同步辐射X射线吸收边辐照技术

介绍了同步辐射Ｘ射线能量收边辐照技术和部分应用研究，简要阐述了单能软Ｘ射线辐射剂量参数的测量和计算方法。     

激光产生等离子体辐射X射线特性研究

本文报导激光等离子体辐射Ｘ射线的测量方法和结果。在“星光”装置上,用１．６μｍ激光辐照Ｎａ／Ｆ和铜靶。用平晶谱仪测量等离子体辐射Ｘ射线绝对强度,并研究了辐射Ｘ射线强度与入射激光功率密度的关系,测量了靶前后辐射强度之比,为光电离机制的Ｘ光激光研究提供了较重要的数据。     

浮栅ROM器件x射线剂量增强效应实验研究

给出了浮栅ROM器件在钴源和北京同步辐射装置(BSRF)3W1白光束线辐照的实验结果;比较了两种辐照的实验结果及其损伤异同性.通过实验在线测得位错误数随总剂量的变化,给出相同累积剂量时x射线辐照和γ射线辐照的总剂量效应损伤等效关系.获得了浮栅ROM器件x射线剂量增强因子.这些结果对器件抗x射线辐射加固技术研究有重要价值 关键词： EEPROM x射线 剂量增强剂量效应 同步辐射     

HL-1M装置中超热电子的X射线辐射测量

用新研制的五通道碘化汞（ＨｇＩ２）半导体探测器阵列分别观测了在欧姆发热、弹丸注入及离子回旋共振加热（ＩＣＲＨ）条件下,ＨＬ－１Ｍ等离子体中的超热电子引起的能量在１０～１５０ｋｅＶ范围内的Ｘ射线辐射强度的时空变化,及超热电子辐射的Ｘ射线能谱。结果显示,在ＩＣＲＨ期间,等离子体边缘的Ｘ辐射增强,超热电子的温度大约为３０ｋｅＶ,ＩＣＲＨ的能量沉积在等离子体边缘。     

数字式X射线辐射扫描成像系统及其应用

数字化图像具有非常突出的优点和广泛的应用,而Ｘ射线成像在医学诊断和工业无损检测等领域占据非常重要的地位,因此Ｘ射线成像的数字化必将成为一种趋势。文章介绍了数字式Ｘ射线辐射扫描成像的特点、原理及其应用前景。采用气体电离室探测器阵列完成了３２路数字式Ｘ射线辐射扫描成像装置系统,其空间分辨率达到０．５ｍｍ,并且获得了比较满意的Ｘ射线图像效果。     

人肝癌SMMC-7721细胞对低剂量γ射线辐射超敏感性的研究

研究了人肝癌细胞SMMC-7721在低剂量γ射线照射下超敏感性和增强的辐射抗性响应。选用对数生长期细胞接受0—6 Gy不同剂量的^60Coγ射线的照射。利用流式细胞仪对细胞进行分选计数,并用克隆形成法检测细胞存活率。发现SMMC-7721细胞存在低剂量辐射超敏感性和增强的辐射抗性响应,即在0—0．3Gy之间细胞表现出单位剂量杀伤增强现象,在0．3—1Gy细胞表现一定的辐射抗性,在1Gy以上,细胞的存活符合线性平方模型。     

同步辐射X射线源的剂量增强效应实验研究

设计了多层平板铝电离室,利用北京同步辐射装置BSRF产生的30—100keV同步辐射硬X射线,测量了不同材料界面Kovar/Au/Al,Pb/Al,Ta/Al的辐射剂量梯度分布,给出了不同材料界面剂量增强因子DEF.在该装置上同时开展了硬X射线辐照引起的CMOS器件4069的剂量增强效应RDEF研究.采用双层膜结构,通过实验给出辐照敏感参数随总剂量的变化关系,从而给出器件损伤增强因子.这些方法为器件抗硬X射线辐射加固技术研究提供了实验技术手段.     

飞秒和纳秒脉冲作用下等离子体X射线辐射特性

对飞秒和纳秒激光作用下的Ａｌ和Ｃｕ等离子体的Ｘ射线辐射进行了测量，分析和比较。实验结果表明在飞秒激光脉冲下等离子体Ｘ射线峰值向短波方向移动。     

同步辐射软X射线接触显微成像

软Ｘ射线显微术适合于自然状态下生物样品的高分辨率显微成像。软Ｘ射线接触显微术是Ｘ射线显微成像方法中最简单也是迄今唯一到接近理论分辨的方法。本文阐述软Ｘ射线接触显微成像的原理和方法，并报告用合理肥步辐射光源进行软Ｘ射线接触显微成像的一些实验结果。     

大气层外核爆炸X－射线辐射场特性研究

Ｘ射线被认为是大气层外反导栏截武器的主要破坏因素。在航天器结构材料的辐射损伤计算中，需要核爆炸Ｘ射线辐射场的数学模式。从Ｐｌａｎｃｋ黑体谱出发，提出按温度梯度分层的归一化黑体谱组合模式，给出Ｘ－射线的释放能量及辐射脉冲，从而建立了大气层外核栏截Ｘ－射线辐射场特性的数学模式     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

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.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

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.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

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.     

Sorting of bending magnets for the SSRF booster

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.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

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.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

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.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.