Yazar "Crespi, F." seçeneğine göre listele
Listeleniyor 1 - 3 / 3
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe DETERMINATION OF LIFETIMES OF EXCITED STATES IN NEUTRON-RICH O-20 ISOTOPE FROM EXPERIMENT WITH THE AGATA plus PARIS plus VAMOS SETUP(JAGIELLONIAN UNIV PRESS, 2019) Ciemala, M.; Ziliani, S.; Crespi, F.; Leoni, S.; Fornal, B.; Maj, A.; Beckers, M.An experiment aiming at measuring lifetimes of the second 2(+) excited states in neutron-rich C and O isotopes was recently performed at the GANIL laboratory, in France. In these nuclei, recent ab initio calculations provide a detailed description of the nuclear excited states, predicting a strong sensitivity of the electromagnetic transition probabilities to the details of the nucleon-nucleon interactions, especially in connection with the role played by the three-body (NNN) forces. Thus, the measurement of 2(+) states lifetimes in this region will be a stringent test of the importance of including the NNN forces in describing the electromagnetic properties of selected nuclear states. This contribution reports on the status of the experimental analysis for the case of lifetimes in O-20.Öğe SHORT-RANGE LIFETIME MEASUREMENTS FOR DEEP-INELASTIC REACTION PRODUCTS: THE 19O TEST CASE(Jagiellonian Univ Press, 2020) Ciemala, M.; Ziliani, S.; Crespi, F.; Leoni, S.; Fornal, B.; Maj, A.; Bednarczyk, P.An experiment, aiming at measuring lifetimes of excited states in neutron-rich C and O isotopes, was performed at the GANIL laboratory with the use of the AGATA segmented HPGe tracking array, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The nuclei of interest were populated in transfer and deep-inelastic processes induced by an O-18 beam at 126 MeV (7.0 MeV/u) on a Ta-181 target. This paper contains a brief description of a novel implementation of a Monte-Carlo technique, which allowed us to obtain excited states lifetimes in the range from tens to hundreds femtoseconds for a reaction with complex initial velocity distribution, making use of the Doppler-shift attenuation method (DSAM). As a test case, we present here the analysis for two states in O-19: 2371-keV 9/2(+) and 2779-keV 7/2(+), for which lifetimes of tau > 400 fs and tau = 140(-40)(+50) fs were obtained, respectively, in agreement with literature values. This newly developed approach will be essential for short lifetimes measurements in neutron-rich systems, exploiting intense ISOL-type beams, currently under development.Öğe SPECTROSCOPY OF NEUTRON-RICH C, O, N AND F ISOTOPES WITH THE AGATA plus PARIS plus VAMOS SETUP AT GANIL(JAGIELLONIAN UNIV PRESS, 2019) Ziliani, S.; Ciemala, M.; Crespi, F.; Leoni, S.; Fornal, B.; Maj, A.; Beckers, M.Recent ab initio calculations pointed out the importance of the three-body terms of the nuclear interaction, in the description of the structure of n-rich systems. The state lifetimes in light n-rich carbon and oxygen nuclei have been predicted to be sensitive to the three-body terms and, in this context, an experiment, aiming at the measurement of these lifetimes, was performed in GANIL in July 2017 with the AGATA and PARIS arrays coupled to the VAMOS++ magnetic spectrometer. Details on the AGATA preliminary data analysis are presented.
