Showing papers by "A. Bracco published in 2021"
01 Nov 2021-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: GALILEO as discussed by the authors, a 4 π high-resolution γ-detection array based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories.
Abstract: GALILEO, a new 4 π high-resolution γ -detection array, based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories. The GALILEO array greatly benefits from a fully-digital read-out chain, customized DAQ, and a variety of complementary detectors to improve the resolving power by the detection of particles, ions or high-energy γ -ray transitions. In this work, a full description of the array, including electronics and DAQ, is presented together with its complementary instrumentation.
15 citations
TL;DR: The Advanced GAmma Tracking Array (AGATA) as mentioned in this paper has seen the realization of the first phases of its construction and exploitation, and a number of nuclear structure studies based on experiments utilizing the principle of γ-ray tracking were carried out in this decade.
15 citations
Istituto Nazionale di Fisica Nucleare1, Spanish National Research Council2, University of Padua3, University of Santiago de Compostela4, GSI Helmholtz Centre for Heavy Ion Research5, University of Milan6, University of Brighton7, University of Vigo8, University of Salamanca9, Polish Academy of Sciences10, Technische Universität München11, University of Delhi12, University of Cologne13, University of Warsaw14, University of Surrey15, Lund University16, Comenius University in Bratislava17, CERN18
TL;DR: In this paper, a newly observed isomer and its measured decay properties indicate that states in 213Pb are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum J=0.
6 citations
University of Milan1, University of Cologne2, Centre national de la recherche scientifique3, International Pentecostal Holiness Church4, University of Groningen5, University of Warsaw6, University of Padua7, Argonne National Laboratory8, Tata Institute of Fundamental Research9, Université Paris-Saclay10
TL;DR: In this paper, a Monte Carlo technique was developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range in products of low-energy heavy-ion binary reactions, with complex velocity distributions.
Abstract: A novel Monte Carlo technique has been developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range in products of low-energy heavy-ion binary reactions, with complex velocity distributions. The method is based on a detailed study of Doppler-broadened $$\gamma $$
-ray lineshapes. Its relevance is demonstrated in connection with the $$^{18}\text {O}(7.0\, \text {MeV/u})+\,^{181}\text {Ta}$$
experiment, performed at GANIL with the AGATA+VAMOS+PARIS setup, to study neutron-rich O, C, N, ... nuclei. Excited states in $$^{17}\text {O}$$
and $$^{19}\text {O}$$
, with known lifetimes, are used to validate the method over the $$\sim 20{-}400\,\text {fs}$$
lifetime-sensitivity range. Emphasis is given to the unprecedented position resolution provided by $$\gamma $$
-tracking arrays, which turns out to be essential for reaching the required accuracy in Doppler-shift correction. The technique is anticipated to be an important tool for lifetime investigations in exotic neutron-rich nuclei, produced with intense ISOL-type beams.
5 citations
4 citations
3 citations
TL;DR: In this article, the structure of the one-valence-particle (VP) and one-hole (VH) nuclei was investigated by using a combination of HPGe detectors and the hybrid configuration mixing model.
Abstract: We present recent results on the structure of the one-valence-particle $^{41}$Ca and $^{49}$Ca, and one-valence-hole $^{47}$Ca, nuclei. The isotopes of interest were populated via the cold-neutron capture reactions $^{40}$Ca(n,$\gamma$), $^{48}$Ca(n,$\gamma$) and $^{46}$Ca(n,$\gamma$), respectively. The experiments were performed at the Institut Laue-Langevin, within the EXILL campaign, which employed a large array of HPGe detectors. The $\gamma$ decay and level schemes of these nuclei were investigated by $\gamma$-ray coincidence relationships, leading to the identification of 41, 10, and 6 new transitions in $^{41}$Ca, $^{47}$Ca, and $^{49}$Ca, respectively. Branching ratios and intensities were extracted for the $\gamma$ decay from each state, and $\gamma$-ray angular correlations were performed to establish a number of transition multipolarities and mixing ratios, thus helping in the spin assignment of the states. The experimental findings are discussed along with microscopic, self-consistent beyond-mean-field calculations performed with the Hybrid Configuration Mixing model, based on a Skyrme SkX Hamiltonian. The latter suggests that a fraction of the low-spin states of the $^{41}$Ca, $^{49}$Ca, and $^{47}$Ca nuclei is characterized by the coexistence of either 2p-1h and 1p-2h excitations, or couplings between single-particle/hole degrees of freedom and collective vibrations (phonons) of the doubly-magic "core".
2 citations
2 citations
University of Milan1, Osaka University2, Technische Universität Darmstadt3, University of York4, Argonne National Laboratory5, United States Army Research Laboratory6, University of Cologne7, University of Groningen8, Tohoku University9, University of Tokyo10, Chinese Academy of Sciences11, Michigan State University12, Florida State University13, Joint Institute for Nuclear Astrophysics14
TL;DR: In this article, the low-lying dipole strength in the 90,94Zr nuclei was investigated via ( p, p ′ γ ) at 80 MeV and ( α, α ′ ǫ ) at 130 MeV.
1 citations
1 citations
Posted Content•
TL;DR: In this paper, high-resolution gamma-ray spectroscopy of 18N was performed with the Advanced GAmma Tracking Array AGATA, following deep-inelastic processes induced by an 18O beam on a 181Ta target.
Abstract: High-resolution gamma-ray spectroscopy of 18N is performed with the Advanced GAmma Tracking Array AGATA, following deep-inelastic processes induced by an 18O beam on a 181Ta target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in 18N below the neutron threshold. Spin and parities are proposed for all located states on the basis of decay branchings and comparison with large-scale shell-model calculations performed in the p-sd space, with the YSOX interaction. Of particular interest is the location of the 0^-_1 and 1^-_2 excitations, which provide strong constrains for cross-shell p-sd matrix elements based on realistic interactions, and help to simultaneously reproduce the ground and first-excited states in 16N and 18N, for the first time. Understanding the 18N structure may also have significant impact on neutron-capture cross-section calculations in r-process modeling including light neutron-rich nuclei.