最新刊期
      卷 0 ， 期 0 ， 2020
      • XUE Chaofan WANG Yong WU Yanqing XU Zijian TAI Renzhong
        Vol. 34, Issue 8, (2011)
        摘要：Ionization chamber is often used to calibrate photon energy of the monochromator and evaluate quantitatively the energy resolving power by measuring photoabsorption or photoionization spectra of various gases.However,the effect of gas collision broadening is usually ignored in conventional method,which results in lower energy resolution than the true value.In this paper,the effect of gas pressure is discussed and an analytical method with gas pressure correction is proposed.It can effectively eliminate the effect of gas collision broadening.  
        关键词：Synchrotron radiation;Energy resolution;Ionization chamber;Gas pressure correction   
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        发布时间：2021-03-05
      • ZHOU Jieping TAN Jun XU Pengshou SHENG Liusi PAN Guoqiang
        Vol. 34, Issue 8, (2011)
        摘要：Near edge X-ray absorption fine structure spectroscopy(NEXAFS) and synchrotron radiation photoelectron spectroscopy(SRPES) were employed to investigate the adsorption mechanism of tryptophan(Trp) onto single-walled carbon nanotubes(SWCNTs).The difference of the carbon K-edge NEXAFS spectra between Trp molecules and Trp-adsorbed SWCNTs shows that a significant interaction occurs among the SWCNTs and Trp molecules adsorbed.However,negligible changes in the peak profiles and energy positions of nitrogen K-edge imply that neither of the two nitrogen atoms in Trp molecule is involved in the interface interaction.A change of the shape of the main absorption peak at the oxygen K-edge reveals that O atoms of the C=O or C-O or both are likely involved in the interface interaction.The fact that the peak at about 529 eV at the O K-edge become sharper and stronger demonstrates that the O atom in the C=O participates in the interface interaction,which was confirmed by O1s SRPES spectrum.  
        关键词：Single-walled carbon nanotubes;Tryptophan;Interface interaction;NEXAFS;SRPES   
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        发布时间：2021-03-05
      • ZHANG Qingxian GE Liangquan GU Yi ZENG Guoqiang LIN Yanchang WANG Guangxi
        Vol. 34, Issue 8, (2011)
        摘要：NaI(Tl) detectors,having a good detection efficiency,are used to detect gamma rays in field surveys.But the poor energy resolution hinders their applications,despite the use of traditional methods to resolve the overlapped gamma-ray peaks.In this paper,the maximum likelihood(ML) solution is used to resolve the spectrum.The ML method,which is capable of decomposing the peaks in energy difference of over 2/3 FWHM,is applied to scale NaI(Tl) the spectrometer.The result shows that the net area is in proportion to the content of isotopes and the precision of scaling is better than the stripping ration method.  
        关键词：Maximum likelihood method;NaI(Tl) detector;Resolving spectrum;Stripping ration   
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        发布时间：2021-03-05
      • SU Ji1 WANG Huaxiang1 XUE Qian1 HAO Kuihong2 1
        Vol. 34, Issue 8, (2011)
        摘要：A low-energy multiphase γ-CT system model was designed by using the Geant4 simulation software toolkits.According to scattering photon rate,image correlation coefficient and relative image error,designs of the collimators,the number of radiation sources and the number of detectors were optimized.The γ-CT system has a scattering photon rate of better than 5%,high measurement sensitivity and high signal-to-noise ratio,as confirmed by measurements with different flow patterns(core flow,bubbly flow,annular flow and stratified flow).  
        关键词：Gamma-ray;GEANT4;Multiphase flow;Image reconstruction   
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        发布时间：2021-03-05
      • CHENG Kun ZHAO Minghua GUQiang LIN Guoqiang
        Vol. 34, Issue 8, (2011)
        摘要：In this paper,a simple high-voltage electron gun operated at 350 kV is designed,with the least average beam current of 10 mA,and an emittance of no more than 20 μm-rad.Combined Superfish and General Particle Tracer(GPT) are used to simulate the parameters.  
          
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        发布时间：2021-03-05
      • ZHANG Jiangyun1 HUANG Ning1 TANG Lili 2 LIU Yanfang2 ZHANG Guanghua3 1
        Vol. 34, Issue 8, (2011)
        摘要：The dosimetric properties of a gamma-radiation field can be measured by a dose-rate meter or by a gamma-spectrometer with spectrum-dose conversion.One of the spectrum dose conversion methods is to evaluate the radiation dosedirectly from integrating the observed pulse height spectrum weighted by a G(E) function,instead of making spectrum analysis.In this paper,energy spectra of 11 single energy point sources in 0.1–2.5 MeV are simulated by using Monte Carlo software MCNP5 for NaI(Tl) detectors of Φ 75 mm×75 mm,Φ 50 mm×50 mm and Φ 25 mm×25 mm.The energy spectra are used as standard spectrum to calculate the G(E) value,so as to calculate corresponding doses.Comparing the results with theoretical value,the error is less than 1.5%.Finally,the G(E)-based γ dose rate of radiation field agreed well(within 5%) with the dose rate measured by a dosimeter.  
        关键词：γ full spectrum method;MCNP5;G(E) function   
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        发布时间：2021-03-05
      • LIU Yuelong1 QU Guopu1 ZHAO Yue1 LIU Yueyong2 1
        Vol. 34, Issue 8, (2011)
        摘要：This work was aimed at developing a software for radioactive-source-free calibration of LaBr3(Ce) scintillator to detect the γ-rays from gaseous β+ annihilation in a Marinelli beaker.Based on a Monte Carlo model,a feasible method of numerical calculation was developed to calculate the detector efficiency.The results of the numerical calculation agreed well with the data obtained using the MCNP code.This is of the first steps in our research efforts to calibrate LaBr3(Ce) detector efficiency without radioactive sources.  
        关键词：Numerical calculation;LaBr3(Ce) detector;MB beaker;Efficiency   
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        发布时间：2021-03-05
      • SUN Fali1,2 XIA Xiaobin1 ZHANG Zhihong1,2 Lü Xiaowen1,2 1
        Vol. 34, Issue 8, (2011)
        摘要：In this study,Monte Carlo simulation was performed on a Poshwich detector for measuring radioactivity of β particles in radioactive aerosol.The detector model consists of plastic scintillator and BGO crystal,with aluminum foil in the front to stop α particles and considerations to prevent the γ-rays from affecting the β-ray detection.Code Geant4 was used to calculate the energy deposition in the scintillators and their attenuation coefficient,The size and the structure of the detector ware determined based on the simulation.  
          
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        发布时间：2021-03-05
      • WU Maojia1 HE Bin1 OUYANG Xiaoping2 CHEN Liang2 WANG Dong1 ZUO Guangxia1 1
        Vol. 34, Issue 8, (2011)
        摘要：For improving detection efficiency of 0.02–0.25 MeV neutrons by boron-loaded plastic scintillation detector(BLPSD),surrounding the scintillator with polyethylene moderator is feasible way.In this paper,the detection efficiency of a BLPSD with front and side PE moderators of different thicknesses is simulated by MCNP code,and the thickness-dependant detection efficiencies are given.The results show the side PE moderator of 80 mm thick increases the BLPSD detection efficiency of 0.02–0.25 MeV neutrons by a factor of about,but the front PE moderator decreases the detection efficiency.Finally,the design structure of BLPSD surrounded by side PE moderator can realize high detection efficiency for a wide spectrum is proved.  
        关键词：Boron-loaded plastic scintillator;MCNP;Detection efficiency;Moderator   
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        发布时间：2021-03-05
      • ZHOU Cheng WANG Fengying ZHU Xiaoxiang
        Vol. 34, Issue 8, (2011)
        摘要：In this paper,the source-free efficiency calibration method is used to verify the HPGe γ-spectrometer.A 60Co standard point source and three body sources were used in the efficiency calibration with the LabSOCS code.The results show that this method can be used as a supplement method to efficiency calculation and laboratory quality control.Meanwhile,the impact factors of source-free efficiency fitting were analyzed.  
        关键词：Source-free efficiency calibration;HPGe γ spectrometer;Scale;Standard volume source   
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        发布时间：2021-03-05
      • XIE Wenxiong GONG Jian LI Jiansheng HUANG Po ZENG Liheng
        Vol. 34, Issue 8, (2011)
        摘要：In this paper,we report the experiment based on time correlation coincidence to measure uranium enrichment.With the time tagged by a 252Cf spontaneous fission neutron source,measurements were done on uranium metal castings of similar quantity(about 8 kg) and shape(hemispherical shell) but in different enrichments.The characteristic of time correlation coincidence counts between the source and detector were obtained.By analyzing these counts,many groups of special parameters can be obtained to characterize the fission signal.These parameters are sensitive to changes in uranium enrichment,with a sensitivity coefficient of 19.4%.Therefore,uranium metal castings of different enrichments can be identified for the purpose of nuclear warhead verification.  
        关键词：Time correlation coincidence method;Uranium;Enrichment;Verification   
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        发布时间：2021-03-05
      • ZHANG Wei1 SHI YueJiang1 WANG Qiuping2 SHEN Yongcai1 DU Xuewei2 LI Yingying1 FU Jia1 WANG Fudi1 Lü Bo1 XU Jingcui1 HE Xiaoye2 1
        Vol. 34, Issue 8, (2011)
        摘要：A high resolution EUV spectrometer has been installed on EAST tokamak for plasma diagnostic.The system employs a concave varied line spacing groove holographic grating(1 200 grooves/mm at grating center) as dispersion elements,covering wavelength range of 50–500 ,with resolution of about 0.16  at 186.6 ,and monitoring up half of EAST plasma(0–450 mm).The time resolution is 20 ms and the spatial resolution achieves 50 mm.During the discharge with Ar injection,good spectra were obtained.Compared to the discharge without pumping Ar at all,the Ar spectrum was clearly observed.The time behavior of the C IV(312.42 ) intensity was analyzed.  
        关键词：Tokamak;Impurity;EUV spectrometer   
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        发布时间：2021-03-05
      • AN Min HE Bin ZUO Guangxia WANG Andong WU Maojia
        Vol. 34, Issue 8, (2011)
        摘要：In this paper,based on the density functional(B3LYP) method with Relativistic Effective Core Potential(RECP),the structures of UD3 and UT3 molecules are optimized.The results show that the ground state of UD3 and UT3 molecules are 4A1,with a disassociation energy of 9.112 eV,which belongs to the C3V symmetry.The standard formed thermodynamic functions for UD3 and UT3 molecules are worked out by thermodynamic method.The calculation results show that UD3 and UT3 molecules have thermodynamic stability under 798.15 K and 698.15 K,respectively.  
        关键词：Uranium deuteride;Uranium tritide;Molecule structure;Thermodynamic stability   
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        发布时间：2021-03-05
      • ZHANG Xi1 LIU Jinhui2 1
        Vol. 34, Issue 8, (2011)
        摘要：60Co γ-ray container inspection system(TC-Scan),developed at Institute of Nuclear and New Energy Technology(INET) of Tsinghua University,is installed at the customs for air-cargo or mega-object inspection against smuggling and prohibited objects.With the development of computer science and technology,3D visualization technology applied to CT inspection system becomes a hotspot.In this paper,a volume rendering visualization system is designed and implemented for TC-Scan,based on ray-casting algorithm.In order to keep flexibility and compatibility for further development,the 3D rendering subsystem is independent from acquisition and reconstruction subsystems.Final rendering results demonstrate legible and distinct 3D vision for container inspection,which improves inspection validity.  
        关键词：60Co;Container inspection;3D visualization;Volume rendering   
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        发布时间：2021-03-05
      • DING Yu1,2 QI Yujin1 ZHANG Xuezhu1 ZHAO Cuilan1 1
        Vol. 34, Issue 8, (2011)
        摘要：In this paper,we report the development of a high-performance image processing platform,which is based on CPU-GPU heterogeneous cluster.Currently,it consists of a Dell Precision T7500 and HP XW8600 workstations with parallel programming and runtime environment,using the message-passing interface(MPI) and CUDA(Compute Unified Device Architecture).We succeeded in developing parallel image processing techniques for 3D image reconstruction of X-ray micro-CT imaging.The results show that a GPU provides a computing efficiency of about 194 times faster than a single CPU,and the CPU-GPU clusters provides a computing efficiency of about 46 times faster than the CPU clusters.These meet the requirements of rapid 3D image reconstruction and real time image display.In conclusion,the use of CPU-GPU heterogeneous cluster is an effective way to build high-performance image processing platform.  
        关键词：CPU-GPU heterogeneous cluster;Parallel computing;3D image reconstruction   
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        发布时间：2021-03-05
      • HUANG Yu1,2 LIU Wei2 XIAO Detao1 WU Shengwei2 ZENG Youshi2 QIAN Yuan2 LI Yulan2 1
        Vol. 34, Issue 8, (2011)
        摘要：A molten salt reactor(MSR) produces large amount of tritium.While the tritium may discharge from the stack,some of the tritium may permeate through the reactor vessel,causing serious effects on mechanical properties and lifetime of the structure materials,and large impact to the environment.In this paper,we give a review on the four methods to control and reduce the permeation of tritium in an MSR,such as increasing the concentration of 7Li,adding Li or Be to the fuel salt,etc.The tritium monitoring,which is fundamental and essential in its control,can reflect the operation status of the MSR.The three methods of monitoring tritium,i.e.liquid scintillation,ionization chamber,and proportional gas counting,are discussed,and accurate tritium monitoring can be achieved by combining the ionization chamber and liquid scintillation.  
        关键词：Molten salt reactor;Tritium;Control;Monitoring   
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        发布时间：2021-03-05
      • WANG Kaisong1 XU Yang1 SONG Yuntao2 WANG Zhongwei21
        Vol. 34, Issue 8, (2011)
        摘要：In the International Thermonuclear Experimental Reactor(ITER) project,in-wall shield(IWS) is used to fill the space between the inner and outer shells of the vacuum vessel,so as to provide neutron shield and reduce the toroidal field ripple.In this paper,structural strength analysis of one block of the neutron shield is carried out based on ANSYS,and the method for removing secondary stress is offered by combining QR algorithm and ANSYS.The result is evaluated,and it meets the design requirements.This provides reference for optimizing design of the neutron shield block.  
        关键词：ITER;Vacuum Vessel;Neutron shielding;Structure;Secondary stress;QR   
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        发布时间：2021-03-05
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