Add to Calendar 2024-11-28T09:00:00 2024-11-28T12:00:00 Exotic Decay Measurements at the Experimental Storage Ring for Neutron Capture Processes Event Information: Abstract:   The slow (s) and rapid (r) neutron capture processes are responsible for producing almost all elements heavier than iron. Both processes require a lot of nuclear data to make more reliable predictions, and heavy-ion storage rings provide unique methods for measuring nuclear masses and exotic decay modes that can play an important role in these processes. A prime example is bound-state β− decay, where the β-electron is produced in a bound state of the decaying nuclei. This decay mode for highly-charged ions can currently only be measured at the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre in Darmstadt, Germany. This thesis describes the analysis of the bound-state β− decay of 205Tl81+ at the ESR. 205Tl is a particularly interesting isotope due to its applications in solar neutrino spectrometry and for dating the early Solar System. A bound β-decay half-life of 291(+33,−27) days was measured, which is much longer than previously predicted. The experimental half-life determines the nuclear matrix element of this transition, which allows for the calculation of accurate astrophysical decay rates of 205Tl and 205Pb in the stellar plasma. This enables models of the s process in asymptotic giant branch (AGB) stars to provide accurate 205Pb yields, which are essential for using 205Pb as a cosmochronometer to date processes in the early Solar System, like the time required for the solar material to isolate from its parent molecular cloud. This thesis presents a preliminary determination of the isolation time of the Solar System using 205Pb. In complement, a heavy-ion detector called PLEIADES was constructed and commissioned at the ESR, which will be used to detect decay products leaving the storage ring acceptance. PLEIADES is a δE–E telescope that uses silicon pads to measure energy loss and a scintillator stopper to measure the total ion energy. It was commissioned with a 208Pb beam at the ESR, and achieved a FWHM resolution of δZ = 0.66 and δA = 1.14.  PLEIADES and its predecessor CsISiPHOS will be used as multi-purpose detectors for future measurements in the ESR. Event Location: HENN 318