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cross sections for Cr, Fe, 
Co, and 
Ni from threshold energy to 150 MeVKunieda, Satoshi; Haight, R. C.*; Kawano, Toshihiko*; Chadwick, M. B.*; Sterbenz, S. M.*; Bateman, F. B.*; Wasson, O. A.*; Grimes, S. M.*; Maier-Komor. P.*; Vonach, H.*; et al.
Physical Review C, 85(5), p.054602_1 - 054602_10, 2012/05
Times Cited Count：25 Percentile：75.56(Physics, Nuclear)Neutron reactions that produce alpha-particles have been investigated for energies from threshold to 150 MeV on elemental chromium, iron, Co and Ni. The cross sections were measured at the Los Alamos Neutron Science Center by direct observation of alpha-particles. The model calculations are made for statistical and pre-equilibrium processes. This study particularly focuses on the pre-equilibrium cluster emission, which is described by the clustering exciton model of Iwamoto and Harada. We calculate the alpha-particle formation factors numerically without any approximations that appeared in the original model. The calculated alpha-particle production cross sections agree well with the measured data, except for the Cr case. With a simple sensitivity study for the level density parameters, it is reported that relatively small changes in the level density parameters improve reproduction of experimental data significantly.
Watanabe, Takehito*; Arakawa, Hiroyuki*; Kajimoto, Tsuyoshi*; Iwamoto, Yosuke; Satoh, Daiki; Kunieda, Satoshi; Noda, Shusaku*; Shigyo, Nobuhiro*; Ishibashi, Kenji*; Nakamura, Takashi*; et al.
Nuclear Instruments and Methods in Physics Research A, 587(1), p.20 - 28, 2008/03
Times Cited Count：1 Percentile：13.53(Instruments & Instrumentation)We have developed a phoswich detector for neutron spectrometry, which adopts a reversed configuration of slow- and fast-decay-time scintillators in its inner and surrounding outer regions, respectively, in the detection of recoil protons from a hydrogenous radiator. The phoswich detector consists of an inner slow, NaI(Tl) scintillator, and an outer fast, plastic scintillator. The response functions of the phoswich detector were measured for neutron energies ranging from 100 to 350 MeV. The experiment used the recoil-proton method and pulse-shape discrimination with the two-gate integration technique using a spallation neutron source at the WNR facility of the LANSCE. To evaluate the effectiveness of the phoswich configuration, full energy deposition fraction was calculated. The calculation confirmed that the phoswich detector with a reversed configuration is useful for neutron measurements.
-only isotope 
Pb from 1 eV to 440 keVDomingo-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：36 Percentile：87.60(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.
PbDomingo-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：28 Percentile：81.66(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 77
8 % to the solar abundance of Pb.
BiDomingo-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：90.12(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.
Th measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeVAerts, 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：89.53(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.
Th measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeVAerts, 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.
La(
,
) cross sectionTerlizzi, 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.
Pb and termination of the -processDomingo-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.
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.
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.
Np fission cross section from 5 eV to 1 MeVFurman, 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.
