[en] A system for electrostatic on-demand beam excitation in PIXE analysis has been built and carefully tested. Significantly increased count rate capability without any need for corrections for electronic dead time and with less target deterioration makes the system superior to a traditional system with electronic pile-up rejection. By adding a fast external electronic pulse pile-up rejection system, a pile-up interval of about 250 ns is obtained. The detailed behaviour of the particle beam during deflection and experience from using the system in routine analysis are reported. (Authors)

[en] Specific advantages with Particle Induced X-Ray Emission are: its 1) multielemental capability, especially when combined with nuclear techniques for lighter elements, 32) speed, 3)low detection limits for small samples and 4) accuracy. To make full use of these advantages, analytical parameters have to be chosen optimally and the facility to be carefully designed. This paper describes an experimental facility constructed to permit continous development work to optimize the analytical conditions and to allow the gradual implementation of automatic control. Emphasis is also put on the simultaneous use of proton induced gamma rays from fluorine. The features and the performance of the set-up including its accuracy, precision and experimental detection limits are reported. (Authors)

[en] The Second International Conference on Particle Induced X-ray Emission (PIXE) and its analytical applications was held in Lund, Sweden, June 9-12, 1980. About a hundred papers were presented, including seven invited talks (PIXE and particle scattering, microbeam analysis, applications to aerosols and biological samples). The main impression left by the conference was that both the PIXE method and its applications are in a phase of fast development. Considerable effort has successfully been devoted to optimizing the basic PIXE technique. Also the great advantage of simultaneously getting information about lighter elements and sample mass was reported to have been successfully employed in routine analyses. PIXE, which was initially considered to be a method mainly for thin samples, has also been shown to be competitive for a variety of thick samples. Data from aerosol studies was presented. With the PIXE-method, it is feasible to perform series of measurements over a long period of time, many samples in parallel and/or samples from sites of poor accessibility. However, the advantages of PIXE may be further exploited in aerosol investigations and some promising lines of sampler development were reported. Sample preparation techniques are crucial for applications to biological samples and several laboratories are engaged in such developmental work. However, it was also evident that PIXE is already giving significant contributions to research in biology and medicine

[en] Specific advantages with Particle Induced X-Ray Emission are: its multielemental capability, especially when combined with nuclear techniques for lighter elements, speed, low detection limits for small samples and accuracy. To make full use of these advantages, analytical parameters have to be chosen optimally and the facility to be carefully designed. This paper describes an experimental facility constructed to permit continuous development work to optimize the analytical conditions and to allow the gradual implementation of automatic control. Emphasis is also put on the simultaneous use of proton induced gamma rays from fluorine. The features and the performance of the set-up including its accuracy, precision and experimental detection limits are reported. (author)

[en] Proton scattering was applied to the problem of elemental quantitative analysis of air particulate matter. Elements up through chlorine may be resolved using 16 MeV protons incident upon targets up to about 1 mg/cm² in thickness. Using the FSU Super FN Tandem Accelerator and a large area solid state proton detector, an analysis can be performed in several minutes. Combination of this technique with proton-induced x-ray emission analysis provides a means of quantitative analysis for all elements. These accelerator based methods are being applied to studies of the composition of air particulate matter in diverse locations such as St. Louis, Mo.; Los Angeles, Ca.; several cities in Florida; and Bermuda. 8 figures

[en] Proton induced X-ray emission analysis is useful in measuring changes in particle size distribution of trace elements on exposure of aerosol to the human lung environment and deposition in the air-ways. PIXE analysis is also useful in detecting variations in particle size distributions of elements as they occur in the atmosphere. For the case of lead aerosol along a highway, it is shown that the extent and site of respiratory deposition of particles depend on their size, and the size distribution may vary under urban atmospheric conditions sufficiently to affect respiratory deposition efficiency. (Auth.)

[en] The simultaneous detection of proton-induced X-rays and gamma-rays enables rapid determination of both major and trace elements in thick homogeneous samples. Using protons of energy 2.55 MeV, the atomic numbers of the elements detectable with this technique were Z = 3, 5, 9, 11-13 from gamma-ray analysis and Z = 13-92 from X-ray analysis. Thick target concentrations were determined from a thoroughly made thin target calibration and from matrix-dependent conversion factors calculated from fundamental parameters. The major compositions of samples needed in these calculations are derived in an iterative procedure using the spectra recorded. The method proposed has been tested on six USGS rock standards. Detection limits for one of the standards are presented. Approximately 20 elements were detected in each sample in 5 min irradiations. For elements well above their detection limits, the results are typically accurate to within 5%. The precision of repeated day-to-day analysis is about 2% (one standard deviation). (orig.)

[en] By combining suitable water preconcentration techniques and Particle-Induced X-ray Emission analysis (PIXE), we have developed a procedure for multielemental sub-ppb water analysis. The preconcentration step consists of adsorbing the metals in the form of organic chelates onto activated carbon, which is pressed to a tablet and then analysed by PIXE. For very low concentrations and small volumes of water, a mini-tablet technique of sample preparation is employed. The versatility of the chelating-adsorption-PIXE procedure is demonstrated for several different kinds of water. (orig.)

[en] A system for electrostatic on-demand beam excitation in PIXE analysis has been built and carefully tested. Significantly increased count rate capability without any need for corrections for electronic dead time and with less target deterioration makes the system superior to a traditional system with electronic pile-up rejection. By adding a fast external electronic pulse pile-up rejection system, a pile-up interval of about 250 ns is obtained. The detailed behaviour of the particle beam during deflection and experience from using the system in routine analysis are reported. (orig.)

[en] A general mass calibration procedure of a PIXE set-up is described. As an example, the results of the calibration of the PIXE set-up in Lund are given. For the calibration commercially available standards were used. The parameters of a physical model were adjusted to fit a calibration curve. To decrease errors due to inhomogeneities of the standard foils, the average from our different pieces of each foil was taken. The accuracy of the calibrated system in Lund is estimated to be better than 5% for individual elements and still less for ratios of adjacent elements. For long-term quality control of the results, a special sample has been designed. This consists of a thick silver plate with a small copper spot in the centre. It is very sensitive to small changes in a PIXE set-up. By analysing this sample periodically, mistakes in the arrangement are promptly detected - a feature which is much appreciated in a mixed research, development and routine analysis laboratory. Also a measure of the long-term stability is obtained. For the Lund system, the long-term stability is 2,5% for a homogeneous sample and 4% for a small (inhomogeneous) sample. (orig.)