质子激发X射线分析——生物医学中痕量元素分析的新技术

本文讨论了质子激发X射线分析对于生物体内各种元素的分析能力,并结合人体和动物的组织、血清、尿、头发中痕量元素分析的实例讨论了质子激发X射线分析的灵敏度、准确度和多元素分析能力,阐明了它在生物医学领域的痕量元素分析中的优点。     

质子激发X射线分析——生物医学中痕量元素分析的新技术

本文讨论了质子激发X射线分析对于生物体内各种元素的分析能力,并结合人体和动物的组织、血清、尿、头发中痕量元素分析的实例讨论了质子激发X射线分析的灵敏度、准确度和多元素分析能力,阐明了它在生物医学领域的痕量元素分析中的优点。     

质子激发X射线分析——生物医学中痕量元素分析的新技术

本文讨论了质子激发X射线分析对于生物体内各种元素的分析能力,并结合人体和动物的组织、血清、尿、头发中痕量元素分析的实例讨论了质子激发X射线分析的灵敏度、准确度和多元素分析能力,阐明了它在生物医学领域的痕量元素分析中的优点。     

放射性同位素源激发能量色散X射线分析及其应用

在分析化学中,X射线荧光分析法是一种应用广泛的分析工具。七十年代以来,由于半导体硅(锂)探测器大量投入使用,从而发展了能量色散X射线分析技术,其中质子激发X射线分析技术的发展尤为迅速,而放射性同位素源激发的X射线分析由于设备简单、操作方便、经费省等优点也有了很大的发展,成了X射线荧光分析中的一个重要分支,有的已成为微量元素分析中的常用工具。在环境科学、生物医学、地质、冶金、考古等许多领域内得到了广泛的应用。     

用PIXE方法研究凤眼莲对水中微量元素的吸收作用

凤眼莲是一种高等水生植物,它能吸收水中的酚、铬、镉、砷、汞、铅等有毒化合物和元素,具有净化池溏的作用。我们应用质子激发X射线分析方法研究凤眼莲对水中微量元素的吸收作用。 样品是将分别在添加有不同浓度、各种金属离子培养液中培育的凤眼莲植株,经去根、烘干、碾粉并过,40目筛处理所得的干粉。由辽宁省环境保护科学研究所提供。     

大气颗粒物中轻元素的PIGE分析

轻元素是大气颗粒物的主要组成部分,质子激发Y射线(PIGE)可以探测大气颗粒物中的轻元素,如Li,B,F,Na,Mg,Al,Si等,是质子激发X射线分析((PIXE)方法的一个良好补充.在中国科学院上海应用物理研究所核分析技术重点实验室的扫描质子微探针系统上实现了PIGE测量.利用PIGE对沙尘暴期间上海的PM,.样品...     

微束背散射分析元素微区分布的研究

微束背散射分析元素微区分布的分析方法使上海原子核研究所的质子微探针能在微区内综合使用质子激发Ｘ射线荧光和背散射等多种核效应，为样品由轻元素到重元素的全面无损、双微（微区、微量）分析提供了依据。应用该方法还测量了Ｓｉ３Ｎ４／ＳｉＣ复合陶瓷材料，证明了该分析方法的可靠性。     

质子加速器开发现状及癌的质子射线治疗

用射线治疗癌,是仅次于外科手术的有效疗法之一,美、日两国各有用于射线治疗的电子直线加速器约3000台和500台。目前,能够迅速提高疗效的质子射线疗法,正从试验研究转入实用阶段。 1.质子射线的特性 射线对生物体的作用,是使构成细胞的分子产生电离或激发。与X射线、轻带电粒子不同,质子、重离子等重带电粒子穿过生物体,在接近射程终点时电离作用急剧增强,     

应用质子激发X射线分析L615白血病小鼠的血、肝和脾中的某些微量元素

建立了应用质子激发X射线分析生物组织中微量元素的方法。用这种方法分析了正常纯系615小鼠和L615白血病小鼠的血、肝和脾中的Fe,Cu和Zn等元素的浓度。对实验结果进行了初步讨论。     

核分析相关技术用于上海市大气污染特征研究

本文研究了近年来上海市区和郊区大气气溶胶颗粒物的污染状况,采用的多种核分析方法及相关技术有质子激发X荧光分析(PIXE)、激光粒径谱仪(LPS)、同步辐射X射线吸收精细结构(XAFS)和扩展X射线吸收谱精细结构(EXAFS)分析等先进技术.充分发挥核分析技术高灵敏度、快速无损、多元素微量微区同时分析的优势,从大气颗粒物的形貌特征、粒径分布、质量浓度、元素浓度、化学价态等入手,对上海大气可吸入颗粒物PM23和PM1o展开多方位的综合研究.     

用PIXE方法分析人发中微量元素时数据质量问题剖析

头发是人体排泄微量元素的器官之一,头发中微量元素的含量间接地反映人体中微量元素的含量。头发中微量元素的含量能反映一定时间内人体微量元素含量的情况。它可以作为环境条件和人体功能的“指示器”,给出环境污染和人体健康与疾病的信息。而发样又     

A quantitative basis for hair analysis using PIXE

The PIXE technique offers the possibility of scanning a single hair strand longitudinally with a millimetre proton beam for trace elements. However, the accuracy of the method has been questioned since the quantification of the mass concentration has been a serious problem. In this paper a specific beam-hair-detector geometry is assumed, and the correction factor accounting for the proton energy loss and the X-ray absorption in a regular hair is calculated. 43 hair segments from 8 individuals, ranging from 45 to 110 μm in in diameter were analyzed giving a mean value of 4.32% (standard deviation 0.25%) for sulphur, and a mean value of 149 ppm (standard deviation 35 ppm) for zinc. It is shown that the correction is important not only for the determination of the absolute elemental concentrations but also for the determination of their relative longitudinal distributions. The secondary corrections accounting for the inhomogeneous elemental distribution over the cross section and the irregular shape and/or the differing mass density of a hair are also calculated. It is concluded that the accuracy and precision of the PIXE method does not become considerably lower when it is applied to single hair strands, and accuracy and precision below 10% may be reached by implementing the procedure described.     

Ionoluminescence technique for nuclear microprobes

Ionoluminescence (IL) produced by MeV/amu particles in the Nuclear Microprobe carries rich information on the nature of the chemistry and physics in the various types of materials, such as the molecular structure and ion's valence, etc. IL/PIXE methods offer unique ways to study the general luminescence phenomenon by directly relating the trace element information provided by PIXE to IL spectroscopic results. The IL can also be used to identify the organic molecular structure, hence, the combination of the IL data with the PIXE elemental data provide a new tool for biology and medicine studies. One example is the epidermis from the human skin, which exhibits a clear IL. IL is very sensitive to the local chemical environment conditions of the excitation point, therefore, it can be very effective to study the beam modification and beam damage effects. The beam damage problem in the Nuclear Microprobe applications is discussed.     

Limited angle STIM and PIXE tomography of single cells

STIM (scanning transmission ion microscopy) tomography has been shown to be a valuable method for the three-dimensional characterization of microsamples. It has, however, rarely been employed for the study of single cells, since a free-standing sample is needed for an ordinary tomography experiment. This requirement places high demands on sample preparation techniques.In this study cells fixated on a substrate rather than free-standing were used for tomography. Since the substrate prevented a full rotation of the sample an algorithm for limited-angle tomography was devised. STIM projections covering only a limited angular range of ca. 120° were supplemented with simulated projections generated from a back and forth iteration between real space and Radon space. The energy loss caused by the substrate was subtracted from each projection. The cells were reconstructed using filtered backprojection. The surface of the cells as well as some interior structures could be reconstructed.Following the STIM projections a lesser number of PIXE (particle induced X-ray emission) projections were taken in order to obtain information about the elemental distribution of the sample. From the PIXE projections the three-dimensional phosphorus distribution within the cell was reconstructed using limited-angle tomography. Superimposition of the STIM and PIXE tomograms revealed the location of intracellular structures.Whereas STIM tomography is sensitive to density contrast, which are greatest at the surface, PIXE tomography is sensitive to changes in elemental concentration. Hence, the combination of the two methods can be very fruitful, while the limited angle approach can compensate some of the difficulties associated with tomography of single cells, namely preparation difficulties and excessive sample damage.     

“野人”毛发的微量元素谱研究

“野人”被称为世界四大怪之一。我们用PIXE技术测定了5份“野人”毛发、10份灵长类或其他野生动物毛发和9份人发,并用模式识别法对这三类毛发作了鉴定和分类。对数据的统计分析表明,“野人”毛发中的所测元素含量均显著高于动物毛发和人发,而动物毛发中的元素含量不全高于人发。这三类毛发的非线性映照图清楚地指明,“野人”、动物和人都各有他们自己的元素谱特征。     

PIXE characterization of Lebanese excavated amphorae from Jiyeh archeological site

Archaeological excavations were undertaken in the Jiyeh archeological site which is located north of Sidon, identified as the Greco-Roman Porphyreon. The first investigations raised suggest a probable pottery production centre. About 40 sherds were analyzed by Proton Induce X-ray Emission technique PIXE in order to identify and characterize the elemental composition of four types of amphorae, using the 1.7 MV tandem accelerator in Beirut. The analysis protocol provided almost 24 elements in one spectrum, including majors, minors and traces. The elemental composition provided by PIXE and based on 12 most abundant elements, ranging from Mg to Zr, was used in a multivariate statistical program and consequently the studied objects were classify into well defined groups.     

Quality control of coins mint using PIXE and RBS analysis

PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in order to control their minting quality. The coins of interest were 100, 250 and 500 Lebanese Lira (LL), which are mainly bulky metals with or without coated layer. Using 3 MeV protons, proton induced X-ray emission PIXE identified and quantified elements while Rutherford backscattering spectrometry RBS checked the thickness of the coated layer. Indeed, the combination of PIXE and RBS provides a powerful tool to investigate the elemental composition of coins, either modern or ancient. In addition, the experimental protocol was checked by analyzing some other coins of known composition, such as 1-euro and 2-euro.     

质子激发X射线荧光分析法测定头发、肾和肝中的微量元素

本文使用质子激发X射线荧光分析法(PIXE)测定正常人发、肝和肾组织中的微量元素。详细介绍了样品的采集制备、实验测定和定量方法,并且使用标准参考物质小牛肝(NBS)、马肾(IAEA)和比对粉末发样检查校正测量系统的准确性。报道了三种器官组织中近二十种微量元素的含量,初步探讨了人体自身器官组织中微量元素含量分布之间的相互关系。