X射线荧光光谱检测系统的研究与设计.doc

X射线荧光光谱检测系统的研究与设计
摘要
X射线荧光(以下简称XRF)光谱法的基本原理是当物质中的原子受到适当的高能辐射的激发后,放射出该原子所具有的特征X射线。根据探测到该元素特征X射线的存在与否的特点,可以定性分析,而其强度的大小可作定量分析。在XRF定量分析中,鉴于高灵敏度和多用途的要求,多数采用高功率的封闭式X射线管为激发源,配以晶体彼长色散法和高效率的正比计数器和闪烁计数器,并用电子计算机进行程序控制、基体校正和数据处理。该法具有准确度高,分析速度快,试样形态多样性及测定时的非破坏性等特点,它不仅用于常量元素的定性和定量分析,而且也可进行微量元素的测定,其检出限多数可达10-6,与分离、富集等手段相结合,可达10-8。测量的元素范围包括周期表中从F~U的所有元素。
本文主要围绕X射线荧光光谱检测进行研究,进行X射线激发源、分光晶体、探测器的选取,应用大学期间学习过的隔离放大器AD277、集成采样/保持器AD582、A/D转换器ADC0809、单片机80C51芯片,设计了X射线荧光光谱检测系统,提出了对一些基本元素的定性和定量的分析,通过多次单点和总体的调试,硬件参数基本正确,系统能够基本正常运行,验证了本系统的基本功能的有效性。
本文针对X射线荧光光谱检测系统,运用我们所学过的专业课基础知识、芯片,设计出本系统,基本得到了预期的功能。
关键词:X射线荧光,单片机,定性/定量分析
X-ray Fluorescence Detection System and Design
Abstract
X ray fluorescent (hereinafter referred to as XRF)spectrum of the law of the basic principle is a matter of the atoms are enough to stimulate the appropriate radiation after the atomic radiation which is x ray. Based on the detected X-ray characteristics of the elements in the presence or absence of features, to qualitative analysis, the size of its intensity can be used for quantitative analysis. In XRF quantitative analysis, in view of the requirements of high sensitivity and multi-purpose, most of the closed high-power X-ray tube as excitation source, together with the crystal long he and efficient dispersion law proportional counter and scintillation counter, with an puter control, matrix correction and data processing. The method has high accuracy, rapid analysis,morphological diversity and the determination of when the sample of non-destructive characteristics, it is not only for the major elements of the qualitative and quantitative analysis, but also for the determination of trace elements, the detection limit of the majority of up to 10-6, with the separation and enrichment of bination of up to 10-8. Measurements include the periodic table of elements from F ~ U of all elements.
This paper around the X-ray fluorescence detection to study X-ray excitation source, analyzer crystal, detector selection, l