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Author n_TOF Collaboration (Tarrío, D. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title Neutron-induced fission cross sections of Th-232 and U-233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility Type Journal Article
Year 2023 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 107 Issue 4 Pages (up) 044616 - 21pp
Keywords
Abstract The neutron-induced fission cross sections of Th-232 and U-233 were measured relative to U-235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th-232, and from 0.7 eV in case of U-233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (nTOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U-233, previous results available in EXFOR, whereas in the case of Th-232 these data were obtained from our measurement, using PPACs and targets tilted 45 degrees with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p, f) data with our (n, f) data on Th-232 and U-233 and on other isotopes studied earlier at nTOF using the same experimental setup.
Address [Tarrio, D.] Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden, Email: diego.tarrio@physics.uu.se
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:001021341000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5618
Permanent link to this record
 
 
Author n_TOF Collaboration (Sarmento, R. et al); Domingo-Pardo, C.; Tain, J.L.
Title Measurement of the (236)U(n, f) cross section from 170 meV to 2 MeV at the CERN n_TOF facility Type Journal Article
Year 2011 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 84 Issue 4 Pages (up) 044618 - 10pp
Keywords
Abstract The neutron-induced fission cross section of (236)U was measured at the neutron Time-of-Flight (nTOF) facility at CERN relative to the standard (235)U(n, f) cross section for neutron energies ranging from above thermal to several MeV. The measurement, covering the full range simultaneously, was performed with a fast ionization chamber, taking advantage of the high resolution of the nTOF spectrometer. The n_TOF results confirm that the first resonance at 5.45 eV is largely overestimated in some nuclear data libraries. The resonance triplet around 1.2 keV was measured with high resolution and resonance parameters were determined with good accuracy. Resonances at high energy have also been observed and characterized and different values for the cross section are provided for the region between 10 keV and the fission threshold. The present work indicates various shortcomings of the current nuclear data libraries in the subthreshold region and provides the basis for an accurate re-evaluation of the (236)U(n, f) cross section, which is of great relevance for the development of emerging or innovative nuclear reactor technologies.
Address [Sarmento, R; Goncalves, IF; Vaz, P; Carrapico, C; de Albornoz, AC; Marques, L; Salgado, J; Tavora, L] ITN, Sacavem, Portugal
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000296521000006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 818
Permanent link to this record
 
 
Author n_TOF Collaboration (Tarrio D. et al.); Domingo-Pardo, C.; Tain, J.L.
Title Neutron-induced fission cross section of Pb-nat and Bi-209 from threshold to 1 GeV: An improved parametrization Type Journal Article
Year 2011 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 83 Issue 4 Pages (up) 044620 - 9pp
Keywords
Abstract Neutron-induced fission cross sections for Pb-nat and Bi-209 were measured with a white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. The experiment, using neutrons from threshold up to 1 GeV, provides the first results for these nuclei above 200 MeV. The cross sections were measured relative to U-235 and U-238 in a dedicated fission chamber with parallel plate avalanche counter detectors. Results are compared with previous experimental data. Upgraded parametrizations of the cross sections are presented, from threshold energy up to 1 GeV. The proposed new sets of fitting parameters improve former results along the whole energy range.
Address [Tarrio, D.; Duran, I.; Paradela, C.] Univ Santiago de Compostela, Santiago De Compostela, Spain, Email: diego.tarrio@usc.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000290163300003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 617
Permanent link to this record
 
 
Author n_TOF Collaboration (Gawlik, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A.
Title Measurement of the Ge-70(n, gamma) cross section up to 300 keV at the CERN n_TOF facility Type Journal Article
Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 100 Issue 4 Pages (up) 045804 - 10pp
Keywords
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.
Address [Gawlik, A.; Andrzejewski, J.; Perkowski, J.; Marganiec, J.] Univ Lodz, Lodz, Poland, Email: claudia.lederer-woods@ed.ac.uk
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000490751000004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4174
Permanent link to this record
 
 
Author n_TOF Collaboration (Dietz, M. et al); Domingo-Pardo, C.; Tain, J.L.
Title Measurement of the Ge-72(n, y) cross section over a wide neutron energy range at the CERN n_TOF facility Type Journal Article
Year 2021 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 103 Issue 4 Pages (up) 045809 - 8pp
Keywords
Abstract The Ge-72(n, gamma) cross section was measured for neutron energies up to 300 keV at the neutron time-of-flight facility n_TOF (CERN), Geneva, for the first time covering energies relevant to heavy-element synthesis in stars. The measurement was performed at the high-resolution beamline EAR-1, using an isotopically enriched (GeO2)-Ge-72 sample. The prompt capture gamma rays were detected with four liquid scintillation detectors, optimized for low neutron sensitivity. We determined resonance capture kernels up to a neutron energy of 43 keV, and averaged cross sections from 43 to 300 keV. Maxwellian-averaged cross section values were calculated from kT = 5 to 100 keV, with uncertainties between 3.2% and 7.1%. The new results significantly reduce uncertainties of abundances produced in the slow neutron capture process in massive stars.
Address [Dietz, M.; Lederer-Woods, C.; Tattersall, A.; Battino, U.; Kahl, D.; Lonsdale, S. J.; Woods, P. J.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland, Email: mirco.dietz@ptb.de
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000647603800002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4811
Permanent link to this record
 
 
Author Briz, J.A.; Nacher, E.; Borge, M.J.G.; Algora, A.; Rubio, B.; Dessagne, P.; Maira, A.; Cano-Ott, D.; Courtin, S.; Escrig, D.; Fraile, L.M.; Gelletly, W.; Jungclaus, A.; Le Scornet, G.; Marechal, F.; Miehe, C.; Poirier, E.; Poves, A.; Sarriguren, P.; Tain, J.L.; Tengblad, O.
Title Shape study of the N = Z nucleus Kr-72 via beta decay Type Journal Article
Year 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 92 Issue 5 Pages (up) 054326 - 10pp
Keywords
Abstract The beta decay of the N = Z nucleus Kr-72 has been studied with the total absorption spectroscopy technique at ISOLDE (CERN). A total B(GT) = 0.79(4)g(A)(2)/4 pi has been found up to an excitation energy of 2.7 MeV. The B(GT) distribution obtained is compared with predictions from state-of-the-art theoretical calculations to learn about the ground state deformation of Kr-72. Although a dominant oblate deformation is suggested by direct comparison with quasiparticle random phase approximation (QRPA) calculations, beyond-mean-field and shell-model calculations favor a large oblate-prolate mixing in the ground state.
Address [Briz, J. A.; Nacher, E.; Borge, M. J. G.; Maira, A.; Escrig, D.; Jungclaus, A.; Sarriguren, P.; Tengblad, O.] CSIC, Inst Estruct Mat, E-28006 Madrid, Spain, Email: jose.briz@subatech.in2p3.fr
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000365867500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2486
Permanent link to this record
 
 
Author n_TOF Collaboration (Mendoza, E. et al); Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A.
Title Measurement and analysis of the Am-241 neutron capture cross section at the n_TOF facility at CERN Type Journal Article
Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 97 Issue 5 Pages (up) 054616 - 21pp
Keywords
Abstract The Am-241(n, gamma) cross section has been measured at the nTOF facility at CERN with the nTOF BaF2 Total Absorption Calorimeter in the energy range between 0.2 eV and 10 keV. Our results are analyzed as resolved resonances up to 700 eV, allowing a more detailed description of the cross section than in the current evaluations, which contain resolved resonances only up to 150-160 eV. The cross section in the unresolved resonance region is perfectly consistent with the predictions based on the average resonance parameters deduced from the resolved resonances, thus obtaining a consistent description of the cross section in the full neutron energy range under study. Below 20 eV, our results are in reasonable agreement with JEFF-3.2 as well as with the most recent direct measurements of the resonance integral, and differ up to 20-30% with other experimental data. Between 20 eV and 1 keV, the disagreement with other experimental data and evaluations gradually decreases, in general, with the neutron energy. Above 1 keV, we find compatible results with previously existing values.
Address [Mendoza, E.; Cano-Ott, D.; Balibrea, J.; Becares, V; Garcia, A. R.; Gonzalez, E.; Lopez, D.; Martinez, T.] Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain, Email: emilio.mendoza@ciemat.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000433032300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3584
Permanent link to this record
 
 
Author n_TOF Collaboration (Tagliente, G. et al.); Domingo-Pardo, C.; Tain, J.L.
Title The Zr-92(n,gamma) reaction and its implications for stellar nucleosynthesis Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 5 Pages (up) 055801 - 9pp
Keywords
Abstract Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the Zr-92(n,gamma) cross section has been remeasured at the CERN n_TOF facility, providing a set of improved parameters for 44 resonances in the neutron energy range up to 40 keV. With this information the cross-section uncertainties in the keV region could be reduced to 5% as required for s-process nucleosynthesis studies and technological applications.
Address [Tagliente, G.; Colonna, N.; Marrone, S.; Terlizzi, R.] Ist Nazl Fis Nucl, I-70126 Bari, Italy, Email: giuseppe.tagliente@ba.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000278144800074 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 444
Permanent link to this record
 
 
Author n_TOF Collaboration (Tagliente, G. et al.); Domingo-Pardo, C.; Tain, J.L.
Title (96)Zr(n,gamma) measurement at the n_TOF facility at CERN Type Journal Article
Year 2011 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 84 Issue 5 Pages (up) 055802 - 8pp
Keywords
Abstract The (n,gamma) cross section of (96)Zr has been investigated at the CERN n_TOF spallation neutron source. High-resolution time-of-flight measurements using an enriched ZrO(2) sample allowed us to analyze 15 resonances below 40 keV with improved accuracy. On average, the capture widths were found to be 25% smaller than reported in earlier experiments. If complemented with the contribution by direct radiative capture, the derived Maxwellian averaged cross sections are consistent with activation data at kT = 25 keV. The present results confirm the astrophysical implications for the s-process branching at (95)Zr.
Address [Tagliente, G; Colonna, N; Marrone, S; Terlizzi, R] Ist Nazl Fis Nucl, I-70126 Bari, Italy, Email: giuseppe.tagliente@ba.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000297121100005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 812
Permanent link to this record
 
 
Author Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D.
Title Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay Type Journal Article
Year 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 115 Issue 6 Pages (up) 062502 - 5pp
Keywords
Abstract Total absorption spectroscopy is used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in Br-87,Br-88 and Rb-94. Accurate results are obtained thanks to a careful control of systematic errors. An unexpectedly large. intensity is observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The gamma branching as a function of excitation energy is compared to Hauser-Feshbach model calculations. For Br-87 and Br-88 the gamma branching reaches 57% and 20%, respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich Rb-94 the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper correction for fluctuation effects on individual transition widths. The difference can be reconciled by introducing an enhancement of 1 order of magnitude in the photon strength to neutron strength ratio. An increase in the photon strength function of such magnitude for very neutron-rich nuclei, if it proves to be correct, leads to a similar increase in the (n, gamma) cross section that would have an impact on r process abundance calculations.
Address [Tain, J. L.; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M. D.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: tain@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000359059100002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2319
Permanent link to this record