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Author (down) 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 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 (down) n_TOF Collaboration (Stamatopoulos, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Investigation of the Pu-240(n, f) reaction at the n_TOF/EAR2 facility in the 9 meV-6 MeV range Type Journal Article
  Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 102 Issue 1 Pages 014616 - 23pp  
  Keywords  
  Abstract Background: Nuclear waste management is considered amongst the major challenges in the field of nuclear energy. A possible means of addressing this issue is waste transmutation in advanced nuclear systems, whose operation requires a fast neutron spectrum. In this regard, the accurate knowledge of neutron-induced reaction cross sections of several (minor) actinide isotopes is essential for design optimization and improvement of safety margins of such systems. One such case is Pu-240, due to its accumulation in spent nuclear fuel of thermal reactors and its usage in fast reactor fuel. The measurement of the Pu-240(n, f) cross section was previously attempted at the CERN nTOF facility EAR1 measuring station using the time-of-flight technique. Due to the low amount of available material and the given flux at EAR1, the measurement had to last several months to achieve a sufficient statistical accuracy. This long duration led to detector deterioration due to the prolonged exposure to the high alpha activity of the fission foils, therefore the measurement could not be successfully completed. Purpose: It is aimed to determine whether it is feasible to study neutron-induced fission at nTOF/EAR2 and provide data on the Pu-240(n, f) reaction in energy regions requested for applications. Methods: The study of the Pu-240(n, f) reaction was made at a new experimental area (EAR2) with a shorter flight path which delivered on average 30 times higher flux at fast neutron energies. This enabled the measurement to be performed much faster, thus limiting the exposure of the detectors to the intrinsic activity of the fission foils. The experimental setup was based on microbulk Micromegas detectors and the time-of-flight data were analyzed with an optimized pulse-shape analysis algorithm. Special attention was dedicated to the estimation of the non-negligible counting loss corrections with the development of a new methodology, and other corrections were estimated via Monte Carlo simulations of the experimental setup. Results: This new measurement of the Pu-240(n, f) cross section yielded data from 9 meV up to 6 MeV incident neutron energy and fission resonance kernels were extracted up to 10 keV. Conclusions: Neutron-induced fission of high activity samples can be successfully studied at the n_TOF/EAR2 facility at CERN covering a wide range of neutron energies, from thermal to a few MeV.  
  Address [Stamatopoulos, A.; Tsinganis, A.; Kokkoris, M.; Vlastou, R.; Diakaki, M.] Natl Tech Univ Athens, Athens, Greece, Email: athanasios.stamatopoulos@cern.ch  
  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:000551057500002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4466  
Permanent link to this record
 

 
Author (down) n_TOF Collaboration (Sosnin, N.V. et al.); Babiano-Suarez, V.; Caballero, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. doi  openurl
  Title Measurement of the 77Se(n,gamma) cross section up to 200 keV at the n_TOF facility at CERN Type Journal Article
  Year 2023 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 107 Issue 6 Pages 065805 - 9pp  
  Keywords  
  Abstract The 77Se(n,gamma) reaction is of importance for 77Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT = 5 keV and kT = 100 keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in 77Se abundances produced through the slow neutron capture process in selected stellar models of 15M0 and 2M0, respectively, compared to using previous recommendation of the cross section.  
  Address [V. Sosnin, N.; Lederer-Woods, C.; Garg, R.; Dietz, M.; Murphy, A. St. J.; Lonsdale, S.; Woods, P. J.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Scotland, Email: nsosnin@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:001023903800002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5599  
Permanent link to this record
 

 
Author (down) n_TOF Collaboration (Praena, J. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Measurement and resonance analysis of the S-33(n,alpha)Si-30 cross section at the CERN n_TOF facility in the energy region from 10 to 300 keV Type Journal Article
  Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 97 Issue 6 Pages 064603 - 10pp  
  Keywords  
  Abstract The (33)(n , alpha)Si-30 cross section has been measured at the neutron time-of-flight (n_TOF) facility at CERN in the neutron energy range from 10 to 300 keV relative to the B-10(n, alpha)(7) Li cross-section standard. Both reactions were measured simultaneously with a set of micromegas detectors. The flight path of 185 m has allowed us to obtain the cross section with high-energy resolution. An accurate description of the resonances has been performed by means of the multilevel multichannel R-matrix code SAMMY. The results show a significantly higher area of the biggest resonance (13.45 keV) than the unique high-resolution (n , alpha) measurement. The new parametrization of the 13.45-keV resonance is similar to that of the unique transmission measurement. This resonance is a matter of research in neutron-capture therapy. The S-33(n, alpha)Si-30 cross section has been studied in previous works because of its role in the production of S-36 in stars, which is currently overproduced in stellar models compared to observations.  
  Address [Praena, J.; Porras, I] Univ Granada, Granada, Spain, Email: jpraena@ugr.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:000434017300004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3597  
Permanent link to this record
 

 
Author (down) n_TOF Collaboration (Patronis, N. et al); Babiano-Suarez, V.; Balibrea Correa, J.; Domingo-Pardo, C.; Ladarescu, I.; Lerendegui-Marco, J. doi  openurl
  Title Status report of the n_TOF facility after the 2nd CERN long shutdown period Type Journal Article
  Year 2023 Publication EPJ Techniques and Instrumentation Abbreviated Journal EPJ Tech. Instrum.  
  Volume 10 Issue 1 Pages 13 - 10pp  
  Keywords Neutron time of flight; Spallation target; Nuclear astrophysics; Neutron physics; Neutron induced fission; Neutron reactions  
  Abstract During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the nTOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the nTOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported.  
  Address [Patronis, N.; Goula, S.; Eleme, Z.; Stamati, M. E.; Vagena, E.] Univ Ioannina, Ioannina, Greece, Email: nikolaos.patronis@cern.ch  
  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 2195-7045 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001008786600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5591  
Permanent link to this record
 

 
Author (down) 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 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 (down) n_TOF Collaboration (Michalopoulou, V. et al); Babiano-Suarez, V.; Caballero, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. doi  openurl
  Title Measurement of the neutron-induced fission cross section of Th-230 at the CERN n_TOF facility Type Journal Article
  Year 2023 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 108 Issue 1 Pages 014616 - 15pp  
  Keywords  
  Abstract The neutron-induced fission cross section of Th-230 has been measured at the neutron time-of-flight facility n_TOF located at CERN. The experiment was performed at the experimental area EAR-1 with a neutron flight path of 185 m, using Micromegas detectors for the detection of the fission fragments. The Th-230(n, f ) cross section was determined relative to the U-235(n, f ) one, covering the energy range from the fission threshold up to 400 MeV. The results from the present work are compared with existing cross-section datasets and the observed discrepancies are discussed and analyzed. Finally, using the code EMPIRE 3.2.3 a theoretical study, based on the statistical model, was performed leading to a satisfactory reproduction of the experimental results with the proper tuning of the respective parameters, while for incident neutron energy beyond 200 MeV the fission of( 230)Th was described by Monte Carlo simulations.  
  Address [Michalopoulou, V; Stamatopoulos, A.; Diakaki, M.; Vlastou, R.; Kokkoris, M.; Tassan-Got, L.] Natl Tech Univ Athens, Dept Phys, Zografou Campus, Athens, Greece, Email: veatriki.michalopoulou@cern.ch  
  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:001063908000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5700  
Permanent link to this record
 

 
Author (down) n_TOF Collaboration (Mendoza, E. et al); Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  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 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 (down) 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 (down) n_TOF Collaboration (Mastromarco, M. et al); Domingo-Pardo, C.; Tain, J.L. url  doi
openurl 
  Title Cross section measurements of Gd-155,Gd-157(n,) induced by thermal and epithermal neutrons Type Journal Article
  Year 2019 Publication European Physical Journal A Abbreviated Journal Eur. Phys. J. A  
  Volume 55 Issue 1 Pages 9 - 20pp  
  Keywords  
  Abstract Neutron capture cross section measurements on Gd-155 and Gd-157 were performed using the time-of-flight technique at the nTOF facility at CERN on isotopically enriched samples. The measurements were carried out in the nTOF experimental area EAR1, at 185 m from the neutron source, with an array of 4 C6D6 liquid scintillation detectors. At a neutron kinetic energy of 0.0253 eV, capture cross sections of 62.2(2.2) and 239.8(8.4) kilobarn have been derived for Gd-155 and Gd-157, respectively, with up to 6% deviation relative to values presently reported in nuclear data libraries, but consistent with those values within 1.6 standard deviations. A resonance shape analysis has been performed in the resolved resonance region up to 181 eV and 307 eV, respectively for Gd-155 and Gd-157, where on average, resonance parameters have been found in good agreement with evaluations. Above these energies and up to 1 keV, the observed resonance-like structure of the cross section has been analysed and characterised. From a statistical analysis of the observed neutron resonances we deduced: neutron strength function of 2.01(28)x10-4 and 2.17(41)x10-4; average total radiative width of 106.8(14) meV and 101.1(20) meV and s-wave resonance spacing 1.6(2) eV and 4.8(5) eV for n + Gd-155 and n + Gd-157 systems, respectively.  
  Address [Mastromarco, M.; Barbagallo, M.; Colonna, N.; Damone, L. A.; Mazzone, A.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: massimi@bo.infn.it  
  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 1434-6001 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000456675600003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3892  
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