Micro-PIXE analysis

Faiz et al. (1996) have applied micro-PIXE analysis to study solute distributions in a single crystal sample of YiBa2Cu307 5 high temperature superconductor (YBCO) of dimensions 1.3 mm x 1.5 mm x 75 pm. It contained a small secondary crystal overgrowth of dimensions 340 x 340 x 100 pm3. The interface region between the smaller crystal and the base crystal was covered with a material which appeared to be residual flux. The instrument employed a 2.5 MeV focused proton beam of about 4 pm resolution, which could scan an area of 500 x 500 pm2 on the sample surface. The microbeam current was kept low (typically about 30 pA) to avoid any damage to the sample. 

As mentioned above, it is possible to maintain insoluble particles, which were scavenged by raindrop, on individual raindrop replicas by collodion film technique. These insoluble particles are the target of micro-PIXE analysis. An example of the elemental map for Si, S, Cl, K, Ca, and Fe is drawn in Fig. 8. Each elemental map was drawn on the 128 x 128 pixels by scanning of about 1 pm micro beam on the sample surface. Because the residual particles were retained on a raindrop replica as several clusters, we could not radiate the microbeam to individual residual particles. However, the visualized elemental maps of six element types in several particle clusters enable us to estimate the chemical mixing state of raindrop residual particles. In addition, it is also presumed that the chemical transformation of dust particles is made by wet scavenging processes. 

As a complement to SRXRF, micro-PIXE analysis could also be performed to obtain quantitative element concentration on groups of several hundred cells on the same samples to complete SRXRF imaging of single cells. In the above SRXRF study by Ortega et al.J cellular iron and zinc concentrations (mgg dry mass) could be obtained by PIXE quantitative micro-analysis by the mean... 

Neutron Activation Analysis X-Ray Fluorescence Particle-Induced X-Ray Emission Particle-Induced Nuclear Reaction Analysis Rutherford Backscattering Spectrometry Spark Source Mass Spectrometry Glow Discharge Mass Spectrometry Electron Microprobe Analysis Laser Microprobe Analysis Secondary Ion Mass Analysis Micro-PIXE... 

PIGE is a rapid, non-destructive technique that is employed in the analysis of light elements such as lithium (10-100 ppm limit of detection), boron (500-1000 ppm limit of detection), and fluorine (1-10 ppm limit of detection), which are often difficult to determine by other analytical means. Because the technique is based upon specific nuclear reactions, the sensitivity of PIGE varies greatly from isotope to isotope, and this non-uniformity of sensitivity has limited its widespread use as a complementary technique to micro-PIXE. 

In 2006, Lobinski et al.1 reported on the imaging and speciation analysis of trace elements to study the element distribution, oxidation state, metal site and metal structure in biological environments using mass spectrometric techniques (LA-ICP-MS, SIMS, MALDI-MS) and non-mass-spectrometric techniques such as micro-PIXE (proton induced X-ray emission), XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) -the latter two techniques are very sensitive due the use of a more intense synchrotron beam.1... 

The application of PIXE (Proton Induced X-Ray Emission) and micro-PIXE to quantitative analysis of impurities in polyethylene are described. The equipment, sources of background which affect the sensitivity and the precision of PIXE measurements are discussed for both thick and thin targets. A number of applications of micro-PIXE to the identification and location of trace elements in the "Trees" found in the polymer insulation of HV cables are presented. 

Electrical trees are essentially breakdown channels whose size, typically 50 to 200 microns, together with the large variations in impurity concentrations in the surrounding polyethylene, makes the identification of the impurities associated with both kinds of trees very difficult by traditional techniques. The use of micro-PIXE for the location and analysis of trace elements in electrical and water trees found in the polyethylene insulation of high voltage cables will be described. 

Data Analysis. For both the macro- and micro-PIXE systems an on line display of the X-ray and RBS spectra is provided by an LSI 11/23, while detailed analysis of the RBS and PIXE spectra are performed using the programs RUMP (1L) and MENUGF (UL) The latter analyzes the 1024... 

Microbeam Particle Induced X-ray Emission (PIXE), often called micro-PIXE, was used for single particle analysis. The greatest advantage of this system is excellent detection limits in the order of 10 -10 g. It also has the merit of a multielement non-destmctive technique with a wide range of elements for various samples. 

Aerosol work has also profited from micro-PIXE, as single particle analysis has become feasible. Accurate correlation between the chemical composition of such particles and their size and shape provides information about the sources of the particles and about the transformations that take place during atmospheric transport. In other environmental studies, micro-PIXE has been used to measure the uptake of trace elements in plants, roots, and trees. In parti cular, tree rings, which also record time information, have been analyzed in several laboratories. 

Particle-induced X-ray emission (PIXE) is an elemental analysis technique that employs a beam of energetic heavy charged particles (usually protons of 1-4 MeV) to induce element-specific X-ray emission. Depending on the sample material and thickness and on the conditions of the analysis, the technique offers detection limits at the 0.1-10 mg kg concentration level for low-Z matrices. Applied in nuclear microprobes, micro-PIXE combines a high sensitivity with the possibility of providing elemental maps with a lateral resolution in the sub-micrometer range. 

From the analysis of several archaeological samples by micro-PIXE, Neff and Dillmann (2001) have shown that ores containing important amount of phosphorus were used in ancient Europe to obtain iron by two different processes called the direct one and the indirect one. Phosphorus content was quantified as the heterogeneous phosphorus distribution was observed in the samples. The results confirm the fact that refining of phosphorus pig iron was possible with ancient refining processes. Moreover it seems that the phosphorus distribution ratio could be a discriminating factor to identify the iron making process. 

PIXE with a proton microprobe has also been developed and has been applied to elemental distribution in plant and animal tissues, and human blood cells and tumors. Further, 3D micro-PIXE also has been developed to perform depth analysis recently and has a spatial resolution of 4 pm by using characteristic titanium K X rays (4.558 keV) produced by 3 MeV protons with beam spot size of 1 pm. ... 

The high-resolution requirement can be achieved using micro-PIXE (p-PIXE) analysis. The detection sensitivity of p-PIXE can reach 1-10 pgg The spatial resolution is typically in the micrometer range, but 0.2 pm is achievable for the latest high-resolution instruments. ... 

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