Calviño Tavares, Francisco
Total activity: 335
Areas of expertise
Active Teaching and Learning Methodologies, Experimental Nuclear Physics, University Management
h index
18
Professional category
University lecturer
Doctoral courses
Doctor en Ciencias Físicas
Research group
GREENER - Research group on studies in energy and radiation.
Department
Department of Physics and Nuclear Engineering
Institute
Institute of Energy Technology
School
Barcelona School of Industrial Engineering (ETSEIB)
E-mail
francisco.calvinoupc.edu
Contact details
UPC directory Open in new window
Orcid
0000-0002-7198-4639 Open in new window
ResearcherID
K-5743-2014 Open in new window
Collaborative networks
   
Links of interest
CERN Open in new window
Richard Felder. Resources in Science and Engineering Education Open in new window

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1 to 50 of 335 results
  • Measurement of the C-12(n, p)B-12 cross section at n_TOF at CERN by in-beam activation analysis

     Žugec, Petar; Colonna, Nicola; Bosnar, Damir; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Physical review C
    Vol. 90, num. 2, p. 021601-1-021601-5
    DOI: 10.1103/PhysRevC.90.021601
    Date of publication: 2014-08-19
    Journal article

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    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.

  • New Beta-delayed neutron measurements in the light-mass fission group

     Äystö, J.; Caballero Folch, Roger; Calviño Tavares, Francisco; Eronen, T.; Gelletly, W.; Gómez Hornillos, María Belén; Moore, I.; Penttila, H.; Reponen, M.; Riego Pérez, Albert; Rissanen, J.; Rubio, B.; Valencia, E.
    Nuclear data sheets
    Vol. 120, p. 74-77
    DOI: 10.1016/j.nds.2014.07.010
    Date of publication: 2014-06-01
    Journal article

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    A new accurate determination of beta-delayed neutron emission probabilities from nuclei in the low mass region of the light fission group has been performed. The measurements were carried out using the BELEN 4 pi neutron counter at the IGISOL-JYFL mass separator in combination with a Penning trap. The new results significantly improve the uncertainties of neutron emission probabilities for Br-91, As-86, As-85, and Ge-85 nuclei.

  • Neutron capture reactions on Fe and Ni isotopes for the astrophysical s-process

     Lederer, Claudia; Massimi, Cristian; Žugec, Petar; Barbagallo, Massimo; Colonna, Nicola; Domingo Pardo, César; Gunsing, Frank; Taín, J.L.; Altstadt, Sebastian; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 120, p. 201-202
    DOI: 10.1016/j.nds.2014.07.046
    Date of publication: 2014-06-01
    Journal article

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    Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at the neutron time-of-flight facility n TOF at CERN focussing on the Fe/Ni mass region. Recent results and future developments in the neutron time-of-flight technique are discussed.

  • The (n,alpha) reaction in the s-process branching point 59Ni

     Weiß, C.; Griesmayer, E.; Andrzejewski, Józef; Badurek, G.; Dressler, Rugard; Koehler, Paul E.; Lederer, Claudia; Altstadt, Sebastian; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 120, p. 208-210
    DOI: 10.1016/j.nds.2014.07.048
    Date of publication: 2014-06-01
    Journal article

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    The (n,alpha) reaction in the radioactive 59Ni is of relevance in nuclear astrophysics as 59Ni 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 59Ni(n,alpha)56Fe cross section. The results of this measurement, with special emphasis on the dominant resonance at 203 eV, are presented here.

  • ß-decay and ß-delayed neutron emission measurements at GSI-FRS Beyond N=126, for r-process nucleosynthesis

     Caballero Folch, Roger; Benlliure, J.; Cortes Rossell, Guillem Pere; Bowry, M.; Calviño Tavares, Francisco; Dillmann, I.; Estradé, A.; Farinon, F.; Geissel, H.; Gelletly, W.; Gómez Hornillos, María Belén; Heil, M.; Nociforo, C.; Kurcewicz, J.; Marganiec, J.; Paradela, C.; Pietri, S.; Prochazka, A.; Maurice, S.; Riego Pérez, Albert; Rubio, B.; Weick, H.; Smith, K.M; Woody, R.W.
    Nuclear data sheets
    Vol. 120, p. 81-83
    DOI: 10.1016/j.nds.2014.07.012
    Date of publication: 2014-06-01
    Journal article

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    New measurements of very exotic nuclei in the neutron-rich region beyond N=126 have been performed at the GSI facility with the fragment separator (FRS). The aim of the experiment is to determine half-lives and beta-delayed neutron emission branching ratios of isotopes of Hg, Tl and Pb in this region. This contribution summarizes final counting statistics for identification and for implantation, as well as the present status of the data analysis of the half-lives. In summary, isotopes of Pt, Au, Hg, Ti, Pb, Bi, Po, At, Rn and Fr were clearly identified and several of them (Hg208-211, Tl211-215, Pb214-218) were implanted with enough statistics to determine their half-lives. About half of them are expected to be neutron emitters, in such cases it will become possible to obtain the neutron emission probabilities, P-n.

  • GEANT4 simulation of the neutron background of the C6D6 set-up for capture studies at n_TOF

     Žugec, Petar; Colonna, Nicola; Bosnar, Damir; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear instruments and methods in physics research. Section A, accelerators SP
    Vol. 760, p. 57-67
    DOI: 10.1016/j.nima.2014.05.048
    Date of publication: 2014-05-20
    Journal article

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    The neutron sensitivity of the C6D6 detector setup used at n_TOF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n_TOF 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 nat-C yield has been discovered, which prevents the use of nat-C 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

  • High-precision measurement of the 238U(n,¿) cross section with the Total Absorption Calorimeter (TAC) at n TOF, CERN

     Massimi, Cristian; Mingrone, Federica; Gunsing, Frank; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 26-30
    DOI: 10.1016/j.nds.2014.08.009
    Date of publication: 2014-05-01
    Journal article

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    The neutron capture cross section of U-238 is fundamental to the design and operation of current reactors and future fast nuclear reactors, and thus must be measured to a high level of accuracy. An experiment has been performed at the CERN n TOF facility using a 4p Total Absorption Calorimeter (TAC) to measure the capture cross section in the resolved resonance region between 1 eV and 25 keV. A preliminary analysis of the TAC data is presented with particular emphasis to the experimental background in this energy region of interest.

  • Fission fragment angular distribution of 232Th(n,f) at the CERN n TOF facility

     Tarrío, D.; Audouin, Ludmila; Tassan Got, Laurence; Altstadt, Sebastian; Andrzejewski, Józef; Barbagallo, Massimo; Bécares, Vicente; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 35-37
    DOI: 10.1016/j.nds.2014.08.011
    Date of publication: 2014-05-01
    Journal article

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    The angular distribution of fragments emitted in neutron-induced fission of 232Th was measured in the white spectrum neutron beam at the n TOF facility at CERN. A reaction chamber based on Parallel Plate Avalanche Counters (PPAC) was used, where the detectors and the targets have been tilted 45 degrees with respect to the neutron beam direction in order to cover the full angular range of the fission fragments. A GEANT4 simulation has been developed to study the setup efficiency. The data analysis and the preliminary results obtained for the 232Th(n,f) between fission threshold and 100 MeV are presented here.

  • Study of 234U(n,f) resonances measured at the CERN n TOF facility

     Tarrío, D.; Audouin, Ludmila; Tassan Got, Laurence; Abbondanno, U.; Andriamonje, S.; Andrzejewski, Józef; Badurek, G.; Becvar, Zdenek; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Pretel Sanchez, M. del Carmen
    Nuclear data sheets
    Vol. 119, p. 42-44
    DOI: 10.1016/j.nds.2014.08.013
    Date of publication: 2014-05-01
    Journal article

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    We present the analysis of the resolved resonance region for the 234U(n,f) cross section data measured at the CERN n TOF facility. The resonance parameters in the energy range from 1 eV to 1500 eV have been obtained with the SAMMY code by using as initial parameters for the fit the resonance parameters of the JENDL-3.3 evaluation. In addition, the statistical analysis has been accomplished, partly with the SAMDIST code, in order to study the level spacing and the Mehta-Dyson correlation.

  • Spin Measurements of n+87Sr for Level Density Studies

     Gunsing, Frank; Fraval, Kevin; Becvar, F.; Mitchell, G.E.; Andrzejewski, Józef; Altstadt, Sebastian; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Belloni, Fabio; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 132-136
    DOI: 10.1016/j.nds.2014.08.037
    Date of publication: 2014-05-01
    Journal article

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    We have used the 4p BaF2 gamma-ray detector array at the n TOF neutron time-of-flight facility at CERN for an experiment in order to determine the spins of resonances of n+87Sr by measuring the gamma-ray spectra and multiplicity distributions. The first results are presented here. We have assigned the orbital momentum to all evaluated resonances on the basis of their neutron widths. Further we have assigned the spin J to 16 s-wave resonances on based the population of low-lying levels.

    We have used the 4p BaF2 gamma-ray detector array at the n TOF neutron time-of-flight facility at CERN for an experiment in order to determine the spins of resonances of n+87Sr by measuring the gamma-ray spectra and multiplicity distributions. The first results are presented here. We have assigned the orbital momentum to all evaluated resonances on the basis of their neutron widths. Further we have assigned the spin J to 16 s-wave resonances on based the population of low-lying levels.

  • A Micromegas detector for neutron beam imaging at the n TOF facility at CERN

     Belloni, Fabio; Andriamonje, S.; Berthoumieux, Eric; Calviani, Marco; Colonna, Nicola; Gunsing, Frank; Tsinganis, A.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 365-367
    DOI: 10.1016/j.nds.2014.08.100
    Date of publication: 2014-05-01
    Journal article

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    Micromegas (Micro-MEsh Gaseous Structure) detectors are gas detectors consisting of a stack of one ionization and one proportional chamber. A micromesh separates the two communicating regions, where two different electric fields establish respectively a charge drift and a charge multiplication regime. The n TOF facility at CERN provides a white neutron beam (from thermal up to GeV neutrons) for neutron induced cross section measurements. These measurements need a perfect knowledge of the incident neutron beam, in particular regarding its spatial profile. A position sensitive micromegas detector equipped with a 10B based neutron/charged particle converter has been extensively used at the n TOF facility for characterizing the neutron beam profile and extracting the beam interception factor for samples of different size. The boron converter allowed to scan the energy region of interest for neutron induced capture reactions as a function of the neutron energy, determined by the time of flight. Experimental results will be presented and compared to simulations, performed by means of the FLUKA code.

  • New measurement of the 25Mg(n,gamma) reaction cross section

     Massimi, Cristian; Koehler, Paul E.; Mingrone, Federica; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Becvar, F.; Belloni, Fabio; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 110-112
    DOI: 10.1016/j.nds.2014.08.031
    Date of publication: 2014-05-01
    Journal article

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    The 25Mg(n,gamma) reaction cross-section has been measured at the neutron time-of-flight facility n TOF at CERN in 2003 and, with an improved experimental set up, in 2012. These measurements aim at addressing important astrophysical issues related to the s process. Highly-enriched 25Mg samples have been used, in the form of MgO powder and Mg metal sample. Preliminary results from the 2012 measurement and comparisons with previous data are shown.

  • Measurement of the 238U radiative capture cross section with C6D6 at the CERN n TOF facility

     Mingrone, Federica; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 18-21
    DOI: 10.1016/j.nds.2014.08.007
    Date of publication: 2014-05-01
    Journal article

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    We present the preliminary results of the U-238(n,gamma) reaction cross section measurement, performed on April 2012 at the CERN n TOF facility using C6D6 scintillation detectors over an energy range from thermal to 1 MeV. The goal of this measurement, which is part of a larger proposal, is to reach an uncertainty of 2% in the cross section. The experimental set-up and the methods used to obtain this result are described.

  • Investigation of neutron-induced reactions at n TOF: an overview of the 2009-2012 experimental program

     Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 5-9
    DOI: 10.1016/j.nds.2014.08.004
    Date of publication: 2014-05
    Journal article

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    The neutron time-of-flight facility n TOF is operating at CERN (Switzerland) since 2001, having started in 2009 a new campaign with an upgraded spallation target. The ambitious program carried out includes a large number of experiments in nuclear technology, astrophysics, basic physics, detector development and medical applications. This paper is devoted to the physics program at n TOF and the measurements performed between 2009 and 2012. Special attention is given to those experiments that have been most challenging, are more important for a particular field, have reached unprecedented levels of accuracy, or have been carried out for the first time ever.

  • The CERN n TOF facility: neutron beams performances for cross section measurements

     Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 1-4
    DOI: 10.1016/j.nds.2014.08.003
    Date of publication: 2014-05-01
    Journal article

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    This paper presents the characteristics of the existing CERN n TOF neutron beam facility (n TOF-EAR1 with a flight path of 185 meters) and the future one (n TOF EAR-2 with a flight path of 19 meters), which will operate in parallel from Summer 2014. The new neutron beam will provide a 25 times higher neutron flux delivered in 10 times shorter neutron pulses, thus offering more powerful capabilities for measuring small mass, low cross section and/or high activity samples.

  • Measurement of the neutron capture cross section of the fissile isotope 235U with the CERN n TOF total absorption calorimeter and a fission tagging based on micromegas detectors

     Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 10-13
    DOI: 10.1016/j.nds.2014.08.005
    Date of publication: 2014-05-01
    Journal article

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    Current and future nuclear technologies require more accurate nuclear data on (n,¿) cross sections and the alpha-ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the strong fission gamma-ray background competing with the weaker gamma-ray cascades used as the experimental signature of the (n,¿) process. A specific setup was used at the CERN n TOF facility in 2012 for the measurement of the (n,gamma) cross section and alpha-ratios of fissile isotopes and used for the case of the 235U isotope. The setup consists of a set of micromegas fission detectors surrounding the 235U samples all placed inside a segmented BaF2 Total Absorption Calorimeter.

  • Capture cross section of 236U: the n TOF results

     Barbagallo, Massimo; Colonna, Nicola; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Bécares, Vicente; Becvar, Zdenek; Belloni, Fabio; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 45-47
    DOI: 10.1016/j.nds.2014.08.014
    Date of publication: 2014-05-01
    Journal article

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    Neutron induced capture cross section on 236U has been measured with high accuracy and high resolution at n TOF, in order to improve data libraries needed for the development of advanced nuclear reactors. Preliminary results obtained with two different detection systems are reported.

  • Measurement of the 242Pu(n,f) cross section at the CERN n TOF facility

     Tsinganis, A.; Berthoumieux, Eric; Colonna, Nicola; Calviani, Marco; Andriamonje, S.; Gunsing, Frank; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 58-60
    DOI: 10.1016/j.nds.2014.08.018
    Date of publication: 2014-05-01
    Journal article

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    The accurate knowledge of relevant nuclear data is crucial for the design of advanced nuclear systems. These data include neutron cross sections of various plutonium isotopes and other minor actinides. The 242Pu(n,f) cross section was measured at the CERN n TOF facility, taking advantage of the wide energy range (from thermal to GeV) and the high instantaneous flux of the neutron beam. Preliminary results for the measurement are presented.

  • Measurement of the 241Am and the 243Am neutron capture cross sections at the n TOF facility at CERN

     Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Becvar, F.; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 65-68
    DOI: 10.1016/j.nds.2014.08.020
    Date of publication: 2014-05-01
    Journal article

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    The capture cross sections of 241Am and 243Am were measured at the n TOF facility at CERN in the epithermal energy range with a BaF2 Total Absorption Calorimeter. A preliminary analysis of the 241Am and a complete analysis of the 243Am measurement, including the data reduction and the resonance analysis, have been performed.

  • Measurement and analysis of 241Am(n,¿) cross sections with C6D6 detectors at the n TOF facility at CERN

     Fraval, Kevin; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Becvar, F.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 72-75
    DOI: 10.1016/j.nds.2014.08.022
    Date of publication: 2014-05-01
    Journal article

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    The 241Am(n,¿) cross sections have been measured at the n TOF facility at CERN using C6D6 liquid scintillators and time of flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit can be extended from 150 eV to 320 eV. The analysis goes from thermal energy to 150 keV, and the unresolved resonance range cross section turns out to be larger than expected by evaluations or otherwise measured by previous works. The thermal cross section is found to be sth = 740 ± 74 barns, which is larger than expected by evaluations and most previous measurements.

  • Measurement of the 54,57Fe(n,gamma) cross section in the resolved resonance region at CERN n TOF

     Taín, J.L.; Lederer, Claudia; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Becvar, F.; Belloni, Fabio; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Nuclear data sheets
    Vol. 119, p. 117-120
    DOI: 10.1016/j.nds.2014.08.033
    Date of publication: 2014-05-01
    Journal article

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    54Fe and 57 Fe are stable iron isotopes, which play an important role in the nucleosynthesis of the slow neutron capture process (s process). In addition, these nuclei are present in many structural materials, and therefore, the knowledge of their neutron capture cross sections is of importance for reactor design studies. This contribution summarizes the results of the (n, gamma) cross sections of these two isotopes in the resolved resonance region. The experiment was carried out at the CERN n TOF facility using the Pulse-Height Weighting Technique in combination with an experimental set-up optimized for reducing neutron induced backgrounds.

  • Measurement and analysis of the Am 241 (n, gamma) cross section with liquid scintillator detectors using time-of-flight spectroscopy at the n-TOF facility at CERN

     Fraval, Kevin; Gunsing, Frank; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Barbagallo, Massimo; Bécares, Vicente; Belloni, Fabio; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    Physical review C
    Vol. 89, num. 4, p. 044609-1-044609-14
    DOI: 10.1103/PhysRevC.89.044609
    Date of publication: 2014-04-23
    Journal article

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    The Am241(n,¿) cross section has been measured at the n-TOF facility at CERN using deuterated benzene liquid scintillators, commonly known as C6D6 detectors, and time-of-flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit was extended from 150 to 320 eV with a total of 172 new resonances not present in current evaluations. The thermal capture cross section was found to be sth=678±68 b, which is in good agreement with evaluations and most previous measurements. The capture cross section in the unresolved resonance region was extracted in the remaining energy range up to 150 keV, and found to be larger than current evaluations and previous measurements. © 2014 American Physical Society.

  • Neutron-induced fission cross section of U-234 measured at the CERN n_TOF facility

     Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Pretel Sanchez, M. del Carmen
    Physical review C
    Vol. 89, num. 4, p. 044606-1-044606-11
    DOI: 10.1103/PhysRevC.89.044606
    Date of publication: 2014-04-15
    Journal article

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    The neutron-induced fission cross section of 234U has been measured at the CERN n_TOF facility relative to the standard fission cross section of 235U from 20 keV to 1.4 MeV and of 238U from 1.4 to 200 MeV. A fast ionization chamber (FIC) was used as a fission fragment detector with a detection efficiency of no less than 97%. The high instantaneous flux and the low background characterizing the n_TOF facility resulted in wide-energy-range data (0.02 to 200 MeV), with high energy resolution, high statistics, and systematic uncertainties bellow 3%. Previous investigations around the energy of the fission threshold revealed structures attributed to ß-vibrational levels, which have been confirmed by the present measurements. Theoretical calculations have been performed, employing the TALYS code with model parameters tuned to fairly reproduce the experimental data

  • Ni-62(n,gamma) and Ni-63(n,gamma) cross sections measured at the n_TOF facility at CERN

     Lederer, Claudia; Massimi, Cristian; Berthoumieux, Eric; Colonna, Nicola; Dressler, Rugard; Guerrero, Carlos; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert; [et, al]
    Physical review C
    Vol. 89, num. 2, p. 025810-1-025810-11
    DOI: 10.1103/PhysRevC.89.025810
    Date of publication: 2014-02-28
    Journal article

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    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 n_TOF 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 n_TOF. 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.

  • 62Ni(n,gamma) and 63Ni(n,gamma) cross sections measured at the n_TOF facility at CERN

     Lederer, Claudia; Massimi, Cristian; Berthoumieux, Eric; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Physical review C
    Vol. 89, num. 2, p. 025810-1-025810-11
    DOI: 10.1103/PhysRevC.89.025810
    Date of publication: 2014-02-28
    Journal article

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    The cross section of the Ni62(n,gamma) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility n_TOF 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 Ni63(n,¿) reaction was measured for the first time at n_TOF. 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.

  • Experimental neutron capture data of 58Ni from the CERN n_TOF facility

     Žugec, Petar; Barbagallo, Massimo; Colonna, Nicola; Bosnar, Damir; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    Physical review C
    Vol. 89, num. 1, p. 014605-1-014605-9
    DOI: 10.1103/PhysRevC.89.014605
    Date of publication: 2014-01-09
    Journal article

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    The 58Ni(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 ± 0.6stat ± 1.8sys 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 58Ni, with a negligible propagation on heavier isotopes. The reason is that, using both the old or the new MACS, 58Ni is efficiently depleted by neutron captures

    The 58Ni(n,γ ) 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 ± 0.6stat ± 1.8sys 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 58Ni, with a negligible propagation on heavier isotopes. The reason is that, using both the old or the new MACS, 58Ni is efficiently depleted by neutron captures.

  • Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF

     Tarrío, D.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Riego Pérez, Albert
    Nuclear instruments and methods in physics research. Section A, accelerators SP
    Vol. 743, p. 79-85
    DOI: 10.1016/j.nima.2013.12.056
    Date of publication: 2014-01-08
    Journal article

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    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° 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 232Th(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

  • High-accuracy determination of the neutron flux at n TOF

     Barbagallo, Massimo; Guerrero, Carlos; Tsinganis, A.; Tarrío, D.; Altstadt, Sebastian; Andriamonje, S.; Andrzejewski, Józef; Audouin, Ludmila; Bécares, Vicente; Becvar, F.; Belloni, Fabio; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    European physical journal A
    Vol. 49, num. 12, p. 15601-15611
    DOI: 10.1140/epja/i2013-13156-x
    Date of publication: 2013-12-18
    Journal article

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    The neutron flux of the n TOF facility at CERN was measured, after installation of the new spallation target, with four different systems based on three neutron-converting reactions, which represent accepted cross sections standards in different energy regions. A careful comparison and combination of the different measurements allowed us to reach an unprecedented accuracy on the energy dependence of the neutron flux in the very wide range (thermal to 1 GeV) that characterizes the n TOF neutron beam. This is a pre-requisite for the high accuracy of cross section measurements at n TOF. An unexpected anomaly in the neutron-induced fission cross section of U-235 is observed in the energy region between 10 and 30 keV, hinting at a possible overestimation of this important cross section, well above currently assigned uncertainties.

    The neutron flux of the n TOF facility at CERN was measured, after installation of the new spallation target, with four different systems based on three neutron-converting reactions, which represent accepted cross sections standards in different energy regions. A careful comparison and combination of the different measurements allowed us to reach an unprecedented accuracy on the energy dependence of the neutron flux in the very wide range (thermal to 1 GeV) that characterizes the n TOF neutron beam. This is a pre-requisite for the high accuracy of cross section measurements at n TOF. An unexpected anomaly in the neutron-induced fission cross section of 235U is observed in the energy region between 10 and 30 keV, hinting at a possible overestimation of this important cross section, well above currently assigned uncertainties.

  • SOLVING CHALLENGES IN NUCLEAR DATA

     Cortes Rossell, Guillem Pere; Pretel Sanchez, M. del Carmen; Calviño Tavares, Francisco
    Competitive project

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  • Master in Nuclear Engineering in Barcelona: aligning university, utility and society objectives

     Batet Miracle, Lluis; Calviño Tavares, Francisco; Dies Llovera, Javier; Duch Guillen, Maria Amor; del Val, Luis; Fernández Olano, Pablo
    Nuclear Education and Training
    p. 411-419
    Presentation's date: 2013-11-19
    Presentation of work at congresses

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  • Máster en Ingeniería Nuclear por la UPC (Máster UPC-ENDESA). Confluencia de objetivos de la universidad, la empresa y la sociedad

     Batet Miracle, Lluis; Duch Guillen, Maria Amor; Calviño Tavares, Francisco; Dies Llovera, Javier; del Val, Luis; Fernández Olano, Pablo
    Reunión Anual de la Sociedad Nuclear Española
    p. 1-7
    Presentation's date: 2013-09-24
    Presentation of work at congresses

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    El Máster en Ingeniería Nuclear por la UPC pretende formar ingenieros nucleares con un nivel alto de competencias que les permitan optar a puestos de responsabilidad en empresas del sector. El Máster cuenta con el patrocinio de ENDESA y la colaboración de entidades y empresas del sector. El Máster está impartido completamente en inglés y está imbricado en EMINE, European Master in Innovation in Nuclear Energy (KIC-InnoEnergy).

  • A new CVD diamond mosaic-detector for (n, a) cross-section measurements at the n_TOF experiment at CERN

     Weiß, C.; Griesmayer, E.; Guerrero, Carlos; Altstadt, Sebastian; Andrzejewski, Józef; Audouin, Ludmila; Badurek, G.; Barbagallo, Massimo; Bécares, Vicente; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    Nuclear instruments and methods in physics research. Section A, accelerators SP
    Vol. 732, p. 190-194
    DOI: 10.1016/j.nima.2013.07.040
    Date of publication: 2013-08-02
    Journal article

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    At the n_TOF experiment at CERN a dedicated single-crystal chemical vapor deposition (sCVD) Diamond Mosaic-Detector has been developed for (n,a) cross-section measurements. The detector, characterized by an excellent time and energy resolution, consists of an array of 9 sCVD diamond diodes. The detector has been characterized and a cross-section measurement has been performed for the 59Ni(n,a)56Fe reaction in 2012. The characteristics of the detector, its performance and the promising preliminary results of the experiment are presented

    At then_TOFexperimentatCERNadedicatedsingle-crystalchemicalvapordeposition(sCVD)Diamond Mosaic-Detectorhasbeendevelopedfor(n,α) cross-sectionmeasurements.Thedetector,characterized by anexcellenttimeandenergyresolution,consistsofanarrayof9sCVDdiamonddiodes.Thedetector has beencharacterizedandacross-sectionmeasurementhasbeenperformedforthe 59Ni(n,α)56Fe reaction in2012.Thecharacteristicsofthedetector,itsperformanceandthepromisingpreliminary results oftheexperimentarepresented.

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    The nucleosynthesis of heavy elements in Stars: The key isotope 25Mg  Open access

     Massimi, Cristian; Koehler, Paul E.; Kopecky, Stefan; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere
    International Nuclear Physics Conference
    p. 1-4
    DOI: 10.1051/epjconf/20146607016
    Presentation's date: 2013-06-02
    Presentation of work at congresses

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    We have measured the radiative neutron-capture cross section and the total neutron-induced cross section of one of the most important isotopes for the s process, the 25Mg. The measurements have been carried out at the neutron time-of-flight facilities n-TOF at CERN (Switzerland) and GELINA installed at the EC-JRC-IRMM (Belgium). The cross sections as a function of neutron energy have been measured up to approximately 300 keV, covering the energy region of interest to the s process. The data analysis is ongoing and preliminary results show the potential relevance for the s process. © Owned by the authors, published by EDP Sciences, 2014.

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    238U(n, gamma) reaction cross section measurement with C6D6 detectors at the n_TOF CERN facility.  Open access

     Mingrone, Federica; Massimi, Cristian; Vannini, Gianni; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Hernandez Prieto, Alvaro; Riego Pérez, Albert
    International Nuclear Physics Conference
    p. 1-4
    DOI: 10.1051/epjconf/20146603061
    Presentation's date: 2013-06-02
    Presentation of work at congresses

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    The radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,¿) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction. © Owned by the authors, published by EDP Sciences, 2014.

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    Measurements of neutron cross sections for advanced nuclear energy systems at n-TOF (CERN)  Open access

     Barbagallo, Massimo; Colonna, Nicola; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Riego Pérez, Albert
    International Nuclear Physics Conference
    p. 10001-p.1-10001-p.4
    DOI: 10.1051/epjconf/20146610001
    Presentation's date: 2013-06
    Presentation of work at congresses

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    The n-TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.

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    Performance of the neutron time-of-flight facility n TOF at CERN  Open access

     Guerrero, Carlos; Tsinganis, A; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Hernandez Prieto, Alvaro; Riego Pérez, Albert; [et, al]
    European physical journal A
    Vol. 49, num. 27, p. 1-15
    DOI: 10.1140/epja/i2013-13027-6
    Date of publication: 2013-02-25
    Journal article

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    The neutron time-of-flight facility n TOF features a white neutron source produced by spallation through 20 GeV/c protons impinging on a lead target. The facility, aiming primarily at the measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.

  • The 93-Zr(n,gamma) reaction up to 8 keV neutron energy

     Tagliente, G.; Milazzo, P.M.; Fujiii, K.; Abbondanno, U.; Aerts, G.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Pretel Sanchez, M. del Carmen
    Physical review C
    Vol. 87, num. 1, p. 14622-1-14622-7
    DOI: 10.1103/PhysRevC.87.014622
    Date of publication: 2013-01-31
    Journal article

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    The (n,¿) reaction of the radioactive isotope 93Zr has been measured at the n_TOF high-resolution time-of-flight facility at CERN. Resonance parameters have been extracted in the neutron energy range up to 8 keV, yielding capture widths smaller (14%) than reported in an earlier experiment. These results are important for detailed nucleosynthesis calculations and for refined studies of waste transmutation concepts.

    he (n,gamma) reaction of the radioactive isotope 93Zr has been measured at the n_TOF high-resolution time-of-flight facility at CERN. Resonance parameters have been extracted in the neutron energy range up to 8 keV,yielding capture widths smaller (14%) than reported in an earlier experiment. These results are important for detailed nucleosynthesis calculations and for refined studies of waste transmutation concepts.

  • Neutron capture cross section of unstable 63-Ni: implications for stellar nucleosynthesis

     Lederer, Claudia; Massimi, Cristian; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; [et, al]
    Physical review letters
    Vol. 110, p. 22501-1-22501-5
    DOI: 10.1103/PhysRevLett.110.022501
    Date of publication: 2013-01-09
    Journal article

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    The 63Ni(n,γ) 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⊙ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

  • Measurement of the neutron-induced fission cross-section of Am-241 at the time-of-flight facility n_TOF

     Belloni, Fabio; Calviani, Marco; Colonna, Nicola; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Pretel Sanchez, M. del Carmen; Poch Mateu, Antoni
    European physical journal A
    Vol. 49, num. 1, p. 1-6
    DOI: 10.1140/epja/i2013-13002-3
    Date of publication: 2013-01
    Journal article

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    Máster en Ingeniería Nuclear por la UPC (Máster UPC-ENDESA). Balance de la primera edición  Open access

     Batet Miracle, Lluis; Duch Guillen, Maria Amor; Calviño Tavares, Francisco; del Val, Luis; Fernández Olano, Pablo
    Reunión Anual de la Sociedad Nuclear Española
    p. 1-8
    Presentation's date: 2012-10-18
    Presentation of work at congresses

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    El Máster en Ingeniería Nuclear por la UPC, está orientado a la formación de ingenieros nucleares con un nivel alto de competencias que les permitan optar a puestos de responsabilidad en empresas del sector. El máster, que ha iniciado su andadura durante el curso 2011-2012, cuenta con el patrocinio de ENDESA y la colaboración de entidades y empresas del sector. En esta ponencia se realiza un balance de los dos primeros semestres del máster y se describen los puntos fuertes y las oportunidades de mejora detectados. En el análisis se ha tenido en cuenta el rendimiento académico de los estudiantes, sus impresiones y el grado de satisfacción. La información se ha recogido a través de encuestas, entrevistas personales y reuniones con todo el grupo de estudiantes. Los 90 créditos ECTS del Máster se reparten en asignaturas obligatorias (46,5) y optativas (13,5) y prácticas externas y Proyecto Final. La participación de expertos externos a la universidad ha sido muy alta (casi un 50 % de la docencia), especialmente en las materias de Gestión de Plantas y Normativa y Seguridad. Todas las materias incluyen actividades basadas en aprendizaje activo y trabajo en equipo: se consigue así que el sistema de evaluación sea una parte integral e inseparable del proceso de aprendizaje. En cada uno de los dos semestres lectivos, los estudiantes desarrollan un proyecto transversal en grupos de tres o cuatro miembros. En general el grado de satisfacción del alumnado es muy bueno, pero se han detectado algunos aspectos referentes a la distribución de la carga de trabajo y a los mecanismos de evaluación que han sido mejorados sobre la marcha. Estas mejoras se incorporarán en la edición de 2012-2013. Creemos que el Máster satisface las expectativas del sector y de la sociedad a la vez que presenta un gran atractivo para los estudiantes.

  • Neutron-induced fission cross section measurement of 233U, 241Am and 243Am in the energy range 0.5MeVE n20MeV at n-TOF at CERN

     Belloni, Fabio; Milazzo, P.M.; Calviani, M.; Colonna, Nicola; Mastinu, P.; Abbondanno, U.; Aerts, G.; Álvarez, H.; Álvarez-Velarde, F.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Poch Pares, Agusti; Pretel Sanchez, M. del Carmen
    Physica scripta
    Vol. 2012, num. T150
    DOI: 10.1088/0031-8949/2012/T150/014005
    Date of publication: 2012-10
    Journal article

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  • ß-delayed neutron emission measurements around the third r-process abundance peak

     Caballero Folch, Roger; Domingo Pardo, César; Taín, J.L.; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Calviño Tavares, Francisco; Riego Pérez, Albert
    La Rábida, International Scientific Meeting on Nuclear Physics
    p. 137-139
    DOI: 10.1063/1.4810816
    Presentation's date: 2012-09-09
    Presentation of work at congresses

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    This contribution summarizes an experiment performed at GSI (Germany) in the neutron-rich region beyond N=126. The aim of this measurement is to provide the nuclear physics input of relevance for r-process model calculations, aiming at a better understanding of the third r-process abundance peak. Many exotic nuclei were measured around 211Hg and 215Tl. Final ion identification diagrams are given in this contribution. For most of them, we expect to derive halflives and and ß -delayed neutron emission probabilities. The detectors used in this experiment were the Silicon IMplantation and Beta Absorber (SIMBA) detector, based on an array of highly segmentedsilicon detectors, and the BEta deLayEd Neutron (BELEN) detector, which consisted of 30 3He counters embedded in a polyethylene matrix.

  • ß-delayed neutron emission measurements around the third r-process abundance peak

     Caballero Folch, Roger; Domingo Pardo, César; Cortes Rossell, Guillem Pere; Calviño Tavares, Francisco; Riego Pérez, Albert
    International Symposium on Nuclei in the Cosmos
    Presentation's date: 2012-08-06
    Presentation of work at congresses

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    The elements heavier than iron are produced in the Universe mainly by means of the slow (s) and rapid (r) neutron capture processes (for a recent review see e.g. [1]). The latter nucleosynthesis mechanism occurs between the valley of stability and the neutron drip line, passing along the neutron shell closures where exceptionally long half-lives and small neutron capture cross sections yield the three characteristic abundance maxima at A ~ 80, 130 and 195.

  • Measurement of the fission fragment angular distribution for Th-232(n,f) at the CERN n-TOF facility

     Tarrío, D.; Tassan Got, Laurence; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Gómez Hornillos, María Belén; Riego Pérez, Albert
    International Conference on Nuclear Reaction Mechanisms
    p. 253-260
    Presentation's date: 2012-06
    Presentation of work at congresses

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    A fission reaction chamber was designed to measure the angular distribution of the fragments emitted in neutron-induced fission reactions at n-TOF. Up to ten Parallel Plate Avalanche Counters can be included and kept at controlled low-pressure gas. Counters are tilted 45° with respect to the neutron beam direction and up to nine targets can be interleaved in between. A first measurement of the 232Th(n,f) was recently done and preliminary experimental results demonstrating the suitability of the setup are presented here.

  • Measurement of resolved resonances of Th-232(n, gamma) at the n_TOF facility at CERN

     Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Poch Pares, Agusti; Pretel Sanchez, M. del Carmen; [et, al]
    Physical review C
    Vol. 85, num. 6, p. 1-17
    DOI: 10.1103/PhysRevC.85.064601
    Date of publication: 2012-06-01
    Journal article

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  • Nuclear Astrophysics at n-TOF, CERN

     Tagliente, G.; Abbondanno, U.; Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Poch, A.; Pretel Sanchez, M. del Carmen
    International Conference on Nuclear Reaction Mechanisms
    p. 503-509
    Presentation's date: 2012-06
    Presentation of work at congresses

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    The neutron time of flight (n-TOF) facility at CERN is a spallation neutron source with white neutron energy spectrum (from thermal to several GeV), covering the full energy range of interest for nuclear astrophysics, in particular for measurements of the neutron capture cross section required in s-process nucleosynthesis. This contribution presents an overview on the astrophysical program carried on at the n-TOF facility, the main results and their implications.

  • Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications

     Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Poch Pares, Agusti; Pretel Sanchez, M. del Carmen
    Physical review C
    Vol. 85, num. 4, p. 4461501-4461515
    DOI: 10.1103/PhysRevC.85.044615
    Date of publication: 2012-04-20
    Journal article

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  • Measurement and resonance analysis of the 237Np neutron capture cross section

     Cortes Rossell, Guillem Pere; Calviño Tavares, Francisco; Poch Pares, Agusti; Pretel Sanchez, M. del Carmen; [et, al]
    Physical review C
    Vol. 85, num. 4, p. 1-15
    DOI: 10.1103/PhysRevC.85.044616
    Date of publication: 2012-04-20
    Journal article

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  • Neutron-induced fission cross section of 245-Cm: New results from data taken at the time-of-flight facility n_TOF

     Calviño Tavares, Francisco; Cortes Rossell, Guillem Pere; Poch Pares, Agusti; Pretel Sanchez, M. del Carmen
    Physical review C
    Vol. 85, num. 34616, p. 3461601-3461610
    DOI: 10.1103/PhysRevC.85.034616
    Date of publication: 2012-03-29
    Journal article

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    The neutron-induced fission cross section of 245Cm was measured at n_TOF in a wide energy range and with high resolution. The energy dependence, measured in a single measurement from 30 meV to 1 MeV neutron energy, has been determined with 5% accuracy relative to the 235U(n,f) cross section. In order to reduce the uncertainty on the absolute value, the data have been normalized at thermal energy to recent measurements performed at ILL and BR1. In the energy range of overlap, the results are in fair agreement with some previous measurements and confirm, on average, the evaluated cross section in the ENDF/B-VII.0 database, although sizable differences are observed for some important resonances below 20 eV. A similar behavior is observed relative to JENDL/AC-2008, a reactor-oriented database for actinides. The new results contribute to the overall improvement of the databases needed for the design of advanced reactor systems and may lead to refinements of fission models for the actinides.

  • Collimation and Beam Loss Studies in High-Intensity Synchrotrons

     Barranco García, Javier
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

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