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Author Guadilla, V. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. url  doi
openurl 
  Title Determination of beta-decay ground state feeding of nuclei of importance for reactor applications Type Journal Article
  Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 102 Issue 6 Pages 064304 - 12pp  
  Keywords  
  Abstract In beta-decay studies the determination of the decay probability to the ground state (g.s.) of the daughter nucleus often suffers from large systematic errors. The difficulty of the measurement is related to the absence of associated delayed gamma-ray emission. In this work we revisit the 4 pi gamma – beta method proposed by Greenwood and collaborators in the 1990s, which has the potential to overcome some of the experimental difficulties. Our interest is driven by the need to determine accurately the beta-intensity distributions of fission products that contribute significantly to the reactor decay heat and to the antineutrinos emitted by reactors. A number of such decays have large g.s. branches. The method is relevant for nuclear structure studies as well. Pertinent formulas are revised and extended to the special case of beta-delayed neutron emitters, and the robustness of the method is demonstrated with synthetic data. We apply it to a number of measured decays that serve as test cases and discuss the features of the method. Finally, we obtain g.s. feeding intensities with reduced uncertainty for four relevant decays that will allow future improvements in antineutrino spectrum and decay heat calculations using the summation method.  
  Address [Guadilla, V; Tain, J. L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S. E. A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, 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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000595153500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4626  
Permanent link to this record
 

 
Author n_TOF Collaboration (Mazzone, A. et al); Babiano-Suarez, V; Caballero, L.; Domingo-Pardo, C.; Ladarescu, I; Tain, J.L. url  doi
openurl 
  Title Measurement of the Gd-154(n, gamma) cross section and its astrophysical implications Type Journal Article
  Year 2020 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 804 Issue Pages 135405 - 6pp  
  Keywords s process; Gd-154; Neutron time of flight; n_TOF  
  Abstract The neutron capture cross section of Gd-154 was measured from 1 eV to 300 keV in the experimental area located 185 m from the CERN n_TOF neutron spallation source, using a metallic sample of gadolinium, enriched to 67% in Gd-154. The capture measurement, performed with four C6D6 scintillation detectors, has been complemented by a transmission measurement performed at the GELINA time-of-flight facility (JRC-Geel), thus minimising the uncertainty related to sample composition. An accurate Maxwellian averaged capture cross section (MACS) was deduced over the temperature range of interest for s process nucleosynthesis modelling. We report a value of 880(50) mb for the MACS at kT = 30 keV, significantly lower compared to values available in literature. The new adopted Gd-154(n, gamma) cross section reduces the discrepancy between observed and calculated solar s-only isotopic abundances predicted by s-process nucleosynthesis models.  
  Address [Mazzone, A.; Barbagallo, M.; Colonna, N.; Damone, L. A.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Bari, Italy, Email: Cristian.Massimi@bo.infn.it  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000548740300022 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4464  
Permanent link to this record
 

 
Author n_TOF Collaboration (Gawlik, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. url  doi
openurl 
  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 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 Guadilla, V. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Nacher, E.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. url  doi
openurl 
  Title Total absorption gamma-ray spectroscopy of the beta-delayed neutron emitters I-137 and Rb-95 Type Journal Article
  Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 100 Issue 4 Pages 044305 - 17pp  
  Keywords  
  Abstract The decays of the beta-delayed neutron emitters( 137)I and Rb-95 have been studied with the total absorption gamma-ray spectroscopy technique. The purity of the beams provided by the JYFLTRAP Penning trap at the ion guide isotope separator on-line facility in Jyvaskyla allowed us to carry out a campaign of isotopically pure measurements with the decay total absorption gamma-ray spectrometer, a segmented detector composed of 18 NaI(T1) modules. The contamination coming from the interaction of neutrons with the spectrometer has been carefully studied, and we have tested the use of time differences between prompt gamma rays and delayed neutron interactions to eliminate this source of contamination. Due to the sensitivity of our spectrometer, we have found a significant amount of beta intensity to states above the neutron separation energy that deexcite by gamma rays, comparable to the neutron emission probability. The competition between gamma deexcitation and neutron emission has been compared with Hauser-Feshbach calculations, and it can be understood as a nuclear structure effect. In addition, we have studied the impact of the beta-intensity distributions determined in this work on reactor decay heat and reactor antineutrino spectrum summation calculations. The robustness of our results is demonstrated by a thorough study of uncertainties and with the reproduction of the spectra of the individual modules and the module-multiplicity gated spectra. This work represents the state-of-the-art of our analysis methodology for segmented total absorption spectrometers.  
  Address [Guadilla, V; Tain, J. L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Nacher, E.; Orrigo, S. E. A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain, Email: guadilla@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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000489250100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4169  
Permanent link to this record
 

 
Author Estienne, M.; Fallot, M.; Algora, A.; Briz-Monago, J.; Bui, V.M.; Cormon, S.; Gelletly, W.; Giot, L.; Guadilla, V.; Jordan, D.; Le Meur, L.; Porta, A.; Rice, S.; Rubio, B.; Tain, J.L.; Valencia, E.; Zakari-Issoufou, A.A. url  doi
openurl 
  Title Updated Summation Model: An Improved Agreement with the Daya Bay Antineutrino Fluxes Type Journal Article
  Year 2019 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 123 Issue 2 Pages 022502 - 6pp  
  Keywords  
  Abstract A new summation method model of the reactor antineutrino energy spectrum is presented. It is updated with the most recent evaluated decay databases and with our total absorption gamma-ray spectroscopy measurements performed during the last decade. For the first time, the spectral measurements from the Daya Bay experiment are compared with the antineutrino energy spectrum computed with the updated summation method without any renormalization. The results exhibit a better agreement than is obtained with the Huber-Mueller model in the 2-5 MeV range, the region that dominates the detected flux. A systematic trend is found in which the antineutrino flux computed with the summation model decreases with the inclusion of more pandemonium-free data. The calculated flux obtained now lies only 1.9% above that detected in the Daya Bay experiment, a value that may be reduced with forthcoming new pandemonium-free data, leaving less room for a reactor anomaly. Eventually, the new predictions of individual antineutrino spectra for the U-235, Pu-239, Pu-241, and U-238 are used to compute the dependence of the reactor antineutrino spectral shape on the fission fractions.  
  Address [Estienne, M.; Fallot, M.; Briz-Monago, J.; Bui, V. M.; Cormon, S.; Giot, L.; Guadilla, V.; Le Meur, L.; Porta, A.; Zakari-Issoufou, A. -A.] Univ Nantes, CNRS, IN2P3, SUBATECH,IMT Atlantique, F-44307 Nantes, France, Email: magali.estienne@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 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000474894200010 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4078  
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