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Lerendegui-Marco, J.*; Guerrero, C.*; Mendoza, E.*; Quesada, J. M.*; Eberhardt, K.*; Junghans, A. R.*; Kimura, Atsushi; n_TOF Collaboration*; 126 of others*
Physical Review C, 97(2), p.024605_1 - 024605_21, 2018/02
Times Cited Count:21 Percentile:84.76(Physics, Nuclear)Chiba, Satoshi; Soukhovitski, E. Sh.*; Capote, R.*; Quesada, J.*
Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), p.9172_1 - 9172_7, 2009/05
Coupled-channels optical model code OPTMAN is widely applied to analyze experimental nucleon-nucleus interaction data. Sophisticated dispersive optical potential forms had been included in the code along with the possibility to calculate direct excitations of isobar analog states in (p,n) reactions. The latter along with accounting of the proton "effective" energy decrease due to Coulomb repulsion by nuclei, leads to full Lane-consistent optical potential. Such approach had been successfully applied to nucleon-nucleus interaction reaction analyses of experimental data for several nuclei up to 200 MeV incident energies.
Soukhovitski, E.*; Chiba, Satoshi; Capote, R.*; Quesada, J.*; Kunieda, Satoshi; Morogovskij, G.*
JAEA-Data/Code 2008-025, 55 Pages, 2008/12
A coupled-channel code to calculate nuclear cross sections, OPTMAN, has been improved after OPTMAN version 8 was published as JAERI-Data/Code 2005-002. The most important addition is the inclusion of dispersive relationships between imaginary and real parts of the optical potential within a Lane consistent formalism. The obtained CCOM potentials allow for the description of nucleon induced reactions up to 200 MeV, including (p,n) reactions with excitation of isobaric analog states. Relativistic corrections consistent with those used in the ECIS06 code are also added.
Capote, R.*; Chiba, Satoshi; Soukhovitskij, E. Sh.*; Quesada, J. M.*; Bauge, E.*
Journal of Nuclear Science and Technology, 45(4), p.333 - 340, 2008/04
Times Cited Count:45 Percentile:92.9(Nuclear Science & Technology)A global dispersive coupled-channel optical model (DCCOM) potential is proposed to describe neutron and proton interactions with actinide nuclei at 0.001 to 200 MeV range. A linear dependence of the geometrical parameters on mass number is employed, and deformation parameters are adjusted for each nucleus to extend the DCCOM determined previously for U and Th to neighboring nuclei, Am, Pu and U. Fitted deformations are in reasonable agreement with those derived theoretically. The present DCCOM is capable of describing not only the cross sections but also the total cross section differences between Th and U up to 200 MeV within experimental uncertainty, verifying that the isovector potential and assumed geometrical parameters are adequate to describe the minute difference of the cross sections of actinide nuclei and its energy dependence.
Quesada, J. M.*; Capote, R.*; Soukhovitskii, E. Sh.*; Chiba, Satoshi
Physical Review C, 76(5), p.057602_1 - 057602_3, 2007/11
Times Cited Count:23 Percentile:79.54(Physics, Nuclear)A previously derived dispersive coupled-channel optical model potential for nucleon scattering on Th and U nuclei has been challenged against experimental data on quasi-elastic () scattering to the isobaric analog states of corresponding target nuclei. The Lane potential derived from the isovector term of the dispersive coupled-channel optical model potential has been shown to approximately reproduce available experimental differential cross-section data for the quasi-elastic () reaction; therefore the approximated Lane consistency of that potential has been established.
Okumusoglu, N. T.*; Gorur, F. K.*; Birchall, J.*; Soukhovitskij, E. Sh.*; Capote, R.*; Quesada, J. M.*; Chiba, Satoshi
Physical Review C, 75(3), p.034616_1 - 034616_10, 2007/03
Times Cited Count:4 Percentile:35.63(Physics, Nuclear)Elastic and inelastic scattering of unpolarized and polarized protons by Ar nuclei for incident energies between 20 and 50 MeV has been studied by reanalyzing experimental scattering spectra for the 2 (1.46 MeV) and 3 (3.68 MeV) levels in the angular range 30 - 160 for incident protons of energies of 25.1, 32.5, and 40.7 MeV. An isospin dependent soft-rotator coupled channels optical model with the potential containing a dispersive term with a nonlocal contribution is used to analyze the data.
Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
Physical Review C, 75(1), p.015806_1 - 015806_9, 2007/01
Times Cited Count:34 Percentile:86.88(Physics, Nuclear)The neutron capture cross section of Pb has been measured at the CERN n_TOF installation with high resolution in the energy range from 1 eV to 440 keV. In the interval between 100 keV and 440 keV we report the average cross section. The background in the entire energy range was reliably determined from the measurement of a Pb sample. We obtain a Maxwellian average capture cross section for Pb at = 30 keV of 79(3) mb, in agreement with previous experiments. However our cross section at = 5 keV is about 35 % larger than the values reported so far. The implications of the new cross section for the -process abundance contributions in the Pb/Bi region are discussed.
Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
Physical Review C, 74(5), p.055802_1 - 055802_6, 2006/11
Times Cited Count:27 Percentile:81.23(Physics, Nuclear)The radiative neutron capture cross section of Pb has been measured at the CERN n_TOF facility using the pulse height weighting technique in the resoleved region. The measurement has been performed with an optimized setup of two scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 778 % to the solar abundance of Pb.
Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
Physical Review C, 74(2), p.025807_1 - 025807_10, 2006/08
Times Cited Count:47 Percentile:90.35(Physics, Nuclear)The neutron capture cross section of Bi has been measured at the CERN n_TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Because Bi is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha decays. In the relevant stellar range of thermal energies between = 5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. The present cross section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.
Aerts, G.*; Abbondanno, U.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; Baumann, P.*; et al.
Physical Review C, 73(5), p.054610_1 - 054610_10, 2006/05
We have measured the neutron capture reaction yield of Th at the neutron tim-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4 %. An independent IAEA evaluation shows good agreement with the data.
Aerts, G.*; Abbondanno, U.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; Baumann, P.*; et al.
Physical Review C, 73(5), p.054610_1 - 054610_10, 2006/05
Times Cited Count:45 Percentile:89.74(Physics, Nuclear)We have measured the neutron capture reaction yield of Th at the neutron time-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4%. An independent IAEA evaluation shows good agreement with the data.
Domingo-Pardo, C.*; O'Brien, S.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; et al.
AIP Conference Proceedings 819, p.288 - 292, 2006/03
The neutron capture cross sections of Pb and Pb have been measured at the CERN n_TOF installation using the time of flight method with the pulse height weighting technique. In a preliminary analysis of Pb we have determined by first time the capture cross sections for two strong -wave resonances below 2.5 keV. In Pb we have determined capture cross sections for a large number of resonances, which were not reported in the two previous capture measurements. We discuss preliminary implications of the new cross sections in the stellar nucleosynthesis of the Pb isotopes.
Terlizzi, R.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
AIP Conference Proceedings 819, p.283 - 287, 2006/03
We measured the neutron capture cross section of La relative to Au in the energy range of 0.6 eV to 9 keV at n_TOF, the neutron time-of-flight facility at CERN. The data were fitted using R-matrix formalism to extract resonance parameters which were used to calculate average level spacings. The data were used to determine Maxwellian-averaged neutron capture cross sections which, in turn, were used to calculate the La abundance synthesized in a steller model of the main component of the process.
Mastinu, P. F.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
Journal of Physics; Conference Series, 41, p.352 - 360, 2006/00
A neutron Time-of-Flight facility (n_TOF) is operative at CERN since 2001. The innovative features of the neutron beam, in particular the high instantaneous flux, the wide energy range, the high resolution and the low background, makes this facility unique for measurements of neutron induced reactions relevant to the field of Emerging Nuclear Technologies, as well as to Nuclear Astrophysics and fundamental Nuclear Physics. The scientific motivations that have led to the construction of this new facility are here presented.
Capote, R.*; Soukhovitskij, E. Sh.*; Quesada, J. M.*; Chiba, Satoshi
Physical Review C, 72(6), p.064610_1 - 064610_6, 2005/12
Times Cited Count:50 Percentile:91.81(Physics, Nuclear)no abstracts in English
Soukhovitskij, E. Sh.*; Capote, R.*; Quesada, J. M.*; Chiba, Satoshi
Physical Review C, 72(2), p.024604_1 - 024604_12, 2005/08
Times Cited Count:67 Percentile:94.73(Physics, Nuclear)Lane consistent coupled channels optical model potential (OMP) containing a dispersive term including nonlocal contribution is used to simultaneously fit the available experimental database (including strength functions and scattering radius) for neutron and proton scattering on strongly deformed Th nucleus. The energy range 0.001-200 MeV is covered. A dispersive coupled-channel optical model (DCCOM) potential with parameters that show a smooth energy dependence and energy independent geometry are determined from fits to the entire data set. Dispersive contribution is shown to be the dominant Coulomb correction to the proton real potential below the Coulomb barrier. Inclusion of nonlocality effects in the absorptive volume potential and its corresponding dispersive contribution to the real potential is needed to achieve an excellent agreement above 100 MeV.
Cano-Ott, D.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; lvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.
AIP Conference Proceedings 769, p.1442 - 1445, 2005/05
Accurate and reliable neutron cross section data for actinides are necessary for the proper design, safety reguartion and precise performance assessment of transmutaion devices. In particular, the neutron capture cross sections of Np, Pu and Am play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. The listed cross sections have been measured in 2004 at n_TOF with a high accuracy due to a combination of features unique in the world.
Furman, W.*; Cennini, P.*; Ketlerov, V.*; Goverdovski, A.*; Konovalov, V.*; Abbondanno, U.*; Aerts, G.*; lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; et al.
AIP Conference Proceedings 769, p.1039 - 1042, 2005/05
A series of measurements of Np fission cross section have been performed at the CERN spallation neutron source facility n_TOF. A fast ionization chamber was used as a fission fragment detector. Total experimental uncertainties are determined to be at the level of 3%. Analysis of experimental data in the neutron energy from 5 eV to 1 MeV showed a systematic deviation from the evaluated data (ENDF/B-VI). This discrepancy amounts to up to the factor of 3 for resolved resonances in the neutron energy range of 5 eV - 2 keV, and is in good agreement with some previous experiments. A similar disagreement at the level of 6-7% was found for higher energies around the threshold. This energy range is essential for the transmutation of neptunium in ADS or fast reactors. It is concluded that an updated evaluation of nuclear data for Np is required.