最新刊期
      卷 0 ， 期 0 ， 2020
      • Issue 7, (2000)
        摘要：The change of the defects in PbWO4 crystals before and after annealing was studied by positron annihilation lifetime spectrum. It was found that the lifetime τ2turned short and the positron capture ability K increased after oxygen annealing.The results for the case of vacuum annealing were the reverse for that of oxygen annealing. Meanwhile, the main emission peak of the crystal after oxygen annealing shifted from 440nm to 485nm, but the peak for the case of vacuum annealing remained at 440nm, i.e. similar to that of an untreated crystal. From the results affected by different treatments, it is proposed that WO3+O- produced by lead vacancy leads to the green luminescence in PbWO4 crystal.  
        关键词：PbWO4 crystal;Positron annihilation;Luminescence mechanism;Lead vacancy;Complex vacancy   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The main work of calibrating a high-resolution electron momentum spectrometer is completing the least-square fitting of the orthogonal polynomials for the response function of the two-dimension position-sensitive detector. Since the spectrometer hasn’t been built yet, the elastic scattering data used for its energy and momentum calibrations were generated by a computer simulation, and a testing calibration process was accomplished based on these data.  
        关键词：Orthogonal polynomials;Elastic scattering;Two-dimension position-sensitive detector   
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        发布时间：2021-03-12
      • ZHOU Gu
        Issue 7, (2000)
        摘要：The C, Ti and Ti+ C ions were implanted into H13 steel, and the cross-sections of the samples were observed by TEM. It is shown that the implanted layer structure has greatly changed. The complex mosaic layer with nano-meter phase is formed.The thickness of the complex layer is greater than the corresponding ion range. The difference of structure among the three ion implanted layers is obvious. The collision parameters of the ions were calculated using TRIM95, showing that the structure change is closely related to the collision parameters of the ions in steel, Finally the close coordination of structure change with implanted conditions were studied.  
        关键词：C ions;Ti ions;MEVVA implantation;Steel;Surface modification;Complex mosaic layer with nano-meter phase;TEM   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The surface layer of 9Cr18 steel was irradiated by using pulsed high current electron beam (PHCEB) after titanium ion implantation. AES was used to analyze the chemical composition of the implanted layer.The micro-hardness of the surface layer before and after the pulsed electron beam irradiation were measured. The enhanced diffusion effect of surface composition on the ion-implatned metal materials by PHCEB was discussed.  
        关键词：Pulsed high current electron beam(PHCEB);Ion implantation;9Cr18 steel;Irradiation treatment;Enhanced diffusion   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：Loss impedance measurements are required to design new cavity for the NSRL upgrade project. A data acquisition and process system based on HP54124T digltal sampling oscilloscope and HPVEE graphical progranuning language was hoplemented. Some initial results on measurement and computation were given.  
        关键词：Loss impedance;Wakefield;HPVEE   
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        发布时间：2021-03-12
      • DING Bingang
        Issue 7, (2000)
        摘要：The angular momentum projected shell model （PSM） was applied to the study of nuclide 131La. The results of theoretical calculations about the rotational bands with configurations πd5/2,π g7/2, π h11/2, πh11/2 [v h11/2]2 and πg7/2 [ ν h11/2]2 were compared with experimental data. The nuclear shape for every rotational band was then specified.  
        关键词：PSM;Prolate spheroid;Oblate spheroid   
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        <引用本文> <批量引用> 7205202 false
        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The density distribution of Cherenkov lights produced by cosmic rays of γ, p and Fe was simulated by Monte Carlo method. The results showed that the slope of the density distribution of Cherenkov lights produced by Fe was obviously flatter than those produced by γ and p, if energy of the primaries was in the range around the " knee" of the energy spectrum. Furthermore, a special distance from the shower core was found, at which the densities of Cherenkov lights produced by the three kinds of primaries are equal. These features may be favourable for estimating the shower energy and may give some criteria to distinguish the light primaries from the heavy ones.  
        关键词：Cherenkov light;Monte Carlo simulation;Cosmic rays   
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        <引用本文> <批量引用> 7205177 false
        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：Minerals have been identified using Mssbauer parameters and artificial neural networks(ANN). The reported Mssbauer parameters of minerals were used to train an ANN called the improved back-propagation network. The excellent corrective ability indicates that it is probably an alternative method in Mssbauer data processing.  
        关键词：Artificial neural network;M■ssbauer spectroscopy;Improved back-propagation algorithm   
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        <引用本文> <批量引用> 7207546 false
        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：A two-gap drift tube buncher and a one-gap grid buncher with linear bunching waveform are used on the SFC axial injection line. The method of charge-discharge is adopted to get high voltage RF linear waveform. Working at the half-frequency bunching mode, the two bunchers can increase the theoretical longitudinal matching efficiency between the injector and the main cyclotron to 100% at any working mode.  
        关键词：Very-low-energy beam bunching;Linear buncher;Charge-discharge high voltage RF generator;Half-frequency bunching method   
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        <引用本文> <批量引用> 7207261 false
        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：A method for thermal neutron flux measurement by γ spectrometer is introduced. The 411keV γ ray peak areas for both Au and Eu foils irradiated in a reference field were first measured by a γ-spectrometer. And the absolute neutron flux for the Au foil was determined by a 4πβ-γ counter Then the neutron flux corresponding to 152Eu can be derived from the 152Eu to 198Au peak area ratio and the above-mentioned absolute neutron flux for Au. For an unknown field, the 411keV peak area of an irradiated Au foil in the field was measured by another γ-spectrometer, which also measured the peak area of the 411keV γ rays from the 152Eu foil irradiated in the reference field. Based on the ratio of these two peak areas and the aforsaid neutron flux for Eu in the reference field, the absolute neutron fiux of the unknown field could be determined.  
        关键词：Absolute neutron flux;γ peak area;γ spectrometer   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：Some Mo2N and Mo2-xTixN films were synthesized by N ion beaxn enhanced deposition and synchronized N-Ti ion beams enhanced deposition methods respectively. The microstructure of the films was determined to be of γ -Mo2N phase by the X-ray diffraction and transmission electron diffraction experiments. The scratch tests demonstrated that the metal ion beam could effectively improve adhesion of the films. The scratch critical loading of the Mo2-xTixN film was measured to be about 3000 gf, which is about twice as large as that of the Mo2N film.The corrosion resistance of the films was analyzed by the anode polarizing tests. The corrosion-self voltage and corrosion-self current of the Mo2N film and the Moz-xTixN film in a 0.5mol/L H2SO4 solution were found to be 32mV, 0.5 p A/cm2 and 166mV, 0.26 μA/cm2 respectively. These results indicated that the corrosion resistance of the Mo2-xTixN film was much better than that of the Mo2N film.  
        关键词：Metal ion beam;Mo2N;Enhanced deposition   
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        发布时间：2021-03-12
      • TAO Xiaoping
        Issue 7, (2000)
        摘要：An atlempt for preparing LaMo cathode materials was carried out. Experimental tests were also made to compare the emission characters and the arc-discharging behavious of the prepared materials and the LaMo sample imported from the USA.Some good results were obtained.  
        关键词：High current ion source;LaMo cathode;LaB6 cathode;Test   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The beam current measurement system for HLS LINAC has been improved. A survey of this system is presented and the measurement results are provided in this paper.  
        关键词：Linac;Beam current;Data acquisition   
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        <引用本文> <批量引用> 7207275 false
        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The principle of using an air ionization chamber to monitor doses in heavy ion radiation research is described. A 239Pu α source was used to measure the saturation curve of the ionization chamber and calculated the collection efficiency. The experimental results showed that the saturation voltage ranged from 50 to 1000V, and a higher collection efficiency was obtained at higher voltage in the saturation area.The method of calculating the collection efficiency is reliable and can be used to correct doses in the experiments with regard to biological effects of heavy ion radiation.  
        关键词：Dose monitoring;Collection efficiency;Ionization chamber   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：The gamma rays-irradiation polymerization of acrylonitrile has been studied by the 13C CPMAS method. The chain structures presented in the homophase polymerization under various irradiation conditions and the polymerization mechanism were discussed.  
        关键词：Acrylonitrile;Irradiation;Polymerization   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：Analyses with XRD and XPS were made for the r.f magnetron sputtering deposited carbon film on tungsten substrate before and after Ar and N ions irradiation.It is found that the microstructure of the carbon film depends on the bombarding ion species. The r.f magnetron sputtering deposited carbon films are amorphous. While the N ion irradiation can induce the formation of C-N and N-W crystalline compounds, the Ar ion irradiation can not induce such a phase transformation. But the latter can effectively reduce oxygen contamination. With increase of Ar ion doses, the content of the contaminating oxygen is decreased. The related mechanism was also discussed in the paper.  
        关键词：Ion irradiation;Carbon films;Phase transformation   
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        发布时间：2021-03-12
      • Issue 7, (2000)
        摘要：This paper presents some measurement results of the radiation field around the 2× 2MV tandem accelerator when 12C2+ ion beam was accelerated. A preliminary discussion is also given.  
        关键词：Tandem accelerator;12C2+ ion beam;Radiation field   
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        发布时间：2021-03-12
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