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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
n_TOF Collaboration (Lederer-Woods, C. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Measurement of Ge-73(n, gamma) cross sections and implications for stellar nucleosynthesis |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
790 |
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Pages |
458-465 |
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Keywords |
Nucleosynthesis; Neutron capture; s process; Germanium; n_TOF |
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Abstract |
Ge-73(n, gamma) cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at kT = 30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of Ge-73 produced in stars, which would explain the low isotopic abundance of Ge-73 in the solar system. |
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Address |
[Lederer-Woods, C.; Battino, U.; Tattersalla, A.; Dietz, M.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland, Email: claudia.lederer-woods@ed.ac.uk |
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Elsevier Science Bv |
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English |
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0370-2693 |
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Notes |
WOS:000460118200058 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3936 |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
n_TOF Collaboration (Lederer-Woods, C. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Ge-74(n, gamma) cross section below 70 keV measured at n_TOF CERN |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
58 |
Issue |
12 |
Pages |
239 - 9pp |
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Abstract |
Neutron capture reaction cross sections on Ge-74 are of importance to determine Ge-74 production during the astrophysical slow neutron capture process. We present new resonance data on Ge-74(n, gamma ) reactions below 70 keV neutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment. |
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Address |
[Lederer-Woods, C.; Lonsdale, S. J.; Woods, P. J.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland, Email: claudia.lederer-woods@ed.ac.uk |
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Springer |
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English |
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1434-6001 |
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Notes |
WOS:000913761400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5472 |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Tain, J.L. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Neutron Capture on the s-Process Branching Point Tm-171 via Time-of-Flight and Activation |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
125 |
Issue |
14 |
Pages |
142701 - 8pp |
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Abstract |
The neutron capture cross sections of several unstable nuclides acting as branching points in the s process are crucial for stellar nucleosynthesis studies. The unstable Tm-171 (t(1/2) = 1.92 yr) is part of the branching around mass A similar to 170 but its neutron capture cross section as a function of the neutron energy is not known to date. In this work, following the production for the first time of more than 5 mg of Tm-171 at the high-flux reactor Institut Laue-Langevin in France, a sample was produced at the Paul Scherrer Institute in Switzerland. Two complementary experiments were carried out at the neutron time-of-flight facility (nTOF) at CERN in Switzerland and at the SARAF liquid lithium target facility at Soreq Nuclear Research Center in Israel by time of flight and activation, respectively. The result of the time -of-flight experiment consists of the first ever set of resonance parameters and the corresponding average resonance parameters, allowing us to make an estimation of the Maxwellian-averaged cross sections (MACS) by extrapolation. The activation measurement provides a direct and more precise measurement of the MACS at 30 keV: 384 (40) mb, with which the estimation from the nTOF data agree at the limit of 1 standard deviation. This value is 2.6 times lower than the JEFF-3.3 and ENDF/B-VIII evaluations, 25% lower than that of the Bao et al. compilation, and 1.6 times larger than the value recommended in the KAlloNiS (v1) database, based on the only previous experiment. Our result affects the nucleosynthesis at the A similar to 170 branching, namely, the Yb-171 abundance increases in the material lost by asymptotic giant branch stars, providing a better match to the available pre-solar SiC grain measurements compared to the calculations based on the current JEFF-3.3 model-based evaluation. |
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Address |
[Guerrero, C.; Lerendegui-Marco, J.; Quesada, J. M.; Cortes-Giraldo, M. A.; Millan-Callado, M. A.; Praena, J.; Rodriguez-Gonzalez, T.; Sabate-Gilarte, M.] Univ Seville, Seville, Spain, Email: cguerrero4@us.es |
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Amer Physical Soc |
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English |
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0031-9007 |
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Notes |
WOS:000574781200004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4551 |
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Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
n_TOF Collaboration (Gawlik, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Measurement of the Ge-70(n, gamma) cross section up to 300 keV at the CERN n_TOF facility |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
100 |
Issue |
4 |
Pages |
045804 - 10pp |
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Keywords |
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Abstract |
Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,gamma) cross section on Ge-70, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n_TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT = 5 keV to kT = 100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sections are in agreement with Walter and Beer (1985) over most of the neutron energy range covered, while they are systematically smaller for neutron energies above 150 keV. We have calculated isotopic abundances produced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A = 60-80. |
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Address |
[Gawlik, A.; Andrzejewski, J.; Perkowski, J.; Marganiec, J.] Univ Lodz, Lodz, Poland, Email: claudia.lederer-woods@ed.ac.uk |
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Amer Physical Soc |
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English |
Summary Language |
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ISSN |
2469-9985 |
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Notes |
WOS:000490751000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4174 |
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Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
n_TOF Collaboration (Gawlik, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Radiative Neutron Capture Cross-Section Measurement of Ge Isotopes at n_TOF CERN Facility and Its Importance for Stellar Nucleosynthesis |
Type |
Journal Article |
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Year |
2021 |
Publication |
Acta Physica Polonica A |
Abbreviated Journal |
Acta Phys. Pol. A |
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Volume |
139 |
Issue |
4 |
Pages |
383-388 |
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Keywords |
n_TOF; neutron time-of-flight; neutron capture cross-section; MACS |
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Abstract |
This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, Ge-70 and Ge-73. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for Ge-70 [Phys. Rev. C 100, 045804 (2019)] and Ge-73 [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes. |
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Address |
[Gawlik, A.; Andrzejewski, J.; Perkowski, J.] Univ Lodz, Lodz, Poland, Email: aleksandra.gawlik@uni.lodz.pl |
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Thesis |
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Publisher |
Polish Acad Sciences Inst Physics |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
0587-4246 |
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Notes |
WOS:000653413700004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4840 |
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Permanent link to this record |