MENGONI , A.

The integral measurement of the 12C(n, p)12B reaction was performed at the neutron time-offlight facility n TOF at CERN. The total number of 12B nuclei produced per neutron pulse of the n TOF beam was determined using the activation technique in combination with a time-of-flight technique. The cross section is integrated over the n TOF neutron...

The radioactive decay of 187Re → 187Os (t 1/2 = 43 Gyr) is suited for dating the onset of heavy-element nucleosynthesis. The radiogenic contribution to the 187Os abundance is the difference between the natural abundance and the corresponding s-process component. This component can be obtained via the well-established σN systematics using the...

Background: Stellar nucleosynthesis of elements heavier than iron is driven by neutron capture processes. 92Zr is positioned at a strategic point along the slow nucleosynthesis path, given its proximity to the neutron magic number N = 50 and its position at the matching region between the weak and main slow processes. Purpose: In parallel with...

The integral cross section of the 12C(n,p)12B reaction has been determined for the first time in the neutron energy range from threshold to several GeV at the n-TOF facility at CERN. The measurement relies on the activation technique with the β decay of 12B measured over a period of four half-lives within the same neutron bunch in which the...

The precise determination of the neutron capture cross sections of 186Os and 187Os is important to define the s-process abundance of 187Os at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of 187Os due to the decay of the unstable 187Re (t1/2=41.2 Gyr) and from this to infer...

Neutron resonance analyses have been performed for the capture cross sections of 186Os, 187Os, and 188Os measured at the n-TOF facility at cern. Resonance parameters have been extracted up to 5, 3, and 8 keV, respectively, using the sammy code for a full R-matrix fit of the capture yields. From these results average resonance parameters were...

We report on the measurement of the 7Be(n,p)7Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous...

The 235U(n, f) cross section was measured at n_TOF relative to 6Li(n, t) and 10B(n,α) , with high resolution (L= 183. 49 (2) m) and in a wide energy range (25meV-170keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the...

New measurements of the 7Be(n,α)4He and 7Be(n,p)7Li reaction cross sections from thermal to keV neutron energies have been recently performed at CERN/n_TOF. Based on the new experimental results, astrophysical reaction rates have been derived for both reactions, including a proper evaluation of their uncertainties in the thermal energy range of...

Ce140(n,γ) is a key reaction for slow neutron-capture (s-process) nucleosynthesis due to being a bottleneck in the reaction flow. For this reason, it was measured with high accuracy (uncertainty ≈5%) at the n_TOF facility, with an unprecedented combination of a high purity sample and low neutron-sensitivity detectors. The measured Maxwellian...