Publications by Year: 2014

Asimakopoulou E-M, Madesis I, Dimitriou A, Zouros TJM, Mertzimekis TJ, Lagoyannis A, Axiotis M. Incorporation of an Ion Post Stripper for the APAPES Experimental Setup. In: Hellenic Nuclear Physics Society; 2014.
Lagaki V, Kouvaris E, Mertzimekis TJ. A new γ-spectroscopy station at the University of Athens. In: Hellenic Nuclear Physics Society; 2014.
Pappa EP, Christopoulou ME, Mertzimekis TJ, Nomikou P, Carey S, Polymenakou P, Papanikolaou D. In-situ CTD scans as a probe for submarine volcano. [Internet]. 2014. Website
Tzifas IT, Godelitsas A, Magganas A, Androulakaki E, Eleftheriou G, Mertzimekis TJ, Perraki M. Uranium-bearing phosphatized limestones of \{NW\} Greece. J. Geochem. Explor. 2014;143:62 – 73.Abstract
Abstract Sedimentary Mesozoic rocks from \{NW\} Greece (Epirus region), and particularly laminated phosphatized limestones, bedded chert-rich limestones and brecciated phosphatized limestones, were examined for their actinide content. Gamma-ray measurements using a \{HPGe\} detector showed that the above geological materials exhibit high radioactivity, mainly attributed to the 238U-series. The 238U content (up to 7700 Bq/kg) was determined by the 1001 keV photopeak of 234mPa, the 238U daughter. Bulk geochemical analyses using ICP-OES/MS showed variable U concentrations with a notable value of 648 ppm in the case of dark organic-rich material hosted into the brecciated phosphatized limestones. Relatively high concentrations of Cd, probably related to apatite, were also revealed. On the other hand, the rock is geochemically depleted in \{LILE\} (e.g. Cs, Rb, K), as well as in As, Sb and Se in contrast to “average phosphorite”. Powder-XRD combined with optical microscopy, SEM–EDS and \{FTIR\} confirmed abundant apatite, besides calcite, as well as organic compounds (organic matter/O.M.) which should be associated to the high U content. According to Th/Sc vs. Zr/Sc discrimination diagrams the organic-rich part of the U-bearing phosphatised limestones exhibits a mafic trend, in contrast to the rest of the studied rocks lying close to typical pelagic sediments. However, Eu/Eu* vs. Ce/Ce* diagrams, in combination with SEM–EDS, indicated that the organic-rich part is a typical sedimentary material whereas the organic-poor (and also U-poor) part of the rock is secondary calcite related to surface waters. As far as we know, the studied rocks from \{NW\} Greece are classified as among the richest U-bearing phosphatized limestones and/or sedimentary phosphorites in the world.
Madesis I, Dimitriou A, Lagoyannis A, Axiotis M, Mertzimekis TJ, Andrianis M, Benis EP, Harissopulos S, Sulik B, Valastyan I. Atomic Physics with Accelerators: Projectile Electron Spectroscopy. [Internet]. 2014. Website
Christopoulou M-E, Mertzimekis TJ, Nomikou P, Papanikolaou D, Carey S. Investigating the active hydrothermal field of Kolumbo volcano using CTD profiling. [Internet]. 2014. Website
Diriken J, Patronis N, Andreyev AN, Antalic S, Bildstein V, Blazhev A, Darby IG, Witte DH, Eberth J, Elseviers J, et al. Study of the deformation-driving orbital in $^{67}_{28}$Ni$_{39}$ using one-neutron transfer reactions. Phys. Lett. B. 2014;736:533–538.Abstract
Abstract The νg$_{9/2}$, d$_{5/2}$, s$_{1/2}$ orbitals are assumed to be responsible for the swift onset of collectivity observed in the region below $^{68}$Ni. Especially the single-particle energies and strengths of these orbitals are of importance. We studied such properties in the nearby $^{67}$Ni nucleus, by performing a (d,p)-experiment in inverse kinematics employing a post-accelerated radioactive ion beam (RIB) at the REX-ISOLDE facility. The experiment was performed at an energy of 2.95 MeV/u using a combination of the T-REX particle detectors, the Miniball γ-detection array and a newly-developed delayed-correlation technique as to investigate μs-isomers. Angular distributions of the ground state and multiple excited states in $^{67}$Ni were obtained and compared with DWBA cross-section calculations, leading to the identification of positive-parity states with substantial νg$_{9/2}$ (1007 keV) and νd$_{5/2}$ (2207 keV and 3277 keV) single-particle strengths up to an excitation energy of 5.8 MeV. 50% of the νd$_{5/2}$ single-particle strength relative to the νg$_{9/2}-orbital is concentrated in and shared between the first two observed 5/2^{+} levels. A comparison with extended Shell Model calculations and equivalent ($^3$He, d) studies in the region around $^{90}_{40}$Zr$_{50}$ highlights similarities for the strength of the negative-parity pf and positive-parity g$_{9/2}$ state, but differences are observed for the d$_{5/2} single-particle strength.