| 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. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- Orsini, Celso Q, et al.
(författare)
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Variation of Elemental Composition with Particle Size in the St. Louis Aerosol
- 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. 91-96
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Tidskriftsartikel (refereegranskat)abstract
- Detailed particle size distribution of elemental constituents have been determined in the St. Louis aerosol by sampling with cascade impactors for particles >0.25 μm aerodynamic diameter and by analyzing using proton-induced X-ray emission, PIXE, for S, Cl, K, Ca, Ti, Mn, Fe, Zn, Br, and Pb. Two rooftop sites were selected for intensive sampling in industrial and residential locations in St. Louis during February 1974, every 12 h for a 7 d period which included clear, rainy, and snowy weather regimes. The data could be compared with the results of a similar study of the St. Louis aerosol during August 1973 when the weather was generally warm and without rain. Both data sets could also be compared with results of studies of Tallahassee, situated in coastal north Florida, and the north Atlantic marine atmosphere of Bermuda. Although variation in elemental concentrations and their size distributions were observed which could be associated with local weather conditions during the February sampling period, the data set was sufficiently large for meaningful average characteristics to be computed. As examples, two elements of pollution importance, sulfur and iron, show the following comparison between St. Louis and the Florida and Atlantic locations: Sulfur in all data sets was most abundant in the smallest particle size classes. Winter and summer concentration in St. Louis air were the same within a factor of two but generally exceeded north Florida concentrations. Bermuda concentrations were intermediate between St. Louis and north Florida, except for largest particles where sea spray derived material was present. The results reflect the importance of gas phase conversion to particulate forms of sulfur, e.g. sulfate, in all three locations. Iron concentrations in St. Louis generally exceeded those in north Florida for smallest particles and to a lesser extent for larger sizes. Concentrations in Bermuda were about 10-fold lower than in St. Louis for all particle sizes. The results reflect the terrestrial dust origin of iron and also suggest that iron is partially pollution-derived in the St. Louis atmosphere, especially in smaller size ranges.
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