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Buch ; Konferenzbeitrag: Nuclear physics in astrophysics - II

Gyürky, Gy

20th international Nuclear Physics Divisional conference of the European Physical Society : Debrecen, Hungary, 16th - 20th May 2005 ; abstracts

(Europhysics conference abstracts ; 29,A)

2005

Körperschaft	European Physical Society / Nuclear Physics Division
Veranstaltung/Kongress	International Nuclear Physics Divisional conference of the European Physical Society (20, 2005.05.16-20, Debrecen)
Verfasserangabe	ed.: Gy. Gyürky
Serientitel	Europhysics conference abstracts ; 29,A
Sprache	Englisch
Umfang	XV, 92 S
Verlag	European Physical Society
Erscheinungsort	Mulhouse
Dokumenttyp	Buch ; Konferenzbeitrag
ISBN	2914771231 ; 9782914771238
Datenquelle	Katalog der Technische Informationsbibliothek Hannover

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Artikel ; Online: Successful Prediction of Total α-Induced Reaction Cross Sections at Astrophysically Relevant Sub-Coulomb Energies Using a Novel Approach.

Mohr, P / Fülöp, Zs / Gyürky, Gy / Kiss, G G / Szücs, T

Physical review letters

2020 Band 124, Heft 25, Seite(n) 252701

Abstract: The prediction of stellar (γ,α) reaction rates for heavy nuclei is based on the calculation of (α,γ) cross sections at sub-Coulomb energies. These rates are essential for modeling the nucleosynthesis of so-called p nuclei. The standard calculations in ... ...

Abstract	The prediction of stellar (γ,α) reaction rates for heavy nuclei is based on the calculation of (α,γ) cross sections at sub-Coulomb energies. These rates are essential for modeling the nucleosynthesis of so-called p nuclei. The standard calculations in the statistical model show a dramatic sensitivity to the chosen α-nucleus potential. The present study explains the reason for this dramatic sensitivity which results from the tail of the imaginary α-nucleus potential in the underlying optical model calculation of the total reaction cross section. As an alternative to the optical model, a simple barrier transmission model is suggested. It is shown that this simple model in combination with a well-chosen α-nucleus potential is able to predict total α-induced reaction cross sections for a wide range of heavy target nuclei above A≳150 with uncertainties below a factor of 2. The new predictions from the simple model do not require any adjustment of parameters to experimental reaction cross sections whereas in previous statistical model calculations all predictions remained very uncertain because the parameters of the α-nucleus potential had to be adjusted to experimental data. The new model allows us to predict the reaction rate of the astrophysically important ^{176}W(α,γ)^{180}Os reaction with reduced uncertainties, leading to a significantly lower reaction rate at low temperatures. The new approach could also be validated for a broad range of target nuclei from A≈60 up to A≳200.
Sprache	Englisch
Erscheinungsdatum	2020-07-08
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	208853-8
ISSN	1079-7114 ; 0031-9007
ISSN (online)	1079-7114
ISSN	0031-9007
DOI	10.1103/PhysRevLett.124.252701
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Buch ; Konferenzbeitrag: Nuclear physics in astrophysics

Gyürky, Gy

17th international Nuclear Physics Divisional conference of the European Physical Society : Debrecen, Hungary, 30th September - 14th October 2002 ; abstracts

(Europhysics conference abstracts ; 26,H)

2002

Körperschaft	European Physical Society / Nuclear Physics Division
Veranstaltung/Kongress	International Nuclear Physics Divisional conference of the European Physical Society (17, 2002.09.30-10.14, Debrecen)
Verfasserangabe	supported by the European Commission ... Ed.: Gy. Gyürky
Serientitel	Europhysics conference abstracts ; 26,H
Sprache	Englisch
Umfang	XVII, 89 S
Verlag	European Physical Soc
Erscheinungsort	Mulhouse
Dokumenttyp	Buch ; Konferenzbeitrag
ISBN	2914771088 ; 9782914771085
Datenquelle	Katalog der Technische Informationsbibliothek Hannover

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Artikel ; Online: Half-life measurement of

Gyürky, Gy / Halász, Z / Kiss, G G / Szücs, T / Fülöp, Zs

Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine

2019 Band 148, Seite(n) 87–90

Abstract: The literature half-life value ... ...

Abstract	The literature half-life value of
Sprache	Englisch
Erscheinungsdatum	2019-03-20
Erscheinungsland	England
Dokumenttyp	Journal Article
ZDB-ID	1142596-9
ISSN	1872-9800 ; 0883-2889 ; 0969-8043
ISSN (online)	1872-9800
ISSN	0883-2889 ; 0969-8043
DOI	10.1016/j.apradiso.2019.03.021
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Measurement of the ^{13}C(α, n_{0})^{16}O Differential Cross Section from 0.8 to 6.5 MeV.

deBoer, R J / Febbraro, M / Bardayan, D W / Boomershine, C / Brandenburg, K / Brune, C / Coil, S / Couder, M / Derkin, J / Dede, S / Fang, R / Fritsch, A / Gula, A / Gyürky, Gy / Hackett, B / Hamad, G / Jones-Alberty, Y / Kelmar, R / Manukyan, K /

Matney, M / McDonaugh, J / Meisel, Z / Moylan, S / Nattress, J / Odell, D / O'Malley, P / Paris, M W / Robertson, D / Shahina / Singh, N / Smith, K / Smith, M S / Stech, E / Tan, W / Wiescher, M

Physical review letters

2024 Band 132, Heft 6, Seite(n) 62702

Abstract: The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of- ...

Abstract	The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.
Sprache	Englisch
Erscheinungsdatum	2024-02-23
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	208853-8
ISSN	1079-7114 ; 0031-9007
ISSN (online)	1079-7114
ISSN	0031-9007
DOI	10.1103/PhysRevLett.132.062702
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Half-life measurement of 66Ga with γ-spectroscopy.

Gyürky, Gy / Farkas, J / Halász, Z / Szücs, T

Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine

2012 Band 70, Heft 1, Seite(n) 278–281

Abstract: The half-life of (66)Ga, an isotope very important for high-energy efficiency calibration of γ-detectors, has been measured using γ-spectroscopy. In order to reduce systematic uncertainties, different source production methods and γ-counting conditions ... ...

Abstract	The half-life of (66)Ga, an isotope very important for high-energy efficiency calibration of γ-detectors, has been measured using γ-spectroscopy. In order to reduce systematic uncertainties, different source production methods and γ-counting conditions have been applied. A half-life value of t(1/2)=(9.312±0.032)h has been obtained in agreement with a recent measurement but in contradiction with some of the earlier results.
Mesh-Begriff(e)	Algorithms ; Gallium Radioisotopes/analysis ; Gallium Radioisotopes/chemistry ; Half-Life ; Radiation Dosage ; Radiometry/methods ; Spectrometry, Gamma/methods
Chemische Substanzen	Gallium Radioisotopes
Sprache	Englisch
Erscheinungsdatum	2012-01
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1142596-9
ISSN	1872-9800 ; 0883-2889 ; 0969-8043
ISSN (online)	1872-9800
ISSN	0883-2889 ; 0969-8043
DOI	10.1016/j.apradiso.2011.08.004
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Buch ; Online: Low Energy measurement of the $^{96}\mathrm{Zr}(\alpha,n)^{99}\mathrm{Mo}$ reaction cross section and its impact on weak r-process nucleosynthesis

Kiss, G. G. / Szegedi, T. N. / Mohr, P. / Jacobi, M. / Gyürky, Gy. / Huszánk, R. / Arcones, A.

2020

Abstract: Lighter heavy elements beyond iron and up to around silver can form in neutrino-driven ejecta in core-collapse supernovae and neutron star mergers. Slightly neutron-rich conditions favour a weak r-process that follows a path close to stability. Therefore, ...

Abstract	Lighter heavy elements beyond iron and up to around silver can form in neutrino-driven ejecta in core-collapse supernovae and neutron star mergers. Slightly neutron-rich conditions favour a weak r-process that follows a path close to stability. Therefore, the beta decays are slow compared to the expansion time scales, and ($\alpha$,n) reactions become critical to move matter towards heavier nuclei. The rates of these reactions are calculated with the statistical model and their main uncertainty, at energies relevant for the weak r-process, is the $\alpha$+nucleus optical potential. There are several sets of parameters to calculate the $\alpha$+nucleus optical potential leading to large deviations for the reaction rates, exceeding even one order of magnitude. Recently the $^{96}$Zr($\alpha$,n)$^{99}$Mo reaction has been identified as a key reaction that impacts the production of elements from Ru to Cd. Here, we present the first cross section measurement of this reaction at energies (6.22 MeV $\leq$ E$_\mathrm{c.m.}$ $\leq$ 12.47 MeV) relevant for the weak r-process. The new data provide a stringent test of various model predictions which is necessary to improve the precision of the weak r-process network calculations. The strongly reduced reaction rate uncertainty leads to very well-constrained nucleosynthesis yields for $Z = 44 - 48$ isotopes under different neutrino-driven wind conditions.
Schlagwörter	Nuclear Experiment
Thema/Rubrik (Code)	660
Erscheinungsdatum	2020-09-28
Erscheinungsland	us
Dokumenttyp	Buch ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Constraining the astrophysical origin of the p-nuclei through nuclear physics and meteoritic data.

Rauscher, T / Dauphas, N / Dillmann, I / Fröhlich, C / Fülöp, Zs / Gyürky, Gy

Reports on progress in physics. Physical Society (Great Britain)

2013 Band 76, Heft 6, Seite(n) 66201

Abstract: A small number of naturally occurring, proton-rich nuclides (the p-nuclei) cannot be made in the s- and r-processes. Their origin is not well understood. Massive stars can produce p-nuclei through photodisintegration of pre-existing intermediate and ... ...

Abstract	A small number of naturally occurring, proton-rich nuclides (the p-nuclei) cannot be made in the s- and r-processes. Their origin is not well understood. Massive stars can produce p-nuclei through photodisintegration of pre-existing intermediate and heavy nuclei. This so-called γ-process requires high stellar plasma temperatures and occurs mainly in explosive O/Ne burning during a core-collapse supernova. Although the γ-process in massive stars has been successful in producing a large range of p-nuclei, significant deficiencies remain. An increasing number of processes and sites has been studied in recent years in search of viable alternatives replacing or supplementing the massive star models. A large number of unstable nuclei, however, with only theoretically predicted reaction rates are included in the reaction network and thus the nuclear input may also bear considerable uncertainties. The current status of astrophysical models, nuclear input and observational constraints is reviewed. After an overview of currently discussed models, the focus is on the possibility to better constrain those models through different means. Meteoritic data not only provide the actual isotopic abundances of the p-nuclei but can also put constraints on the possible contribution of proton-rich nucleosynthesis. The main part of the review focuses on the nuclear uncertainties involved in the determination of the astrophysical reaction rates required for the extended reaction networks used in nucleosynthesis studies. Experimental approaches are discussed together with their necessary connection to theory, which is especially pronounced for reactions with intermediate and heavy nuclei in explosive nuclear burning, even close to stability.
Sprache	Englisch
Erscheinungsdatum	2013-06
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	205657-4
ISSN	1361-6633 ; 0034-4885
ISSN (online)	1361-6633
ISSN	0034-4885
DOI	10.1088/0034-4885/76/6/066201
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Proton-Capture Rates on Carbon Isotopes and Their Impact on the Astrophysical ^{12}C/^{13}C Ratio.

Skowronski, J / Boeltzig, A / Ciani, G F / Csedreki, L / Piatti, D / Aliotta, M / Ananna, C / Barile, F / Bemmerer, D / Best, A / Broggini, C / Bruno, C G / Caciolli, A / Campostrini, M / Cavanna, F / Colombetti, P / Compagnucci, A / Corvisiero, P / Davinson, T /

Depalo, R / Di Leva, A / Elekes, Z / Ferraro, F / Formicola, A / Fülöp, Zs / Gervino, G / Gesuè, R M / Guglielmetti, A / Gustavino, C / Gyürky, Gy / Imbriani, G / Junker, M / Lugaro, M / Marigo, P / Masha, E / Menegazzo, R / Paticchio, V / Perrino, R / Prati, P / Rapagnani, D / Rigato, V / Schiavulli, L / Sidhu, R S / Straniero, O / Szücs, T / Zavatarelli, S

Physical review letters

2023 Band 131, Heft 16, Seite(n) 162701

Abstract: The ^{12}C/^{13}C ratio is a significant indicator of nucleosynthesis and mixing processes during hydrogen burning in stars. Its value mainly depends on the relative rates of the ^{12}C(p,γ)^{13}N and ^{13}C(p,γ)^{14}N reactions. Both reactions have been ...

Abstract	The ^{12}C/^{13}C ratio is a significant indicator of nucleosynthesis and mixing processes during hydrogen burning in stars. Its value mainly depends on the relative rates of the ^{12}C(p,γ)^{13}N and ^{13}C(p,γ)^{14}N reactions. Both reactions have been studied at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Italy down to the lowest energies to date (E_{c.m.}=60 keV) reaching for the first time the high energy tail of hydrogen burning in the shell of giant stars. Our cross sections, obtained with both prompt γ-ray detection and activation measurements, are the most precise to date with overall systematic uncertainties of 7%-8%. Compared with most of the literature, our results are systematically lower, by 25% for the ^{12}C(p,γ)^{13}N reaction and by 30% for ^{13}C(p,γ)^{14}N. We provide the most precise value up to now of 3.6±0.4 in the 20-140 MK range for the lowest possible ^{12}C/^{13}C ratio that can be produced during H burning in giant stars.
Sprache	Englisch
Erscheinungsdatum	2023-11-05
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	208853-8
ISSN	1079-7114 ; 0031-9007
ISSN (online)	1079-7114
ISSN	0031-9007
DOI	10.1103/PhysRevLett.131.162701
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Coulomb suppression of the stellar enhancement factor.

Kiss, G G / Rauscher, T / Gyürky, Gy / Simon, A / Fülöp, Zs / Somorjai, E

Physical review letters

2008 Band 101, Heft 19, Seite(n) 191101

Abstract: It is commonly assumed that reaction measurements for astrophysics should be preferably performed in the direction of a positive Q value to minimize the impact of the stellar enhancement factor, i.e., the difference between the laboratory rate and the ... ...

Abstract	It is commonly assumed that reaction measurements for astrophysics should be preferably performed in the direction of a positive Q value to minimize the impact of the stellar enhancement factor, i.e., the difference between the laboratory rate and the actual stellar rate. We show that the stellar effects can be minimized in the charged particle channel, even when the reaction Q value is negative. As a demonstration, the cross section of the astrophysically relevant 85Rb(p,n)85Sr reaction has been measured by activation between 2.16 < or = Ec.m. < or = 3.96 MeV and the astrophysical reaction rate for (p, n) as well as (n, p) is directly inferred from the data. The presented arguments are also relevant for other alpha- and proton-induced reactions in the p and rp processes. Additionally, our results confirm a previously derived modification of a global optical proton potential.
Sprache	Englisch
Erscheinungsdatum	2008-11-07
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	208853-8
ISSN	1079-7114 ; 0031-9007
ISSN (online)	1079-7114
ISSN	0031-9007
DOI	10.1103/PhysRevLett.101.191101
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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