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dc.contributor.authorSauerwein, A.
dc.contributor.authorEndres, J.
dc.contributor.authorNetterdon, L.
dc.contributor.authorZilges, A.
dc.contributor.authorFoteinou, V.
dc.contributor.authorProvatas, G.
dc.contributor.authorKonstantinopoulos, T.
dc.contributor.authorAxiotis, M.
dc.contributor.authorAshley, S. F.
dc.contributor.authorHarissopulos, S.
dc.contributor.authorRauscher, T.
dc.date.accessioned2013-05-24T13:45:10Z
dc.date.available2013-05-24T13:45:10Z
dc.date.issued2012-09-14
dc.identifier.citationSauerwein , A , Endres , J , Netterdon , L , Zilges , A , Foteinou , V , Provatas , G , Konstantinopoulos , T , Axiotis , M , Ashley , S F , Harissopulos , S & Rauscher , T 2012 , ' Investigation of the reaction Ge-74(p,gamma)As-75 using the in-beam method to improve reaction network predictions for p nuclei ' , Physical Review C , vol. 86 , no. 3 , 035802 . https://doi.org/10.1103/PhysRevC.86.035802
dc.identifier.issn2469-9985
dc.identifier.otherPURE: 1610030
dc.identifier.otherPURE UUID: 0a9c3f61-8161-4242-8fa6-009e552c85b1
dc.identifier.otherWOS: 000308737500009
dc.identifier.otherScopus: 84866696915
dc.identifier.urihttp://hdl.handle.net/2299/10673
dc.description.abstractBackground: Astrophysical models studying the origin of the neutron-deficient p nuclides require knowledge of proton capture cross sections at low energy. The production site of the p nuclei is still under discussion but a firm basis of nuclear reaction rates is required to address the astrophysical uncertainties. Data at astrophysically relevant interaction energies are scarce. Problems with the prediction of charged particle capture cross sections at low energy were found in the comparisons between previous data and calculations in the Hauser-Feshbach statistical model of compound reactions. Purpose: A measurement of Ge-74(p,gamma)As-75 at low proton energies, inside the astrophysically relevant energy region, is important in several respects. The reaction is directly important because it is a bottleneck in the reaction flow which produces the lightest p nucleus Se-74. It is also an important addition to the data set required to test reaction-rate predictions and to allow an improvement in the global p + nucleus optical potential required in such calculations. Method: An in-beam experiment was performed, making it possible to measure in the range 2.1 Results: The resulting cross sections were compared to Hauser-Feshbach calculations using the code SMARAGD. Only a constant renormalization factor of the calculated proton widths allowed a good reproduction of both total and partial cross sections. The accuracy of the calculation made it possible to check the spin assignment of some states in As-75. In the case of the 1075-keV state, a double state with spins and parities of 3/2- and 5/2- is needed to explain the experimental partial cross sections. A change in parity from 5/2(+) to 5/2(-) is required for the state at 401 keV. Furthermore, in the case of Ge-74, studying the combination of total and partial cross sections made it possible to test the gamma width, which is essential in the calculation of the astrophysical As-74(n,gamma)As-75 rate. Conclusions: Between data and statistical model prediction a factor of about two was found. Nevertheless, the improved astrophysical reaction rate of Ge-74(p,gamma) (and its reverse reaction) is only 28% larger than the previous standard rate. The prediction of the As-74(n,gamma)As-75 rate (and its reverse) was confirmed, the newly calculated rate differs only by a few percent from the previous prediction. The in-beam method with high-efficiency detectors proved to be a powerful tool for studies in nuclear astrophysics and nuclear structure.en
dc.format.extent13
dc.language.isoeng
dc.relation.ispartofPhysical Review C
dc.subjectSTATISTICAL-MODEL CALCULATIONS
dc.subjectPROCESS NUCLEOSYNTHESIS
dc.subjectMASSIVE STARS
dc.subjectCROSS-SECTIONS
dc.subjectASTROPHYSICAL REACTION-RATES
dc.subjectS-PROCESS
dc.subjectRP-PROCESS
dc.subjectFINITE NUCLEI
dc.subjectOPTICAL-MODEL
dc.subjectPROTON CAPTURE
dc.titleInvestigation of the reaction Ge-74(p,gamma)As-75 using the in-beam method to improve reaction network predictions for p nucleien
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionScience & Technology Research Institute
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1103/PhysRevC.86.035802
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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