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Author |
n_TOF Collaboration (Massimi, C. et al.); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
Neutron spectroscopy of Mg-26 states: Constraining the stellar neutron source Ne-22(alpha, n)Mg-25 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume  |
768 |
Issue |
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Pages |
1-6 |
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Keywords |
s Process; alpha+Ne-22; Neutron spectroscopy |
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Abstract |
This work reports on accurate, high-resolution measurements of the Mg-25(n, gamma)Mg-26 and Mg-25(n, tot) cross sections in the neutron energy range from thermal to about 300 keV, leading to a significantly improved Mg-25(n, gamma)Mg-26 parametrization. The relevant resonances for n+Mg-25 were characterized from a combined R-matrix analysis of the experimental data. This resulted in an unambiguous spin/parity assignment of the corresponding excited states in Mg-26. With this information experimental upper limits of the reaction rates for Ne-22(alpha, n)Mg-25 and Ne-22(alpha, gamma)Mg-26 were established, potentially leading to a significantly higher (alpha, n)/(alpha, gamma) ratio than previously evaluated. The impact of these results has been studied for stellar models in the mass range 2 to 25 M-circle dot. (C) 2017 The Author(s). Published by Elsevier B.V. |
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Address |
[Massimi, C.; Barbagallo, M.; Becvar, F.; Bisterzok, S.; Castelluccio, D. M.; Eleftheriadis, C.; Finocchiaro, P.; Kokkoris, M.; Marganiec, J.; Plompen, A.; Praena, J.; Rubbia, C.; Weiss, C.] Ist Nazl Fis Nucl, Bologna, Italy, Email: cristian.massimi@bo.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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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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 |
0370-2693 |
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:000400677700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3112 |
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Author |
Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Tain, J.L.; Algora, A.; Berthoumieux, E.; Colonna, N.; Domingo-Pardo, C.; Gonzalez-Romero, E.; Heil, M.; Jordan, D.; Kappeler, F.; Lampoudis, C.; Martinez, T.; Massimi, C.; Plag, R. |
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Title |
Monte Carlo simulation of the n_TOF Total Absorption Calorimeter |
Type |
Journal Article |
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Year |
2012 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
671 |
Issue |
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Pages |
108-117 |
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Keywords |
Monte Carlo simulation; Geant4; Neutron cross-sections; Time-of-flight; Neutron capture |
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Abstract |
The n_TOF Total Absorption Calorimeter (TAC) is a 4 pi BaF2 segmented detector used at CERN for measuring neutron capture cross-sections of importance for the design of advanced nuclear reactors. This work presents the simulation code that has been developed in GEANT4 for the accurate determination of the detection efficiency of the TAC for neutron capture events. The code allows to calculate the efficiency of the TAC for every neutron capture state, as a function of energy, crystal multiplicity, and counting rate. The code includes all instrumental effects such as the single crystal detection threshold and energy resolution, finite size of the coincidence time window, and signal pile-up. The results from the simulation have been validated with experimental data for a large set of electromagnetic de-excitation patterns: beta-decay of well known calibration sources, neutron capture reactions in light nuclei with well known level schemes like Ti-nat, reference samples used in (n,gamma) measurements like Au-197 and experimental data from an actinide sample like Pu-240. The systematic uncertainty in the determination of the detection efficiency has been estimated for all the cases. As a representative example, the accuracy reached for the case of Au-197(n,gamma) ranges between 0.5% and 2%, depending on the experimental and analysis conditions. Such a value matches the high accuracy required for the nuclear cross-section data needed in advanced reactor design. |
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Address |
[Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Gonzalez-Romero, E.; Martinez, T.] CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain, Email: carlos.guerrero@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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 |
0168-9002 |
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:000301474600013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
973 |
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Author |
n_TOF Collaboration (Massimi, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
85 |
Issue |
4 |
Pages |
044615 - 15pp |
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Keywords |
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Abstract |
We have measured the neutron capture cross sections of the stable magnesium isotopes Mg-24,Mg-25,Mg-26 in the energy range of interest to the s process using the neutron time-of-flight facility n_TOF at CERN. Capture events from a natural metal sample and from samples enriched in Mg-25 and Mg-26 were recorded using the total energy method based on (C6H6)-H-2 detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on s-process analyses was investigated. At 30 keV the new values of the stellar cross section for Mg-24, Mg-25, and Mg-26 are 3.8 +/- 0.2 mb, 4.1 +/- 0.6 mb, and 0.14 +/- 0.01 mb, respectively. |
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Address |
[Massimi, C.; Vannini, G.] Univ Bologna, Dipartimento Fis, Bologna, Italy, Email: Cristian.Massimi@bo.infn.it |
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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 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 |
0556-2813 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000303069400003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
994 |
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Author |
n_TOF Collaboration (Massimi, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Au-197(n,gamma) cross section in the resonance region |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
81 |
Issue |
4 |
Pages |
044616 - 22pp |
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Keywords |
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Abstract |
The (n,gamma) cross section of Au-197 has been measured at nTOF in the resolved resonance region, up to 5 keV, with the aim of improving the accuracy in an energy range where it is not yet considered standard. The measurements were performed with two different experimental setup and detection techniques, the total energy method based on C6D6 detectors, and the total absorption calorimetry based on a 4 pi BaF2 array. By comparing the data collected with the two techniques, two accurate sets of neutron-capture yields have been obtained, which could be the basis for a new evaluation leading to an extended cross-section standard. Overall good agreement is found between the n_TOF results and evaluated cross sections, with some significant exceptions for small resonances. A few resonances not included in the existing databases have also been observed. |
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Address |
[Domingo-Pardo, C.] GSI Helmholtzzentrum Schwerionenforsch GmbH, Darmstadt, Germany, Email: c.domingopardo@gsi.de |
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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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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 |
0556-2813 |
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 |
ISI:000277209500051 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
463 |
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| Permanent link to this record |
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Author |
n_TOF Collaboration; Gunsing, F.; Berthoumieux, E.; Borella, A.; Belgya, T.; Szentmiklosi, L.; Schillebeeckx, P.; Drohe, J.C.; Wynants, R.; Colonna, N.; Marrone, S.; Tagliente, G.; Terlizzi, R.; Domingo-Pardo, C.; Tain, J.L.; Martinez, T.; Massimi, C.; Mastinu, P.M.; Milazzo, P.M. |
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Title |
Neutron Capture on (209)Bi: Determination of the Production Ratio of (210m)Bi/(210g)Bi |
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 |
1670-1675 |
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Keywords |
ND2010; Nuclear data; Neutron capture; Branching ratio; Statistical decay; (209)Bi; (210)Bi; (210)Po |
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Abstract |
Neutron capture on (209)Bi produces either an isomeric state (210m)Bi with a half life of 3 x 106 years, or the ground state (210g)Bi which decays with a half life of 5 days to the alpha emitter (210)Po. Therefore the neutron capture cross section ratio (209)Bi(n,gamma)(210m)Bi/(210g)Bi plays an important role in predicting the short- and long-term radio-toxicity produced by (209)Bi under neutron irradiation. This ratio is dependent on the neutron energy. We have measured this ratio for cold neutrons at the cold neutron beam facility of the Budapest Neutron Centre by observing the population of the ground-and the metastable state using high resolution gamma-ray spectroscopy. The same technique has been used at the pulsed white neutron source GELINA of the IRMM, Geel in combination with the neutron time-of-flight technique. Results for the neutron-energy dependent branching ratio will be presented. In addition we performed simulations using a statistical decay code. |
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Address |
[Gunsing, F; Berthoumieux, E; Borella, A] CEA Saclay, IRFU, SPhN, F-91911 Gif Sur Yvette, France, Email: gunsing@cea.fr |
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Corporate Author |
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Thesis |
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Publisher |
Korean Physical Soc |
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 |
0374-4884 |
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:000294080700051 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
736 |
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