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Seminar | Physics Division

# Recent Results from Gamma-Ray Spectroscopy at ISAC

PHY Semnar

Abstract: High energy-resolution gamma-ray spectroscopy continues to be an important component of low-energy nuclear science research. The exotic isotopes produced by the ISAC facility at TRIUMF are studied using both decay spectroscopy and in-beam spectroscopy of accelerated beams for a variety of nuclear structure, nuclear astrophysics, and standard model measurements.

One recent highlight in decay spectroscopy was the measurements of gamma rays and conversion electrons following beta decay of 80Ga with the GRIFFIN spectrometer and associated auxiliary detectors. This study focused on a first excited 0+ state in 80Ge that had been reported to lie below the first 2+ state, far lower than predicted by large-basis shell model calculations and had been interpreted as a shape coexisting state. The GRIFFIN results provide comprehensive evidence that this low-lying 0+ state does not exist at the reported energy. A second recent result is a measurement of the 83Rb(p,gamma)84Sr reaction with inverse kinematics at an effective centre-of-mass energy of 2.4 MeV. This was the first science experiment with the EMMA recoil separator and utilized the TIGRESS in-beam gamma-ray spectrometer with upgraded acquisition electronics. The preliminary result from ongoing analysis is that measured cross section was found to be approximately one-quarter of that predicted by statistical model calculations.