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001-es BibID:	BIBFORM018705
Első szerző:	Dombovári Péter
Cím:	Accumulation of uranium on austenitic stainless steel surfaces / Péter Dombovári, Péter Kádár, Tibor Kovács, János Somlai, Krisztián Radó, István Varga, Renáta Buják, Kálmán Varga, Pál Halmos, János Borszéki, József Kónya, Noémi M. Nagy, László Kövér, Dezső Varga, István Cserny, József Tóth, Lajos Fodor, Attila Horváth, Tamás Pintér, János Schunk
Dátum:	2007
ISSN:	0013-4686
Megjegyzések:	The surface contamination by uranium in the primary circuit of PWR type nuclear reactors is a fairly complex problem as (i) different chemical forms (molecular, colloidal and/or disperse) of the uranium atoms can be present in the boric acid coolant, and (ii) only limited pieces of information about the extent, kinetics and mechanism of uranium accumulation on constructional materials are available in the literature. A comprehensive program has been initiated in order to gain fundamental information about the uranium accumulation onto the main constituents of the primary cooling circuit (i.e., onto austenitic stainless steel type 08X18H10T (GOSZT 5632-61) and Zr(1%Nb) alloy). In this paper, some experimental findings on the time and pH dependences of U accumulation obtained in a pilot plant model system are presented and discussed. The surface excess, oxidation state and chemical forms of uranium species sorbed on the inner surfaces of the stainless steel tubes of steam generators have been detected by radiotracer (alpha spectrometric), ICP-OES and XPS methods. In addition, the passivity, morphology and chemical composition of the oxide-layers formed on the studied surfaces of steel specimens have been analyzed by voltammetry and SEM-EDX. The experimental data imply that the uranium sorption is significant in the pH range of 4-8 where the intense hydrolysis of uranyl cations in boric acid solution can be observed. Some specific adsorption and deposition of (mainly colloidal and disperse) uranyl hydroxide to be formed in the solution prevail over the accumulation of other U(VI) hydroxo complexes. The maximum surface excess of uranium species measured at pH 6 (Gamma(sample) = 1.22 mu g cm(-2) U congruent to 4 x 10(-9) mol cm(-2) UO2(OH)(2)) exceeds a monolayer coverage. (c) 2006 Elsevier Ltd. All rights reserved.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban uranium stainless steel accumulation
Megjelenés:	Electrochimica Acta. - 52 : 7 (2007), p. 2542-2551. -
További szerzők:	Kádár Péter Kovács Tibor Somlai János Radó Krisztián Varga István Buják Renáta Varga Kálmán Halmos Pál (kémikus) Borszéki János Kónya József (1937-) (vegyész) Nagy Noémi, M. (1960-) (vegyész, angol szakfordító) Kövér László (1949-) (fizikus) Varga Dezső Cserny István (fizikus) Tóth József (fizikus) Fodor Lajos Horváth Attila Pintér Tamás Schunk János
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001-es BibID:	BIBFORM008805
Első szerző:	Kövér László (fizikus)
Cím:	Determination of overlayer thickness by QUASES analysis of photon-excited KLL Auger spectra of Ni and Cu films / L. Kövér, S. Tougaard, J. Tóth, L. Daróczi, I. Szabó, G. Langer, M. Menyhárd
Dátum:	2001
ISSN:	0142-2421
Megjegyzések:	Quantitative characterization of overlayer nanostructures is important for many practical applications and has become a feasible task for electron spectroscopy. The QUASES (Quantitative Analysis of Surfaces by Electron Spectroscopy) software package, developed recently, provides a general tool for quantification in XPS by analysing the spectral shape of the background caused by inelastic scattering of the signal electrons and has been applied successfully for determining the thickness of surface films in the nanometre range. In this work the application of such analysis is extended to metallic films having several tens of nanometre thickness and the accuracy of the results is tested by using independent methods. Both Ni and Cu KLL Auger spectra were photoexcited from Ni and Cu overlayers (deposited onto Si substrates) of different thicknesses in the 10-60 nm range, and were measured with high energy resolution. The film thickness values from the QUASES spectral shape analysis are compared with the data obtained by using a quartz crystal microbalance, cross-sectional transmission electron microscopy and scanning probe microscopy (SPM). Good consistency has been found for the thickness values obtained from the spectral shape analysis and from microscopy, especially for Ni films. Assuming nominal film thickness, the values of the inelastic mean free path of 6-7 keV energy electrons in Ni and Cu were also determined, showing good (Ni) or reasonable (Cu) agreement with those proposed by Powell and Jablonski. The effect of island formation was shown by the QUASES spectral shape analysis and confirmed by SPM, Copyright (C) 2001 John Wiley & Sons, Ltd.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Surface and interface analysis. - 31 : 4 (2001), p. 271-279. -
További szerzők:	Tougaard, S. Tóth József (fizikus) Daróczi Lajos (1965-) (fizikus) Szabó István András (1956-) (fizikus) Langer Gábor Antal (1950-) (fizikus) Menyhárd Miklós
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001-es BibID:	BIBFORM002791
Első szerző:	Novák Mihály (fizikus)
Cím:	A simple statistical model for quantitative analysis of plasmon structures in XPS and Auger spectra of free-electron-like materials / M. Novák, L. Kövér, S. Egri, I. Cserny, J. Tóth, D. Varga, W. Drube
Dátum:	2007
Megjegyzések:	aA method is presented for analysing the energy loss part (dominated by contributions from extrinsic, intrinsic and surface plasmon excitations) of electron spectra excited from free-electron-like solids by X-rays. It is an improved version of the model originally proposed by Steiner, H?ochst and H?ufner and it accounts for contributions of electrons suffering multiple energy losses of different origin. Applied for analysing a Ge 2s photoelectron spectrum excited from a thin Ge layer, the applicability of the method to separate contributions to the inelastic background of the spectra due to intrinsic, extrinsic and surface plasmons is demonstrated. The aim of this work to give a detailed description of the simple statistical model applied in ref. [M. Nov?ak, S. Egri, L. K?ov?er, I. Cserny, W. Drube, W.S.M. Werner, Surf. Sci. 601 (2007) 2344] for practical analysis of photoelectron spectra. The effects of the application of energy loss distributions (for single bulk and single surface excitations) derived by using different methods are also investigated.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban plazmon XPS Auger-elektron spektroszkópia
Megjelenés:	Journal of Electron Spectroscopy and Related Phenomena. - 163 (2007), p. 7-14. -
További szerzők:	Kövér László (1949-) (fizikus) Cserny István (fizikus) Tóth József (fizikus) Varga Dezső (1939-) (fizikus) Drube, Wolfgang Egri Sándor (1966-) (fizikus)
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