Title: Systematic β-decay spectroscopy of odd-Hg isotopes: probing shape-coexistence and intruder configurations in odd-Au nuclei in the experiment IS521
Speaker: Matus Sedlak (Slovak Academy of Sciences, SK)
Abstract: The experiment IS521 at ISOLDE targets the β-decay of odd-mass mercury isotopes into the corresponding odd-mass gold daughters. This time we are aiming for the decay of 185Hg as a next step in our systematic study. This nucleus lies close to the mid-shell region (N≈104) and is expected to provide critical insight into shape-coexistence phenomena, intruder proton configurations (e.g., h9/2, f7/2, i13/2) and their evolution with neutron number in odd-Au systems.
The novelty of the proposed measurement is the simultaneous detection of γ-rays and conversion electrons with high resolution, allowing extraction of internal conversion coefficients and the identification of E0 transitions which serve as direct fingerprints of 0⁺→0⁺ mixing and coexisting shapes. The advanced instrumentation ( TATRA tape transport system, Si(Li) conversion-electron detector, BEGe/HPGe γ-ray array and digital DAQ) and measurements at ISOLDE make this goal feasible with a modest number of shifts.
This talk will present the scientific motivation, detailing prior studies, the experimental setup and strategy, and the expected physics outcome: namely improved level schemes in ¹⁸⁵Au, quantification of E0 strengths, disentangling the interplay of intruder and normal configurations, and benchmarking particle-plus-triaxial-rotor models in a region of rapid structural evolution.
By advancing our understanding of odd-Au nuclei and shape-coexistence close to mid-shell, this work contributes to the broader picture of shell-evolution and collective phenomena in heavy systems.
