Decay modes of the 9/2− isomeric state in Tl183

Abstract

The internal transition decay and α decay of the T1/2=53.3ms, 9/2− isomeric state in the neutron-deficient isotope, Tl183, have been studied using the Resonance Ionization Laser Ion Source and the Windmill detection setup at the ISOLDE facility at CERN. Clean samples of Tl183m were produced by selective laser ionization and subsequent mass separation. An internal transition cascade of 356.5–272.2 keV γ rays has been identified. Multipolarities of these transitions have been determined by means of simultaneous γ-ray and conversion-electron spectroscopy. Improved data for the fine structure of the Tl183m→Au179 decay were deduced. This involves a 6058 keV α-decay transition, which populates a previously unknown state in Au179, that is tentatively assigned as a (9/2−). It is interpreted as a coupling of the 1h9/2 proton-intruder with the excited 0+ state in the Pt178 core.1 MoreReceived 11 January 2022Accepted 3 March 2022DOI:https://doi.org/10.1103/PhysRevC.105.034338Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAlpha decayCollective modelsElectromagnetic transitionsEnergy levels & level densitiesIsomer decaysNuclear decayNuclear spin & parityNuclear structure & decaysRare & new isotopesShell modelProperties150 ≤ A ≤ 189Nuclear Physics