[Triumf-seminars] TRIUMF Colloquium today at 14:00

[TRIUMF Seminars]

Date/Time: Thu 2016-06-02 at 14:00

Location:  Auditorium          

Speaker:   Frank Strieder (South Dakota School of Mines & Technology)

Title:     Underground Nuclear Astrophysics - Yesterday, Today, and Tomorrow

Abstract: It is in the nature of astrophysics that many of the processes and objects are physically inaccessible. Thus, it is important that those aspects that can be studied in the laboratory are well understood. Nuclear reactions are such quantities that can be partly measured in the laboratory. These reactions influence the nucleosynthesis of the elements in the Big Bang as well as in all objects formed thereafter, and control the associated energy generation and evolution of stars. Since more than 20 years LUNA (Laboratory for Underground Nuclear Astrophysics) has been measuring cross sections relevant for hydrogen burning in the Gran Sasso Laboratory and demonstrated the research potential of an underground accelerator facility. Unfortunately, the number of reactions is limited by the energy range accessible with the 400 kV LUNA accelerator. The CASPAR (Compact Accelerator System for Performing Astrophysical Research) Collaboration is implementing a high intensity 1 MV accelerator at the Sanford Underground Research Facility (SURF) and overcome the current limitation at LUNA. The installation of the accelerator facility is almost completed and first experiments will start in late summer 2016. This project will primarily focus on the neutron sources for the s-process, e.g. 13C(alpha,n)16O and 22Ne(alpha,n)25Mg, and lead to unprecedented measurements compared to previous studies in Earth's surface laboratories. However, next generation underground accelerator facilities are already on the horizon, and higher voltage accelerators that can provide heavier ion species as well as higher beam intensities will allow for studies of the 12C(alpha,gamma)16O reaction as well as 12C+12C fusion. In both reactions the extrapolation of existing direct data into the relevant astrophysical temperature range of helium and carbon burning, respectively, carries significant uncertainties and successful underground measurements would add greatly to our understanding of late stellar evolution.

Stimulants available 15 minutes before the talk.

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