小角X射线散射若干方法研究

发布时间：2018-02-04 12:40

本文关键词： 仪器参数数据初级处理程序周期长度粒子尺寸简易加热炉　出处：《安徽大学》2017年硕士论文　论文类型：学位论文

【摘要】：小角X射线散射(SAXS)是测量物质内部散射单元结构信息的常用方法。本论文就SAXS方法开展了以下五个方面的研究:一.SAXS仪器参数和样品散射角度标定方法研究。大面积二维探测器已经成为许多SAXS仪器的标准配置。当SAXS仪器上的探测器和直通光垂直时,散射图像具有圆对称性,此时若有一个具有纳米尺度的周期性结构的样品被测试,探测器将会收集到圆的衍射环,圆中心点与直通光中心点重合;当探测器倾斜时,散射图像的圆对称性就不复存在,圆的衍射环就会变成椭圆,椭圆中心点与直通光中心点不重合。样品散射图像对应的散射角度或散射矢量标定依赖于仪器参数的标定,即需要知道样品至探测器距离、探测器倾斜角度和直通光中心点坐标这三个仪器参数。传统的仪器参数标定方法大都基于探测器垂直(或近似垂直)于直通光的设置,极少数涉及倾斜的情况,还没有探测器倾斜角度的标定方法报道。本研究发展了用标准样品衍射环标定探测器处于任意姿态下(垂直和倾斜)的仪器参数(探测器倾角或称偏转角、样品至探测器距离、探测器上直通光斑中心)和样品散射角度的方法,模拟建立了相应的几何关系,具体推导了相应的计算公式,编译了相应的计算语句。以北京同步辐射1W2A小角站的实验为例,用标准样品SBA-]5标定了 SAXS仪器参数,用标准样品硬脂酸银验证了该方法的可靠性。二.SAXS数据初级处理程序开发。SAXS实验测试后,需对散射图像进行初级数据处理,然后再进行进一步的样品结构参数计算。初级处理过程通常包括仪器参数标定、散射角度标定、二维图像转为一维数据、背底扣除、消模糊(准直误差校正)等几个步骤。已有不少研究者开发了不同的数据初级处理软件,但目前没有一个软件集成了上述五个功能,分散操作,麻烦费时;而且对于探测器倾斜的情况,还没有相应的软件能计算探测器倾角进而计算其它仪器参数。为此,本研究开发了一款SAXS数据初级处理程序,用Matlab语言编写,将上述五个功能集于一体,适合于探测器垂直或倾斜的任意姿态,提高了数据初级处理的准确性和自动化程度,且可实现批处理。三.周期性结构样品的周期长度d值测量。随着科学的发展,越来越多的纳米d值的材料被制备,当d值为若干纳米尺度时,对应的衍射角则落在了小角散射的范围。精确测定d值,对于认识这类材料的结构,实现其结构可控具有重要意义,因此成为了 SAXS的应用方向之一。测量d值需要知道样品至探测器的距离,但是探测内部感光面的具体位置通常是不知道的,手工米尺测量距离的方法太过粗糙。本研究采用移动样品或探测器的方法进行实验,通过采集衍射环来计算d值,避免直接测量样品至探测器距离来进行d值的计算,以期提高d值测量精度。详细分析了移动样品和移动探测器这两种方法的区别,推导了相应的计算公式,讨论了探测器倾斜的影响,模拟分析了误差变化规律,并用标准样品进行了验证。四.应用SAXS测量溶液中粒子尺寸的一种新方法。SAXS是测量溶液中粒子尺寸的常用手段。实际测量中出于对散射强度的要求,溶液浓度不能太低,因此干涉效应不可避免。传统的处理干涉效应的方法是制备并测量不同浓度的溶液,然后对散射曲线进行外推。传统的方法不仅制备操作麻烦,而且外推散射曲线人为性较大。为此,本研究提出一种溶液中粒子尺寸测量的新方法。直接对任意浓度球形(或近似球形)粒子溶液的实测SAXS曲线进行变换,通过寻找峰位的方法来计算相应于干涉效应可忽略的无限稀释溶液中粒子的尺寸。与传统方法不同,该方法仅需要测量任意一种浓度的溶液,不需要知道溶液浓度,且不需要对实验曲线进行外推延长。并对该方法进行了模拟和实验验证。五.一款SAXS原位测量专用简易样品加热炉研制。原位加热实验是同步辐射SAXS领域的近年来研究热点。本研究设计开发了一款SAXS原位测量专用简易样品加热炉,它主要由温控器、样品池、固定架组成,采用挤压密封的办法,具备构造简略、操作容易的特点。采用该装置分别进行了石墨烯溶液加热和褐煤粉末加热干燥的SAXS原位测试,实验结果验证了该加热炉的实用性。
[Abstract]:Small angle X ray scattering (SAXS) is a common method for measuring material internal scattering unit structure information. This paper studies the following five aspects: the development of the SAXS method for calibration of a.SAXS instrument parameter and sample scattering angle. A large area of two-dimensional detector has become the standard configuration of many SAXS instruments. When the SAXS instrument. The detector and the straight vertical light, scattering image with circular symmetry, if has a nano scale periodic structure of the tested samples, the detector will collect diffraction ring round and round the center point and point light in the heart through coincidence; when the detector is tilted circular symmetry scattering image is not exist, will become an ellipse diffraction ring circle, ellipse center and straight optical center point do not coincide. The scattering angle of the corresponding scattering image of the sample or the scattering vector depends on the parameters of the calibration instrument calibration, which is required To know the sample to detector distance, tilt angle and light detector through the center coordinates of the three parameters of the instrument. The instrument parameters of traditional calibration methods are mostly based on the vertical detector (or near vertical) in the direct light settings for a few inclined, there were no reports of detector tilt angle calibration method was developed in this study. In any attitude detector calibration standard sample for diffraction ring (vertical and inclined) instrument parameters (detector angle or angle, sample to detector distance, the detector through the spot center) method and sample scattering angle, established the corresponding simulation geometry, deduced the corresponding calculation formula, compiled calculation statement corresponding. Using Beijing synchrotron radiation 1W2A small angle station experiment as an example, using the standard sample of SBA-]5 calibration of the SAXS instrument parameters, using standard sample silver stearate test The reliability of the method. The primary test program development two.SAXS.SAXS experimental data, the primary scattering image data processing, then the sample structure parameters for further calculations. The primary process includes instrument calibration, scattering angle calibration, two-dimensional image to one-dimensional data, background subtraction, deblurring (collimation error correction) of several steps. Many researchers have developed different primary data processing software, but does not currently have a software integration of the above five functions, decentralized operation, time-consuming and trouble; for the detector tilt, but also does not have the corresponding calculation software can calculate other parameters of angle detector instrument for., this study developed a SAXS primary data processing program, using Matlab language, the above five functions, suitable for vertical or inclined probe The arbitrary attitude, improve the degree of automation and accuracy of data processing and can achieve the primary, batch processing. Three. The cycle length of the periodic structure of D value of the sample measurement. With the development of science, more and more D nano materials were prepared, when the D value is some nano scale, the corresponding diffraction angle it falls on the range of small angle scattering. The accurate determination of D value, the cognitive structure of this type of materials, it is of great significance to achieve the controllable structure, which has become one of the application direction of SAXS. D measurements need to know the sample to detector distance, but the specific position detection of internal photosensitive surface is usually not known. A manual method of measuring distance is too rough. The method of moving the sample or detector experiments, through the acquisition of diffraction rings to calculate the D value, avoid the direct measurement of the sample to detector distance to D value meter Count, in order to improve the D value measurement accuracy. A detailed analysis of the differences between mobile and mobile detector samples of the two methods, and the corresponding calculating formulas are derived, the influence of detector tilt discussion, simulation analysis of the variation of the error, and verified by standard samples. Four. Using a new method of particle measurement solution SAXS size.SAXS is a commonly used method for measuring particles in solution. The size of the actual measurement based on scattering intensity, the concentration is too low, so the interference effect is inevitable. The traditional method of processing of the interference effect is the preparation and measurement of different concentration solution, and then extrapolating the scattering curves of the traditional method. Not only the preparation of complicated operation, and artificial scattering curve extrapolation is larger. Therefore, this study proposes a new solution method in the measurement of particle size. The spherical directly to any concentration (or nearly spherical ) measured SAXS particle solution of transformation, by looking for the method to calculate the peak particle solution corresponding to infinite dilution interference effect can be neglected in size. Unlike the traditional method, this method only needs the measurement of arbitrary a solution concentration, do not need to know the concentration of the solution, and does not need to extrapolate the experimental curve extended. And the method is simulated and verified by the experiments. The research and development of 5 SAXS in situ measurement special simple heating furnace. In situ heating experiment is the synchrotron radiation field of SAXS research in recent years. The research design and development of a simple SAXS in situ measurement special heating furnace, which is mainly composed of the thermostat, the sample pool, a fixed frame, the extrusion sealing method has simple structure, easy to operate features. Using this device were Shi Moxi solution heating and heating dry lignite powder SAXS In situ test, the experimental results verify the practicability of the reheating furnace.

【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O434.1

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