Showing papers by "A. Bracco published in 2001"
TL;DR: Evidence is presented for the assignment of the excited T SD band as a wobbling mode built on the yrast TSD band, based on comparisons to new calculations in which an aligned particle is coupled to a strongly deformed triaxial rotor.
Abstract: The nucleus ${}^{163}\mathrm{Lu}$ has been populated through the fusion-evaporation reaction ${}^{139}\mathrm{La}{(}^{29}\mathrm{Si},5n{)}^{163}\mathrm{Lu}$ with a beam energy of 152 MeV. The electromagnetic properties of several connecting transitions between two presumably triaxial, strongly deformed (TSD) bands have been studied. Evidence is presented for the assignment of the excited TSD band as a wobbling mode built on the yrast TSD band, based on comparisons to new calculations in which an aligned particle is coupled to a strongly deformed triaxial rotor. The wobbling mode is uniquely related to triaxiality in nuclei.
197 citations
TL;DR: In this article, three superdeformed (SD) bands have been found in 168Hf and lifetime measurements revealed a large quadrupole moment, Q t ∼11.4 e b, for the strongest band (TSD1).
34 citations
TL;DR: In this article, the level scheme of 70Br was established by means of particle-gated γ-γ and γγ-γ coincidences, and the Coulomb energy differences between isobaric analogue states in 70Br and 70Se show a deviation from the expected behaviour which could be related to dripline effects.
Abstract: Gamma ray transitions de-exciting states in the N = Z nucleus 70Br have been identified for the first time using the GASP and EUROBALL arrays coupled with ancillary detectors. The level scheme of 70Br has been established by means of particle-gated γ-γ and γ-γ-γ coincidences. The Coulomb energy differences between isobaric analogue states in 70Br and 70Se show a deviation from the expected behaviour which could be related to dripline effects.
29 citations
TL;DR: The next generation of 4 pi arrays for high-precision gamma-ray spectroscopy will involve "gamma-ray tracking front-end on digital signal processing techniques, which allows to extract energy, timing and spatial information on the interactions of a gamma -ray in the Ge detector by pulse shape analysis of its signals.
16 citations
TL;DR: In this article, the properties of the thermally excited rotational motion up to the region of rotational damping were studied experimentally in the superdeformed nucleus 143 Eu and the effective lifetime of the excited discrete rotational bands forming ridge structures in matrices was measured at the EUROBALL array using the DSAM technique, giving a quadrupole momentQt 10 e b.
13 citations
12 citations
TL;DR: In this article, the problems with reconstructing the trajectory of /spl gamma-ray and identifying their interaction points in segmented coaxial HPGe detectors are discussed in view of their importance in the design of the next generation of detector arrays for /spl Gamma-ray spectroscopy studies.
Abstract: The problems with reconstructing the trajectory of /spl gamma/-rays and identifying their interaction points in segmented coaxial HPGe detectors are discussed here in view of their importance in the design of the next generation of detector arrays for /spl gamma/-ray spectroscopy studies In fact, the tracking quality of the /spl gamma/-ray interactions in the medium controls the overall detection efficiency This paper focuses on two main points One is the study of how the tracking reconstruction efficiency is affected by the ability of disentangling multiple interactions per segment The other is the study of the consequences that different types of segmentation have on the overall efficiency Two geometries have been chosen: that of a single cylindrical detector and that of a spherical shell
11 citations
TL;DR: In this article, the alignment gain is interpreted in terms of a mixed crossing where an h 9/2 and an h 11/2 quasiproton provide the two signatures of the aligning configuration.
Abstract: High-spin properties of the nucleus 169Hf have been studied through the fusion evaporation reaction 96Zr(76Ge,3n)169Hf at a beam energy of 310 MeV The known rotational bands have been extended considerably and 6 new bands have been established, four of which form coupled bands with pronounced M1 connections Quasiparticle assignments are suggested for the new band structures, and it appears that coupling to vibrational degrees of freedom plays a role Both coupled bands involve the excitation of quasiprotons In the region of highest spin, a large alignment gain is interpreted in terms of a mixed crossing where an h
9/2 and an h
11/2 quasiproton provide the two signatures of the aligning configuration
9 citations
TL;DR: In particular, the negative-parity band has been identified with the highest I = 13-level at 10.6 MeV as discussed by the authors, interpreted as the band-terminating state for the (d3/2-1.1/1.7/2.5) configuration.
Abstract: High-spin states of the 44Ca nucleus populated in the 68 MeV 18O + 30Si reaction have been studied in a γ-γ-recoil coincidence experiment. The level scheme of 44Ca has been extended up to 12.2 MeV. In particular, the negative-parity band has been identified with the highest I = 13- level at 10.6 MeV. This state is interpreted as the band-terminating state for the ( d
3/2
-1
f
7/2
5) configuration.
7 citations
01 Oct 2001
TL;DR: In this paper, the electromagnetic properties of several connecting transitions between two presumably triaxial, strongly deformed (TSD) bands have been studied, and the excited TSD band is assigned as a wobbling mode built on the yrast TSD bands, based on comparisons to new calculations in which an aligned particle is coupled to a strong deformed rotor.
Abstract: The nucleus ${}^{163}\mathrm{Lu}$ has been populated through the fusion-evaporation reaction ${}^{139}\mathrm{La}{(}^{29}\mathrm{Si},5n{)}^{163}\mathrm{Lu}$ with a beam energy of 152 MeV. The electromagnetic properties of several connecting transitions between two presumably triaxial, strongly deformed (TSD) bands have been studied. Evidence is presented for the assignment of the excited TSD band as a wobbling mode built on the yrast TSD band, based on comparisons to new calculations in which an aligned particle is coupled to a strongly deformed triaxial rotor. The wobbling mode is uniquely related to triaxiality in nuclei.
7 citations
Journal Article•
TL;DR: In this paper, the role played by the y-decay of the GDR on the population of superdeformed configurations was investigated with the EUROBALL array equipped with large volume BaFz detectors.
TL;DR: In this paper, two aspects of rotational motion of thermally excited nuclei are discussed: discrete rotational bands, ergodic bands, damping of the rotational motions, and strength functions of mixing of basis bands and of EP transitions over one or two decay steps.
Journal Article•
Journal Article•
TL;DR: In this paper, the quadrupole moment is measured in even-N Lu isotopes and in odd-odd 164Lu where the i13/2 proton is coupled to different neutron orbitals.
Journal Article•
TL;DR: The next generation of 4 pi arrays for high-precision gamma -ray spectroscopy AGATA will consist of gamma-ray tracking detectors and a front-end ELSE detector as mentioned in this paper.
Abstract: The next generation of 4 pi arrays for high-precision gamma -ray spectroscopy AGATA will consist of gamma -ray tracking detectors. They represent high-fold segmented Ge detectors and a front-end el ...
TL;DR: In this paper, the high-energy γ-rays from the GDR decay of 147Eu*, produced in the reaction 37Cl+110Pd at bombarding energy of 160 and 170 MeV, were measured in coincidence with discrete transitions in residual nuclei and analyzed with statistical model using a Monte Carlo approach.
Abstract: The high-energy γ-rays from the GDR decay of 147Eu*, produced in the reaction 37Cl+110Pd at bombarding energy of 160 and 170 MeV, were measured in coincidence with discrete transitions in residual nuclei and analyzed with statistical model using a Monte Carlo approach. It is found that the present analysis gives information on the moment of inertia at very high spins in different residual nuclei.
TL;DR: In this paper, the authors measured the width of the 147Eu compound nucleus as a function of nuclear spin and temperature, and the behavior of the GDR width was described by the predictions of the thermal shape fluctuation model.
Abstract: Results from the measurement of the GDR built on excited states of the 147Eu compound nucleus are presented. Data corresponding to restricted regions of angular momenta and more selected data, associated with different residual nuclei are discussed. The behaviour of the GDR width, measured as a function of nuclear spin and temperature, is well described by the predictions of the thermal shape fluctuation model.
Posted Content•
TL;DR: In this article, the possible existence of Jacobi shape transition in hot 46Ti at high angular momenta was investigated with the Giant Dipole Resonance exclusive experiments, and the GDR spectra and the angular distributions were consistent with predictions of the thermal shape fluctuation model indicating elongated nuclear shapes.
Abstract: The possible existence of Jacobi shape transition in hot 46Ti at high angular momenta was investigated with the Giant Dipole Resonance exclusive experiments. The GDR spectra and the angular distributions are consistent with predictions of the thermal shape fluctuation model indicating elongated nuclear shapes.