Á.Z. Kiss

The new ATOMKI scanning proton microprobe

Abstract The scanning proton microprobe of the institute of nuclear research (ATOMKI) in Debrecen is based on an Oxford Microbeams coupled quadrupole doublet focussing system built up to the 0° beam line of the 5 MV single ended Van de Graaff accelerator. With the setup described here PIXE analysis, Rutherford backscattering spectrometry and detection of backscattered secondary electrons can be carried out simultaneously. A modified version of the PIXYKLM computer program developed in the institute is used for the evaluation of the PIXE spectra. Applications discussed are related to investigations performed on metal archaeological samples and individual aerosol particles.

Thick target γ-ray yields for light elements measured in the deuteron energy interval of 0.7–3.4 MeV

Abstract With the aim of providing missing basic data for deuteron-induced γ-ray emission (DIGE, or d-PIGE) analysis a completion of our earlier work (Kiss et al., 1994) has been performed. Typical γ-ray spectra, tables for the most suitable γ-ray lines for elemental analysis and a complete series of absolute thick-target yields for the most characteristic γ-rays of elements with Z=3–20 (except for Be, Ne, P and Ar) in the deuteron energy range of 0.7–3.4 MeV are presented. An analytical formula fitting well the measured yield curves is suggested for the yield calculations in elemental analysis, and also for the effective design and operation of low background experiments. The capability of this method is illustrated in the examples by spectra taken on an industrial glass and an obsidian sample.

Proton beam micromachining on PMMA, Foturan and CR-39 materials

In this paper we investigate further the potential of proton beam micromachining (PBM) on three different materials: the polymers PMMA and CR-39, and the photowritable glass Foturan. A focused beam of 2 MeV protons delivered by the nuclear microprobe of ATOMKI was used to pattern these materials. The parameters of PBM and the obtained structures are presented.

Realization of the simultaneous micro-PIXE analysis of heavy and light elements at a nuclear microprobe

Abstract A new in-vacuum micro-PIXE experimental set-up has been realised at an Oxford-type scanning nuclear microprobe facility. It is based on the simultaneous use of an ultra thin windowed detector and a conventional Be-windowed one for the measurement of the characteristic X-rays of light and heavier elements in the E≈0.2–6 keV and E>4 keV energy ranges, respectively. Complete analytical characterisation of samples from carbon to uranium is possible in a single irradiation process. Performance and technical developments are described in detail.

Magnetic spherules: Cosmic dust or markers of a meteoritic impact?

Abstract Magnetic spherules from several localities in Hungary were analyzed and the results were compared to analytical data of similar objects found in Japan, Slovakia and Hawaii. The studies were carried out using micro-PIXE technique. On the basis of morphological features and elemental compositions it was concluded that signs of a new meteoritic impact could be found.

Thick target yields of deuteron induced gamma-ray emission from light elements

Abstract To provide basic data for deuteron induced γ-ray emission (DIGME) analysis measurements were made of the thick-target γ-ray yields, produced by bombarding samples of Z = 3–19 elements (except Be, Ne, P and Ar) with 0.7 ⩽ Ed ⩽ 3.4 MeV deuterons. The absolute thick-target yield curves of the most suitable γ-rays for elemental analysis are presented. A direct comparison with γ-yields from PIGME is also given.

Application of a Clover-Ge-BGO detector system for PIGE measurements at a nuclear microprobe

Abstract The application of a high efficiency Clover–Ge–BGO detector system for PIGE elemental analysis at the Debrecen nuclear microprobe is demonstrated. Advantages and disadvantages of this facility are discussed. Detection limits for Li, B, F, Na, Al and Si in different sample matrixes are presented.

Stopping powers of 1.5–7.2 MeV 4He ions in Havar, nickel, Kapton and Mylar

Abstract Stopping powers of 1.5–7.2 MeV 4 He ions in Havar, nickel, Kapton and Mylar have been determined in transmission geometry. For Mylar, several foil thicknesses were used (3.7, 6.7, 12.1 μm) to check the foil thickness influence on the results. The stopping power values obtained were found to be independent of the foil thickness within the experimental accuracy of the present study (3%). The experimental values are compared with calculated values obtained by using Braggs rule and the Ziegler semiempirical parameters. The available literature data is surveyed and compared with the values obtained in the present study.

Contribution of PIGE technique to the study of obsidian glasses

Abstract An application of the particle induced gamma-ray emission (PIGE) method with the use of a CLOVER-Ge-BGO detector system (Elekes et al., 1999) for the analysis of source materials of obsidians of archaeological use is reported in this work. Grouping and association of samples resulted via various magmatic processes, with diverse provenances, is detailed based on the light element concentration data. A comparison of PIGE with the laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) on heavier elements is presented.

Calibration of an UTW Si(Li) detector in the 0.28–22.1 keV energy range at a nuclear microprobe

Abstract The efficiency of an ultra thin windowed Si(Li) detector has been determined experimentally in the photon energy range of 0.28–22.1 keV at the Debrecen scanning nuclear microprobe facility. The calibration technique was based on the measurement of thick targets made from pure elements and chemical compounds by PIXE technique. Characteristic X-ray spectra were fitted and PIXE cross-sections were calculated by the new version of the PIXEKLM program package. The efficiency function was determined by fitting the detector parameters in order to minimize the difference between the measured and calculated efficiency values. The accuracy of the method is estimated to be 20–10% in the 0.28–1 keV energy range and 10–5% above 1 keV. An overview of theoretical and experimental aspects of the efficiency calibration procedure will be presented.