E. Koltay

Measurements of relative thick target yields for PIGE analysis on light elements in the proton energy interval 2.4–4.2 MeV

In order to extend the energy range of the systematic investigation on relative thick target yields performed by ANTTILA et al2 for 1≤Ep≤2.4 MeV bombarding energies, gamma spectra and yield data are presented for elements Z=3–9, 11–17, 19–21 in the energy range 2.4≤Ep≤4.2 MeV and the results are discussed from the point of view of PIGE analysis.

Experimental and theoretical calibration of a PIXE setup for K and L X-rays

Abstract K and L line calibration has been performed for a PIXE setup by the independent use of experimental and theoretical methods. In the former case, thin film standards of known thicknesses were applied, while in the latter one cross section values were derived from different theoretical models. Programs REV5S and PIXEKL developed here were used for spectrum evaluation and concentration determination, respectively. They proved to be reliable and especially appropriate for routine serial evaluation of spectra measured on samples of nearly identical matrices. As a result of the work, an accurate calibration of the setup has been obtained and it was shown that experimental and theoretical techniques used lead to calibration curves which fit each other reasonably well.

Concentration profile determination by pixe analysis utilizing the variation of beam energy

Abstract The applicability of the PIXE method by varying the beam energy for in-depth analysis was investigated. The measurements were carried out on different Al samples containing Zn and Mg, annealed during different time periods. The Zn concentration profiles for samples with different annealing were determined up to 30 μm. The method has a relatively poor depth resolution but its advantages (non-destructive multi-elemental method, applicable for a wide range of elements) make it useful especially in connection with some other profiling methods.

Enrichment of desert soil elements in Takla Makan dust aerosol

During a Hungarian expedition in 1994 to arid regions of north-western China, atmospheric aerosol samples were collected in the Takla Makan Desert and on some sites in mountains surrounding the Tarim Basin. PIXE data obtained for the composition and enrichment factors of the regional aerosol clearly reflected that a heavy accumulation of salts has been formed in the closed inland basin. When compared to the regional soil composition data published by other authors, it turned out that S and Cl, showing high enrichment relative to average crust composition, are of soil origin.

ON THE DETECTION OF LOW-ENERGY 4He, 12C, 14N, 16O IONS IN PC FOILS AND ITS USE IN NUCLEAR REACTION MEASUREMENTS

Abstract It is shown that by using a proper etching reagent the registration sensitivity of polycarbonate foils can be enhanced and they prove to be very suitable track recorders for alpha-particles emitted from nuclear reactions. At 6 MeV an energy resolution of 0.2 MeV can be achieved when using the track diameters as a measure of the particle energy. A theoretical way to calculate the track parameters important in nuclear reaction measurements involving alpha-particles recorded in polycarbonate foils is given. For this purpose the track etch rate vs residual range curve was determined by a parameter optimization procedure. The energy resolution of the track-diameter method as a function of the particle energy was predicted. In our earlier studies the track-diameter method was mostly used in angular distribution measurements of (d,α) nuclear reactions. In this work it is shown that with polycarbonate foils it can be well applied to excitation function measurements, as well. Such studies are presented for the α0 and α1 groups of the 27Al(p,α) 24Mg reaction in an energy interval between 1540 and 1920 keV. Finally, preliminary results on the track etching properties of low-energy O+, N+, C+ and He+ ions accelerated with a 5MV Van de Graaff generator are given.

Elemental composition of aerosol particles under background conditions in hungary

Abstract The elemental composition of aerosol particles under regional background conditions is determined by using the PIXE method. The results of a sampling program carried out in 1988 and 1989 are presented. It is shown that sulfur and silicon have the highest concentrations indicating that the aerosol is partly of anthropogenic and partly of soil origin. The origin of particles is further discussed on the basis of enrichment factors and elemental ratios. The concentrations measured are compared to the concentrations calculated by a long-range transport model. Some other results of modeling are also mentioned.

PIXE eleemental analysis of erythrocyte and blood plasma samples from human pregnancies

Elemental concentrations of P, S, Cl, K, Ca, Fe, Ni, Cu, Zn, Br, Rb have been determined in erythrocyte and blood plasma samples from normal and diabetic human pregnancies. Average values, the dependence of the concentrations on the time during gestation period, the correlation coefficients for pairs of elements as well as for the same elements in plasma and erythrocyte samples are given. A marked difference appeared in a number of cases between normal and diabetic pregancies.

Levels of 28Si from the 24Mg(α, α)24Mg and 24Mg(α, γ)28Si reactions

Abstract Excitation functions have been measured at six angles for 24 Mg(α, α) 24 Mg up to E α 4.94 MeV. Multi-level R -matrix analysis was performed for nineteen resonances. More than ha of the determined spin-parities and other resonance parameters are new values. The 24 Mg(α, γ) 28 Si studies of Maas et al. were extended up to E α = 5.13 MeV. Resonance strengths and branchin ratios were determined. The γ-ray angular distribution measurement at E α = 3.79 MeV gives J π = 2 + value for the resonance. A comparison of the results obtained in different reaction channel is given and the possibility of clusterisation in some excited states of 28 Si is discussed.

An evaluation of elemental concentrations in atmospheric aerosols over hungary: Regional signatures and long-range transport modelling

Abstract Elemental concentrations for minor and trace elements were measured systematically by PIXE method over long periods in rural sites of Hungary. The data obtained were used to deduce vanadium- and selenium-related concentration ratios as elemental signatures in tracing long-range transport of air masses. The observed variations of the ratios in different measuring periods and a comparison with published data indicate the limitation of this method of tracing. With a source-oriented approach, estimates have been deduced for elemental concentrations and for the contribution to the concentrations by the emissions in Hungary and in neighbouring countries by the aid of a long-range transport model applied to an annual average air trajectory.

Elemental concentrations and regional signatures in atmospheric aerosols over Hungary

Samples of atmospheric particles collected during one year at rural sites were analysed up to 20 elements by PIXE. The average concentrations, enrichment factors and size distribution curves are presented and discussed. Concentration ratios for selected trace elements sometimes used as tracers in following long distance transport of air masses were deduced and compared with the data of Rahn. Conclusions were drawn from these regional signatures on the contribution of eastern European area to the aerosols detected in the artic atmosphere.