The 93Zr(n, γ) reaction up to 8 keV neutron energy

The (n,γ) 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.EC FIKW-CT-2000-0010

Application of Photon Strength Functions to (n,g ) measurements with the n_TOF TAC

The neutron capture cross section measurements at the CERN n_TOF facility are performed using a new detection system, the segmented Total Absorption Calorimeter (TAC). All measurements are performed in reference to the well known Au σ(n,γ). The accuracy of the measurements depends on the accuracy of the TAC detection efficiency, which is calculated by means of Monte Carlo simulations. In this MC simulation photon strength functions and level densities play a major role as ingredients used for the generation of primary events, that is the electromagnetic cascades following the (n,γ) process. We have calculated the TAC detection efficiency for the case of Au (n,γ) by adjusting the photon strength functions of Au so that the simulation reproduces the experimental data. Both the MC method and the uncertainty of the results are discussed

CERN n_TOF facility: Performance report

An innovative neutron Time-of-Flight facility (n_TOF) has recently become operative at CERN. The high neutron flux is obtained by the spallation of 20 GeV/c protons onto a solid lead target. The proton beam is delivered by the Proton Synchrotron (PS) at CERN capable of providing up to four sharp bunches (RMS 6 ns) with an intensity of 7x10^12 protons per bunch within a 14.4s supercycle. The present report describes the outstanding characteristics of this facility: high neutron flux of 10^6 n/cm^2/7x10^12 p at 185 m, wide spectral function from 1 eV up to 250 MeV, low repetition rates, an excellent energy resolution of 2x10^-4 in the resonance region and low background conditions. These unique features open new possibilities for high precision neutron induced cross section measurements relevant to Nuclear Technology, Nuclear Astrophysics and fundamental Nuclear Physics

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

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.Comisión Europea FIKW-CT-2000-00107 24967

GARFIELD + RCo Digital Upgrade: a Modern Set-up for Mass and Charge Identification of Heavy Ion Reaction Products

An upgraded GARFIELD + Ring Counter (RCo) apparatus is presented with improved performances as far as electronics and detectors are concerned. On one side fast sampling digital read out has been extended to all detectors, allowing for an important simplification of the signal processing chain together with an enriched extracted information. On the other side a relevant improvement has been made in the forward part of the setup (RCo): an increased granularity of the CsI(Tl) crystals and a higher homogeneity in the silicon detector resistivity. The renewed performances of the GARFIELD + RCo array make it suitable for nuclear reaction measurements both with stable and with Radioactive Ion Beams (RIB), like the ones foreseen for the SPES facility, where the Physics of Isospin can be studied.Comment: 13 pages, 19 figures - paper submitted to Eur. Phys. J.

Isotope analysis in central heavy ion collisions at intermediate energies

Symmetry energy is a key quantity in the study of the equation of state of asymmetric nuclear matter. Heavy ion collisions at low and intermediate energies, performed at Laboratori Nazionali di Legnaro and Laboratori Nazionali del Sud, can be used to extract information on the symmetry energy coefficient Csym, which is currently poorly known but relevant both for astrophysics and for structure of exotic nuclei.Comment: 2 pages, 1 figure. Proceedings of 7th International Conference on Radioactive Nuclear Beams (RNB7), to be published in The European Physical Journal

Measurement of the neutron capture cross sections of 233U, 237Np, 240,242Pu, 241,243Am and 245Cm with a total absorption calorimeter at n_TOF

Proposal: Measurement of the neutron capture cross sections of 233U, 237Np, 240,242Pu, 241,243Am and 245Cm with a Total Absorption Calorimeter at n_TOFAccurate and reliable neutron capture cross section data for actinides are necessary for the proper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems (ADS). The goal of this proposal is the measurement of the neutron capture cross sections of 233U, 237Np, 240,242Pu, 241,243Am and 245Cm at n_TOF with an accuracy of 5%. 233U plays an essential role in the Th fuel cycle, which has been proposed as a safer and cleaner alternative to the U fuel cycle. The capture cross sections of 237Np, 240,242Pu, 241,243Am and 245Cm play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. A high accuracy can be achieved at n_TOF in such measurements due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the facility, innovative Data Acquisition System based on flash ADCs and the use of a high performance Total Absorption Calorimeter as a detection device.Postprint (published version