最新刊期
      卷 0 ， 期 0 ， 2020
      • WANG Baoliang~1 ZHAO Minghua~1 HOU Mi~2 PEI Shilun~2 ZHANG Meng~1 1
        Vol. 34, Issue 12, (2011)
        摘要：In this paper,the simulation,physical design,optimization,structure and particle dynamics of the 2856 MHz double-feed coupler are described.The HFSS and CST particle studio are used to simulate the 3D double-feed coupler structure.The three-frequency method is applied to the coupler matching.The module PIC(particle in cell) is used to accomplish the particle dynamics simulation.The result is useful for design of double-feed coupler.  
        关键词：HFSS;CST particle studio;Double-feed coupler;Three-frequency method   
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        发布时间：2021-03-05
      • QI Binchuan~
        Vol. 34, Issue 12, (2011)
        摘要：Shanghai Deep Ultraviolet Free Electron Laser(SDUV-FEL) test facility is an integrated multi-purpose test bed for FEL principles.In this paper,we focus on the development of an interlock system for SDUV-FEL vacuum protection.Hardware and software of the system implementations are introduced.A distributed control system composed of a PLC,an embedded computer and consoles based on EPICS toolkit is described in details.The system has been used for cascaded HGHG FEL experiment.Stability and reliability has been demonstrated.  
        关键词：Vacuum interlock system;SDUV-FEL;PLC;EPICS   
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        发布时间：2021-03-05
      • YANG Tongsuo~1 WANG Tuanbu~1 YANG Weiping~2 1
        Vol. 34, Issue 12, (2011)
        摘要：It is feasible to measure solid state nuclear tracks in apatite by using thermal analysis method.In this paper,a-particle nuclear track annealing mechanisms are discussed on the basis of experimental data.The normal distribution of spectral function of potential well may affect the annealing curve shape,and thermal analysis of observed phenomena is given.  
        关键词：Lattice damage;Potential well distribution;Annealing mechanism;Solid state nuclear tracks probe CLC 0572.1   
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        发布时间：2021-03-05
      • QIAO Shuang JING Shiwei
        Vol. 34, Issue 12, (2011)
        摘要：The neutron tubes developed at our lab were remodeled by improving the vacuum to 2×10-6Pa,increasing magnetic field intensity of ion source terminal to 0.33 T,and optimizing thickness（2.2μm） of the target coating based on experiments.In this way,a yield of 109/s can be achieved with theΦ50 mm neutron tube,and working at a yield of5×107/s,the life can be over 4000 h,with a stability of better than 2%.  
        关键词：Neutron tube;Yield;Stability;Vacuum;Coating   
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        发布时间：2021-03-05
      • ZHUO Jun NIU Shengli ZHU Jinhui XIE Honggang HUANG Liuxing
        Vol. 34, Issue 12, (2011)
        摘要：Elastic backscattering probabilities for Fe,Cu,Ag and Au were calculated by Monte Carlo method.The Mott cross-section with Dirac-Hatree-Fock atomic potential was used to describe and calculate the elastic scattering electrons traversing in the solids.A function between assumed values of the electron inelastic mean free path(IMFP) and elastic backscattering probability for normal incidence of the electron beam was given by the Monte Carlo code. With the relation between the elastic backscattering probability and the IMFP in the solid,the IMFPs of Fe,Cu,Ag and Au with electron energy from 100 eV to 2000 eV were determined.And a comparison between the present method and atomic generalized oscillator strength(GOS) model showed that IMFPs calculated by the present method agreed well with those from the GOS model.It is therefore recommended that the M-C simulation be used for determining IMFP when elastic backscattering probability can be correctly measured.  
        关键词：Low-energy electron;Elastic backscattering probability;Inelastic mean free path;Monte Carlo simulation   
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        发布时间：2021-03-05
      • LUO Qi HUShipeng SUN Huibin LIU Guoqin ZHAO Haige
        Vol. 34, Issue 12, (2011)
        摘要：By using multi-gamma ray sources of 152Eu and 133Ba placed 20 cm from the HPGe detector,its detection efficiency was obtained.Combined with the distance recurrence relation,which was derived by single-gamma ray sources of 241Am and 137Cs,the detector efficiency calibration curve at 2 cm could be deduced.Finally,by comparing the experiment results with the simulation results by the MCNP code,the coincidence factor could be determined.  
        关键词：HPGe detector;Efficiency calibration;MCNP;Coincidence factor   
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        发布时间：2021-03-05
      • WANG Dong YANG Gaozhao PENG Taiping
        Vol. 34, Issue 12, (2011)
        摘要：The photon collecting efficiency of cylinder and cone type ST401 plastic scintillators wrapped with film reflector was simulated with the Geant4 code,and measurement of the detector output current were performed with a collimated 60Co 7-ray source.For cylinder scintillator,the simulation and measurements show that aluminum foil improved the photon collection efficiency by a factor of 2.72 and 1.99,respectively,while for cone scintillator the improvement were 4.57 and 2.45,respectively.The reflecting films have better effect for cone scintillators,and an optimized cone shape was obtained.  
        关键词：ST401 scintillator;Photon collecting efficiency;Monte Carlo simulation;Geant4   
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        发布时间：2021-03-05
      • WU Wensheng HE Jingzhi
        Vol. 34, Issue 12, (2011)
        摘要：Some factors should be considered in selecting a crystal scintillator type inγlogging and n-γlogging.In this paper,spectra of 0.662 and 6.13 MeVγ-rays using NaI,BGO and LaBr3 scintillators are simulated with an M-C code,so as to compare theirγ-ray energy deposition spectra and detector responses,and analyze the detector parameter effects on the spectrum.The results show that in the low energy region,the detector length and diameter have greater effect on detection efficiency of BGO than that of NaI and LaBr3,and the diameter effect on the detection efficiency is greater than that of the length.In high energy region,the detector size effect is small,and the crystal diameter affects less than the crystal length.Among the three types of crystal scintillators,BGO has the greatest detection efficiency,and the highest intensity in terms of the full energy peak and backscattering peak in low energy region,and photon peaks and the first-escaping peak in high energy region.  
        关键词：Nuclear logging;Scintillation crystal;Energy deposition spectrum;Detector response;Monte Carlo simulation   
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        发布时间：2021-03-05
      • SONGRuiying~1 YANG Jihua~2 SHI Huidong~1 LVChaofeng~1 SUQingjie~1 SONG Ruiqing~1 1
        Vol. 34, Issue 12, (2011)
        摘要：In this paper,we report the coupling system of RF power,accelerating cavity and beam acceleration of the petal-shaped accelerator developed at Ningbo Superpower High-tech Co.,Ltd.The stability requirement on amplitude-frequency characteristics are derived by considering the beam loading and cavity detuning.The implementation scheme of low level controller based on digital AFC and AVC is proposed.The working process and implementation method of AFC and PID algorithm are described.Test results show that the stability index of cavity voltage is less than 0.8%,and the digital AFC and AVC closed-loop function has been proved by a 24-h test operation of the system.  
        关键词：Petal-shaped irradiation accelerator;Beam loading;Digital AFC;Digital AVC;PID algorithm   
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        发布时间：2021-03-05
      • ZHOU Shuo HU Yating MA Xiaolan LI Hua
        Vol. 34, Issue 12, (2011)
        摘要：Neutron moderation and neutron transport in target-moderator-reflector(TMR) system of China spallation neutron source(CSNS) were simulated by using MCNP code.Neutron energy spectra and angular distributions were calculated using different sets of parameters.The results show that placing the poison in the center of decoupled poisoned hydrogen moderator(DPHM) with a deviation of 5 mm to the downstream window can optimize the design.  
        关键词：CSNS;Neutron moderation;Monte Carlo method   
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        发布时间：2021-03-05
      • DANGYufeng HE Jiaheng JIANG Lin MA Zongping WANG Jing JIAN Yuan
        Vol. 34, Issue 12, (2011)
        摘要：In this work,the self-shielding effect of 125I seed source was investigated.Adopting the direct and indirect methods,the self-shielding coefficients of 125I seed source core,which were prepared under technical conditions of self-established palladium method,were measured.The results show that with certain surface areas of the adsorbing basal materials,the initial activities of adsorbing solution do not affect adsorbing rates of the basal materials,and the self-shielding coefficients of 125I seed source core are about 64%,and the addition of NaS2O3 makes the self-shielding effect coefficients decline greatly.  
        关键词：Brachytherapy seed;Self-shielding   
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        发布时间：2021-03-05
      • ZHANG Wenhui LIN Jian XIE Zhi XU Xuee
        Vol. 34, Issue 12, (2011)
        摘要：Bamboo samples collected in mountain areas of Fujian province were mechanically pulverized into saw dust.This breaks the covalent bonds of bamboo molecules and free radicals are formed.ESR characterization of the bamboo saw dust samples of 20,200 and 500 mesh showed that the relative intensity of the 500 mesh saw dust was the highest,and that of the 20 mesh was the lowest（g=2.0033）.After 60Coγ-ray irradiation,the intensity of free radicals increased sharply.At>100 kGy,the free radicals tended to be saturated at about 40 times of the free radicals produced mechanically.The intensity of free radicals increased exponentially with the dose below 100 kGy,and decay coefficients of the free radicals in the three samples were different.  
        关键词：Bamboo;Free radical;γ-ray   
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        发布时间：2021-03-05
      • Vol. 34, Issue 12, (2011)
        摘要：Pork samples were soaked in antioxidant solution(1 g/L),vacuum-packaged,irradiated at 3 kGy by Co y-rays or 10 MeV electron beams,and refrigerated at 0℃-4℃for 30 d.On Day 1,10,20,25 and 30 post irradiation, total bacterial counts,peroxide values,thiobarbituric acid reactive substances,volatiles and off-odor of the irradiated pork samples were analyzed.The total bacterial counts were<10 cfu/g on Day 30.The peroxide values,thiobarbituric acid reactive substances and volatiles contents of pork irradiated by theγ-rays were higher than pork irradiated by electron beams.Pork irradiated byγ-rays combined with antioxidant treatment was most close to the control in odor, with a similarity of 89.68%.The results showed that E-beam irradiation reduced lipid oxidation and volatiles contents,γ-ray irradiation helped to reduce off-odor,and addition of antioxidant could effectively reduce lipid oxidation and off-odor.  
        关键词：Irradiation;Lipid oxidation;Off-odor;Antioxidant;Pork   
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        发布时间：2021-03-05
      • LIANG Xiang WANG Hongliang TANG Ganghua HUANG Tingting WU Kening
        Vol. 34, Issue 12, (2011)
        摘要：Semi-automated synthesis of(S-[l8F]-fluoromethyl)-L-cysteine(l8F-MCYS) was achieved with the modified commercial synthesizer and PET imaging of aseptic inflammatory mice was performed with l8F-MCYS.l8FCH2Br as l8F-fluoromethylation agent was prepared by l8F-fluorination of dibromomethane. l8F-MCYS was obtained from the reaction of l8FCH2Br with L-cysteine dissolved in dimethyl sulfoxide（DMSO） and purification on the solid-phase extraction cartridges.Without correction,the radiochemical yield of l8F-MCYS was （10.0±3.0）%(n=4,based on l8F ),the radiochemical purity of l8F-MCYS was more than 95%,and the total synthesis time was about 35 min.It was found that l8F-MCYS had high uptake in the inflammatory tissues,but l8F-MCYS was unstable.Thus,l8F-MCYS is not a potential PET tracer for amino acid imaging and it is necessary for us to develop a novel stable l8F-labelled cysteine.  
        关键词：(S-[18F]-methyl)-L-cysteine;Inflammation;PET imaging;18F-FDG   
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        发布时间：2021-03-05
      • WANG Dongyan~1 PAN Lvde~2 ZHANG Bin~1 SU Chenghai~1 WU Yiwei~1 SANG Shibiao~1 ZHANG Wei~1 JIANG Jiwei~1 DENG Shengming~1 XU Fengpo~1 1
        Vol. 34, Issue 12, (2011)
        摘要：The work was aimed at studying clinical significance of increased l8F-FDG（fluorodeoxyglucose） uptake in sternum.Forty-six patients with increased l8F-FDG uptake in sternum in PET/CT examination were analyzed retrospectively,grouped according to the disease types.SUVmax（maximal standardized uptake value） values of focus were measured,and CT features and the distribution of increased l8F-FDG uptake were compared.Fifty normal volunteers were used as controls.T-test was used to compare the SUVmax among patients groups,and between the controls and patients groups.Between malignant sternal metastasis group and hematopathy group,Chi square test was carried out to check the distribution of increased l8F-FDG uptake and sternum bone changes,and to see whether the vertebrae or ribs were involved.The final diagnoses of all the patients were confirmed by pathology.The SUVmax value of patients groups was significantly higher than the controls（p<0.001）.Malignant sternal metastasis group and hematopathy group was each twenty-three cases,account for 50%（23/46）,there was no significant difference between the SUVmax value of the two groups（p=0.181）.Increased l8F-FDG uptake in sternum of malignant sternal metastasis group mainly showed focal,whereas the hematopathy group showed more diffused（χ2=10.52,p=0.001）. With the sternal bone changes or not,there was significant difference between the two groups（χ2=7.10,p=0.008）. These both groups often involved vertebrae or ribs（χ2=1.10,p=0.295）.Increased l8F-FDG uptake in sternum should be highly alert to malignant tumor metastasis or hematopathy.The distribution of increased l8F-FDG uptake and bone changes in sternum,which had a great reference value to identify the two kinds of diseases,but this could not identify whether the vertebrae or ribs was affected.  
        关键词：Sternum;Deoxyglucose;Malignancy;Metastasis;Hematopathy   
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        发布时间：2021-03-05
      • XIE Jun HUANG Yanhua ZHAO Liping LI Zhaoyang DU Kai TONG Weichao YUAN Guanghui YI Taimin ZHENG Fengcheng XING Pifeng
        Vol. 34, Issue 12, (2011)
        摘要：The technology of single point diamond turning(SPDT) is capable of achieving sample surface roughness of less than 10 nm and shape accuracy of less than 100 nm,which are crucial parameters for ultra precision machining. In research of equation of state(EOS) of materials,a target must have a surface roughness of less than 50 nm,a thickness uniformity of over 98%,and a maximum peak-to-valley height of less than 200 nm,with a proximity theatrical density.A target fabricated by SPDT has the same density as the original material,with required machining precision and surface roughness.In this paper,we report some SPDT applications in laser EOS targets fabrication, which include planar-shaped,step-shaped,and wedge-shaped targets with copper or aluminum.  
        关键词：Single point diamond turning(SPDT);Diamond tool;Ultra precision machining;Equation of state(EOS);Target   
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        发布时间：2021-03-05
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