Study of the 15^{15}15O$(2p,\gamma )^{17}$Ne Cross Section by Coulomb Dissociation of 17^{17}17Ne for the rprprp Process of Nucleosynthesis (original) (raw)
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The 15 O(2p, γ) 17 Ne cross section has been studied by the inverse reaction, the Coulomb dissociation of 17 Ne. The experiment has been performed at the GSI. The 17 Ne excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb dissociation cross sections (σ Coul ) have been extracted, which provide a photoabsorption (σ photo ) and a radiative capture cross section (σ cap ). Additionally, important information about the 17 Ne nuclear structure will be obtained. The analysis is in progress.
Journal of Physics: Conference Series, 2016
The time-reversed reaction 15 O(2p,) 17 Ne has been studied by the Coulomb dissociation technique. Secondary 17 Ne ion beams at 500 AMeV have been produced by fragmentation reactions of 20 Ne in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-R 3 B experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary di↵erential and integral Coulomb Dissociation cross sections (Coul) have been calculated, which provide a photoabsorption (photo) and a radiative capture cross section (cap). Additionally, important information about the nuclear structure of the 17 Ne nucleus will be obtained. The analysis is in progress.
Cross section of the 14N(α,p 0) 17O nuclear reaction for analytical applications
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1996
The cross section of the "N(~,pa)170 reaction for NRA applications was measured for a-particle energies between 4 and 5 MeV and a laboratory scattering angle of 135' at the 7 MV Van de Graaff accelerator of IRMM by irradiation of polyimide (kapton) foils. Absolute cross section values were derived by normalizing the proton yields on the edge yields of the simultaneously measured RBS spectra of the cY-projectiles on the Ta backings of the polyimide samples. The cross section errors are less than 10%.
14N(α,p)17O nuclear reaction cross-section at 4.9–6.1MeV
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2005
The 14 N(a,p) 17 O nuclear reaction cross-section was measured in the energy range 4.9-6.1 MeV at the laboratory angle h = 172°in order to apply ion beam analysis to the detection of N in metal oxynitride layers. Comparison between the new calculation and data in literature was performed, highlighting important discrepancies between the new results and old cross-section data. Application of the new calculations to a standard TiN film suggests improved accuracy for the data in the present work.
Determination of the Neutron-Capture Rate of 17C for the R-process Nucleosynthesis
2016
With the R^3B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of ^18C at a projectile energy around 425 AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of ^17C into the ground state of ^18C. Those data have been used to constrain theoretical calculations for transitions populating excited states in ^18C. This allowed to derive the astrophysical cross section σ^*_nγ accounting for the thermal population of ^17C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures T_9≤1 GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of ^17C on the production of second- and third-peak elements in contrast to ear...
Comparison of electromagnetic and nuclear dissociation of Ne17
Physical Review C, 2018
The Borromean dripline nucleus 17 Ne has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp process, where the two-proton capture reaction 15 O(2p, γ) 17 Ne, plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of 17 Ne structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u 17 Ne beam was directed towards lead, carbon and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of 17 Ne were disentangled. The relative populations of sand d-states in 16 F were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system 15 O+2p. The 17 Ne EMD data were compared to current theoretical models. None of them yields, however, satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process.
Cross section of the (alpha,p14N(alpha,p0)17O nuclear reaction for analytical applications
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1996
The cross section of the 14N (α,p 0) 17O reaction for NRA applications was measured for α-particle energies between 4 and 5 MeV and a laboratory scattering angle of 135° at the 7 MV Van de Graaff accelerator of IRMM by irradiation of polyimide (kapton) foils. Absolute cross section values were derived by normalizing the proton yields on the edge yields of the simultaneously measured RBS spectra of the α-projectiles on the Ta backings of the polyimide samples. The cross section errors are less than 10%.
(n,γ) cross-sections of light p nuclei: Towards an updated database for the p process
2018
Abstract.: The nucleosynthesis of elements beyond iron is dominated by the s and r processes. However, a small amount of stable isotopes on the proton-rich side cannot be made by neutron capture and is thought to be produced by photodisintegration reactions on existing seed nuclei in the so-called "p process”. So far most of the p-process reactions are not yet accessible by experimental techniques and have to be inferred from statistical Hauser-Feshbach model calculations. The parametrization of these models has to be constrained by measurements on stable proton-rich nuclei. A series of (n,γ) activation measurements on p nuclei, related by detailed balance to the respective photodisintegrations, was carried out at the Karlsruhe Van de Graaff accelerator using the 7Li(p, n) 7Be source for simulating a Maxwellian neutron distribution of kT = 25keV. We present here preliminary results of our extended measuring program in the mass range between A = 74 and A = 132, including first e...