The very neutron-rich oxygen isotopes 25

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version. Take down policyWhile the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

An experiment has been carried out using the 9Be(3He, r)9B* reaction at a beam energy of 33 MeV. A large acceptance silicon-strip array was used to detect the 9B* break-up in coincidence with the triton ejectiles in the high-resolution Munich-Q3D spectrograph. The excitation energy regime <3 MeV has been explored and the spectrum resulting from proton decaying states, isolated and characterized. Additional resonance strength is observed at 1.86 MeV ±70 keV(stat) ±35 keV(syst), in agreement with two other recent measurements at higher energies and different angles. The consequences for the "missing" >/2+ first excited state are discussed. Additionally, the branching ratios for the 2.36 MeV 5/i~ state have been measured as r»o/r = 0.98 ± 0.12 and i> /r = 0.016 ± 0.008, in close agreement with earlier work.

Determination of the neutron-capture rate of ^{17}C for rprocess nucleosynthesis With the R 3 B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of 18 C at a projectile energy around 425 AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of 17 C into the ground state of 18 C. Those data have been used to constrain theoretical calculations for transitions populating excited states in 18 C. This allowed to derive the astrophysical cross section σ * nγ accounting for the thermal population of 17 C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures 2 T9 ≤ 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 17 C on the production of second-and third-peak elements in contrast to earlier sensitivity studies.