Chasing Triaxiality: Probing the low-energy structure of A=109 Ru-Pd

Mallory Smith, University of Notre Dame
Monday, May 02, 2:00 PM - Post Doc Candidate
1200 FRIB Laboratory

Abstract:  Far from stability, nuclear structure and the onset of deformation evolves rapidly. Reliable structure information is crucial in understanding this shape evolution across isotopic and isobaric chains, and is also critical to nuclear astrophysics, where structure observables are important inputs for modeling reaction pathways. In particular, the neutron-rich midshell region around A=110 is known to exhibit rapid structure changes. The onset of deformation in A~110 nuclei remains under discussion, and different types of deformations have been observed within a small window of the nuclear landscape, including shape-phase transitions, triaxial deformation and oblate configurations. We have investigate the A=109 β-decay chain produced from the fission of 238U at the University of Jyväskylä IGISOL facility. Gamma-ray transitions were measured with a multidetector array consisting of two high-purity germanium detectors and two LaBr3(Ce) scintillators, and also a plastic scinti llator for β-detection. Triple coincidence β-γ-γ events were recorded and used to check / extend level schemes, as well as extract picosecond-range level lifetimes via the Advanced Time Delay Technique pioneered by H. Mach. Results will be presented on the low-energy structure of 109Tc, 109Ru and 109Pd in the context of the A=109 decay chain and the region. Support from the NSF through grants PHY0822648 and PHY0758100 is gratefully acknowledged.