Nanosecond lifetime measurements of I^π=9/2^- intrinsic excited states and low-lying B(E1) strengths in ¹⁸³Re using combined HPGe-LaBr₃ coincidence spectroscopy

This paper presents precision measurements of electromagnetic decay probabilities associated with electric dipole transitions in the prolate-deformed nucleus ¹⁸³Re. The nucleus of interest was formed using the fusion evaporation reaction ¹⁸⁰Hf(⁷Li,4n)¹⁸³Re at a beam energy of 30 MeV at the tandem accelerator at the HH-IFIN Institute, Bucharest Romania. Coincident decay gamma rays from near-yrast cascades were detected using the combined HPGe-LaBr₃ detector array ROSPHERE. The time differences between cascade gamma rays were measured using the LaBr₃ detectors to determine the half-lives of the two lowest lying spin-parity 9/2^- states at excitation energies of 496 and 617 keV to be 5.65(5) and 2.08(3) ns respectively. The deduced E1 transition rates from these two states are discussed in terms of the K-hindrance between the low-lying structures in this prolate-deformed nucleus. - Highlights: •Measurement made of EM transition probabilities from low-lying I^π=9/2^- states in ¹⁸³Re. •ROSPHERE gamma-ray array used to isolating discrete gamma-ray cascades. • Derived the reduced hindrances of E1 transitions in ¹⁸³Re related to K-quantum number conservation.