Exploring the Proton Drip Line Near A=70 with Rare-Isotope Beams
- Andrew Rogers, Lawrence Berkeley National Laboratory (LBNL)
Wednesday, November 13, 2:00 PM - Special Seminar
NSCL Lecture Hall
Neutron-deficient nuclei along and beyond the N=Z line play a key role in our understanding of astrophysics, weak-interaction physics, and nuclear structure. For instance, the nuclear-structure properties of 69Br and 73Rb are important for characterizing the reaction pathway through 68Se and 72Kr — so-called waiting-point nuclei in the astrophysical rp process — significantly influencing stellar environments and events such as type I x-ray bursts. In addition, masses and beta-decay properties in this region, where both protons and neutrons occupy the same valence orbitals, are of significant interest in nuclear-structure studies. Probing these systems in the laboratory is extremely challenging: nuclei with N=Z lie progressively further away from the valley of beta stability with increasing mass. Rare-isotope beams and associated techniques are a necessary and powerful tool for accessing such nuclei at the limits of stability. In this talk, I will discuss two recent experiments, utilizing fragmentation beams at NSCL and GANIL, focused on measuring the properties of 69Br as well as Tz = -1/2, -1, -3/2 nuclei in this mass region. To further explore the proton drip line at NSCL, e.g., between Kr and Zr at N=Z, development of fragmentation beams driven by a 92Mo primary beam has been proposed. I will discuss the advantages of this endeavor and associated physics.