| 1. |
- Ahlberg, Mats, et al.
(författare)
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Proton-Induced X-Ray Analysis of Steel Surfaces for Microprobe Purposes
- 1975
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 123:2, s. 385-393
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Tidskriftsartikel (refereegranskat)abstract
- A study of the detection limits for the elements with Z = 15-92 in thick target steel surfaces using proton-induced X-ray technique has been performed. Samples were irradiated with a broad proton beam of 2 mm diameter and the X-rays were detected by a Si(Li) detector. Detection limits at levels down to the order of 10 ppm were achieved with simultaneous measurement of several elements. Mylar and chromium absorbers were introduced in front of the semiconductor detector and irradiations at two different proton energies (1.0 and 2.5 MeV) were carried out in order to elucidate their effects on detection limits. The results are valid for microbeam analysis.
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| 2. |
- Akselsson, Roland, et al.
(författare)
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A Beam Mapping Method
- 1971
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 91:4, s. 663-664
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Bohgard, Mats, et al.
(författare)
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MeV Protons for the Characterization of Aerosols in Work Environments
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 459-463
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Tidskriftsartikel (refereegranskat)abstract
- In this paper the advantages of accelerator-based chemical analysis of work environment aerosols are discussed. Use of the PIXE method is central, but in order to take full advantage of the possibilities of an accelerator laboratory, it should be combined with nuclear methods such as particle-induced nuclear reactions and/or particle scattering for simultaneous measurements of light elements. It is also important to develop optimum sampling techniques for the analytical methods required. Some information about the current set-up in Lund is given. In a companion paper, the potential of PIXE for work environment tasks is illustrated by a summary of the design of two major studies. Some results are also included.
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| 4. |
- Carlsson, Lars-Eric, et al.
(författare)
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PIXE Analysis of Samples of Intermediate Thickness
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 179-183
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for making accurate matrix corrections in PIXE analyses of samples of intermediate thickness has been developed. The transmission of a collimated X-ray beam through different parts of the sample is measured with a Si(Li) detector to determine the thickness and shape of the sample. Experiments have been performed using uniform polymer foils doped with known concentrations of different elements and with thicknesses ranging from 1.5 to 11 mg/cm2. The results from these samples indicate that the accuracy of the correction procedure is better than 5%. The correction procedure has been applied to, e.g., samples obtained in single orifice cascade impactors.
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| 5. |
- Carlsson, Lars-Eric, et al.
(författare)
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Rapid Determination of Major and Trace Elements in Geological Material with Proton-Induced X-Ray and Gamma-Ray Emission
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 531-537
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Tidskriftsartikel (refereegranskat)abstract
- 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 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).
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| 6. |
- Desaedeleer, Georges G, et al.
(författare)
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Monitoring Aerosol Elemental Composition in Particle Size Fractions for Predicting Human Respiratory Uptake
- 1977
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 142:1-2, s. 97-99
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Johansson, Eva-Marta, et al.
(författare)
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A Chelating Agent - Activated Carbon - PIXE Procedure for Sub-ppb Analysis of Trace Elements in Water
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 221-226
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Johansson, Gerd, et al.
(författare)
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Calibration and Long-Term Stability of a PIXE Set-Up
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 81-88
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Tidskriftsartikel (refereegranskat)abstract
- 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 four 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.
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| 9. |
- Johansson, Thomas B, et al.
(författare)
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X-Ray Analysis: Elemental Trace Analysis at the 10-12 g Level
- 1970
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 84:1, s. 141-143
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Tidskriftsartikel (refereegranskat)abstract
- Using protons in the MeV region as excitation source and a high resolution Si(Li)-detector, X-ray analysis is capable of detecting many elements at the 10−12 g level simultaneously.
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| 10. |
- Kaufmann, Henry C., et al.
(författare)
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REX - A Computer Programme for PIXE Analysis
- 1977
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 142:1-2, s. 251-257
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Tidskriftsartikel (refereegranskat)abstract
- The implementation of a physics-based model for non-linear least-squares analysis of proton-induced X-ray emission spectra via a Fortran programme REX is discussed. The modelling of distinct spectral components and of the physical effects involved is briefly discussed. Results are presented in graphical and tabular form. The limitations of the present model are discussed and future refinements indicated.
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