Unit:
Department of PhysicsLibrary of the School of Science
Author:
Zyriliou Aikaterini
Dissertation committee:
Θεόδωρος Μερτζιμέκης, Αναπληρωτής Καθηγητής, Τμήμα Φυσικής, ΕΚΠΑ
Ευστάθιος Στυλιάρης, Καθηγητής, Τμήμα Φυσικής, ΕΚΠΑ
Αναστάσιος Λαγογιάννης, Διευθυντής Ερευνών, ΙΠΣΦ/ΕΚΕΦΕ «Δημόκριτος»
Μιχαήλ Κόκκορης, Καθηγητής, ΣΕΜΦΕ, ΕΜΠ
Διονύσιος Μπονάτσος, Διευθυντής Ερευνών, ΙΠΣΦ/ΕΚΕΦΕ «Δημόκριτος»
Νίκη Σαουλίδου, Αναπληρώτρια Καθηγήτρια, Τμήμα Φυσικής, ΕΚΠΑ
Nikolay Minkov, Professor, INRNE, Bulgarian Academy of Sciences
Original Title:
Nuclear structure investigations at medium–weight isotopes
Translated title:
Nuclear structure investigations at medium–weight isotopes
Summary:
This work focuses on the nuclear structure and spectroscopic properties of even-even isotopes of Ytterbium (164-180Yb) and Tungsten (172-186W). This mass region is of significant interest due to its unexplored nature and the presence of intriguing structural phenomena, including deformation, shape changes, and shape coexistence. The present work combines theoretical calculations and experimental measurements to provide insights into the behavior and structure of these nuclei.
The theoretical part of the work involves extensive calculations using different models, including the Interacting Boson Model-1 (IBM-1), to study the energy levels, electric quadrupole moments Q, and electric quadrupole transition probabilities B(E2) for Yb and W isotopes. The results agree with previous experimental measurements and contribute to the knowledge of deformation, shape changes in neutron-rich nuclei.
Experimental measurements were conducted in the National Laboratory IFIN-HH in Romania, focused on the spectroscopic study of Yb and W isotopes using advanced techniques, such as Fast Electronics Scintillation Timing (FEST) and Differential Decay Curve Method (DDCM). These experiments provided valuable data on the energy levels, lifetimes, and decay properties of the excited states in the nuclei. The measurements were performed using ROSPHERE detector array, including HPGe detectors, LaBr3(Ce) scintillators, and particle identification detectors (Si). As a result, the lower limits of the lifetimes for the isotopes 172,174,176,178Yb were determined through the reaction 18O + natYb at 72 MeV beam energy using FEST. In addition, the result for the 6+ state in 182W was obtained for the first time via the reaction 181Ta(11B, 10Be)182W using the plunger device for lifetime measurements.
Main subject category:
Science
Keywords:
nuclear structure, even-even nuclei, gamma spectroscopy, lifetimes, IBM-1, theoretical models
Number of references:
210
