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Accueil > Séminaires > Séminaires passés > Séminaires de 2010 > From nuclear reactions to astrophysics

Christian Diget

From nuclear reactions to astrophysics

Jeudi 18 Mars 2010, à 14h15

Nuclear processes driving the energy production and nuclear synthesis in stars often cannot be studied directly in the laboratory. This is because the reactions in many cases involve short-lived nuclei, and are furthermore hindered by the Coulomb repulsion of the nuclei, making direct observation of the reactions difficult or even impossible. The triple-alpha reaction where three helium nuclei fuse to carbon through the so-called Hoyle state is in this category as are many reactions related to the breakout from the Hot-CNO cycle in for example X-ray bursts, a nuclear run-away on the surface of neutron stars. Instead of direct measurements, the reactions must be studied indirectly in beta-decay or in reaction studies both of which can probe the nuclear structure that determine the astrophysical processes.

The Silicon Highly-segmented Array for Reactions and Coulex (SHARC) is a new multipurpose array for charged-particle detection designed to address such questions, and is used in conjunction with the TIGRESS γ-ray spectrometer [1] at TRIUMF/ISAC, Canada [2]. Upcoming experiments include indirect studies of astrophysical reactions such as the Hot-CNO breakout reaction 18Ne + alpha → 21Na + proton.

[1] C. E. Svensson, et al., J. Phys. G 31, S1663 (2005).
[2] R. Laxdal, et al., in Proceedings of LINAC08, Victoria, BC, Canada (2008), p. 97.