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March 30, 20215:00 pm – 6:00 pm (CDT)

The 22Ne(α,n)/(α,γ) branching ratio: Payoff after a long and winding road of research efforts


Shuya Ota (Texas A&M University)


Dan Melconian

Event Details

Payoff after a long and winding road of research efforts The slow neutron capture process (s-process) in AGB stars and massive stars forms about half of the elements heavier than Fe in the solar system. The impact of this process on chemical evolution in the Galaxy is thus tremendous. One of the keys to further constraining the process is determining notoriously hard-to-measure cross section of the 22Ne+α→25Mg+n reaction [22Ne(α,n)], which is the main source of uncertainties in predicted s-process abundances. Experimental difficulties due to the extremely small cross sections were circumvented in the present study by a new technique to measure the 22Ne(α,n)/(α,γ) branching ratio using a magnetic spectrograph at the TAMU Cyclotron Institute. In this talk, I will show how the expected s-process abundances, especially in core-collapse supernovae, are drastically changed due to the reduced – and now well-constrained – cross sections from our measurements. Finally, I will discuss future experiments to understand the origin of chemical elements using radioactive ion beams.

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