Browsing by Author "Canete, L."

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Further Evidence for Shape Coexistence in ^{79}Zn^{m} near Doubly Magic ^{78}Ni
(2023-12-01) Nies, L.; Canete, L.; Dao, D. D.; Giraud, S.; Kankainen, A.; Lunney, D.; Nowacki, F.; Bastin, B.; Stryjczyk, M.; Ascher, P.; Blaum, K.; Cakirli, R. B.; Eronen, T.; Fischer, P.; Flayol, M.; Girard Alcindor, V.; Herlert, A.; Jokinen, A.; Khanam, A.; Köster, U.; Lange, D.; Moore, I. D.; Müller, M.; Mougeot, M.; Nesterenko, D. A.; Penttilä, H.; Petrone, C.; Pohjalainen, I.; de Roubin, A.; Rubchenya, V.; Schweiger, Ch; Schweikhard, L.; Vilen, M.; Äystö, J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Isomers close to doubly magic _{28}^{78}Ni_{50} provide essential information on the shell evolution and shape coexistence near the Z=28 and N=50 double shell closure. We report the excitation energy measurement of the 1/2^{+} isomer in _{30}^{79}Zn_{49} through independent high-precision mass measurements with the JYFLTRAP double Penning trap and with the ISOLTRAP multi-reflection time-of-flight mass spectrometer. We unambiguously place the 1/2^{+} isomer at 942(10) keV, slightly below the 5/2^{+} state at 983(3) keV. With the use of state-of-the-art shell-model diagonalizations, complemented with discrete nonorthogonal shell-model calculations which are used here for the first time to interpret shape coexistence, we find low-lying deformed intruder states, similar to other N=49 isotones. The 1/2^{+} isomer is interpreted as the bandhead of a low-lying deformed structure akin to a predicted low-lying deformed band in ^{80}Zn, and points to shape coexistence in ^{79,80}Zn similar to the one observed in ^{78}Ni. The results make a strong case for confirming the claim of shape coexistence in this key region of the nuclear chart.
Long-sought isomer turns out to be the ground state of 76Cu
(2024-06) Canete, L.; Giraud, S.; Kankainen, A.; Bastin, B.; Nowacki, F.; Ascher, P.; Eronen, T.; Girard Alcindor, V.; Jokinen, A.; Khanam, A.; Moore, I. D.; Nesterenko, D.; De Oliveira, F.; Penttilä, H.; Petrone, C.; Pohjalainen, I.; De Roubin, A.; Rubchenya, V.; Vilen, M.; Äystö, J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Isomers close to the doubly magic nucleus 78Ni (Z=28, N=50) provide essential information on the shell evolution and shape coexistence far from stability. The existence of a long-lived isomeric state in 76Cu has been debated for a long time. We have performed high-precision mass measurements of 76Cu with the JYFLTRAP double Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line facility and confirm the existence of such an isomeric state with an excitation energy Ex=64.8(25) keV. Based on the ratio of detected ground- and isomeric-state ions as a function of time, we show that the isomer is the shorter-living state previously considered as the ground state of 76Cu. The result can potentially change the conclusions made in previous works related to the spin-parity and charge radius of the 76Cu ground state. Additionally, the new 76Cu(n,γ) reaction Q-value has an impact on the astrophysical rapid neutron-capture process.
Measurement of the 2+→0+ ground-state transition in the β decay of F 20
(2019-12-24) Kirsebom, O. S.; Hukkanen, M.; Kankainen, Anu; Trzaska, W. H.; Stroemberg, D. F.; Martinez-Pined, G.; Andersen, K.; Bodewits, E.; Brown, B. A.; Canete, L.; Cederkall, J.; Enqvist, T.; Eronen, Tommi; Fynbo, H. O. U.; Geldhof, S.; de Groote, R.; Jenkins, D. G.; Jokinen, Ari; Joshi, P.; Khanam, A.; Kostensalo, Joel; Kuusiniemi, Pasi; Langanke, K.; Moore, Iain; Munch, M.; Nesterenko, D. A.; Ovejas, J. D.; Penttilä, H.; Pohjalainen, Tapio; Reponen, M.; Rinta-Antila, S.; Riisager, K.; de Roubin, A.; Schotanus, P.; Srivastava, P. C.; Suhonen, Jouni; Swartz, J. A.; Tengblad, O.; Vilen, M.; Vinals, S.; Aysto, J.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
We report the first detection of the second-forbidden, nonunique, 2(+) -> 0(+), ground-state transition in the beta decay of F-20. A low-energy, mass-separated F-20(+) beam produced at the IGISOL facility in Jyvaskyla, Finland, was implanted in a thin carbon foil and the beta spectrum measured using a magnetic transporter and a plastic-scintillator detector. The beta-decay branching ratio inferred from the measurement is b(beta) = [0.41 +/- 0.08(stat) +/- 0.07(sys)] x 10(-5) corresponding to log ft = 10.89(11), making this one of the strongest second-forbidden, nonunique beta transitions ever measured. The experimental result is supported by shell-model calculations and has significant implications for the final evolution of stars that develop degenerate oxygen-neon cores. Using the new experimental data, we argue that the astrophysical electron-capture rate on Ne-20 is now known to within better than 25% at the relevant temperatures and densities.