2024

Alayed, B.; Page, R. D.; Joss, D. T.; Uusitalo, J.; Qi, C.; Briscoe, A. D.; AlAqeel, M. A. M.; Andel, B.; Antalic, S.; Auranen, K.; Ayatollahzadeh, H.; Badran, H.; Barber, L.; Beeton, G.; Birova, M.; Bogdanoff, V.; Cubiss J., G.; Cullen, D. M.; Deary, J.; Forsberg, U.; Grahn, T.; Greenlees, P. T.; Hilton, J. B.; Illana, A.; Joukainen, H.; Judson, D. S.; Julin, R.; Jutila, H.; Keatings, J. M.; Labiche, M.; Leino, M.; Lewis, M. C.; Louko, J.; Luoma, M.; Martel, I.; McCarter, A.; McKee, P. P.; Mosat, P.; Nathaniel, S. N.; Neuvonen, O.; O'Donnell, D.; Ojala, J.; Page, C. A. A.; Plaza, A. M.; Pakarinen, J.; Papadakis, P.; Parr, E.; Partanen, J.; Rahkila, P.; Romero, J.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Saygi, B.; Smallcombe, J.; Smith, J. F.; Sorri, J.; Sullivan, C. M.; Szwec, S.; Tann, H.; Tolosa-Delgado, A.; Uusikylä, E.; Venhart, M.; Waring, L. J.; Zimba, G.

Excited states in the neutron-deficient nuclide 155 Hf have been investigated in experiments performed at the Accelerator Laboratory of the University of Jyväskylä. The 155 Hf nuclei were produced in fusion-evaporation reactions induced by beams of 295 and 315 MeV 58 Ni ions bombarding an isotopically enriched 102 Pd target and separated using the recoil mass separator MARA. An isomeric state having a half-life of 510(30) ns was discoveredand is interpreted as a seniority 𝜐=3, (𝜋⁢ℎ211/2⊗𝜈⁢𝑓7/2)⁢27/2− configuration. The 𝛾-ray transitions emitted in the deexcitation of the isomeric state to the ground state were identified and a level scheme was constructed, from which the excitation energy of the isomer was determined to be 2581.5(10) keV. A 𝐵⁡(𝐸⁢2) value of 0.45(3) W.u. was deduced for the 105.4 keV transition depopulating the isomeric state. The deduced level scheme and 𝐵⁡(𝐸⁢2) value are compared with systematics and shell-model calculations.