|
|
Cavallaro, M., De Napoli, M., Cappuzzello, F., Orrigo, S. E. A., Agodi, C., Bondi, M., et al. (2017). Investigation of the Li-10 shell inversion by neutron continuum transfer reaction. Phys. Rev. Lett., 118(1), 012701–5pp.
Abstract: This Letter reports a study of the highly debated 10Li structure through the d(Li-9,p)Li-10 one-neutron transfer reaction at 100 MeV. The Li-10 energy spectrum is measured up to 4.6 MeV and angular distributions corresponding to different excitation energy regions are reported for the first time. The comparison between data and theoretical predictions, including pairing correlation effects, shows the existence of a p(1/2) resonance at 0.45 +/- 0.03 MeV excitation energy, while no evidence for a significant s-wave contribution close to the threshold energy is observed. Moreover, two high-lying structures are populated at 1.5 and 2.9 MeV. The corresponding angular distributions suggest a significant s(1/2) partial-wave contribution for the 1.5 MeV structure and a mixing of configurations at higher energy, with the d(5/2) partial-wave contributing the most to the cross section.
|
|
|
|
Guadilla, V. et al, Algora, A., Tain, J. L., Agramunt, J., Aysto, J., Jordan, D., et al. (2019). Large Impact of the Decay of Niobium Isomers on the Reactor (v)over-bar(e) Summation Calculations. Phys. Rev. Lett., 122(4), 042502–6pp.
Abstract: Even mass neutron-rich niobium isotopes are among the principal contributors to the reactor antineutrino energy spectrum. They are also among the most challenging to measure due to the refractory nature of niobium, and because they exhibit isomeric states lying very close in energy. The beta-intensity distributions of Nb-100gs,Nb-100m and Nb-102gs,Nb-02m beta decays have been determined using the total absorption.-ray spectroscopy technique. The measurements were performed at the upgraded Ion Guide Isotope Separator On-Line facility at the University of Jyvaskyla. Here, the double Penning trap system JYFLTRAP was employed to disentangle the beta decay of the isomeric states. The new data obtained in this challenging measurement have a large impact in antineutrino summation calculations. For the first time the discrepancy between the summation model and the reactor antineutrino measurements in the region of the shape distortion has been reduced.
|
|
|
|
Cappuzzello, F., Rea, C., Bonaccorso, A., Bondi, M., Carbone, D., Cavallaro, M., et al. (2012). New structures in the continuum of C-15 populated by two-neutron transfer. Phys. Lett. B, 711(5), 347–352.
Abstract: The C-13(O-18,O-16)C-15 reaction has been studied at 84 MeV incident energy. The ejectiles have been detected at forward angles and C-15 excitation energy spectra have been obtained up to about 20 MeV. Several known bound and resonant states of C-15 have been identified together with two unknown structures at 10.5 MeV (FWHM = 2.5 MeV) and 13.6 MeV (FWHM = 2.5 MeV). Calculations based Oil the removal of two uncorrelated neutrons from the projectile describe a significant part of the continuum observed in the energy spectra. In particular the structure at 10.5 MeV is dominated by a resonance of C-15 near the C-13 + n + n threshold. Similar structures are found in nearby nuclei such as C-14 and Be-11.
|
|
|
|
Algora, A., Ganioglu, E., Sarriguren, P., Guadilla, V., Fraile, L. M., Nacher, E., et al. (2021). Total absorption gamma-ray spectroscopy study of the beta-decay of Hg-186. Phys. Lett. B, 819, 136438–7pp.
Abstract: The Gamow-Teller strength distribution of the decay of Hg-186 into Au-186 has been determined for the first time using the total absorption gamma spectroscopy technique and has been compared with theoretical QRPA calculations using the SLy4 Skyrme force. The measured Gamow-Teller strength distribution and the half-life are described by mixing oblate and prolate configurations independently in the parent and daughter nuclei. In this theoretical framework the best description of the experimental beta strength is obtained with dominantly prolate components for both parent Hg-186 and daughter Au-186. The approach also allowed us to determine an upper limit of the oblate component in the parent state. The complexity of the analysis required the development of a new approach in the analysis of the X-ray gated total absorption spectrum.
|
|
|
|
Vitez-Sveiczer, A. et al, Algora, A., Morales, A. I., Rubio, B., Agramunt, J., Guadilla, V., et al. (2022). The beta-decay of Kr-70 into Br-70: Restoration of the pseudo-SU(4) symmetry. Phys. Lett. B, 830, 137123–8pp.
Abstract: The beta-decay of the even-even nucleus Kr-70 with Z=N+2, has been investigated at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center using the BigRIPS fragment separator, the ZeroDegree Spectrometer, the WAS3ABI implantation station and the EURICA HPGe cluster array. Fifteen gamma-rays associated with the beta-decay of( 70)Kr into Br-70 have been identified for the first time, defining ten populated states below E-exc=3300 keV. The half-life of Kr-70 was derived with increased precision and found to be t(1/2)=45.19 +/- 0.14 ms. The beta-delayed proton emission probability has also been determined as epsilon(p)=0.545(23)%. An increase in the beta-strength to the yrast 1(+) state in comparison with the heaviest Z=N+2 system studied so far (Ge-62 decay) is observed that may indicate increased np correlations in the T=0 channel. The beta-decay strength deduced from the results is interpreted in terms of the proton-neutron quasiparticle random-phase approximation (pnQRPA) and also with a schematic model that includes isoscalar and isovector pairing in addition to quadrupole deformation. The application of this last model indicates an approximate realization of pseudo-SU(4) symmetry in this system.
|
|
