(α, n) Reactions in Inverse Kinematics Using SECAR
ORAL
Abstract
Observations of metal poor stars in the galactic halo have found significant amounts of star-to-star
scatter in the abundances of elements around Z = 38-47. The nucleosynthesis occurring in the
neutrino driven winds of core collapse supernovae provides a possible explanation for these obser-
vations. In these explosive environments (α, n) reactions close to stability drive heavy element
enrichment. Our knowledge about the nature of this enrichment is limited by the
poorly known nuclear cross sections for these reactions.
Direct measurements of these (α, n) cross sections at astrophysical energies are therefore essential
ingredients for our nuclear and stellar models. In this talk I will discuss a novel
technique for measuring these reactions in inverse kinematics using a recoil separator to detect the
heavy reaction products in coincidence with neutrons. The first measurements of this type have
been carried out using The Separator for Capture Reactions (SECAR) located within NSCL/FRIB.
Principles of the experimental technique will be described along with a discussion of the technical
challenges of using SECAR for this specific purpose.
scatter in the abundances of elements around Z = 38-47. The nucleosynthesis occurring in the
neutrino driven winds of core collapse supernovae provides a possible explanation for these obser-
vations. In these explosive environments (α, n) reactions close to stability drive heavy element
enrichment. Our knowledge about the nature of this enrichment is limited by the
poorly known nuclear cross sections for these reactions.
Direct measurements of these (α, n) cross sections at astrophysical energies are therefore essential
ingredients for our nuclear and stellar models. In this talk I will discuss a novel
technique for measuring these reactions in inverse kinematics using a recoil separator to detect the
heavy reaction products in coincidence with neutrons. The first measurements of this type have
been carried out using The Separator for Capture Reactions (SECAR) located within NSCL/FRIB.
Principles of the experimental technique will be described along with a discussion of the technical
challenges of using SECAR for this specific purpose.
*This work was supported in part by the U.S. Department of Energy Office of Science under Grants No. DEFG02- 88ER40387 and DE-SC0019042 and the U.S. National Nuclear Security Administration through Grant No. DE-NA0003909. We also benefited from support by the U.S. National Science Foundation under Grant No. PHY-1430152 (Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements)
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Presenters
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Caleb A Marshall
- Ohio University