Isomer spectroscopy of neutron-rich ¹⁶⁸Tb₁₀₃

Journal Article · Thu Dec 29 00:00:00 EST 2016 · Radiation Physics and Chemistry (1993)

DOI:https://doi.org/10.1016/j.radphyschem.2016.12.011· OSTI ID:1393951

Gurgi, L. A.; Regan, P. H.; Söderström, P. -A.; Watanabe, H.; Walker, P. M.; Podolyák, Zs.; Nishimura, S.; Berry, T. A.; Doornenbal, P.; Lorusso, G.; Isobe, T.; Baba, H.; Xu, Z. Y.; Sakurai, H.; Sumikama, T.; Catford, W. N.; Bruce, A. M.; Browne, F.; Lane, G. J.; Kondev, F. G. ; Odahara, A.; Wu, J.; Liu, H. L.; Xu, F. R.; Korkulu, Z.; Lee, P.; Liu, J. J.; Phong, V. H.; Yag, A.; Zhang, G. X.; Alharbi, T.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Estrade, A.; Fukuda, N.; Griffin, C.; Ideguchi, E.; Inabe, N.; Kanaoka, H.; Kojouharov, I.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lee, E. J.; Lee, C. S.; Lotay, G.; Moon, C. -B.; Nishizuka, I.; Nita, C. R.; Patel, Z.; Roberts, O. J.; Schaffner, H.; Shand, C. M.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Yoshida, S.; Valiente-Dòbon, J. J.

In-flight fission of a 345 MeV per nucleon ²³⁸U primary beam on a 2 mm thick ⁹Be target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus ¹⁷⁰Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified event-by-event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent β-decay. Discrete γ-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr₃) fast-timing scintillation detectors from the FATIMA collaboration. This paper presents the internal decay of a metastable isomeric excited state in the odd-odd nucleus ¹⁶⁸Tb, which corresponds to a single proton-neutron hole configuration in the valence maximum nucleus ¹⁷⁰Dy. These data represent the first information on excited states in this nucleus, which is the most neutron-rich odd-odd isotope of terbium (Z = 65) studied to date. Here, Nilsson configurations associated with an axially symmetric, prolate-deformed nucleus are proposed for the ¹⁶⁸Tb ground state the observed isomeric state by comparison with Blocked BCS-Nilsson calculations.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: United Kingdom Science and Technology Facilities Council; USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1393951
• Alternate ID(s): OSTI ID: 1550646
• Journal Information: Radiation Physics and Chemistry (1993), Vol. 140, Issue C; ISSN 0969-806X
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
Gamma-ray spectroscopy and nuclear isomerism
Nuclear eneregy-level schemes
Possible two-quasiparticle configurations
Structure of neutron-rich radioisotopes