54Fe and 57Fe are stable iron isotopes, which play an important role in the nucleosynthesis of the slow neutron capture process (s process). In addition, these nuclei are present in many structural ...materials, and therefore, the knowledge of their neutron capture cross sections is of importance for reactor design studies. This contribution summarizes the results of the (n, γ) cross sections of these two isotopes in the resolved resonance region. The experiment was carried out at the CERN n_TOF facility using the Pulse-Height Weighting Technique in combination with an experimental set-up optmized for reducing neutron induced backgrounds.
The angular distribution of fragments emitted in neutron-induced fission of 232Th was measured in the white spectrum neutron beam at the n_TOF facility at CERN. A reaction chamber based on Parallel ...Plate Avalanche Counters (PPAC) was used, where the detectors and the targets have been tilted 45∘ with respect to the neutron beam direction in order to cover the full angular range of the fission fragments. A GEANT4 simulation has been developed to study the setup efficiency. The data analysis and the preliminary results obtained for the 232Th(n,f) between fission threshold and 100 MeV are presented here.
The neutron capture cross section of 238U is fundamental to the design and operation of current reactors and future fast nuclear reactors, and thus must be measured to a high level of accuracy. An ...experiment has been performed at the CERN n_TOF facility using a 4π Total Absorption Calorimeter (TAC) to measure the capture cross section in the resolved resonance region between 1 eV and 25 keV. A preliminary analysis of the TAC data is presented with particular emphasis to the experimental background in this energy region of interest.
A 352-MHz one-cell photocathode electron gun is studied. The simulations with PARMELA are done with two values of peak accelerating fields: 21 and 10 MV/m. Three cavity profiles are compared. The ...results are also discussed in view of the previous analytic theory. The space-charge effect with peak current greater than 300 A covers the RF effect. The beam qualities are not sensitive to cavity design.< >
The 25Mg(n,γ) reaction cross-section has been measured at the neutron time-of-flight facility n_TOF at CERN in 2003 and, with an improved experimental set up, in 2012. These measurements aim at ...addressing important astrophysical issues related to the s process. Highly-enriched 25Mg samples have been used, in the form of MgO powder and Mg metal sample. Preliminary results from the 2012 measurement and comparisons with previous data are shown.
The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very ...accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN – n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.
The n_TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the ...features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.
A Monte Carlo code combined with a particle tracking program has been used to study a stroboscopic laser diagnostic system that is able to detect a string-like ordered ion beam. Different ion species ...have been studied to evaluate the diagnostics capability.
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