Speaker
Description
In recent astronomical observations, stellar abundance patterns of certain elements cannot be explained by traditional nucleosynthesis processes, namely the slow (s) and rapid (r) neutron-capture processes. Therefore, the emergence of an independent nucleosynthesis pathway, the intermediate (i-) process, is required to explain these observations. However, some open questions remain for the i process, such as potential astrophysical site where this process occurs, and the conditions required for this process to take place. For nuclei that are involved along this pathway, structural properties such as masses and $\beta$-decay half-lives are experimentally well constrained except for neutron-capture reaction rates, which are almost entirely provided by theory.
Current models that explore the i-process significantly underproduce the abundances of strontium (Sr) compared to observational data, while neighbouring elements such as yttrium (Y) and zirconium (Zr) are well described through this comparison. It is evident that this discrepancy is due to the uncertainties associated with the nuclear physics input, especially on the neutron-capture reaction rate of the $^{88}$Kr(n,$\gamma$)$^{89}$Kr reaction.
In this presentation, the first experimental constraint on the $^{88}$Kr(n,$\gamma$)$^{89}$Kr reaction rate will be discussed utilizing the $\beta$-Oslo method, obtained by exploiting its statistical properties. The indirect method of $\beta$-decay from $^{89}$Br into $^{89}$Kr was utilized at the CARIBU facility in Argonne National Laboratory. Subsequent $\gamma$-rays were detected the using the Summing NaI(Tl) detector, SuN, with the combination of the SuNTAN tape transport system and a plastic scintillator barrel, SuNSPOT.
This presentation will feature the experimentally constrained reaction rate for $^{89}$Kr, with a discussion on its impact on current i-process models and on the underproduction of Sr.
| Contribution category | Experiment |
|---|---|
| Presenter status | Postdoc |