ABBONDANNO , U.

The neutron Time-of-Flight facility at CERN was built to measure the neutron capture and fission cross sections. A short description of the facility, the detectors and the data analysis techniques will be illustrated. A short review of the preliminary results on the fission cross sections is presented together with the implications in...

The (n,γ) cross section of 96Zr has been investigated at the CERN n-TOF spallation neutron source. High-resolution time-of-flight measurements using an enriched ZrO2 sample allowed us to analyze 15 resonances below 40 keV with improved accuracy. On average, the capture widths were found to be 25% smaller than reported in earlier experiments. If...

We have measured the neutron capture reaction yield of 232Th 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...

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...

The neutron Time of Flight (n_TOF) facility at CERN is a source of a wide-range (1 eV

The capture cross section of the 139La has been measured relative to 197Au standard at n_TOF. We provide here a short description of the experimental apparatus and of the data analysis procedures. The extracted resonance parameters allow to calculate the fundamental nuclear quantities such as average spacing l=0 = 268 ± 22 eV, l=1 < 250 eV...

The accurate knowledge of the 151Sm(n,γ) cross section has important implications for the nuclear technologies as well as for fundamental studies. Due to its radioactivity, the only experimental data available on 151Sm were derived from a transmission measurement [1]. Nowadays thanks to the innovative features of neutron time-of-flight facility...

The151Sm(n,γ)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm...

Accurate 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. In particular, the neutron-capture cross sections of 237Np, 240Pu, and 243Am play a key role in...

The 151Sm(n, γ) cross section was measured with the time-of-flight technique from 0.6 eV up to 1 MeV relative to the Au standard with an overall uncertainty of typically 6%. Neutrons were produced by spallation at the innovative nTOF facility at CERN; the γ rays from capture events were detected with organic C6D6 scintillators. Experimental...

The neutron capture cross section of 209 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. Additional experimental sources of...

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...

The neutron capture cross sections of the Zr isotopes have important implications in nuclear astrophysics and for reactor design. The small cross section of the neutron magic nucleus 90Zr, which accounts for more than 50% of natural zirconium represents one of the key isotopes for the stellar s-process, because it acts as a bottleneck in the...

All the stable lead isotopes and 209Bi have been recently measured at n_TOF [1] (CERN) in the range from 1 eV up to 1 MeV, using an optimized experimental setup. A set of two homemade C6D6 detectors with carbon-fibre canning was designed to greatly reduce the sensitivity to scattered neutrons. Surrounding elements like the sample holder and the...

Accurate 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. In particular, the neutron capture cross sections of 237Np, 240Pu and 243Am play a key role in the...

The neutron capture cross sections of the Zr isotopes play an important role in nucleosynthesis studies. The s-process reaction flow between the Fe seed and the heavier isotopes passes through the neutron magic nucleus Zr90 and through Zr91,92,93,94, but only part of the flow extends to Zr96 because of the branching point at Zr95. Apart from...

Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the 92Zr(n,γ) cross section has been remeasured at the CERN n-TOF facility, providing a set of...

The neutron capture cross sections of the Zr isotopes are relevant to studies in nuclear structure, nuclear astrophysics, and nuclear technology. The valence neutron of 91Zr with respect to the neutron magic nucleus 90Zr has interesting implications for the statistical analysis in the proximity of shell closures. In stellar nucleosynthesis, the...

The yield of the neutron capture reaction 232Th(n,γ) has been measured at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV. The reduction of the acquired data to the capture yield for resolved resonances from 1 eV to 4 keV is described and compared to a recent evaluated data set. The resonance parameters...

The nuclear resonance parameters and the capture cross section of the neutron magic isotope La139 have been measured relative to Au197 in the energy range of 0.6 eV to 9 keV at the neutron time-of-flight (n_TOF) facility at CERN. We describe the experimental apparatus and the data analysis procedures, which concerned mainly the efficiency...

The radiative neutron capture cross section of 207 Pb has been measured at the CERN neutron time of flight installation n TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron...

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...

During the 2004 campaign, the n_TOF collaboration measured neutron fission cross sections for 233U, 241,243Am, 245Cm, as well as the fission standards 235,238U, using a sealed Fission Ionization Chamber (FIC). The setup included a total of 16 targets and 18 electrodes mounted together in a 50-cm length chamber, allowing the measurements of all...

The 233U(n,f) cross section has been measured at the white neutron source n-TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from ∼30 meV to 1 MeV neutron energy. The 233U(n,f) cross section has been determined relative to a reference sample of 235U(n,f) measured simultaneously with the same...

The (n,γ) cross section of 197Au has been measured at n-TOF in the resolved resonance region, up to 5keV, with the aim of improving the accuracy in an energy range where it is not yet considered standard. The measurements were performed with two different experimental setup and detection techniques, the total energy method based on C6D6...