共查询到20条相似文献,搜索用时 302 毫秒
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研制了一套宽光谱探测系统,该系统包括紫外成像探测器和X射线成像探测器两个工作单元。利用该系统对高功率微波(HPM)源运行及聚四氟乙烯介质窗受微波场作用而发生击穿时实验环境中的紫外线和X射线进行了初步诊断。结果表明:HPM源运行参数为重复频率100 Hz,运行时间5 s,介质窗未发生击穿时,微波源二极管区产生的X射线剂量为9.28×102~1.64×103 Gy,介质窗发生击穿时,环境中X射线剂量为5.38×102~1.09×103 Gy;随着微波脉冲重复频率和运行时间的增加,产生的X射线剂量明显增加。此外,利用该系统证实了实验环境中紫外线的存在。 相似文献
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室温下首先采用160keVHe离子注入单晶Si样品到剂量5×1016ions/cm2,部分样品再接受80keVSi离子辐照到较高的剂量5×1015ions/cm2或接受高密度H等离子体处理.应用透射电镜观测分析了800℃高温退火引起的空腔的形成形貌.结果表明,附加Si离子辐照或H等离子体处理会影响Si中空腔的生长.就Si离子附加辐照而言,由于辐照引入富余的间隙子型缺陷,因此,它会抑制空腔的生长,而高密度H等离子体处理则有助于空腔的生长.定性地讨论了实验结果. 相似文献
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研究了电子通量对ZnO/K2SiO3热控涂层光学性能的影响。分别采用通量为5×1011/cm2·s,8×1011/cm2·s,1×1012/cm2·s 和5×1012/cm2·s的电子对试样进行辐照。电子辐照下涂层的光学性能发生了退化,并且发现了退化涂层在空气中的“漂白”现象。分析了ZnO/K2SiO3热控涂层光学性能的退化机制,同时讨论了电子通量对太阳光谱吸收系数的影响。实验结果发现,在5×1011~1×1012/cm2·s的电子通量范围内,电子通量对ZnO/K2SiO3热控涂层光学性能的影响相同。因此在这个电子通量范围内,采用加速地面试验来模拟空间的电子辐照效应是有效的。 相似文献
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描述了如何使用蒙特卡罗方法评估产生在加速器屏蔽混凝土中的感生放射性. 使用EGS4程序模拟了NaI闪烁探测器测量屏蔽混凝土块表面剂量率时, 对于半径和厚度的响应. 结果发现,在屏蔽混凝土块半径和厚度分别达到40cm和30cm时, 表面剂量率达到饱和. 研究了东京大学SF回旋加速器北墙位置8和位置9的表面剂量率, 并和使用NaI闪烁探测器的测量结果进行了对比, 发现模拟和实验结果符合很好. 并且, 获得了表面剂量和表面感生放射性之间的转换系数, 对于60Co转换系数为0.90(Bq·g-1)·(μSv·h-1)-1, 对于152Eu转换系数为1.26(Bq·g-1)·(μSv·h-1)-1. 这样, 就可以通过NaI闪烁探测器表面剂量的测量结果简单评估加速器设备屏蔽混凝土中的感生放射性. 相似文献
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使用二次离子质谱仪分析了附加的空位型缺陷对单晶Si中注入B原子热扩散的影响. Si中B原子是通过30keV B离子室温注入而引入的, 注入剂量为2×1014cm-2. Si中附加的空位型缺陷通过两种方式产生: 一是采用40或160keV He离子注入单晶Si到剂量5×1016cm-2,并经800°C退火1h; 二是采用0.5MeV F或O离子辐照单晶Si到剂量5×1015cm-2.结果显示, 不同方式产生的附加的空位型缺陷均能抑制注入的B原子在随后热激活退火中发生瞬间增强扩散效应, 并且抑制的效果依赖于离子的种类和离子的能量. 结合透射电子显微镜和卢瑟福背散射分析结果对以上抑制效应进行了定性的讨论. 相似文献
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Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide 总被引:1,自引:0,他引:1
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs. 相似文献
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A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output. 相似文献
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S. G. Nedel’ko M. A. Krysyuk A. L. Apanasenko L. N. Lymarenko Z. T. Moroz 《Journal of Applied Spectroscopy》1997,64(1):55-61
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped
with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly
described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation
(5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum
cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics
of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure
crystals is analyzed (preliminarily).
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997. 相似文献
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The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper. 相似文献
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A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
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Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use. 相似文献
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We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed. 相似文献
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Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell. 相似文献