Dr Daniel Doherty
Phone: Work: 01483 68 6802
Room no: 17 BC 04
- 'Measurement of key resonance states for the 30P(p, γ)31Sreaction rate, and the production of intermediate-mass elements in nova explosions'.
Physics Letters B,
[ Status: Accepted ]Repository URL: http://epubs.surrey.ac.uk/id/eprint/813682
We report the first experimental constraints on spectroscopic factors and strengths of key resonances in the 30P(p, γ)31Sreaction critical for determining the production of intermediate-mass elements up to Ca in nova ejecta. The 30P(d, n)31Sreaction was studied in inverse kinematics using the GRETINA γ-ray array to measure the angle-integrated cross-sections of states above the proton threshold. In general, negative-parity states are found to be most strongly produced but the absolute values of spectroscopic factors are typically an order of magnitude lower than predicted by the shell-model calculations employing WBP Hamiltonian for the negative-parity states. The results clearly indicate the dominance of a single 3/2−resonance state at 196 keV in the region of nova burning T≈0.10–0.17GK, well within the region of interest for nova nucleosynthesis. Hydrodynamic simulations of nova explosions have been performed to demonstrate the effect on the composition of nova ejecta.
- 'Triaxiality near the 110Ru ground state from Coulomb excitation'.
Physics Letters B, 766, pp. 334-338.Repository URL: http://epubs.surrey.ac.uk/id/eprint/813684
A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2=12s) isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.