Chemical Applications of Ion Accelerators

Koltay, E.; Pászti, F.; Kiss, Á.Z.

doi:10.1007/978-1-4419-0720-2_33

Cited by 11 publications

(9 citation statements)

References 118 publications

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“…Both types of targets were investigated by proton induced X-ray emission (PIXE) technique [39]. For this purpose the PIXE setup of MTA Atomki installed on the left 45 • beamline of the 5-MV Van de Graaff accelerator [40] was used.…”

Section: A Targetsmentioning

confidence: 99%

Cross section of α -induced reactions on Au197 at sub-Coulomb energies

et al. 2019

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Background: Statistical model calculations have to be used for the determination of reaction rates in large-scale reaction networks for heavy-element nucleosynthesis. A basic ingredient of such a calculation is the α-nucleus optical model potential. Several different parameter sets are available in literature, but their predictions of α-induced reaction rates vary widely, sometimes even exceeding one order of magnitude.Purpose: This paper presents the result of α-induced reaction cross-section measurements on gold which could be carried out for the first time very close to the astrophysically relevant energy region. The new experimental data are used to test statistical model predictions and to constrain the α-nucleus optical model potential.Method: For the measurements the activation technique was used. The cross section of the (α,n) and (α,2n) reactions was determined from γ-ray counting, while that of the radiative capture was determined via X-ray counting. Results:The cross section of the reactions was measured below Eα = 20.0 MeV. In the case of the 197 Au(α,2n) 199 Tl reaction down to 17.5 MeV with 0.5-MeV steps, reaching closer to the reaction threshold than ever before. The cross section of 197 Au(α,n) 200 Tl and 197 Au(α,γ) 201 Tl was measured down to Eα = 13.6 and 14.0 MeV, respectively, with 0.5-MeV steps above the (α,2n) reaction threshold and with 1.0-MeV steps below that. Conclusions:The new dataset is in agreement with the available values from the literature, but is more precise and extends towards lower energies. Two orders of magnitude lower cross sections were successfully measured than in previous experiments which used γ-ray counting only, thus providing experimental data at lower energies than ever before. The new precision dataset allows us to find the best-fit α-nucleus optical model potential and to predict cross sections in the Gamow window with smaller uncertainties.

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Section: A Targetsmentioning

confidence: 99%

Cross section of α -induced reactions on Au197 at sub-Coulomb energies

et al. 2019

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“…The precise knowledge of the target (and backing) impurities is also of crucial importance, because alphainduced reactions on low mass impurities could poison the measured gamma spectra. To characterize the targets, the well-known particle induced x-ray emission (PIXE) technique was used [37], too. The energy and the intensity of the proton beam provided by the Van de Graaff accelerator of Atomki was 2 MeV and 1 nA, respectively.…”

Section: A Target Preparation and Characterizationmentioning

confidence: 99%

α -induced reactions on In115 : Cross section measurements and statistical model analysis

et al. 2018

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Background: α-nucleus optical potentials are basic ingredients of statistical model calculations used in nucleosynthesis simulations. While the nucleon+nucleus optical potential is fairly well known, for the α+nucleus optical potential several different parameter sets exist and large deviations, reaching sometimes even an order of magnitude, are found between the cross section predictions calculated using different parameter sets. Purpose: A measurement of the radiative α-capture and the α-induced reaction cross sections on the nucleus 115 In at low energies allows a stringent test of statistical model predictions. Since experimental data are scarce in this mass region, this measurement can be an important input to test the global applicability of α+nucleus optical model potentials and further ingredients of the statistical model. Methods: The reaction cross sections were measured by means of the activation method. The produced activities were determined by off-line detection of the γ rays and characteristic x rays emitted during the electron capture decay of the produced Sb isotopes. Results:The simultaneous measurement of the (α,γ ) and (α,n) cross sections allowed us to determine a best-fit combination of all parameters for the statistical model. The α+nucleus optical potential is identified as the most important input for the statistical model. The best fit is obtained for the new Atomki-V1 potential, and good reproduction of the experimental data is also achieved for the first version of the Demetriou potentials and the simple McFadden-Satchler potential. The nucleon optical potential, the γ -ray strength function, and the level density parametrization are also constrained by the data although there is no unique best-fit combination. Conclusions:The best-fit calculations allow us to extrapolate the low-energy (α,γ ) cross section of 115 In to the astrophysical Gamow window with reasonable uncertainties. However, still further improvements of the α-nucleus potential are required for a global description of elastic (α,α) scattering and α-induced reactions in a wide range of masses and energies.

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“…For thick homogeneous targets in which the bombarding particles are completely stopped and the emitted X-rays are subjected to considerable absorption in the sample, the yield of each X-ray peak can be calculated according to iterative procedures similar to those applied to electron and X-ray excitation [5].…”

Section: Quantitative Analysismentioning

confidence: 99%

“…However, in favourable circumstances and for homogeneous samples, a systematic comparison between the theoretical and experimental calibration methods proves that the determination of elemental concentrations can be performed with an overall accuracy of 3-5% [5,6]. However, in favourable circumstances and for homogeneous samples, a systematic comparison between the theoretical and experimental calibration methods proves that the determination of elemental concentrations can be performed with an overall accuracy of 3-5% [5,6].…”

Section: Quantitative Analysismentioning

confidence: 99%