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Jungclaus, A. et al, Gadea, A., & Montaner-Piza, A. (2016). beta decay of semi-magic Cd-130: Revision and extension of the level scheme of In-130. Phys. Rev. C, 94(2), 024303–8pp.
Abstract: The beta decay of the semi-magic nucleus Cd-130 has been studied at the RIBF facility at the RIKEN Nishina Center. The high statistics of the present experiment allowed for a revision of the established level scheme of In-130 and the observation of additional beta feeding to high- lying core-excited states in In-130. The experimental results are compared to shell-model calculations employing a model space consisting of the full major N = 50-82 neutron and Z = 28-50 proton shells and the NA-14 interaction, and good agreement is found.
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Jungclaus, A. et al, Gadea, A., & Montaner-Piza, A. (2017). Observation of a gamma-decaying millisecond isomeric state in Cd-128(80). Phys. Lett. B, 772, 483–488.
Abstract: A new high-spin isomer in the neutron-rich nucleus Cd-128 was populated in the projectile fission of a U-238 beam at the Radioactive Isotope Beam Factory at RIKEN. A half-life of T-1/2 = 6.3(8) mswas measured for the new state which was tentatively assigned a spin/parity of (15(-)). The experimental results are compared to shell model calculations performed using state-of-the-art realistic effective interactions and to the neighbouring nucleus Cd-129. In the present experiment no evidence was found for the decay of a 18(+) E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h(11/2) and the 0g(9/2) orbit, respectively, which is predicted to exist by the shell model. (C) 2017 The Author(s). Published by Elsevier B.V.
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Jungclaus, A. et al, Gadea, A., & Montaner-Piza, A. (2024). Excited-State Half-Lives in 130 Cd and the Isospin Dependence of Effective Charges. Phys. Rev. Lett., 132(22), 222501–7pp.
Abstract: The known I pi = 8 & thorn; 1 , E x = 2129-keV isomer in the semimagic nucleus 130 Cd 82 was populated in the projectile fission of a 238 U beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, E x = 2001.2(7) keV, and half-life, T 1 =2 = 57(3) ns, of the I pi = 6 & thorn; 1 state based on gamma gamma coincidence information. Furthermore, the halflife of the 8 & thorn; 1 state, T 1 =2 = 224(4) ns, was remeasured with high precision. The new experimental information, combined with available data for 134 Sn and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for 132 Sn, a doubly magic nucleus far -off stability. A comparison to analogous information for 100 Sn provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.
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Kaya, L. et al, & Gadea, A. (2018). Millisecond 23/2(+) isomers in the N=79 isotones Xe-133 and Ba-135. Phys. Rev. C, 98(5), 054312–16pp.
Abstract: Detailed information on isomeric states in A approximate to 135 nuclei is exploited to shell-model calculations in the region northwest of doubly magic nucleus Sn-132. The N = 79 isotones Xe-133 and Ba-135 are studied after multinucleon transfer in the Xe-136 + Pb-208 reaction employing the high-resolution Advanced GAmma Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy and in a pulsed-beam experiment at the FN tandem accelerator of the University of Cologne Germany utilizing a Be-9 + Te-130 fusion-evaporation reaction at a beam energy of 40 MeV. Isomeric states are identified via delayed gamma-ray spectroscopy. Hitherto tentative excitation energy spin and parity assignments of the 2017-keV J(pi) = 23/2(+) isomer in Xe-133 are confirmed and a half-life of T-1/2 = 8.64(13) ms is measured. The 2388-keV state in Ba-135. is identified as a J(pi) = 23/2(+) isomer with a half-life of 1.06(4) ms. The new results show a smooth onset of isomeric J(pi) = 23/2(+) states along the N = 79 isotones and close a gap in the high-spin systematics towards the recently investigated J(pi) = 23/2(+) isomer in Nd-139. The resulting systematics of M2 reduced transition probabilities is discussed within the of the nuclear shell model. Latest large-scale shell-model calculations employing the SN100PN, GCN50:82, SN100-KTH and a realistic effective interaction reproduce the experimental findings generally well and give insight into the structure of the isomers.
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Krolas, W. et al, & Gadea, A. (2011). Coupling of the proton-hole and neutron-particle states in the neutron-rich (48)K isotope. Phys. Rev. C, 84(6), 064301–8pp.
Abstract: Excited states in the Z = 19, N = 29 neutron-rich (48)K isotope have been studied using deep-inelastic transfer reactions with a thick target at Gammasphere and with a thin target at the PRISMA-CLARA spectrometer. The lowest excited states were located; they involve a proton hole in the s(1/2) or d(3/2) orbital coupled to a p(3/2) neutron. A new 7.1(5)-ns, 5(+) isomer, the analog of the 7/2 isomer in (47)K, was identified. Based on the observed gamma-decay pattern of the isomer a revised spin-parity assignment of 1(-) is proposed for the ground state of (48)K.
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