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Rauscher T.,University of Hertfordshire | Rauscher T.,Institute of Nuclear Research ATOMKI | Rauscher T.,University of Basel
Physical Review C - Nuclear Physics | Year: 2013

It has been shown in previous work that a suppression of the stellar enhancement factor (SEF) occurs in some endothermic reactions at and far from stability. This effect is re-evaluated using the ground-state contributions to the stellar reaction rates, which were shown to be better suited to judging the importance of excited-state contributions than the previously applied SEFs. An update of the tables shown in the latter work is given. The new evaluation finds 2350 cases (out of a full set of 57 513 reactions) for which the ground-state contribution is larger in the reaction direction with a negative reaction Q value than in the exothermic direction, thus providing exceptions to the commonly applied Q value rule. The results confirm the Coulomb suppression effect but lead to a larger number of exceptions than previously found. This is due to the fact that often a large variation in the g.s. contribution does not lead to a sizable change in the SEF. On the other hand, several previously identified cases do not appear anymore because it is found that their g.s. contribution is smaller than inferred from the SEF. © 2013 American Physical Society. Source


Kitagawa A.,Japan National Institute of Radiological Sciences | Fujita T.,Japan National Institute of Radiological Sciences | Muramatsu M.,Japan National Institute of Radiological Sciences | Biri S.,Institute of Nuclear Research ATOMKI | Drentje A.G.,Japan National Institute of Radiological Sciences
Review of Scientific Instruments | Year: 2010

Heavy ion radiotherapy awakens worldwide interest recently. The clinical results obtained by the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan have clearly demonstrated the advantages of carbon ion radiotherapy. Presently, there are four facilities for heavy ion radiotherapy in operation, and several new facilities are under construction or being planned. The most common requests for ion sources are a long lifetime and good stability and reproducibility. Sufficient intensity has been achieved by electron cyclotron resonance ion sources at the present facilities. © 2010 American Institute of Physics. Source


Mohr P.,Diakonie Klinikum Schwabisch Hall GGmbH | Mohr P.,Institute of Nuclear Research ATOMKI
Physical Review C - Nuclear Physics | Year: 2011

Elastic scattering data for 141Pr(α,α)141Pr have been analyzed to derive a new energy-dependent local potential for the 141Pr-α system. This potential is used successfully to predict the cross section of the 141Pr(α,n)144Pm reaction at low energies where new experimental data have become available very recently. In contrast to various global potentials, this new potential is able to reproduce simultaneously elastic scattering data around and above the Coulomb barrier and reaction data below the Coulomb barrier for the 141Pr-α system. Reasons for the partial failure of the global potentials are explained by intrinsic properties of the scattering matrix and their variation with energy. The new local potential may become the basis for the construction of a new global α-nucleus potential. © 2011 American Physical Society. Source


Mohr P.,Diakonie Klinikum Schwabisch Hall GGmbH | Mohr P.,Institute of Nuclear Research ATOMKI | Matic A.,University of Groningen
Physical Review C - Nuclear Physics | Year: 2013

The 18Ne(α,p)21Na reaction is one key for the breakout from the hot CNO cycles to the rp-process. Recent papers have provided reaction rate factors NA which are discrepant by at least one order of magnitude. The compatibility of the latest experimental results is tested, and a partial explanation for the discrepant N A〈σv⌠is given. A new rate factor is derived from the combined analysis of all available data. The new rate factor is located slightly below the higher rate factor found by Matic at low temperatures and significantly below at higher temperatures whereas it is about a factor of 5 higher than the lower rate factor recently published by Salter. © 2013 American Physical Society. Source


Mohr P.,Diakonie Klinikum Schwabisch Hall GGmbH | Mohr P.,Institute of Nuclear Research ATOMKI
Physical Review C - Nuclear Physics | Year: 2013

Angular distributions of elastic 140Ce(α,α)140Ce scattering are analyzed in the framework of the optical model from low energies around the Coulomb barrier up to about 40 MeV. From the local fits the total reaction cross section σreac is extracted. This procedure requires experimental scattering data with small uncertainties. The results for σreac are compared to predictions of different systematic global potentials. It is found that the total reaction cross section σreac is well predicted from all global potentials under study although the reproduction of the angular distributions is not perfect in all cases. In addition, the lower energy limit for the extraction of σreac from elastic scattering angular distributions is analyzed. Finally, the potentials under study are used to calculate the 143Nd(n,α)140Ce cross section, and the predictions are compared to experimental data. © 2013 American Physical Society. Source

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