：The principle and realization of fly back quasi-resonant switching mode power supply are described in this paper. The general design consideration for some key circuits is presented, the cause of power consumption on MOSFET on-off is anatomized and the means of reducing it are put forward. Then a 24V1A high efficiency isolating quasi-resonant power supply with the SMPS chip IRIS4015 produced by IR Company is realized, and relevant circuit diagrams and operating waveforms are given.  
        关键词：Efficiency;Quasi-resonance;Electro-magnetic interference(EMI)   
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        发布时间：2021-03-12
      • LUO Yuyu XIAO Tiqiao CHEN Min LIU Lixiang ZENG Danhua DU Guohao XU Hongjie
        Issue 2, (2007)
        摘要：Factors that affect the image quality of in-line outline X-ray imaging are investigated with 4W1A light source in Beijing Synchrotron Radiation Facility (BSRF). The experimental results show that better edge-enhancing effect can be achieved in vertical direction of the synchrotron radiation beam. Higher contrast can be obtained for larger size samples. The image contrast increases with the sample-detector distance (SDD), and there is an optimal distance. The influence of detector resolution is also investigated, the better contrast and higher edge-sharpness can be achieved for the detectors with higher spatial resolution.  
        关键词：In-line out line X-ray imaging;Image quality;Synchrotron radiation   
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        发布时间：2021-03-12
      • ZHANG Guobin WU Wenqing SHI Junyan ZHOU Hongjun QI Zeming FU Yibing Huo Tonglin
        Issue 2, (2007)
        摘要：This paper describes the design and commissioning of the vacuum-ultraviolet circular dichroism facility at NSRL. At 0.5nm resolution, the normal incident beamline can provide ultraviolet and vacuum-ultraviolet radiation at fluxes higher than 1012ph/s, which is converted into the plane polarized light using a polarizer and subsequently converted into the circularly polarized light using a photoelastic modulator with a switching frequency of 50 kHz. Example spectra of (1s)-(+)-10-camphorsulphonic acid (CSA) and myoglobin are given. Normally, the measurable wavelength range is 178—300 nm. But the short wavelength limit can be shifted to 140nm by using special solvent and short light-pass sample cell.  
        关键词：Circular dichroism;Protein secondary structure;Vacuum-ultraviolet spectroscopy   
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        发布时间：2021-03-12
      • AN Shuangli1,2 JIANG Dikui1 GUO Panlin1 1
        Issue 2, (2007)
        摘要：Based on the RS485 general bus structure and the operation LabVIEW software environment, the vacuum control system for the Shanghai Electron Beam Ion Trap (EBIT) Facility was developed. The commissioning results show that this system has achieved all the design requirements. The realization methods for the tele-operation of vacuum devices, the data acquisition and the vacuum interlock are described in this paper. The system has been successfully applied to the Shanghai EBIT Facility.  
        关键词：Electron Beam Ion Trap(EBIT);Vacuum control;RS485 general bus;LabVIEW   
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        发布时间：2021-03-12
      • SONG Yufeng1,3 ZHU Zhiyong1 SUN Youmei2 JIN Yunfan2 PAN Qiangyan1 1
        Issue 2, (2007)
        摘要：Single crystalline α-Al2O3 samples were irradiated with 1.157GeV 56Fe ions at room temperature to fluence range from 5×1011 to 6×1012cm-2. The radiation induced defects were investigated by ultraviolet-visible and photoluminescence spectra measurements. Various anion vacancies such as F, F+, F2+, F22+and F2 color centers were induced by the irradiation with the production cross-sections ranging from 40 to 90nm2. The number densities of the defects increase with the increase of fluence and come to saturation at high fluences. However, no distinct changes in their relative amount between these centers were observed. From comparison with theoretical calculations it is realized that the initial production rate of anion single vacancies at room temperature is about half of that produced by nuclear energy loss processes at low temperature.  
        关键词：High energy heavy ion;Single crystal alpha-alumina;Color centers   
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        发布时间：2021-03-12
      • LI Fei1 LI Qinghui1 GAN Fuxi1 ZHANG Bin2 CHENG Huansheng2 SHEN Shifang3 1
        Issue 2, (2007)
        摘要：Proton induced X-ray emission (PIXE) technique is an effective method for the chemical composition analysis of ancient glass samples without destruction. Chemical composition of the ancient glass samples dated from the Warring States Period (770—476 B.C.) to the Six Dynasties Period (220—589 A.D.), which were unearthed in Sichuan area, was quantitatively determined by the PIXE technique. The results show that the glass Bi (disc) and the glass eye beads of the Warring States Period all belong to the PbO-BaO-SiO2 system. According to the composition and shape, we infer that these glass Bi and eye beads were made in China. Whereas, the chemical compositions of the glass ear pendants and beads of the Six Dynasties Period are varied, including K2O-CaO-SiO2, K2O-SiO2 and other glass systems. Based on the obtained results and those from literatures, some questions related to the technical propa-gation of the ancient Chinese glass are discussed.  
        关键词：Proton induced X-ray emission;Ancient glass;Chemical composition analysis   
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        发布时间：2021-03-12
      • ZHENG Liping XU Zijian ZHU Zhiyuan XIA Huihao ZHU Dezhang YU Xiaohan
        Issue 2, (2007)
        摘要：Recently, a new capillary optics focus element, which is composed of many bent-multi-walled nanotubes, can be used to produce the high strength nanometer-X-ray beams. In the world, as new elements of diffraction propagation of X-ray, the single-walled nanotubes (rope) and the fullerites (C60 crystal) have caused great interest in the world. This paper introduces the progress of the above studied field.  
        关键词：Carbon nanotube (rope);Fullerites (C60 crystal);Capillary;Channeling;X-ray propagation   
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        发布时间：2021-03-12
      • CHEN Guoyun
        Issue 2, (2007)
        摘要：The host MgB4O7 and the phosphor MgB4O7:Dy were synthesized under the condition of high temperature by using magnesium carbonate and boric acid. The 2-dimensional (2D) glow curve and 3-dimensional (3D) emission spectra of this TL material were measured by using RGD-3 reader and the 3D TL/OSL automatic spectrometer. From the experiment we can conclude that: 1) the phosphor MgB4O7:Dy has two TL glow peaks at about 220℃ and 380℃; 2) the wavelengths of the TL emission spectra of Dy3+ are 480nm, 575nm and 660nm; 3) the intensity ratio of glow peak at about 220℃ to that at about 380℃ can be raised gradually through high temperature treatment. However, both temperature and wavelength of the glow peaks have no obvious change. By comparing the 3D emission spectra between MgB4O7:Dy and MgSO4:Dy, we have verified that in the TL materials doped with trivalence rare earth ions, temperature of the glow peak is mainly decided by the host and wavelength of the glow peak mainly depends on the transition of energy level of the rare earth ions.  
        关键词：Magnesium tetraborate;Dysprosium;Thermoluminescence   
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        发布时间：2021-03-12
      • WANG Shuang XU Xiankun WANG Shufang ZENG Xianyin
        Issue 2, (2007)
        摘要：The two-phase chloramine-T method was applied in the radioiodine-labeling of polyethylene glycol modification of recombinant human interleukin-6 (PEG-rhIL-6). The iodine incorporation was determined by trichloroacetic acid (TCA) and a γ-ray survey meter. The labeled compound was purified by ultrafiltration. The purity of the labeled PEG-rhIL-6 was determined by TCA. The fragmentation of labeled protein was determined by SDS-PAGE-electrophoresis. The labeling efficiencies under different reaction conditions were compared, and the results demonstrated that the optimal conditions for total volume, pH, dosage of added protein, volume of chloramine-T, reaction time and temperature are 100μL, pH=7.4, 25μg, 15μL (20g/L), 40─50 min and room temperature, respectively.  
        关键词：PEG-rhIL-6;Two-phase chloramine-T method;Reaction condition   
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        发布时间：2021-03-12
      • HU Zhengguo1,2 XU Zhiguo1 XIAO Guoqing1 SUN Zhiyu1 XU Hushan1 ZHANG Xueheng1,2 MAO Ruishi1,2 ZHANG Hongbin1 HUANG Tianheng1,2 FU Fen1,2 TANG Bin1,2 TU Xiaolin1,2 WANG Meng1 XIAO Zhigang1 WANG Jiansong1 LI Qiang1 GUO Zhongyan1 1
        Issue 2, (2007)
        摘要：An ionization chamber (IC) with a sensitive area of 250mm×250 mm was developed for the Institute of Modern Physics (IMP) heavy ion therapy facility. The gap was 10 mm between the anode and the cathode. A good plateau was seen in a large voltage range from 900V to 3000V when the IC was operated at (85.0±0.2) kPa with P10 (10% CH4+90% Ar) as flowing gas. By putting the different thicknesses of polymethyl methacrylate (PMMA) in front of the IC, the Bragg curve for the beam in PMMA was measured by the IC. During the test, the voltage of 2300 V was applied to the anode of the IC. The measured Bragg peak for 75 MeV/u 12C6+ ions in the PMMA was located at 13.73 mm and the FWHM was 0.19mm.  
        关键词：Heavy ions therapy;Ionization chamber;Bragg peak;Positron emission tomography   
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        发布时间：2021-03-12
      • WU Aidong WU Yican
        Issue 2, (2007)
        摘要：Empirical and semi-empirical routine dose calculation algorithms have been commonly selected for the radiation treatment planning system, though they have limited accuracy for dose distribution calculation. The Monte Carlo method can precisely give the above distributions, but its long CPU time affects clinic application. This paper presents a calculation instance. Namely, based on the CT data of a patient’s head and neck, the Monte Carlo code is used to investigate the effect of different voxel sizes on the accuracy of dose distribution calculation and the computing time.  
        关键词：Dose calculation;Voxel size;CT image;Monte Carlo method   
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        发布时间：2021-03-12
      • DING Weimin1 TIAN Jiahe2 YANG Xiaohua3 BAI Jinzhu4 SHEN Li4 ZHANG Jinming2 1
        Issue 2, (2007)
        摘要：To probe the possibility of in vivo tracking stem cells implanted in rabbit spinal cords with radionuclide imaging, 3×106 human neural progenitor cells (hNPC-TERT) were implanted in rabbit spinal cord. D2 receptor expression of the cells before or after transplantation was quantitatively and qualitatively analyzed with radioligand receptors assay and immunofluorescence respectively. At 20 min after injection of 11C-raclopride, rabbits received PET scan or were sacrificed and spinal cords removed and received PET scan. D2 receptor expression of hNPC-TERT cells was proved by immunofluorescence. Radioligand receptors assay showed that hNPC-TERT cell highly expressed D2 receptor (Bmax=8×104) with high affinity to raclopride (Kd=1.518 nmol/L). PET (Positron Emission Tomography) scans on animals showed visible accumulations of radioactivity at hNPC-TERT cell transplantation sites but not at HeLa cell transplantation sites. The ROI analysis showed a statistical difference between the maximal standard uptake value on transplantation sites of the two groups. The result was further proved by the ex vivo PET imaging of spinal cord. The success in displaying the implanted cells in spinal cord provides the feasibility of in vivo tracking of stem cells after transplantation with radionuclide imaging.  
        关键词：Stem cells transplantation;Positron emission tomography;D2 receptor;Tracking   
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        发布时间：2021-03-12
      • ZHAO Youxin
        Issue 2, (2007)
        摘要：In order to research Metal-Oxide-Simiconductor Field Effect Transistor (MOSFET)’s radiation effects, such as the single event upset, single event burnout, single event gate rupture, and single event latch-up, the equipment for specially testing radiation effect of MOSFET is developed. This paper introduces its composition of hardware and software, and the measuring technology. It is successful in the experiments of testing MOSFET’s radiation effect by using 252Cf source, laser equipment of testing radiation effect and HI-13 tandem accelerator. Some testing results accomplished in HI-13 tandem accelerator are reported.  
        关键词：MOSFET;Radiation effect;Laser;252Cf;Testing equipment;Tandem accelerator   
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        发布时间：2021-03-12
      • ZHANG Wende BAI Lixin ZHANG Huige
        Issue 2, (2007)
        摘要：In the radioactive measurements of environmental samples, if a constant measurement accuracy is required, the higher the detection efficiency, the less measurement time and the higher utilization ratio of the spectrometer. For the same sample volume, the shape of cylindric samples may affect the detection efficiency. The detection efficiencies of cylindric samples with the same volume but variable shapes have been simulated with MCNP-4B, and verified by experiments. It is shown that efficiency of the cylindric sample with a size of Φ12m×3cm is the highest, which is about 20% higher than that for general cylindric samples with a size of Φ7.5cm×7.5cm.  
        关键词：Detection efficiency;Monte Carlo simulation method;MCNP   
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        发布时间：2021-03-12
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