T. J. Mertzimekis
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View article: Characterization of a novel, large volume CdZnTe detector for marine applications
Characterization of a novel, large volume CdZnTe detector for marine applications Open
A large-volume (4 cm3) monolithic CdZnTe detector was selected for a novel underwater γ-radiation sensing instrument for radioactivity measurements near the seabed. The focus of this paper was to characterize the detector to ada…
View article: Triaxial Shapes in Even–Even Nuclei: A Theoretical Overview
Triaxial Shapes in Even–Even Nuclei: A Theoretical Overview Open
Triaxial shapes in even–even nuclei have been considered since the early days of the nuclear collective model. Although many theoretical approaches have been used over the years for their description, no effort appears to have been made fo…
View article: A study of natural radioactivity in thermal springs in Greece using gamma and alpha spectrometry
A study of natural radioactivity in thermal springs in Greece using gamma and alpha spectrometry Open
Thermal springs have a geographical distribution that is mostly shaped by major tectonic phenomena, such as volcanic events and extended fault zones. Thermal springs are known to exhibit elevated activities of natural radioisotopes, such a…
View article: Triaxial shapes in even-even nuclei: A theoretical overview
Triaxial shapes in even-even nuclei: A theoretical overview Open
Triaxial shapes in even-even nuclei have been considered since the early days of the nuclear collective model. Although many theoretical approaches have been used over the years for their description, no effort appears to have been made fo…
View article: Triaxiality in Er isotopes in the framework of IBM-1
Triaxiality in Er isotopes in the framework of IBM-1 Open
The nuclear structure in the even–even 160-180 Er chain of isotopes is investigated by means of a mean-field-derived IBM-1 Hamiltonian with an intrinsic triaxial deformation derived from fermionic proxy-SU(3) irreducible representations (i…
View article: Lifetime measurements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Mo</mml:mi><mml:mprescripts/><mml:none/><mml:mn>102</mml:mn></mml:mmultiscripts></mml:math> interpreted in the interacting boson model and the X(5) symmetry
Lifetime measurements in interpreted in the interacting boson model and the X(5) symmetry Open
Lifetimes of low-lying excited states in Mo
View article: Simulating the response of a HPGe-based spectrometer for in situ, long-term operation near the seabed
Simulating the response of a HPGe-based spectrometer for in situ, long-term operation near the seabed Open
A novel underwater $$\gamma$$ -spectrometer, equipped with a HPGe crystal and utilizing electromechanical cooling, is introduced, and results from detailed Monte Carlo simulations are presented. The spectrometer, which is currently in th…
View article: On the missing yield of in-beam radiative proton-capture cross section measurements relevant to the <i>p</i> process
On the missing yield of in-beam radiative proton-capture cross section measurements relevant to the <i>p</i> process Open
The in-beam angular distribution method has been extensively used for the measurement of important cross sections for the p process nucleosynthesis. However, transitions that are beyond the detection limit of each setup, as well as the con…
View article: Robustness of the Proxy-SU(3) Symmetry in Atomic Nuclei and the Role of the Next-Highest-Weight Irreducible Representation
Robustness of the Proxy-SU(3) Symmetry in Atomic Nuclei and the Role of the Next-Highest-Weight Irreducible Representation Open
The proxy-SU(3) symmetry predicts, in a parameter-free way, the collective deformation variables β and γ in even–even atomic nuclei away from closed shells based on the highest weight irreducible representations (irreps) of SU(3) in the re…
View article: Robustness of the proxy-SU(3) symmetry in atomic nuclei and the role of the next highest weight irreducible representation
Robustness of the proxy-SU(3) symmetry in atomic nuclei and the role of the next highest weight irreducible representation Open
The proxy-SU(3) symmetry predicts, in a parameter-free way, the collective deformation variables beta and gamma in even-even atomic nuclei away from closed shells based on the highest weight irreducible representations (irreps) of SU(3) in…
View article: Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry
Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry Open
The proxy-SU(3) symmetry predicts, in a parameter-free way, based only on the Pauli principle and the short-range nature of the nucleon-nucleon interaction, non-vanishing values of the collective variable gamma almost everywhere across the…
View article: Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry
Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry Open
The proxy-SU(3) symmetry predicts, in a parameter-free way, based only on the Pauli principle and the short-range nature of the nucleon–nucleon interaction, non-vanishing values of the collective variable γ almost everywhere across the nuc…
View article: Seven years of the proxy-SU(3) shell model symmetry
Seven years of the proxy-SU(3) shell model symmetry Open
The proxy-SU(3) symmetry was first presented in HINPw4 in Ioannina in May2017, justified within the Nilsson model and applied to parameter-free predictions of the collective variables beta and gamma in medium-mass and heavy nuclei. Major s…
View article: Monitoring of the radioactivity in the marine environment: a White Paper - Part I
Monitoring of the radioactivity in the marine environment: a White Paper - Part I Open
Radioactivity in the marine environment, although present since the Earth’s formation, is comparatively understudied in contrast to aerial and terrestrial environments. A thorough examination of the radioactivity levels in aquatic environm…
View article: Collectivity at the prolate-oblate transition: The <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:msubsup><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mo linebreak="badbreak" linebreakstyle="after">+</mml:mo></mml:mrow></mml:msubsup></mml:math> lifetime of 190W
Collectivity at the prolate-oblate transition: The lifetime of 190W Open
View article: Lifetime measurement in 182W using the Differential Decay Curve Method
Lifetime measurement in 182W using the Differential Decay Curve Method Open
This work focuses on the lifetime measurement and spectroscopic properties of 182W. The mass region around this nucleus is of significant interest due to its unexplored nature and the presence of intriguing structural phenomena, including …
View article: Radioactivity studies in soils from Northwestern Greece
Radioactivity studies in soils from Northwestern Greece Open
Natural radioactivity is examined in soil samples collected from Northwestern Epirus, specifically in Pogoni and Zagori areas. The focus was to determine experimentally the specific activity for naturally occurring isotopes (40K, U and Th …
View article: Nuclear lifetime measurements around Z=50
Nuclear lifetime measurements around Z=50 Open
In the present work, a dedicated experimental study of the lifetimes of in Te and Sb isotopes was undertaken at the 9 MV Tandem accelerator at the IFIN-HH. Beams of 11B at 35 MeV impinged on a natAg target to populate the nuclei of interes…
View article: Shape/phase transitions and shape coexistence in even-even nuclei
Shape/phase transitions and shape coexistence in even-even nuclei Open
Shape/phase transitions have been observed in certain regions of the nuclear chart. Shape coexistence is also known to occur in various regions of the nuclear chart, forming islands. The interrelation between these two concepts is consider…
View article: Validation and Testing of Novel Underwater Sensors at the Hydrothermal Vent Field of Milos
Validation and Testing of Novel Underwater Sensors at the Hydrothermal Vent Field of Milos Open
A prototype mobile underwater CdZnTe-based spectrometer was tested under realistic environmental conditions under the scope of the RAMONES Research Programme. Field measurements took place on the island of Milos, which is characterized by …
View article: A study of the nuclear structure of even-even Te isotopes in the Interacting Boson Model framework
A study of the nuclear structure of even-even Te isotopes in the Interacting Boson Model framework Open
The even-even tellurium isotopes (Z=52) are part of a region beyond the closed proton shell at Ζ=50 and are generally considered to exhibit vibrational-like properties. These properties are investigated in the present work using the the In…
View article: A Study of natural radioactivity in urban parks
A Study of natural radioactivity in urban parks Open
Urban parks are typically undisturbed natural locations inside metropolitan areas, attracting human recreation activities. The present work focuses on studying the radioactivity levels in urban parks in the metropolitan areas of Athens, Ba…
View article: A comparative study of γ-ray spectrometers in various applications
A comparative study of γ-ray spectrometers in various applications Open
The present work concentrates on the detailed study of various types of γ-radiation spectrometers used mainly for applications. More specifically, various experiments were carried out to characterize and compare two (2) different high-puri…
View article: Fast-timing measurements of nuclear lifetimes in the Z ~ 50 region
Fast-timing measurements of nuclear lifetimes in the Z ~ 50 region Open
The neutron–deficient region around the Z=50 major shell closure provides fertile grounds for nuclear structure studies, as single–particle degrees of freedom compete with collective phenomena to form several of the observed spectroscopic …
View article: αSPECT: Adaptation of existing radon detectors to deep-sea operation
αSPECT: Adaptation of existing radon detectors to deep-sea operation Open
Among the naturally occurring radioactive materials (NORM), radon and its isotopes 222Rn and 220Rn, being the only gaseous products, have a significant role due to their unique transport properties and common chemical characteristics withi…
View article: Revisiting the nuclear magnetic octupole moment
Revisiting the nuclear magnetic octupole moment Open
The nuclear magnetic octupole moment is revisited as a potentially useful observable for nuclear structure studies. The magnetic octupole moment, $Ω$, is examined in terms of the nuclear collective model including weak and strong coupling.…
View article: Mean-field derived IBM-1 Hamiltonian with intrinsic triaxial deformation
Mean-field derived IBM-1 Hamiltonian with intrinsic triaxial deformation Open
An interacting-boson-model-1 (IBM-1) Hamiltonian, derived from self-consistent mean-field calculations using a Skyrme energy density functional is employed for the study of energy spectra and $B(E2)$ transition strengths in the even-even $…
View article: Characterization of a CZT-based spectrometer for underwater operation via simulations and experiments
Characterization of a CZT-based spectrometer for underwater operation via simulations and experiments Open
The harsh environmental conditions in the marine environment pose various constraints on developing efficient instruments to carry out long-term, in situ radioactivity measurements. In addition, the strong attenuation of γ-rays in the wate…
View article: Prolate-oblate shape transitions and O(6) symmetry in even-even nuclei: A theoretical overview
Prolate-oblate shape transitions and O(6) symmetry in even-even nuclei: A theoretical overview Open
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to obla…
View article: Prolate-oblate shape transitions and O(6) symmetry in even–even nuclei: a theoretical overview
Prolate-oblate shape transitions and O(6) symmetry in even–even nuclei: a theoretical overview Open
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to obla…