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Author (up) n_TOF Collaboration (Lederer, C. et al.); Giubrone, G.; Tain, J.L.
Title Ni-62(n,gamma) and Ni-63(n,gamma) cross sections measured at the n_TOF facility at CERN Type Journal Article
Year 2014 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 89 Issue 2 Pages 025810 - 11pp
Keywords
Abstract The cross section of the Ni-62(n,gamma) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility nTOF at CERN. Capture kernels of 42 resonances were analyzed up to 200 keV neutron energy and Maxwellian averaged cross sections (MACS) from kT = 5-100 keV were calculated. With a total uncertainty of 4.5%, the stellar cross section is in excellent agreement with the the KADoNiS compilation at kT = 30 keV, while being systematically lower up to a factor of 1.6 at higher stellar temperatures. The cross section of the Ni-63(n,gamma) reaction was measured for the first time at nTOF. We determined unresolved cross sections from 10 to 270 keV with a systematic uncertainty of 17%. These results provide fundamental constraints on s-process production of heavier species, especially the production of Cu in massive stars, which serve as the dominant source of Cu in the solar system.
Address [Lederer, C.; Wallner, A.; Pavlik, A.] Univ Vienna, Fac Phys, A-1010 Vienna, Austria, Email: claudia.lederer@ph.ed.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 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000332175500012 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1717
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Author (up) n_TOF Collaboration (Mendoza, E. et al); Domingo-Pardo, C.; Tain, J.L.
Title Measurement and analysis of the Am-243 neutron capture cross section at the n_TOF facility at CERN Type Journal Article
Year 2014 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 90 Issue 3 Pages 034608 - 16pp
Keywords
Abstract Background: The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Improvement of the Am-243(n, gamma) cross section uncertainty. Method: The Am-243(n, gamma) cross section has been measured at the n_TOF facility at CERN with a BaF2 total absorption calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The Am-243(n, gamma) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature have been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the Am-243(n, gamma) cross section uncertainty and suggest that this cross section is underestimated up to 25% in the neutron energy range between 50 eV and a few keV in the present evaluated data libraries.
Address [Mendoza, E.; Cano-Ott, D.; Guerrero, C.; Alvarez-Velarde, F.; Balibrea, J.; Gonzalez-Romero, E.; Martinez, T.; Villamarin, D.; Vicente, M. C.] CIEMAT, E-28040 Madrid, Spain
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:000341912100005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1935
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Author (up) n_TOF Collaboration (Tarrio, D. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF Type Journal Article
Year 2014 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 743 Issue Pages 79-85
Keywords Fission; Neutron; Anisotropy; Angular distribution; Th-232; Gas detectors
Abstract A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (n_TOF) facility at CERN. The detectors and the samples were tilted 45 degrees with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the Th-232(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup.
Address [Tarrio, D.; Duran, I.; Paradela, C.; Caamano, M.] Univ Santiago de Compostela, Santiago De Compostela, Spain, Email: dtarriov@gmail.com
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000334005000011 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1746
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Author (up) n_TOF Collaboration (Weiss, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title The (n,alpha) Reaction in the s-process Branching Point Ni-59 Type Journal Article
Year 2014 Publication Nuclear Data Sheets Abbreviated Journal Nucl. Data Sheets
Volume 120 Issue Pages 208-210
Keywords
Abstract The (n,alpha) reaction in the radioactive Ni-59 is of relevance in nuclear astrophysics as Ni-59 can be considered as the first branching point in the astrophysical s-process. Its relevance in nuclear technology is especially related to material embrittlement in stainless steel. However, there is a discrepancy between available experimental data and the evaluated nuclear data files for this reaction. At the n_TOF facility at CERN, a dedicated system based on sCVD diamond diodes was set up to measure the Ni-59(n,alpha)Fe-56 cross section. The results of this measurement, with special emphasis on the dominant resonance at 203 eV, are presented here.
Address [Weiss, C.; Griesmayer, E.; Badurek, G.; Jericha, E.; Leeb, H.] Vienna Univ Technol, Atominst, Vienna, Austria, Email: christina.weiss@cern.ch
Corporate Author Thesis
Publisher Academic Press Inc Elsevier Science Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0090-3752 ISBN Medium
Area Expedition Conference
Notes WOS:000339860100058 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1876
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Author (up) n_TOF Collaboration (Zugec, P. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title Experimental neutron capture data of Ni-58 from the CERN n_TOF facility Type Journal Article
Year 2014 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 89 Issue 1 Pages 014605 - 9pp
Keywords
Abstract The Ni-58(n,gamma) cross section has been measured at the neutron time of flight facility n_TOF at CERN, in the energy range from 27 meV up to 400 keV. In total, 51 resonances have been analyzed up to 122 keV. Maxwellian averaged cross sections (MACS) have been calculated for stellar temperatures of kT = 5-100 keV with uncertainties of less than 6%, showing fair agreement with recent experimental and evaluated data up to kT = 50 keV. The MACS extracted in the present work at 30 keV is 34.2 +/- 0.6(stat) +/- 1.8(sys) mb, in agreement with latest results and evaluations, but 12% lower relative to the recent KADoNIS compilation of astrophysical cross sections. When included in models of the s-process nucleosynthesis in massive stars, this change results in a 60% increase of the abundance of Ni-58, with a negligible propagation on heavier isotopes. The reason is that, using both the old or the new MACS, Ni-58 is efficiently depleted by neutron captures.
Address [Zugec, P.; Bosnar, D.] Univ Zagreb, Fac Sci, Dept Phys, Zagreb 41000, Croatia, Email: pzugec@phy.hr
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:000332151100002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1727
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Author (up) n_TOF Collaboration (Zugec, P. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title GEANT4 simulation of the neutron background of the C6D6 set-up for capture studies at n_TOF Type Journal Article
Year 2014 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 760 Issue Pages 57-67
Keywords GEANT4 simulations; Neutron time of flight; Neutron background; N_TOF; Neutron capture
Abstract The neutron sensitivity of the Cr6D6 detector setup used at nTOF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire nTOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a(nat)-C sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured C-nat yield has been discovered, which prevents the use of C-nat data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron background for two different samples are demonstrating the important role of accurate simulations of the neutron background in capture cross-section measurements.
Address [Zugec, P.; Bosnar, D.] Univ Zagreb, Fac Sci, Dept Phys, Zagreb 41000, Croatia, Email: pzugec@phy.hr
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000338350500008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1828
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Author (up) n_TOF Collaboration (Zugec, P. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
Title Measurement of the C-12(n, p)B-12 cross section at n_TOF at CERN by in-beam activation analysis Type Journal Article
Year 2014 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 90 Issue 2 Pages 021601 - 5pp
Keywords
Abstract The integral cross section of the C-12(n, p)B-12 reaction has been determined for the first time in the neutron energy range from threshold to several GeV at the n_TOF facility at CERN. The measurement relies on the activation technique with the beta decay of B-12 measured over a period of four half-lives within the same neutron bunch in which the reaction occurs. The results indicate that model predictions, used in a variety of applications, are mostly inadequate. The value of the integral cross section reported here can be used as a benchmark for verifying or tuning model calculations.
Address [Zugec, P.; Bosnar, D.] Univ Zagreb, Fac Sci, Dept Phys, Zagreb 41000, Croatia, Email: nicola.colonna@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:000340744900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1894
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Author (up) Odintsov, S.D.; Olmo, G.J.; Rubiera-Garcia, D.
Title Born-Infeld gravity and its functional extensions Type Journal Article
Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 90 Issue 4 Pages 044003 - 8pp
Keywords
Abstract We investigate the dynamics of a family of functional extensions of the (Eddington-inspired) Born-Infeld gravity theory, constructed with the inverse of the metric and the Ricci tensor. We provide a generic formal solution for the connection and an Einstein-like representation for the metric field equations of this family of theories. For particular cases we consider applications to the early-time cosmology and find that nonsingular universes with a cosmic bounce are very generic and robust solutions.
Address [Odintsov, Sergei D.] Inst Catalana Recerca & Estudis Avancats, Barcelona 08010, Spain, Email: gonzalo.olmo@csic.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 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000339999700005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1880
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Author (up) Olmo, G.J.; Rubiera-Garcia, D.
Title Semiclassical geons at particle accelerators Type Journal Article
Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 02 Issue 2 Pages 010 - 25pp
Keywords modified gravity; Wormholes; quantum black holes
Abstract We point out that in certain four-dimensional extensions of general relativity constructed within the Palatini formalism stable self-gravitating objects with a discrete mass and charge spectrum may exist. The incorporation of nonlinearities in the electromagnetic field may effectively reduce their mass spectrum by many orders of magnitude. As a consequence, these objects could be within (or near) the reach of current particle accelerators. We provide an exactly solvable model to support this idea.
Address [Omla, Gonzalo J.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@csic.es;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000332711400010 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1733
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Author (up) Olmo, G.J.; Rubiera-Garcia, D.; Sanchis-Alepuz, H.
Title Geonic black holes and remnants in Eddington-inspired Born-Infeld gravity Type Journal Article
Year 2014 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 74 Issue 3 Pages 2804 - 6pp
Keywords
Abstract We show that electrically charged solutions within the Eddington-inspired Born-Infeld theory of gravity replace the central singularity by a wormhole supported by the electric field. As a result, the total energy associated with the electric field is finite and similar to that found in the Born-Infeld electromagnetic theory. When a certain charge-to-mass ratio is satisfied, in the lowest part of the mass and charge spectrum the event horizon disappears, yielding stable remnants. We argue that quantum effects in the matter sector can lower the mass of these remnants from the Planck scale down to the TeV scale.
Address [Olmo, Gonzalo J.] Univ Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@csic.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000333033300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1730
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