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1.
利用一套罗斯滤片系统测量激光轰击固体金属Ti平面靶产生的X射线辐射通量,系统包括两个相同的X射线探测器及相应滤膜。罗斯滤片法的优点在于利用相邻核素对X射线相似的阻止率,可滤出一个窄的能带并去除高能部分的干扰,获得了Ti平面靶K壳层X光辐射产额。实验结果表明:硬X射线能段在4.5~4.9keV之间的K壳特征辐射占优,连续谱所占份额较低(与晶体谱仪一致);随着激光能量的增加,特征辐射增加;激光强度接近2×1015 W/cm2时,能量转换效率出现峰值。  相似文献   

2.
对某城市的5个不同功能区进行土壤采样,并对每个采样点的土壤应用X射线荧光光谱仪测试其8种重金属的含量,利用富集因子计算每个功能区8种重金属的污染程度等级的隶属度,然后利用模糊数学方法对5个功能区的污染程度进行了综合评价,最后得到5个功能区重金属污染程度的排序向量。由此可以判定每个功能区受污染程度,其中工业区和主干道路区重金属污染程度最轻,生活区和公园区重金属污染程度较重。  相似文献   

3.
王耀才  石艺尉 《光学学报》1996,16(6):22-826
利用X射线在探针中的康普顿散射以及电子在光纤中的契仑柯夫效应可以构成光纤X射线探针和测量系统,本文对此做了理论和实验研究,推导了光纤探针的灵敏度公式,给出了计算结果,并做了实验标定,讨论了光纤探针测量系统的构成,测量的动态范围和响应时间。  相似文献   

4.
以带通平响应为优化目标,通过残余响应、带外残余响应相对误差以及残余响应平整度3个参数来优化滤片的厚度,设计了一套共有7个能量通道、连续覆盖18~88keV能谱范围的Ross滤片谱仪。该谱仪能量通道宽度在2~20keV之间。多数能量通道的带外残余响应相对误差低于10%,残余响应平整度优于20%。将该谱仪应用于微聚焦X光机上的高Z金属球壳高能X射线背光照相实验,结果表明:在不同的实验条件下,Ross滤片谱仪测得的能谱形状与理论模型给出的结果符合较好,测得的能谱不仅能够很好地解释背光照相图像,而且可用于根据图像反推客体的面密度。  相似文献   

5.
基于液晶可调变滤色器(LCTF)的光谱成像系统具有光谱分辨率高、结构紧凑、控制灵活等特点。搭建了一套可见光波段的高分辨率LCTF光谱成像系统,对系统的光谱图像获取及彩色图像重建方法进行了研究;建立了系统的光谱及颜色重建模型;基于标准色卡及标准测色系统,对该系统的颜色复现效果进行了实验验证;实验结果表明,该LCTF光谱成像系统的彩色图像颜色复现精度达可到较小色差水平。  相似文献   

6.
简要论述了氧化铝的X射线荧光光谱分析方法原理、样品处理、设备特点;在德国布鲁克公司的S4型X射线荧光光谱仪上用融片法分析氧化铝中的杂质含量,重点论述了用X射线荧光光谱法代替传统的化学分析方法的优势和不足.  相似文献   

7.
Electron energy spectra from intense laser double ionization of helium   总被引:1,自引:0,他引:1  
The double ionization of helium in the strong-field limit has been studied using an electron-ion coincidence technique. The observed double ionization electron energy spectra differ significantly from the single ionization distributions. This gives new support to the rescattering model of double ionization and explicitly reveals the role of backward electron emission following the e-2e ionizing collision.  相似文献   

8.
冯贤平  韩申生 《光学学报》1994,14(4):42-345
通过合理而有效地按排多种探测仪器,观察到等离子体X射线激光介质的空间非均匀现象。在保证入射激光经最佳组合透镜后焦线均匀性前提下,由实验显示等离子体介质的空间不均匀性主要来自靶材质量和调焦精度。此外,入射激光脉宽的大小变化将会引起等离子体整个辐射空间和时间范围的明显变化。  相似文献   

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10.
We report additional rich fine structures in high-resolution near-edge x-ray-absorption fine structure (NEXAFS) spectra of large organic molecules using NTCDA on Ag(111) as an example. These fine structures are completely interpreted as vibronic coupling to electronic core excitations. The coupling is mode selective; predominantly one vibronic mode couples to each excitation. The fit results suggest the occurrence of a Davydov splitting, first observed for core excitons. Morphological differences substantially influence the electron-vibron coupling, indicating a strong intermolecular interaction. Thus NEXAFS becomes a more subtle probe for organic solids.  相似文献   

11.
KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator (VIRCATOR) device. HPM power measurements were carried out using a transmitting-receiving system in the presence of intense high frequency (a few MHz) electromagnetic noise. Initially, the diode detector output signal could not be recorded due to the high noise level persisting in the ambiance. It was found that the HPM pulse can be successfully detected using wide band antenna, RF cable and diode detector set-up in the presence of significant electromagnetic noise. Estimated microwave peak power was ∼59.8 dBm (∼1 kW) at 7 m distance from the VIRCATOR window. Peak amplitude of the HPM signal varies on shot-to-shot basis. Duration of the HPM pulse (FWHM) also varies from 52 ns to 94 ns for different shots.  相似文献   

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14.
X射线干涉仪以非常稳定的单晶硅晶格作为长度单位 ,可以实现亚纳米精度的微位移测量。提出了将 X射线干涉仪和扫描隧道显微镜结合起来 ,利用单晶硅的晶格尺度测量扫描探针显微镜样板节距的技术方案 ,并进行了实验研究  相似文献   

15.
土壤重金属铅元素的X射线荧光光谱测量分析   总被引:3,自引:0,他引:3  
在实验室条件下,利用NITON XLt793型便携式X射线荧光光谱重金属分析仪测量并分析土壤中铅元素的X射线荧光光谱特性。分别以铅的Lα(10.55 keV)和Lβ(12.61 keV)特征谱线作为分析线,分析了不同基体元素对分析线的影响;测定在不同铅浓度下的特征谱线强度变化。结果表明铅的质量分数在10×10-6~1 800×10-6范围内,元素的光谱强度与浓度之间呈现较好的线性关系;建立了铅元素的定标曲线,并计算得到铅的检出限为7.89×10-6。  相似文献   

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17.
A thorough analysis of low convergence speed and ghosting artifacts in temporal high-pass filter correction has been undertaken in this paper and it has found out that the keys of these problems are the interference of a large sum of unrelated scene information in the nonuniformity correction (NUC) process. In order to overcome these drawbacks, a new scene-based NUC technique based on bilateral filter has been developed. This method separates the original input frames into two parts and it estimates the NUC parameters only by using the residuals. The experimental results have shown that it can significantly increase convergence speed and reduce ghosting artifacts.  相似文献   

18.
Physics of the Solid State - We show how the combined use of the methods of Rutherford backscattering of ions and X-ray fluorescence analysis under conditions of total external reflection of the...  相似文献   

19.
By revealing the relationship between edge visibility and imaging parameters in in-line phase contrast imaging (PCI), we propose a method to quantitatively measure the contribution of absorption and phase shift from acquired images. We also prove that edge visibility will grow with the increasing source-object distance and object-detector distance. The result is validated by relative phase factor and by experiments conducted on a microfocus x-ray source. This method provides a new approach to evaluate in-line PCI images and is helpful for deciding imaging parameters.  相似文献   

20.
《Physics letters. A》1987,123(2):95-100
The non-linear properties of charge-transfer exciton dynamics at intense pumping are investigated. The shift of an absorption band of an arbitrary cell, induced by the electric field of the available excitons, results in spatial and orientational ordering of the excitons. The side bands appear in the absorption and fluorescence spectra.  相似文献   

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