Panagiotis Misaelides | Aristotle University of Thessaloniki (original) (raw)

Papers by Panagiotis Misaelides

The accurate determination of deuteron depth profile presents a strong analytical challenge for a... more The accurate determination of deuteron depth profile presents a strong analytical challenge for all the principal IBA (Ion Beam Analysis) techniques. As far as NRA (Nuclear Reaction Analysis) is concerned, the 2 H(d,p) reaction, seems to be a promising candidate, especially in the case of complex matrices, or for the study of deep-implanted deuteron layers. In the present work differential cross-section values for the 2 H(d,p) reaction have been determined at 140 o , 160 o and 170 o , for E d,lab =900-1600 keV, with an energy step of 50 keV, using a well-characterized, thin C:D target deposited on a polished Si wafer. The experimental results were analyzed using the R-matrix calculations code AZURE.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2018

The differential cross sections of the elastic 7 Li(d,d 0) scattering were measured at five angle... more The differential cross sections of the elastic 7 Li(d,d 0) scattering were measured at five angles (125°, 140°, 150°, 160°and 170°) with silicon surface barrier (SSB) detectors and for deuteron energies ranging from 900 to 2000 keV, in steps of 5-50 keV. The target used was a thin nat LiF target. The whole experimental procedure and analysis are presented and the results, compared to those already present in literature for the scattering angle of 125°, appear to be in a good agreement. Furthermore, for the low energy region (up to ∼ E 1300 keV d lab , , depending on the angle) the cross section values correspond to the sum of the 7 Li(d,d 0) and 7 Li(d,p 0) cross section values due to peak overlap.

The interaction of granitic biotite with aqueous solutions of La, Nd, Th and U (concentration 10 ... more The interaction of granitic biotite with aqueous solutions of La, Nd, Th and U (concentration 10 to 1000 mg. l 1) was studied using instrumental neutron activation analysis (INAA) and 12 C-Rutherford backscattering spectroscopy (12 C-RBS). For comparison, the sorption of La and Nd by granitic feldspar and natural zeolite heulandite was also investigated. The experimental results showed that biotite exhibits higher sorption ability towards La and Nd, (maximum uptake 2.09 and 7.98 mg/g, respectively) than the feldspar and the heulandite. The interaction of biotite with Th is also intense, the metal being preferably concentrated at the near-surface layers of the crystals. This indicates that other sorption mechanisms (adsorption and surface precipitation) than ion-exchange take place at the solid/solution interface. The same phenomenon was also observed in the case of U, although the corresponding metal uptake was found to be considerably lower.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010

The development and initial results of a method for the determination of differential cross secti... more The development and initial results of a method for the determination of differential cross sections for electron scattering by molecular oxygen are described. The method has been incorporated into an existing package of computer programs which, given spectroscopic factors, dissociation energies and an energy-loss spectrum for electron-impact excitation, determine the differential cross sections for each electronic state relative to that of the elastic peak. Enhancements of the original code were made to deal with particular aspects of electron scattering from O 2 , such as the overlap of vibrational levels of the ground state with transitions to excited states, and transitions to levels close to and above the dissocation energy in the Herzberg and Schumann-Runge continua. The utility of the code is specifically demonstrated for the ''6-eV states'' of O 2 , where we report absolute differential cross sections for their excitation by 15-eV electrons. In addition an integral cross section, derived from the differential cross section measurements, is also reported for this excitation process and compared against available theoretical results. The present differential and integral cross sections for excitation of the ''6-eV states'' of O 2 are the first to be reported in the literature for electronimpact energies below 20 eV.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1992

The oxidation of Al-implanted (implantation energy 40 keV, dose 10 6-10" AI ions/cmZ) AISI 321 st... more The oxidation of Al-implanted (implantation energy 40 keV, dose 10 6-10" AI ions/cmZ) AISI 321 stainless steel samples in air has been studied at temperatures between 450 and 650°C using the "O(d,p) 170 nuclear reaction. The determination of the distribution of! the implanted Al atoms has been performed using the resonance at 992 keV of the Z7 AI(p,1') 28 Si nuclear reaction. The determined oxygen profiles indicate that the implantation of 5 x 10 6 and 10" AI ions/cmZ leads to an improvement of the oxidation resistance of the studied steel samples. The passivation/corrosion behaviour of the AI-implanted steel samples in 0.5M aqueous sulphuric acid solution has also been investigated electrochemically using potentiodynamic and cyclovoltammetric techniques. The passivation potential values and the repassivation moving to more positive values indicate an improvement of the corrosion resistance of the AI-implanted steel samples.

The 31 P(d,d 0 ) 31 P elastic scattering differential cross-sections were measured, for the first... more The 31 P(d,d 0 ) 31 P elastic scattering differential cross-sections were measured, for the first time, in the energy range E d,lab =900-2400 keV, using a variable energy step, for elastic backscattering spectrometry (EBS) purposes. The measurements were performed at the 5.5 MV TN11 HV Tandem Accelerator of the N.C.S.R. “Demokritos”, implementing a high precision goniometer. The experimental setup consisted of five silicon surface barrier (SSB) detectors, placed at the laboratory scattering angles between 130° and 170° (in steps of 10°). The target used was a thin GaP layer evaporated on a self-supporting carbon foil. To validate the obtained results, benchmarking measurements were performed, using a polished GaP crystal. The determined cross-section datasets are compared with the corresponding ones using Rutherford’s formula, and similarities and discrepancies will be discussed and analyzed.

Modified Clay and Zeolite Nanocomposite Materials, 2019

This chapter provides an overview of the application of clay minerals and natural zeolites to rad... more This chapter provides an overview of the application of clay minerals and natural zeolites to radioactive waste immobilization and disposal. Their potential role as engineered barrier systems and as host rocks in geological disposal facilities as well as their utilization as permeable reactive barriers and remediation agents for limiting the spread of radionuclides in the environment is also presented in the form of specific cases.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Abstract The elastic scattering of deuterons on natN has been studied in the present work in the ... more Abstract The elastic scattering of deuterons on natN has been studied in the present work in the energy range of Ed,lab = 1000–2200 keV, in steps of 10 keV, at six backscattering detection angles (120°, 130°, 140°, 150°, 160° and 170°), suitable for analytical purposes. The measurements were performed using the 5.5 MV TN11 HV Tandem Accelerator of N.C.S.R. “Demokritos”, Athens, Greece and a high-precision goniometer. The target used for the measurements was a self-supported Si3N4 thin foil, with an ultra-thin Au layer evaporated on top for normalization purposes. The obtained differential cross-section datasets are compared to already existing ones in literature and the observed similarities and discrepancies are discussed and analyzed, along with the effect of the various nuclear reaction mechanisms in low-energy deuteron elastic scattering.

Surface and Coatings Technology, 2006

Abstract New experimental results are presented on the structure and the elemental and phase comp... more Abstract New experimental results are presented on the structure and the elemental and phase composition of hybrid coatings, which were deposited on a substrate of AISI 321 stainless steel using a combination of plasma-detonation, vacuum-arc and subsequent High-Current Electron Beam (HCEB) treatment. We found that an increase in energy density intensified mass transfer processes and resulted in changes in aluminum oxide phase composition (γ → α and β → α). Also we observed the formation of a nanocrystalline structure in Al 2 O 3 coatings. Electron beam treatment of a hybrid coating surface induced higher adhesion, decreased the intensity of surface wear and increased corrosion resistance in a sulphuric acid solution. The corrosion resistance of the coatings was studied in several electrolytic solutions (0.5 M H 2 SO 4 , 1 M HCl, 0.75 M NaCl) using electrochemical techniques. In most cases the corrosion resistance was improved, except those in NaCl solutions. The nano-hardness of the protecting coating was 13 GPa before electron beam melting and 9 GPa after it (as a result of TiN and Al 2 O 3 sub-layers mixing).

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2005

Abstract Ion beam analysis was used in order to characterize Al 2 O 3 layers deposited on stainle... more Abstract Ion beam analysis was used in order to characterize Al 2 O 3 layers deposited on stainless steel by plasma detonation techniques and Al 2 O 3 /Cr/TiN composite protective coatings. The aluminum depth distribution was determined using the 991 keV resonance of the 27 Al(p, γ) 28 Si reaction, whereas the 14 N(d, α) 12 C reaction was utilized for the nitrogen profiling. The determination of the titanium depth distribution was performed by Rutherford backscattering spectrometry (RBS). The ratio of Al:O and Ti:N in the investigated Al 2 O 3 and TiN layers was found to be close to the stoichiometric one. The effect of an additional high current electron beam (HCEB) treatment on the composition of the coatings was also investigated. Titanium and nitrogen diffusion from the surface to the interior was observed in the case of the coatings treated by HCEB.

Applied Radiation and Isotopes

Journal of the Serbian Chemical Society

The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions ... more The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions (boron concentration: 100?5000 mg L-1) of non-adjusted and pre-adjusted pH (pHnat, pHinit 8.0, 9.0 and 10.0) aqueous solutions was investigated using a batch technique. The boron concentration in the solutions after sorption was determined photometrically. The results indicated that the pH-dependent boron uptake was related to the protonation/deprotonation of the surface functional groups of the resin and to the boron speciation in solutions of different pH values. The maximum boron sorption capacity observed in solutions of pH 9.0 was 55 mg g-1 exceeding the majority of other commercial or alternative sorbents. Five empirical adsorption equations (Freundlich, Langmuir, Redlich?Peterson, Langmuir?Freundlich and Toth) were applied to the modelling of the boron adsorption equilibrium. The modelling results identified the homogenous boron sorption from acidic and heterogeneous from alkaline...

Journal of Radioanalytical and Nuclear Chemistry, 2016

Journal of Radioanalytical and Nuclear Chemistry, 2014

Science of The Total Environment, 1995

The thorium and uranium uptake from their aqueous solutions by unpretreated and NaCl-pretreated z... more The thorium and uranium uptake from their aqueous solutions by unpretreated and NaCl-pretreated zeolite-bearing volcanoclastic rock samples from Metaxades (Thrace, Greece) has been studied using a batch-type method. The concentration of the solutions varied between 50 and 20000 mg/1. The NaCl pretreatment of the materials improved the thorium but not the uranium uptake. The absolute thorium uptake by the pretreated material, determined using neutron activation and X-ray fluorescence techniques, reached 12.41 mg/g, whereas the uranium uptake by the raw material was 8.70 mg/g. The uptake distribution coefficients (K d) indicated that the relative thorium and uranium uptake is higher for initial concentrations below 250 mg/1. The zeolitic materials showed exceptional resistance to the initial low pH of the solutions used. The pH in was significantly increased due to the simultaneous hydrogen-ion uptake. The thorium and uranium uptake is a rather complicated phenomenon related to the aqueous chemistry of the elements, the nature of the constituent minerals and the properties of the zeoliferous rock specimens. The various metal species are bound through different uptake processes such as ion-exchange, adsorption and surface precipitation. Microporous minerals (zeolites, phyllosilicates) are mainly responsible for the considerable uptake ability of the rock samples studied.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008

The surface of a typical Greek (Thassian) dolomitic marble was studied after interaction with U-a... more The surface of a typical Greek (Thassian) dolomitic marble was studied after interaction with U-and Th-containing aqueous solutions (1000 mg/L, free-drift experiments for 1 week at atmospheric P CO 2), using 12 C-RBS and Laser l-Raman spectroscopy. Powder-XRD and SEM-EDS were also applied to investigate the phases deposited on the surface of the interacted samples. The obtained results indicated a considerable removal of U from the aqueous medium mainly due to massive surface precipitation of amorphous UO 2-hydroxide phases forming a relatively thick (lm-sized) coating on the carbonate substrate. The interaction of Th with dolomitic marble surface is also intense leading to a formation of an amorphous Th-hydroxide layer of similar thickness but of significantly lower elemental atomic proportion.

Journal of Radioanalytical and Nuclear Chemistry Articles, 1996