最新刊期
      卷 0 ， 期 0 ， 2020
      • Issue 6, (1994)
        摘要：Two groups of samples implanted by P+ and P respectively were measured with slow positron beams. Unlike the unimplanted sample, the defects in the implanted samples result in obvious changes of the positron annihilation S parameter. The defect profiles of the samples and the defect’s trapping coefficients are obtained from fitting the experimental results. The differences in defect types and annealing behavior between P+ and P implanted samples are discussed.  
        关键词：Slow positron beams;Ion implantation;S parameters;Defects   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：he scanning electron microscopy （SEM） combined with electron probe microanalyzer（EPMA） technique was used to measure the composition difference between the convex and concave regions of the sputtered surface. The experimental results show that the "surface element localized enrichment" phenomenon occurs in a single-phase Cu-12at.% An alloy after 30keV Ar+ ions bombardment to a dose of 1.4×1018ions/cm2 as in multi-phase alloys. A model considering the effects of both the initial stage of the localized enrichment and the capillary pressure （Laplace pressure） producing a selective drift force was proposed for explaining these results.  
        关键词：Sputtering;Single-phase alloy;Element localized enrichment   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：A method of calculating sensitivity of PIN neutron detector system with a thick absorber, that is, the model of Layers and Pieces with Monte-Carlo （LPMC）simulation has been put forward. The program LPMC was written in FORTRAN 77language. The error of the calculation is not more than 1.88%. The results from LPMC calculation are in agreement with the experiments within the above error,thus the shortcoming of over-deviations for the LP calculation has been avoided.  
        关键词：Neutrons;Sensitivity;Model;Recoil protons   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：The energy deposition for electron beams in Si-SiO2 materials has been calculated with the two-group theory of electron transportation. The absorption dose for 1.0MeV and 1.5MeV electrons in MOS capacitors was measured with an extrspolation ionization chamber which is equivalent to silicon in stopping power.The chemical structure, interface states and C-V curve of the MOS samples were analyzed before and after irradiation with X-ray photoelectron spectroscopy （XPS）,Auger electron spectroscopy （AES）, deep level transient spectroscopy （DLTS） and C-V method. According to the theory and experimental data, the relationship among election energy deposition, ionizing damage and radiation effect is derived from a view point of dosimetry. Finally, a preliminary explaination for the ionizing damage mechanisms is given.  
        关键词：Electron beam;Si-SiO2 system;Energy deposition;Ionization damage;Radiation effect   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：A time interval formula for neutrons emitted by an isotope neutron source and reacted by a medium is derived. The probability series corresponding to s-fold time interval is assumed. By changing the moderating power of the medium the time interval of close neutrons is measured. The experimental result is compared with the calculation from the formula.  
        关键词：Close neutrons;Moderating power;s-fold time interval   
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        <引用本文> <批量引用> 8408409 false
        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：universal formula of sputtering yield for normal incidence of mono-energetic ions on single element targets is presented. The results based on this method are compared with the Monte Carlo simulation and the experimental data. By means of Wilcoxon two-sample paired signed rank test, the statistically significant difference of the above results is discussed.  
        关键词：Sputtering yield;Analytical evaluation;Monte Carlo simulation   
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        <引用本文> <批量引用> 8408452 false
        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：The expert system OPTRAN（Ver 1.0） used for beam transportation line design is introduced. The knowledge storage and reasoning principle, of which the intelligence part of OPTRAN are composed, have been described in detail. By using OPTRAN（Ver 1.0）, the design of a beam transportation line for extracted ion beam of Cyclone 30 was completed.  
        关键词：Beam transportation line;Expert system;Knowledge storage;Reasoning principle;Cyclone 30   
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        <引用本文> <批量引用> 8408709 false
        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：The relation between positron annihilation lifetime and defects in BaFxCl2-x:Eu2+ phosphors is studied. The experimental result shows that the formation of F centers is influenced by the x value （or the F/Cl ratio） of the samples. The relation between the x value and the type and concentration of F centers is also presented.  
        关键词：Positron annihilation lifetime;Photostimulable luminescence （PSL）;Color centers   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：The fundamental functions of the control and scanning system in the Beijing FEL spectrometer are reported. The magnetic field analysis of the slow deflection coil and the specification of the microsecond pulse generator are introduced.  
        关键词：Slow deflector;Wiggler   
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        发布时间：2021-04-09
      • Yuan Suoxiang
        Issue 6, (1994)
        摘要：This paper describes a method of measuring energy of electrons from accelerators. An electyon beam with a certain energy bombarding a set of stacked pieces of cover glass, will cause some of them to change color. The range of electrons in glass can be obtained. With the Berger’s table for the ranges of electrons in silicon and with the linear interpolation the electron energy can be determined. Finally, an E-Vr curve （electron energy E versus the corresponding reading Vr of the rotary voltage meter） is established. A nuclear reaction method has been used for the energy calibration. The relative deviation is about 1.5%. Having advantages of simplicity, easiness and good accuracy, this method is quite well for measuring electron energy.  
        关键词：Electron accelerators;Electron energy;Electron range;Cover glass;Silicon;Rotary voltage meter   
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        发布时间：2021-04-09
      • Su Ning
        Issue 6, (1994)
        摘要：A sort of corrosion phenomenon in the wave-guide system of a medical electron linear accelerator is described. The XRD analysis of the corrosion product was made and a hypothesis about corrosion mechanism and some preventive measures were proposed.  
        关键词：Medical accelerator;Waveguide system;Corrosion   
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        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：Divergent X-ray radiation has been focused into a small spot（φ500μm） by an X-ray lens made of polycapillaries, increasing power density by 104 times. The new X-ray lens has been applied to the XRF analysis. The detection limits of 10-9-10-10g have been obtained by means of the new technique with a 2W X-ray tube.  
        关键词：X-ray;XRF analysis;X-ray lens   
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        <引用本文> <批量引用> 8408528 false
        发布时间：2021-04-09
      • Issue 6, (1994)
        摘要：The measurements of indoor radon concentration in representative dwellings in Shenyang City were made by CSR detectors, and the results were compared with those obtained by the grab sampling technique. It was shown that the results of the latter were 15%-50% less, and CSR detectors were more suitable for the environment radon investigation.  
        关键词：CSR detectors;Radon concentration   
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        发布时间：2021-04-09
      • Liu Shuzheng
        Issue 6, (1994)
        摘要：Epidemiological studies in some areas of high natural radioactivity did not demonstrate a rise in cancer mortality in accordance with the increased exposure of the population to low level radiation as suggested by the linear model. Studies on inhabitants in some of these areas showed increased reactivity of T lymphocytes to mitogens and enhanced unscheduled DNA synthesis （UDS）. Animal experiments also disclosed potentiation of immune functions, stimulated UDS and induction of a cytogenetic adaptive response in lymphocytes after single or chronic exposure to low dose radiation. The mechanism of immunoenhancement after low dose radiation was analyzed in terms of the cellular events in the immune organs, the systemic regulation of these processes and the molecular basis of the above changes. The possible role of proteins induced by low dose radiation in the mechanism of the cytogenetic adaptive response was discussed.  
        关键词：Low level radiation;Immunologic stimulation;Unscheduled DNA synthesis;Cytogenetic adaptive response   
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        发布时间：2021-04-09
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