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Author n_TOF Collaboration (Lederer-Woods, C. et al.); Domingo-Pardo, C.; Tain, J.L. doi  openurl
  Title Destruction of the cosmic gamma-ray emitter Al-26 in massive stars: Study of the key Al-26(n, alpha) reaction Type Journal Article
  Year 2021 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 104 Issue 3 Pages (down) L032803 - 6pp  
  Keywords  
  Abstract Neutron destruction reactions of the cosmic gamma-ray emitter Al-26 are of importance to determine the amount of Al-26 ejected into our galaxy by supernova explosions and for Al-26 production in asymptotic giant branch stars. We performed a new measurement of the Al-26(n, alpha) reaction up to 160-keV neutron energy at the neutron time-of-flight facilities n_TOF at CERN and GELINA at EC-JRC. We provide strengths for ten resonances, six of them for the first time. We use our data to calculate astrophysical reactivities for stellar temperatures up to 0.7 GK. Our results resolve a discrepancy between the two previous direct measurements of this reaction, and indicate higher stellar destruction rates than the most recently recommended reactivity.  
  Address [Lederer-Woods, C.; Woods, P. J.; Davinson, T.; Estrade, A.; Kahl, D.; Lonsdale, S. J.] Univ Edinburgh, Sch Phys & Astron, Peter Guthrie Tait Rd, Edinburgh EH9 3FD, Midlothian, Scotland, 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:000704560300002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4988  
Permanent link to this record
 
 
Author Langer, C. et al; Domingo-Pardo, C. doi  openurl
  Title Determining the rp-Process Flow through Ni-56: Resonances in Cu-57(p,gamma)Zn-58 Identified with GRETINA Type Journal Article
  Year 2014 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 113 Issue 3 Pages (down) 032502 - 5pp  
  Keywords  
  Abstract An approach is presented to experimentally constrain previously unreachable (p,gamma) reaction rates on nuclei far from stability in the astrophysical rp process. Energies of all critical resonances in the Cu-57(p,gamma)Zn-58 reaction are deduced by populating states in Zn-58 with a (d, n) reaction in inverse kinematics at 75 MeV/u, and detecting.-ray-recoil coincidences with the state-of-the-art gamma-ray tracking array GRETINA and the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The results reduce the uncertainty in the Cu-57(p,gamma) reaction rate by several orders of magnitude. The effective lifetime of Ni-56, an important waiting point in the rp process in x-ray bursts, can now be determined entirely from experimentally constrained reaction rates.  
  Address [Langer, C.; Montes, F.; Bazin, D.; Brown, B. A.; Browne, J.; Cyburt, R. H.; Gade, A.; Keek, L.; Kontos, A.; Lemasson, A.; Lunderberg, E.; Meisel, Z.; Noji, S.; Nunes, F. M.; Perdikakis, G.; Pereira, J.; Quinn, S. J.; Recchia, F.; Schatz, H.; Scott, M.; Simon, A.; Spyrou, A.; Stevens, J.; Stroberg, S. R.; Weisshaar, D.; Wheeler, J.; Wimmer, K.; Zegers, R. G. T.] Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA, Email: langer@nscl.msu.edu  
  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:000344180500004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1991  
Permanent link to this record
 
 
Author Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A. doi  openurl
  Title Strong one-neutron emission from two-neutron unbound states in beta decays of the r-process nuclei Ga-86,Ga-87 Type Journal Article
  Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 100 Issue 3 Pages (down) 031302 - 6pp  
  Keywords  
  Abstract beta-delayed one-neutron and two-neutron branching ratios (P-1n and P-2n) have been measured in the decay of A = 84 to 87 Ga isotopes at the Radioactive-Isotope Beam Factory (RIBF) at the RIKEN Nishina Center using a high-efficiency array of He-3 neutron counters (BRIKEN). Two-neutron emission was observed in the decay of Ga-84,Ga-85,Ga-87 for the first time and the branching ratios were measured to be P-2n = 1.6(2)%, 1.3(2)%, and 10.2(28)(stat)(5)(sys)%, respectively. One-neutron branching ratio of Ga-87 (P-1n = 81(9)(stat)(8)(sys)%) and half-life of 29(4) ms were measured for the first time. The branching ratios of Ga-86 were also measured to be P-1n = 74(2)(stat)(8)(sys)% and 16.2(9)(stat)(6)(sys)% with better precision than a previous study. The observation that P-1n > P-2n for both Ga-86,Ga-87 was unexpected and is interpreted as a signature of dominating one-neutron emission from the two-neutron unbound excited states in Ge-86,Ge-87. In order to interpret the experimental results, shell-model and Hauser-Feshbach statistical model calculations of delayed particle and gamma-ray emission probabilities were performed. This model framework reproduces the experimental results. The shell model alone predicts P-2n significantly larger than P-1n for the Ga-87 decay, and it is necessary to invoke a statistical description to successfully explain the observation that P-1n > P-2n. Our new results demonstrate the relevance and importance of a statistical description of neutron emission for the prediction of the decay properties of multineutron emitters and that it must be included in the r-process modeling.  
  Address [Yokoyama, R.; Grzywacz, R.; Rasco, B. C.; Brewer, N.; Heideman, J.; King, T. T.; Madurga, M.; Singh, M.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA, Email: ryokoyam@utk.edu  
  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:000486641000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4145  
Permanent link to this record
 
 
Author n_TOF Collaboration (Tagliente, G. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Zr-92(n, gamma) and (n,tot) measurements at the GELINA and n_TOF facilities Type Journal Article
  Year 2022 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 105 Issue 2 Pages (down) 025805 - 14pp  
  Keywords  
  Abstract Background: Stellar nucleosynthesis of elements heavier than iron is driven by neutron capture processes. Zr-92 is positioned at a strategic point along the slow nucleosynthesis path, given its proximity to the neutron magic number N = 50 and its position at the matching region between the weak and main slow processes. Purpose: In parallel with recent improved astronomical data, the extraction of accurate Maxwellian averaged cross sections (MACSs) derived from a more complete and accurate set of resonance parameters should allow for a better understanding of the stellar conditions at which nucleosynthesis takes place. Methods: Transmission and capture cross section measurements using enriched Zr-92 metallic samples were performed at the time-of flight facilities GELINA of JRC-Geel (BE) and nTOF of CERN (CH). The neutron beam passing through the samples was investigated in transmission measurements at GELINA using a Li-glass scintillator. The gamma rays emitted during the neutron capture reactions were detected by C6D6 detectors at both GELINA and nTOF. Results: Resonance parameters of individual resonances up to 81 keV were extracted from a combined resonance shape analysis of experimental transmissions and capture yields. For the majority of the resonances the parity was determined from an analysis of the transmission data obtained with different sample thicknesses. Average resonance parameters were calculated. Conclusions: Maxwellian averaged cross sections were extracted from resonances observed up to 81 keV. The MACS for kT = 30 keV is fully consistent with experimental data reported in the literature. The MACSs for kT less than or similar to 15 keV are in good agreement with those derived from the ENDF/B-VIII.0 library and recommended in the KADoNTS database. For kT higher than 30 keV differences are observed. A comparison with MACSs obtained with the cross sections recommended in the JEFF-3.3 and JENDL-4.0 libraries shows discrepancies even for kT less than or similar to 15 keV.  
  Address [Tagliente, G.; Barbagallo, M.; Colonna, N.; Mastromarco, M.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, 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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000766732800002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5163  
Permanent link to this record
 
 
Author n_TOF Collaboration (Moreno-Soto, J. et al); Babiano-Suarez, V.; Caballero-Ontanaya, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. doi  openurl
  Title Constraints on the dipole photon strength for the odd uranium isotopes Type Journal Article
  Year 2022 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 105 Issue 2 Pages (down) 024618 - 14pp  
  Keywords  
  Abstract Background: The photon strength functions (PSFs) and nuclear level density (NLD) are key ingredients for calculation of the photon interaction with nuclei, in particular the reaction cross sections. These cross sections are important especially in nuclear astrophysics and in the development of advanced nuclear technologies. Purpose: The role of the scissors mode in the M1 PSF of (well-deformed) actinides was investigated by several experimental techniques. The analyses of different experiments result in significant differences, especially on the strength of the mode. The shape of the low-energy tail of the giant electric dipole resonance is uncertain as well. In particular, some works proposed a presence of the E1 pygmy resonance just above 7 MeV. Because of these inconsistencies additional information on PSFs in this region is of great interest. Methods: The gamma-ray spectra from neutron-capture reactions on the U-234, U-236, and U-238 nuclei have been measured with the total absorption calorimeter of the n_TOF facility at CERN. The background-corrected sum-energy and multi-step-cascade spectra were extracted for several isolated s-wave resonances up to about 140 eV. Results: The experimental spectra were compared to statistical model predictions coming from a large selection of models of photon strength functions and nuclear level density. No combination of PSF and NLD models from literature is able to globally describe our spectra. After extensive search we were able to find model combinations with modified generalized Lorentzian (MGLO) E1 PSF, which match the experimental spectra as well as the total radiative widths. Conclusions: The constant temperature energy dependence is favored for a NLD. The tail of giant electric dipole resonance is well described by the MGLO model of the E1 PSF with no hint of pygmy resonance. The M1 PSF must contain a very strong, relatively wide, and likely double-resonance scissors mode. The mode is responsible for about a half of the total radiative width of neutron resonances and significantly affects the radiative cross section.  
  Address [Moreno-Soto, J.; Berthoumieux, E.; Dupont, E.; Gunsing, F.; Bacak, M.] Univ Paris Saclay, CEA Irfu, F-91191 Gif Sur Yvette, France, Email: jmoreno53@us.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:000810791100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5278  
Permanent link to this record
 
 
Author n_TOF Collaboration (Lerendegui-Marco, J. et al.); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Radiative neutron capture on Pu-242 in the resonance region at the CERN n_TOF-EAR1 facility Type Journal Article
  Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 97 Issue 2 Pages (down) 024605 - 21pp  
  Keywords  
  Abstract The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with uranium to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. However, an extensive use of MOX fuels, in particular in fast reactors, requires more accurate capture and fission cross sections for some Pu isotopes. In the case of Pu-242 there are sizable discrepancies among the existing capture cross-section measurements included in the evaluations (all from the 1970s) resulting in an uncertainty as high as 35% in the fast energy region. Moreover, postirradiation experiments evaluated with JEFF-3.1 indicate an overestimation of 14% in the capture cross section in the fast neutron energy region. In this context, the Nuclear Energy Agency (NEA) requested an accuracy of 8% in this cross section in the energy region between 500 meV and 500 keV. This paper presents a new time-of-flight capture measurement on Pu-242 carried out at nTOF-EAR1 (CERN), focusing on the analysis and statistical properties of the resonance region, below 4 keV. The Pu-242(n, gamma) reaction on a sample containing 95(4) mg enriched to 99.959% was measured with an array of four C6D6 detectors and applying the total energy detection technique. The high neutron energy resolution of nTOF-EAR1 and the good statistics accumulated have allowed us to extend the resonance analysis up to 4 keV, obtaining new individual and average resonance parameters from a capture cross section featuring a systematic uncertainty of 5%, fulfilling the request of the NEA.  
  Address [Lerendegui-Marco, J.; Guerrero, C.; Quesada, J. M.; Cortes-Giraldo, M. A.; Praena, J.; Sabate-Gilarte, M.] Univ Seville, Dept Fis Atom Mol & Nucl, E-41012 Seville, Spain, Email: cguerrero4@us.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:000424190700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3474  
Permanent link to this record
 
 
Author n_TOF Collaboration (Paradela, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. url  doi
openurl 
  Title High-accuracy determination of the U-238/U-235 fission cross section ratio up to approximate to 1 GeV at n_TOF at CERN Type Journal Article
  Year 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 91 Issue 2 Pages (down) 024602 - 11pp  
  Keywords  
  Abstract The U-238 to U-235 fission cross section ratio has been determined at nTOF up to approximate to 1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at nTOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++ /Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to approximate to 1 GeV.  
  Address [Paradela, C.; Tarrio, D.; Leal-Cidoncha, E.; Duran, I.; Alvarez, H.] Univ Santiago de Compostela, Santiago De Compostela, Spain, 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:000350174000004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2139  
Permanent link to this record
 
 
Author n_TOF Collaboration (Lederer-Woods, C. et al.); Domingo-Pardo, C.; Tain, J.L. doi  openurl
  Title Destruction of the cosmic gamma-ray emitter Al-26 in massive stars: Study of the key Al-26(n, p) reaction Type Journal Article
  Year 2021 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 104 Issue 2 Pages (down) L022803 - 7pp  
  Keywords  
  Abstract The Al-26(n, p) Mg-26 reaction is the key reaction impacting on the abundances of the cosmic gamma-ray emitter Al-26 produced in massive stars and impacts on the potential pollution of the early solar system with Al-26 by asymptotic giant branch stars. We performed a measurement of the Al-26(n, p) Mg-26 cross section at the high-flux beam line EAR-2 at the n_TOF facility (CERN). We report resonance strengths for eleven resonances, nine being measured for the first time, while there is only one previous measurement for the other two. Our resonance strengths are significantly lower than the only previous values available. Our cross-section data range to 150 keV neutron energy, which is sufficient for a reliable determination of astrophysical reactivities up to 0.5 GK stellar temperature.  
  Address [Lederer-Woods, C.; Woods, P. J.; Davinson, T.; Kahl, D.; Lonsdale, S. J.] Univ Edinburgh, Sch Phys & Astron, Peter Guthrie Tait Rd, Edinburgh EH9 3FD, Midlothian, Scotland, 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:000691442700005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4949  
Permanent link to this record
 
 
Author n_TOF Collaboration (Lederer, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. url  doi
openurl 
  Title Neutron Capture Cross Section of Unstable Ni-63: Implications for Stellar Nucleosynthesis Type Journal Article
  Year 2013 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 110 Issue 2 Pages (down) 022501 - 5pp  
  Keywords  
  Abstract The Ni-63(n, gamma) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from kT = 5-100 keV with uncertainties around 20%. Stellar model calculations for a 25M(circle dot) star show that the new data have a significant effect on the s-process production of Cu-63, Ni-64, and Zn-64 in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.  
  Address [Lederer, C.; Paradela, C.; Wallner, A.] Univ Vienna, Fac Phys, A-1090 Vienna, Austria  
  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:000313336500005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1305  
Permanent link to this record
 
 
Author n_TOF Collaboration (Zugec, P. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. url  doi
openurl 
  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 (down) 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  
Permanent link to this record
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