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Author Sahin, E. et al; Gadea, A.; Algora, A.
Title Structure of the N=50 As, Ge, Ga nuclei Type Journal Article
Year 2012 Publication Nuclear Physics A Abbreviated Journal Nucl. Phys. A
Volume 893 Issue Pages 1-12
Keywords NUCLEAR REACTIONS U-238(Se-82, Ga-81), (Se-82, Ge-82), (Se-82, As-83), E=515 MeV; measured E-gamma, I-gamma (theta), gamma gamma-coin, reaction fragments, (fragment)gamma-coin using PRISMA magnetic spectrometer, gamma after deexcitation using Ge Compton-suppressed detectors of CLARA array, thin and thick target; deduced sigma(theta), levels, J, pi; calculated levels, J, pi using shell model
Abstract The level structures of the N = 50 As-83, Ge-82, and Ga-81 isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the gamma-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N = 50 shell closure in the region of Ni-78 (Z = 28). The comparison of the experimental level schemes with the shell-model calculations yields an N = 50 energy gap value of 4.7(3) MeV at Z = 28. This value, in a good agreement with the prediction of the finite-range liquid-drop model as well as with the recent large-scale shell model calculations, does not support a weakening of the N = 50 shell gap down to Z = 28.
Address [Sahin, E.; de Angelis, G.; Gadea, A.; Corradi, L.; Fioretto, E.; Gottardo, A.; Guiot, B.; Modamio, V.; Napoli, D. R.; Silvestri, R.; Stefanini, A. M.; Valiente-Dobon, J. J.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: eda.sahin@lnl.infn.it
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0375-9474 ISBN Medium
Area Expedition Conference
Notes WOS:000310091000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1191
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Author AGATA Collaboration; Domingo-Pardo, C.; Bazzacco, D.; Doornenbal, P.; Farnea, E.; Gadea, A.; Gerl, J.; Wollersheim, H.J.
Title Conceptual design and performance study for the first implementation of AGATA at the in-flight RIB facility of GSI Type Journal Article
Year 2012 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 694 Issue Pages 297-312
Keywords gamma-Ray spectroscopy; Tracking; Monte Carlo
Abstract The main objective of the Advanced GAmma Tracking Array (AGATA) is the investigation of the structure of exotic nuclei at the new generation of RIB facilities. As part of the preparatory phase for FAIR-NUSTAR, AGATA is going to be installed at the FRS fragmentation facility of the GSI centre for an experimental campaign to be performed in 2012 and 2013. Owing to its gamma-ray tracking capabilities and the envisaged enhancement in resolving power, a series of in-flight gamma-ray spectroscopy experiments are being planned. The present work describes the conceptual design of this first implementation of AGATA at GSI-FRS, and provides information about the expected performance figures. According to the characteristics of each particular experiment, it is foreseen that the target-array distance is adjusted in order to achieve the optimum compromise between detection efficiency and energy resolution, or to cover an specific angular range of the emitted electromagnetic radiation. Thus, a comprehensive Monte Carlo study of the detection sensitivity in terms of photopeak efficiency, resolution and peak-to-total ratio, as a function of the target-array distance is presented. Several configurations have been investigated, and MC-calculations indicate that a remarkable enhancement in resolving power can be achieved when double-cluster AGATA detectors are developed and implemented. Several experimental effects are also investigated. This concerns the impact of passive materials between the target and the array, the angular distribution of the detection efficiency and the influence of target thickness effects and transition lifetimes in the attainable detection sensitivity. A short overview on half-life measurements via lineshape effects utilizing AGATA is also presented. (C) 2012 Elsevier B.V. All rights reserved.
Address [Domingo-Pardo, C.; Gadea, A.] Univ Valencia, CSIC, IFIC, Valencia, Spain, Email: domingo@ific.uv.es
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000311020500041 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1240
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Author AGATA Collaboration (Crespi, F.C.L. et al); Gadea, A.
Title Response of AGATA segmented HPGe detectors to gamma rays up to 15.1 MeV Type Journal Article
Year 2013 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 705 Issue Pages 47-54
Keywords AGATA; Gamma-ray spectroscopy; Gamma-ray tracking; HPGe detectors; Pulse-shape and gamma-ray tracking algorithms; Semiconductor detector performance and simulations
Abstract The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(B-11,n gamma)C-12 at E-beam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed.
Address [Crespi, F. C. L.; Avigo, R.; Camera, F.; Bottoni, S.; Bracco, A.; Ceruti, S.; Giaz, A.; Leoni, S.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Vandone, V.] Univ Milan, Dipartimento Fis, I-20133 Milan, Italy, Email: fabio.crespi@mi.infn.it
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000314826000009 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1329
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Author Gottardo, A. et al; Gadea, A.; Algora, A.
Title New μs isomers in the neutron-rich Hg-210 nucleus Type Journal Article
Year 2013 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 725 Issue 4-5 Pages 292-296
Keywords
Abstract Neutron-rich nuclei in the lead region, beyond N = 126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in Hg-210: the 8(+) isomer expected from the seniority scheme in the vg(9/2) shell and a second one at low spin and low excitation energy. The decay strength of the 8(+) isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3(-) state, although this is in contrast with theoretical expectations.
Address [Gottardo, A.; Valiente-Dobon, J. J.; de Angelis, G.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: andrea.gottardo@lnl.infn.it
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000324223100014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1588
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Author Goasduff, A.; Valiente-Dobon, J.J.; Lunardi, S.; Haas, F.; Gadea, A.; de Angelis, G.; Bazzacco, D.; Courtin, S.; Farnea, E.; Gottardo, A.; Michelagnoli, C.; Mengoni, D.; Napoli, D.R.; Recchia, F.; Sahin, E.; Ur, C.A.
Title Counting rate measurements for lifetime experiments using the RDDS method with the new generation gamma-ray array AGATA Type Journal Article
Year 2014 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 758 Issue Pages 1-3
Keywords Lifetime measurement; gamma spectroscopy; Counting rate
Abstract The differential Recoil Distance Doppler Shift (RDDS) method after multinucleon transfer (MNT) reactions to measure lifetimes of excited states in neutron-rich nuclei requires the use of a thick energy degrader for the recoiling ejectiles that are then detected in a spectrometer. This type of measurements greatly benefits from the use of the new generation segmented gamma-ray detectors, such as the AGATA demonstrator which offers unprecedented energy and angular resolutions. In order to make an optimized choice of the material and the thickness of the degrader for lifetime measurements using the RODS method after MNT, an experiment has been performed with the AGATA demonstrator. Counting rate measurements for different degraders are presented.
Address [Goasduff, A.; Haas, F.; Courtin, S.] Univ Strasbourg, IPHC, F-67037 Strasbourg, France, Email: Alain.Goasduff@csnsm.in2p3.fr
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000338348900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1829
Permanent link to this record