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Author |
n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Study of Photon Strength Function of Actinides: the Case of (235)U, (238)Np and (241)Pu |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
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Volume |
59 |
Issue |
2 |
Pages |
1510-1513 |
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Keywords |
Photon/Gamma strength functions; Pygmy; Scissor mode; n_TOF; Total absorption calorimeter; TAC; Neutron capture |
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Abstract |
The decay from excited levels in medium and heavy nuclei can be described in a statistical approach by means of Photon Strength Functions and Level Density distributions. The study of electromagnetic cascades following neutron capture based on the use of high efficiency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF of actinides, in particular (235)U, (238)Np and (241)Pu. Our study includes the search for resonance structures in the PSF below S(n) and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature. |
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Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Guerrero, C; Alvarez-Velarde, F; Ano-Ott, DC; Martinez, T; Mendoza, E; Villamarin, D] Ctr Invest Energet Medioambientales & Technol CIE, Madrid, Spain, Email: carlos.guerrero@ciemat.es |
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Publisher |
Korean Physical Soc |
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English |
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Series Volume |
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ISSN |
0374-4884 |
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Conference |
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Notes |
WOS:000294080700013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
731 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
Performance of the neutron time-of-flight facility n_TOF at CERN |
Type |
Journal Article |
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Year |
2013 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
49 |
Issue |
2 |
Pages |
27 - 15pp |
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Keywords |
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Abstract |
The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20 GeV/c protons impinging on a lead target. The facility, aiming primarily at the measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities. |
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Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Guerrero, C.; Tsinganis, A.; Berthoumieux, E.; Weiss, C.; Chiaveri, E.; Calviani, M.; Vlachoudis, V.; Andriamonje, S.; Boccone, V.; Brugger, M.; Cerutti, F.; Chin, M.; Ferrari, A.; Hernandez-Prieto, A.; Kadi, Y.; Losito, R.; Roman, F.; Rubbia, C.; Versaci, R.] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland, Email: carlos.guerrero@cern.ch |
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Thesis |
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Publisher |
Springer |
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English |
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Series Volume |
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ISSN |
1434-6001 |
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Expedition |
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Conference |
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Notes |
WOS:000315601600011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1358 |
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Permanent link to this record |
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Author |
Guerrero, C.; Tessler, M.; Paul, M.; Lerendegui-Marco, J.; Heinitz, S.; Maugeri, E.A.; Domingo-Pardo, C.; Dressler, R.; Halfon, S.; Kivel, N.; Koster, U.; Palchan-Hazan, T.; Quesada, J.M.; Schumann, D.; Weissman, L. |
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Title |
The s-process in the Nd-Pm-Sm region: Neutron activation of Pm-147 |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
797 |
Issue |
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Pages |
134809 - 6pp |
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Keywords |
Nucleosynthesis; Neutron capture; Nuclear reactions; s-process; MACS; Neutron activation |
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Abstract |
The Nd-Pm-Sm branching is of interest for the study of the s-process, related to the production of heavy elements in stars. As Sm-148 and Sm-150 are s-only isotopes, the understanding of the branching allows constraining the s-process neutron density. In this context the key physics input needed is the cross section of the three unstable nuclides in the region: Nd-147 (10.98 d half-life), Pm-147 (2.62 yr) and Pm-148 (5.37 d). This paper reports on the activation measurement of Pm-147, the longest-lived of the three nuclides. The cross section measurement has been carried out by activation at the SARAF LiLiT facility using a 56(2) μg target. Compared to the single previous measurement of Pm-147, the measurement presented herein benefits from a target 2000 times more massive. The resulting Maxwellian Averaged Cross Section (MACS) to the ground and metastable states in Pm-148 are 469(50) mb and 357(27) mb. These values are 41% higher (to the ground state) and 15% lower (to the metastable state) than the values reported so far, leading however to a total cross section of 826(107) mb consistent within uncertainties with the previous result and hence leaving unchanged the previous calculation of the s-process neutron density. |
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Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Guerrero, C.; Lerendegui-Marco, J.; Quesada, J. M.] Univ Seville, Seville, Spain, Email: cguerrero4@us.es |
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Publisher |
Elsevier |
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English |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000488071200026 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4161 |
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Permanent link to this record |
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Author |
Guerrero, C.; Domingo-Pardo, C.; Kappeler, F.; Lerendegui-Marco, J.; Palomo, F.R.; Quesada, J.M.; Reifarth, R. |
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Title |
Prospects for direct neutron capture measurements on s-process branching point isotopes |
Type |
Journal Article |
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Year |
2017 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
53 |
Issue |
5 |
Pages |
87 - 5pp |
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Keywords |
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Abstract |
The neutron capture cross sections of several unstable key isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure directly due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n, gamma) measurement, where high neutron fluxes and effective background rejection capabilities are required. At present there are about 21 relevant s-process branching point isotopes whose cross section could not be measured yet over the neutron energy range of interest for astrophysics. However, the situation is changing with some very recent developments and upcoming technologies. This work introduces three techniques that will change the current paradigm in the field: the use of gamma-ray imaging techniques in (n,gamma) experiments, the production of moderated neutron beams using high-power lasers, and double capture experiments in Maxwellian neutron beams. |
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Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Guerrero, C.; Lerendegui-Marco, J.; Quesada, J. M.] Univ Seville, Dept Fis Atom Mol & Nucl, E-41012 Seville, Spain, Email: carlos.guerrero@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000400982700002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3129 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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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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Keywords |
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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 ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[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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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Area |
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Expedition |
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Conference |
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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 |