The next generation nuclear instrumentsagata and neda, and nuclear structure studies near n=z line

Resumen

The first part of this thesis is devoted to the development of a large array of neutron detectors NEDA and their conceptual design using Monte-Carlo simulations. NEDA (NEutron Detector Array) aims to build a neutron detector array with high efficiency based on liquid scintillators. NEDA will be coupled to the high-purity γ-ray detector arrays, like AGATA, EXOGAM, to be used as a trigger or complementary detector in the contemporary nuclear physics experiments which aim to investigate the structure of the exotic nuclei. The importance of NEDA is related to its capability to filter the reaction channels including multiple neutron evaporation with high efficiency. The simulations of the conceptual design of NEDA for the near-future campaign at GANIL is presented. The NEDA detectors together with the Neutron Wall promise up to 7.62(11)% and 1.89(11)% efficiencies for two- and three-neutron detection comparing to the Neutron Wall standalone 3.93(10)% and 0.55(14)%, respectively. The results of this study has been published in The European Physical Journal - Section: A (2016) 52: 55 and our study has been selected for the cover of the March 2016 issue. In the framework of NEDA, besides the simulations, I have been actively participating to the tests which aimed to characterize the prototypes and their functionality with digital sampling electronics. The preparation and the outcomes of these tests are also discussed. The second part is devoted to the analysis of two experiments. The first experiment has been done at GANIL with EXOGAM - Neutron Wall - DIAMANT setup using fusion-evaporation reaction 32S + 28Si. The analysis of this experiment provided experience on the Neutron Wall, which the NEDA detectors will replace. The preparation, analysis and the results of this experiment are discussed. The second experimental activity has been done at GSI - Fragment Separator Facility (FRS) using the AGATA - PreSPEC setup to investigate the collectivity in 52Fe above the isomeric state 12+. The unstable 52Fe beam at relativistic energies with an isomeric ratio of 16(2)% underwent Coulomb excitation by heavy 197Au target. The reduced matrix element of the candidate for the 12+ → 14+ has been measured experimentally and compared with the LSSM calculations, suggesting a larger degree of collectivity in the involved states.