Forensic analysis of tempered sheet glass by particle induced X-ray emission (PIXE)

The elemental concentrations of five trace elements in tempered sheet glass fragments were determined using particle-induced X-ray emission (PIXE) spectrometry. The trace element concentrations for calcium, iron, manganese, strontium, and titanium are compared to those obtained by inductively-coupled plasma-atomic emission spectrometry (ICP-AES) following complete digestion by hydrofluoric acid. For these five elements, the absolute concentrations obtained by both methods are shown to agree well over a wide range of concentrations. The limits of detection for trace elements are typically lower for the ICP-AES method. However, we show that the concentrations of these five elements can be accurately measured by the PIXE method. Since PIXE is an entirely non-destructive method, there exists a niche for this technique to be used as a complement to the more sensitive ICP-AES technique in the forensic analysis of sheet glass.     

An external sub-milliprobe optimized for PIXE analysis of archaeological samples

A simple and compact electrostatic quadrupole triplet lens has been designed and fabricated as part of the dedicated beam line for analysis of archaeological samples. A Fortran based ion optics program has been developed to simulate the beam line and lens parameters to achieve a focused sub-millimeter beam spot. The results of simulations are utilized to design and fabricate beam-line elements. The beam spot was measured by wire scanning method to be 0.3 mm for the object-slit width of 1 mm at a distance of 15 mm from the exit window. The improved Ion Beam Analysis setup allows accelerated PIXE analysis of samples whose details are comparable with the beam probe in size. The PIXE spectrum obtained by external analysis of a historical enameled ceramic sample with a sub-millimeter beam is compared with that obtained by in-vacuum standard PIXE analysis.     

Quantitative analysis of a metalloprotein compositional stoichiometry with PIXE and PESA

An absolute measurement of the heavy element concentrations in a dried sample of aqueous protein solution has been combined with the absolute measurement of protein molecular concentration in the same sample. The ratio of these two measurements yields the metal-to-protein compositional stoichiometry of the metalloprotein. This combination of two Ion Beam Analysis techniques (Particle-Induced X-ray Emission and Proton Elastic Scattering Analysis) allows quantitative assessment of the metal atom to protein ratio in metalloproteins without direct measurement of sulfur atoms within the protein for the first time. While these results only demonstrate success with a single well-known metalloprotein, this combination of measurement ratios holds promise for future Ion Beam Analysis studies of metalloproteins.     

A PROGRAM FOR QUANTITATIVE PIXE ANALYSIS OF THICK SAMPLE

A program for quantitative PIXE analysis of thick sample (TSPIXE) without reference material has been developed at Fudan University. Our program can be applied to the energy range of 10 keV to 10 MeV and is suitable for the analysis of all elements with 11 < Z < 92. NBS reference materials were analyzed to provide the experimental test of TSPIXE program.     

GIC4117串列加速器外束PIXE/PIGE分析系统

本文介绍在北京师范大学GIC4117串列加速器上建立的外束PIXE/PIGE分析系统,和基于此系统的薄样品外束PIXE/PIGE定量分析方法。给出了2010年Teflon滤膜采集的361个气溶胶样品外束PIXE分析得到的各元素平均探测限和最低探测限,并同真空PIXE分析探测限进行了比较。利用标准样品给出了激发曲线不同坪区薄样品外束PIGE分析F和Na的探测限,通过测定¹⁹F(p, p′γ)¹⁹F激发的197 keV γ射线得到的F的探测限可达73.9 ng•cm^-2,Na的探测限可达198.9 ng•cm^-2。     

样品位置对外束PIXE分析的影响

通过改变标准样品的前后位置和摆放角度,研究样品位置对外束PIXE分析中Ar、Si、Ca、Fe等元素的特征X射线归一化峰面积的影响,并以此为依据分析外束PIXE对样品定位精度的要求。结果表明：为使由样品位置变化引起的相对误差在5%以内,样品摆放位置需精确到±0.14mm;为使由样品角度引起的相对误差在5%以内,样品摆放角度需精确到±1°。     

External-beam PIXE analysis of small sculptures

Non-destructive analysis of precious art objects is an important tool to solve provenance problems or to facilitate restoration. External beam PIXE analysis is one of the most powerful and popular methods used in this respect. The paper summarises the external beam PIXE set-up at the Accelerator Laboratory in Budapest, and two selected applications are described. Different parts of a small Cambodian metal sculpture probably made in the 11th century were analysed. It was observed that the sculpture was composed of an iron core and an outer bronze shell. This sculptural technique was well known in the Middle-East but no indication has been found about its use in the Far-East, yet. Before its restoration paint traces on a wooden relief of St. Jerome made by an unknown artist in about 1600 were analysed. Different white and red paints were distinguished at selected points and the presence of titanium on a certain part of the relief was attributed to a repainting in modern times.     

A new method to combine IBA of fine aerosols with Radon-222 to determine source characteristics

Accelerator based ion beam analysis (IBA) techniques were used to determine the elemental composition of aerosol samples from four sites near Sydney, Australia. Hourly measurements of atmospheric Radon-222 (radon) concentration were made at the same sites. We evaluate a new method for quantifying the degree of distribution of aerosol sources based on the correlation analysis of two consecutive years (2007-2008) of IBA and radon data.Seasonal cycles and trends in concentrations of key elemental constituents of the sampled aerosols are characterised, and explained in terms of the regional Sydney climatology and proximity of measurement sites to the coast. Site-to-site correlation analysis was then undertaken between elements to quantify the extent to which a source had a regional impact or was only local to a site (site-specific). This was followed by correlation analysis of elements and radon at each site to identify the degree of spatial and temporal uniformity of the source at each site.Silicon concentrations (usually associated with soil sources), were overall well correlated between three of the four sites, indicative of a regional source for three sites and a local source for the fourth site. Conversely, the highest sulfur correlations were observed between sites that were closest together.On a site-by-site basis, radon was well correlated with black carbon and potassium and particularly during winter when domestic heating constitutes a distributed source. However, in summer the correlation of radon with BC and K was poor indicating that the distribution of these sources varies over the summer fetch region. Radon was also positively correlated with silicon and titanium, but the correlation coefficient for the entire data set was smaller than for black carbon. In summer and winter, when fetch regions were constrained by the prevailing meteorology, silicon and titanium showed a better correlation with radon. A small negative correlation was seen between sodium (a marker for sea salt) and radon.     

PIXE analysis of ancient Chinese Changsha porcelain

In this work, proton induced X-ray emission (PIXE) method was applied for the analysis of ancient Chinese Changsha porcelain produced in the Tang dynasty (AD 618–907). A collection of glazed potsherds was obtained in the complex of the famous kiln site at Tongguan, Changsha city, Hunan province. Studies of elemental composition were carried out on ten selected Changsha potsherds. Minor and trace elements such as Ti, Mn, Fe, Co, Cu, Rb, Sr, and Zr in the material of the porcelain glaze were determined. Variation of these elements from sample to sample was investigated. Details of results are presented and discussed.     

Chemical shift measurements of PIXE spectra using a position-sensitive crystal spectrometer

The in-air high-resolution PIXE system composed of a flat analyzing crystal and a position-sensitive proportional counter was applied to measure line shifts of Si K and P K X-rays from various samples induced by an external proton beam. Line shifts that reflect chemical environments of atoms in target samples were determined with the precision of 0.1 eV. The utility of the method for chemical state analysis of minor elements down to the order of 0.1% was demonstrated.     

Charge integration in external-beam PIXE

Direct measurements of the beam current in external-beam PIXE are difficult due to the ionization of air molecules. A method for indirect charge integration has been earlier presented by our research group. The method utilizes the light emission from air molecules excited by the particle beam. The light emission originates from the second positive band system in N₂. The light was measured with a photomultiplier tube. The geometry and the electronics have been improved during the six years that have passed since the method was taken into use. The current from the PM-tube is today about 210 times higher than the particle beam current measured by the means of a Faraday cup. This amplification is useful in the monitoring of small beam currents. The linearity and accuracy of the improved system are discussed.     

Trace metal distribution studies in river water by PIXE

Proton induced X-ray Emission (PIXE) has been used to measure the trace metals especially heavy metals in Chaliyar river water samples to assess the impact of pollutants from the industrial wastes. Water samples were collected in summer and rainy seasons from three different depths along the course of the river. Measurements were carried out with 2 MeV proton beam using a 3 MV tandem pelletron accelerator at Institute of Physics, Bhubaneswar. Results from the water Samples collected in both the seasons show that the concentrations of certain heavy metals like Hg, Zn and Pb are more than the prescribed limits. This is because of pollution due to industrial wastes, indicating a need for improvement in the industrial waste treatment.     

PIXE研究的进展

本文介绍第四届国际PIXE会议上关于PIXE的应用开发和研究进展的情况,PIXE在环境科学、生物医学、材料、地质、考古以及其它领域得到广泛开发利用,与此同时,PIXE在方法学和技术方面也在不断改进。     

Homogeneity study of an Fe impurity in unalloyed Zn using PIXE

We have studied the distribution of an Fe impurity in unalloyed Zn material along line scans in spots of 1 mm diameter each using PIXE. In order to achieve the necessary precision (1%) in the determination of this low Fe content (about 100 mg/kg), a sufficient counting rate of Fe X-rays is needed without overloading the counting electronics with Zn X-rays at the same time. Therefore, the development of our PIXE analysis system had to take into account: (a) optimising the thickness of a Ni absorber foil in order to selectively reduce the counting rate of Zn without adding an unproportionally high Ni counting rate, (b) implementing a triggered ion beam deflection system capable of handling very high counting rates (up to 8 kcps), (c) developing the spectrum evaluation code to take account of the selective absorption by the Ni foil. The results of our PIXE measurements showed an inhomogeneity in Fe of up to 10%, considered too high to accept this zinc material as a new reference material.     

Characterization of human fingernail elements using PIXE technique

PIXE technique was employed in the determination of the major, minor and trace elemental concentrations in finger-nails of 62 healthy young adults (30 females and 32 males), aged between 20 and 37 years. The elemental concentrations in the nails of the analyzed population provide good reference data set for further health studies. The PIXE measurements were carried out using 1.8 MeV collimated proton beam from the 2.5 MV AN-2000 Van de Graaff accelerator at INFN, LNL, Legnaro (Padova), Italy. The results show the presence of twenty elements. Their metabolic roles in humans are presented and discussed. The comparison of our results with those of other authors are also presented.     

用GUPIXWIN软件解谱的PIXE分析系统刻度

使用标准样品比较法,通过计算校正GUPIXWIN中的刻度因子H,对使用GUPIXWIN软件解谱的PIXE分析系统进行了刻度。分析了测得的H值随能量变化的原因,并用刻度后的PIXE系统分析了1组大气颗粒物样品。将GUPIXWIN分析结果与AXIL解谱的结果进行了比较,绝大多数测量结果相对偏差在±10%以内。     

两次PIXE国际横向比对分析结果

介绍了两次ＰＩＸＥ国际横向比对中实验方案的设计思想，对一些具体问题的解决办法以及定量分析中的质量保证和质量控制的实施情况。     

用PIXE和自身对照方式研究肿瘤中痕量元素的变化

用质子X荧光分析法(PIXE)分析了15只小白鼠的S180纤维肉瘤和正常组织中15种元素含量,采用自身对照形式研究痕量元素变化,以消除生物个体的差异。另取健康小鼠作空白,数据作统计分析,结果发现Fe、Zn、As和Cu/Zn以及多种元素比值有明显的差异,并讨论了这些元素与肿瘤的关系。