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n_TOF Collaboration(Amaducci, S. et al), Babiano-Suarez, V., Caballero-Ontanaya, L., Domingo-Pardo, C., Ladarescu, I., & Tain, J. L. (2021). First Results of the Ce-140(n,gamma)Ce-141 Cross-Section Measurement at n_TOF. Universe, 7(6), 200–11pp.
Abstract: An accurate measurement of the Ce-140(n,gamma) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the Ce-140 capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in Ce-140 to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the Ce-140 Maxwellian-averaged cross-section.
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n_TOF Collaboration(Lederer, C. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Au-197(n,gamma) cross section in the unresolved resonance region. Phys. Rev. C, 83(3), 034608–11pp.
Abstract: The cross section of the reaction Au-197(n,gamma) was measured with the time-of-flight technique at the n_TOF (neutron time-of-flight) facility in the unresolved resonance region between 5 and 400 keV using a pair of C6D6 (where D denotes H-2) liquid scintillators for the detection of prompt capture gamma rays. The results with a total uncertainty of 3.9%-6.7% for a resolution of 20 bins per energy decade show fair agreement with the Evaluated Nuclear Data File Version B-VII.0 (ENDF/B-VII.0), which contains the standard evaluation. The Maxwellian-averaged cross section (MACS) at 30 keV is in excellent agreement with the one according to the ENDF/B-VII.0 evaluation and 4.7% higher than the MACS measured independently by activation technique. Structures in the cross section, which had also been reported earlier, have been interpreted as being due to clusters of resonances.
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n_TOF Collaboration(Belloni, F. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Neutron-induced fission cross-section of U-233 in the energy range 0.5 < E-n < 20 MeV. Eur. Phys. J. A, 47(1), 2–7pp.
Abstract: The neutron-induced fission cross-section of U-233 has been measured at the CERN nTOF facility relative to the standard fission cross-section of U-235 between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against alpha-particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the nTOF facility result in data with uncertainties of approximate to 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the U-233(n, f) cross-section and, consequently, the design of energy systems based on the Th/U cycle.
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n_TOF Collaboration(Paradela, C. et al), Domingo-Pardo, C., & Tain, J. L. (2010). Neutron-induced fission cross section of U-234 and Np-237 measured at the CERN Neutron Time-of-Flight (n_TOF) facility. Phys. Rev. C, 82(3), 034601–11pp.
Abstract: A high-resolution measurement of the neutron-induced fission cross section of U-234 and Np-237 has been performed at the CERN Neutron Time-of-Flight facility. The cross sections have been determined in a wide energy range from 1 eV to 1 GeV using the evaluated U-235 cross section as reference. In these measurements the energy determination for the U-234 resonances could be improved, whereas previous discrepancies for the Np-237 resonances were confirmed. New cross-section data are provided for high neutron energies that go beyond the limits of prior evaluations, obtaining important differences in the case of Np-237.
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n_TOF Collaboration(Tarrio D. et al.), Domingo-Pardo, C., & Tain, J. L. (2011). Neutron-induced fission cross section of Pb-nat and Bi-209 from threshold to 1 GeV: An improved parametrization. Phys. Rev. C, 83(4), 044620–9pp.
Abstract: Neutron-induced fission cross sections for Pb-nat and Bi-209 were measured with a white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. The experiment, using neutrons from threshold up to 1 GeV, provides the first results for these nuclei above 200 MeV. The cross sections were measured relative to U-235 and U-238 in a dedicated fission chamber with parallel plate avalanche counter detectors. Results are compared with previous experimental data. Upgraded parametrizations of the cross sections are presented, from threshold energy up to 1 GeV. The proposed new sets of fitting parameters improve former results along the whole energy range.
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