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International audience; Target properties such as thickness and composition are essential ingredients in nuclear physics experiments, therefore, dedicated analyses to evaluate them before and/or after the measurement are often performed. In some experimental techniques, the exploited detectors allow for the evaluation of these properties on-line, i.e. directly during the experiment. In this paper, we report on the use of analysis methods coming from the Rutherford backscattering spectroscopy technique to obtain on-line information on the target used in a nuclear physics experiment. This measurement was performed at INFN LNL by exploiting the low-energy Coulomb excitation technique. The results have been compared with an independent Rutherford backscattering spectroscopy analysis of the same target performed at INFN LABEC in Florence.

ispartof: PHYSICAL REVIEW C vol:103 issue:4 status: published

The electromagnetic structure of Zn66 at low excitation energy was investigated via low-energy Coulomb excitation at INFN Legnaro National Laboratories, using the Gamma Array of Legnaro Infn Laboratories for nuclEar spectrOscopy (GALILEO) γ-ray spectrometer coupled to the SPIDER (Silicon PIe DEtectoR). A set of reduced E2, E3, and M1 matrix elements was extracted from the collected data using the gosia code, yielding 12 reduced transition probabilities between the low-spin states and the spectroscopic quadrupole moment of the 21+ state. The B(E2) values for transitions depopulating the 02+ state have been determined for the first time, allowing for the lifetime of this state to be deduced and, consequently, the ρ2(E0;02+→01+) monopole transition strength to be extracted. In addition, the B(E3;31−→01+) value has been determined for the first time in a Coulomb excitation experiment. The obtained results resolve the existing discrepancies between literature lifetimes and demonstrate that Zn66 cannot be described by using simple collective models. Therefore, new state-of-the-art beyond-mean-field and large-scale shell-model calculations were performed in order to interpret the structure of this nucleus. Both the experimental and theoretical results suggest that the triaxial degree of freedom has an important impact on electromagnetic properties of Zn66, while the unique features of the 02+ state indicate its distinct and rather isolated structure.

International audience; SPIDER is a new array of segmented silicon detectors for low-energy Coulomb-excitation experiments, designed as an ancillary device for modern γ -ray spectrometers such as GALILEO and AGATA. Currently, it is used at the INFN Legnaro National Laboratories (LNL) for experiments with the GALILEO γ -ray array and the stable beams provided by the Tandem-XTU, ALPI-PIAVE accelerator complex. In this paper, a detailed description of SPIDER is presented, as well as the outcomes from the first in-beam experiment of the array coupled with GALILEO. In particular, radiation damage and cross-talk/charge-sharing effects induced by energetic heavy ions in SPIDER are investigated and the capabilities of the array to perform on-line Rutherford back-scattering analysis of the exploited target are presented. The material reported here can be used to plan future experiments with the GALILEO-SPIDER setup with the presently available stable beams at LNL and paves the way for future experimental campaigns with the radioactive beams provided in the near future by the SPES facility at LNL.

Low-energy Coulomb excitation is one of the simplest and most known tools to study the nuclear shape; for this reason it is nowadays widely used at radioactive beam facilities. The SPES facility, for the acceleration of radioactive beams will soon provide the first exotic beams at the Laboratori Nazionali di Legnaro (LNL) in Italy.a#13; To this end a new particle detector (Silicon PIe DEtectoR) to be used for Coulomb excitation studies has been installed at LNL. SPIDER has been coupled to the GALILEO array of germanium detectors, and a number of experiments have been already successfully performed. This paves the way for future experiments with the radioactive beams provided by the SPES facility.