Speaker
Description
The region of $\alpha$ decaying nuclei close to $^{100}$Sn offers a unique opportunity to study $\alpha$ decays, where the valence nucleons occupy the same orbitals. This might give a rise to exceptionally high $\alpha$-particle preformation factor, leading to very fast $\alpha$ decay. This kind of enhanced $\alpha$ decay was suggested already in 1965 [1], however, to date there is no confirmation for the existence of this so called superallowed $\alpha$ decay. The most enhanced known $\alpha$ emitter is $^{212}$Po, however, this case is lacking the $N=Z$ symmetry. The $\alpha$ decays of $^{112}$Ba, $^{108}$Xe, and $^{104}$Te are expected to compete for the fastest known $\alpha$ decay [2].
The astrophysical $rp$-process has been proposed to terminate with rapid $\alpha$ decays of proton rich tellurium isotopes. The details of the termination depends on the single proton separation energies of antimony isotopes [3]. These energies can be probed indirectly by measuring the proton and $\alpha$-decay energies in this region.
In this presentation, preliminary results of an experiment performed at ATLAS, Argonne National Laboratory, using the Fragment Mass Analyzer (FMA) to study charged-particle decays in the $^{100}$Sn region will be presented.
[1] R. Macfarlane et al., Phys. Rev. Lett. 14, 4 (1965)
[2] P. Mohr, Eur. Phys. J. A 31, 23 (2007)
[3] C. Mazzocchi, et al, Phys. Rev. Lett. 98, 212501 (2007)
This work is supported by the U.S Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
