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n_TOF Collaboration(Lederer, C. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2013). Neutron Capture Cross Section of Unstable Ni-63: Implications for Stellar Nucleosynthesis. Phys. Rev. Lett., 110(2), 022501–5pp.
Abstract: The Ni-63(n, gamma) 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(circle dot) star show that the new data have a significant effect on the s-process production of Cu-63, Ni-64, and Zn-64 in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.
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n_TOF Collaboration(Tagliente, G. et al.), Domingo-Pardo, C., & Tain, J. L. (2013). The Zr-93(n, gamma) reaction up to 8 keV neutron energy. Phys. Rev. C, 87(1), 014622–7pp.
Abstract: The (n, gamma) reaction of the radioactive isotope Zr-93 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. DOI: 10.1103/PhysRevC.87.014622
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Jordan, D., Tain, J. L., Algora, A., Agramunt, J., Domingo-Pardo, C., Gomez-Hornillos, M. B., et al. (2013). Measurement of the neutron background at the Canfranc Underground Laboratory LSC. Astropart Phys., 42, 1–6.
Abstract: The energy distribution of the neutron background was measured for the first time at Hall A of the Canfranc Underground Laboratory. For this purpose we used a novel approach based on the combination of the information obtained with six large high-pressure He-3 proportional counters embedded in individual polyethylene blocks of different size. In this way not only the integral value but also the flux distribution as a function of neutron energy was determined in the range from 1 eV to 10 MeV. This information is of importance because different underground experiments show different neutron background energy dependence. The high sensitivity of the setup allowed to measure a neutron flux level which is about four orders of magnitude smaller that the neutron background at sea level. The integral value obtained is Phi(Hall A) = (3.44 +/- 0.35) x 10(-6) cm(-2) s(-1).
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n_TOF Collaboration(Guerrero, C. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2013). Performance of the neutron time-of-flight facility n_TOF at CERN. Eur. Phys. J. A, 49(2), 27–15pp.
Abstract: 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.
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n_TOF Collaboration(Belloni, F. et al), Domingo-Pardo, C., & Tain, J. L. (2013). Measurement of the neutron-induced fission cross-section of Am-241 at the time-of-flight facility n_TOF. Eur. Phys. J. A, 49(1), 2–6pp.
Abstract: The neutron-induced fission cross-section of Am-241 has been measured relative to the standard fission cross-section of U-235 between 0.5 and 20 MeV. The experiment was performed at the CERN nTOF facility. Fission fragments were detected by a fast ionization chamber by discriminating against the alpha-particles from the high radioactivity of the samples. The high instantaneous neutron flux and the low background of the nTOF facility enabled us to obtain uncertainties of approximate to 5%. With the present results it was possible to resolve discrepancies between previous data sets and to confirm current evaluations, thus providing important information for design studies of future reactors with improved fuel burn-up.
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